Component Focus: Pages 3-6 - Welcome to FTM Board Club · 2017-02-23 · Component Focus: Pages 3-6...

I S S U E 1 7 0 2

Application Spotlight on:

Power

Component Focus: Pages 3-6 STMicroelectronics’ low-voltage TS985 single-channel comparator draws just 14µA

Design Notes: Pages 7-9 CUI explains the latest EU CoC Tier 2 efficiency standards, plus SiC MOSFETs from Microsemi

Application Spotlight: Pages 10-25 Compact 6W-rated DC-DC converter modules from RECOM fit in space-constrained designs

Technical View: Pages 26-27 ROHM Semiconductor: Reduce the size and cost of an auxiliary power supply with SiC technology

S T A R P R O D U C T

S E E P R E V I O U S I S S U E S O F F T M AT W W W. M Y- F T M . C O M

Families of ARM core-based MCUs optimised for motor- and power-control applications

The Kinetis® V series of MCUs from NXP Semiconductors, based on the ARM® Cortex®-M0+, Cortex-M4 and Cortex-M7 cores, are intended for use in a wide range of motor-control and digital power-conversion applications.

Drawing on NXP’s extensive expertise in motor and power control, the Kinetis V series MCUs enable system developers to realise secure, connected, high-efficiency designs.

All the V series families are supported by a full enablement suite of software from NXP and third-party sources, including reference designs, software libraries and motor-configuration tools. These enablement resources include:• Kinetis motor suite: supports three-phase

Brushless DC (BLDC) and Permanent-Magnet Synchronous Motors (PMSM), providing a Field-Oriented Control (FOC) algorithm which is suitable for both sensorless and sensored control implementations

NXP SEMICONDUCTORS

• Embedded software libraries: algorithms for mathematical, motor-control and power-conversion functions and for filters

• Reference designs for PMSM, BLDC and AC induction motors

• FreeMASTER GUI-based debug monitor and data visualisation tool

• Motor-control development toolbox: MATLAB®/Simulink® plug-in tool for automatic code generation

• Kinetis software development kit, a software framework for application development

• MQX™ real-time operating system• Processor Expert® Eclipse plug-in tool

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APPLICATIONS• Networking equipment • Telecoms and datacoms equipment • Servers• Data-storage equipment • Point-of-load power supplies

FEATURES• Compliant with PMBus 1.3 and AVSBus

protocols• Flexible phase configuration • Cycle-by-cycle current protection with

average and peak thresholds • Autonomous auto-phase dropping with

adjustable current thresholds • Over-voltage and under-voltage protections

APPLICATIONS• Motor control• Power conversion

FEATURES (V1 series)• Dual watchdogs for compliance with IEC

60730 safety regulations • Four-channel DMA• Cyclic redundancy check• Hardware divide and square root in

processor core• Two UART interfaces• One serial peripheral interface

170202 For samples or pricing [email protected]


F T M T E C H N O L O G Y W A T C HN E W S I N B R I E F

F O L L O W U S N O W – S E A R C H F T M B O A R D C L U B O N

Power-converter performanceto make gains as wide bandgap

technology comes of age

Over the past 20 years, the performance gains in AC-DC and DC-DC power supplies have nearly all resulted from a series of minor innovations to existing, proven topologies. Over time, the scale of change attributable to these small, incremental improvements has been impressive.

Hassan MatougVertical Segment ManagerFuture Power Solutions

There is some evidence, however, that this gradual rate of improvement might not be sufficient in future to meet the requirements of a market which is subject to radical changes demanded by regulators and end-users.

For instance, the Level VI standards imposed by the US Department of Energy on external power supplies is likely to require the complete re-design of many AC-DC adapters; the EU CoC Tier 2 regulations described by CUI on pages 8-9 are even stricter. Likewise, medically approved power supplies will in future have to comply with the IEC 60601-1-2 4th edition standard enforcing more stringent limits on conducted or radiated emissions and ESD. Home appliances are also facing changes to their standards, such as the new EN 60335-1. AC-DC converter ICs such as the VIPer01 from STMicroelectronics, featured on page 24, will help power-supply manufacturers to conform to the new rules.

New, tougher regulations also call for greatly improved fundamental power-conversion technology, and this makes it likely that the latest wide bandgap semiconductor materials, such as Silicon Carbide (SiC) and Gallium Nitride (GaN) will become ever more popular. Examples from STMicro, on page 21, ROHM Semiconductor, on page 16, and Microsemi, on page 7, are featured in this issue of FTM.

Wide bandgap components and modules enable converters to switch at higher frequencies and to operate at higher temperatures. As a result, the number, weight and size of supporting components such as passives, magnetics and heat-sinks can often be dramatically reduced, while allowing for greater conversion efficiency.

New Murata supercap just 0.4mm highMurata has introduced the world’s thinnest supercapacitor, which features a profile of just 0.4mm. The DMHA14R5V353M4ATA0 supercapacitor is intended for use in peak power-assist applications in wearable devices, smart cards, e-paper devices and other highly space-constrained products. The 4.5V device has a capacity of 35mF.

ams launches world’s first digital multi-spectral sensor-on-chip products

ams has launched the world’s first series of multi-spectral sensor-on-chip solutions. Supplied in a small 4.5 x 4.4mm LGA package, the AS7262 visible-range sensor and AS7263 near-infrared sensor each offer six calibrated spectral channels.

The ams sensor ICs will enable developers to design a new generation of handheld spectral analysers for consumer and industrial applications that offer performance to match that of much bigger, more expensive laboratory equipment.

Future Electronics to distribute Briowireless products globallyFuture Electronics has signed a global distribution agreement with Briowireless Inc. The Briowireless portfolio of products will be supported by the specialist Future Connectivity Solutions division of Future Electronics.

Briowireless is a manufacturer of industrial-grade socket modems, providing PTCRB-certified and standards-compliant cellular modules to OEMs and developers. Using the BitPipe family of products, customers can accelerate the time-to-market of solutions for the Internet of Things, and cut development costs.

Digital power controllers are also helping to reduce size and component count. System designers can therefore expect to see the power density and efficiency of modules increase quite dramatically – a contrast to the incremental gains that the industry has enjoyed in previous years.

Another dramatic change in power-system design is to be found in the move from centralised to distributed power architectures. A distributed power architecture enables the intensive use of standard, low-cost, multiple-source and digitally-controlled DC-DC converters such as the devices offered by the AMP Alliance, and the TS3004x devices from Semtech featured on page 12.

Through its team of AC-DC and DC-DC power-system design specialists, Future Electronics is able to help customers in the EMEA region to meet the challenges of new regulations and end-user demand. I urge readers of FTM to take advantage of their support.

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©Copyright 2017 Future Electronics Ltd. All trademarks contained herein are the property of their respective owners. Applications for product samples, badge boards, demonstration boards, Future Electronics’ boards and other advertised materials from Future Electronics are offered subject to qualification. Images of product packages throughout this publication are for illustration purposes and not necessarily an exact representation of the advertised part.

Intersil has released 12 new digital multiphase DC-DC power controllers and a companion smart power stage, including the industry’s first digital solution with an Adaptive Voltage Scaling Bus (AVSBus™). They are suitable for use with any microprocessor, ASIC or FPGA.

The new digital controllers provide up to seven phases assignable in any combination across two outputs, and work with the ISL99227 smart power stage to provide a scalable power system supporting loads ranging from 10A up to 450A.

The digital multiphase family is comprised of three groups of controllers. The ISL68137 and ISL68134 controllers use the AVSBus to power and communicate with ARM-based processors in networking, computing and wireless telecoms equipment. The AVSBus is a 50MHz high-speed bus which connects directly to the processor to communicate telemetry data and deliver efficiency savings through adaptive voltage positioning.

Two general-purpose controllers, the ISL68127 and ISL68124, may be used to

INTERSILpower network processors, FPGAs, SoCs and graphics accelerators. Eight controllers – the ISL69147/44, ISL69137/34, ISL69128/27 and ISL69125/24 – have an additional secondary high-speed interface to power the latest Intel and AMD processors in cloud-computing applications.

The ISL681xx and ISL691xx controllers are based on a high-performance digital engine featuring a patented synthetic current-control architecture which tracks each phase current with zero latency. This allows the device to respond to any load transient with precise current and voltage positioning, while requiring 30% less capacitance than competing devices. Synthetic current control also makes it possible to develop reliable systems using all ceramic capacitors.

Apply now at my-boardclub.comFast-track board request code: FTM72A

Orderable Part Number: ISL68137-61P-EV1Z


Orderable Part Number: FRDM-KV10Z, FRDM-KV31F

Industry’s first digital multiphase PWM controllers with AVSBus and synthetic current control

C O M P O N E N T F O C U S


Inertia-locking connectors include features to help prevent half-mated connections

Make first, break last connector offers superior grounding performance

The GRACE INERTIA series of wire-to-board and wire-to-wire power connectors from TE Connectivity (TE) helps manufacturers and assemblers to avoid the risk of defects attributable to half-mated connections and other errors in assembly.

TE Connectivity (TE) has added a product with Make First, Break Last (MFBL) functionality as part of its POWER TRIPLE LOCK line of connectors.

The GRACE INERTIA connectors employ an inertia locking mechanism to simultaneously complete the circuit and lock the connector. This approach to the connector design recognises that visual inspection for half-mating is difficult – manufacturers commonly implement complicated inspection processes to detect half-mated connections.

The GRACE INERTIA connector’s lock-on mechanism, however, minimises the need for inspection, since it does not pass an electric current if it is half-mated. This means that a simple electrical conductivity test may be used to detect half-mated connections, making it easy to prevent defective products from being shipped to customers.

The new MFBL connector’s application-specific grounding design permits the ground connection to be established before power connections are made, and maintains the connection until the power connections are broken. This capability fulfils a key requirement of a variety of mid-range power connections in appliances and commercial building equipment.

Using TE’s proven POWER TRIPLE LOCK connector design, the MFBL connector can facilitate easier assembly and more secure connections than other pin-and-socket connector solutions.

TE CONNECTIVITY

TE CONNECTIVITYThe three-position, wire-to-panel or wire-to-wire MFBL connector is based on a 6.0mm centreline pitch. Like other POWER TRIPLE LOCK connectors, it is rated for 600V AC or

DC, although the MFBL connector

is limited to a 12A maximum current, as its contacts accept wire

no larger than AWG 16.

Like TE’s other POWER TRIPLE

LOCK connectors, the MFBL connectors offer

polarisation and keying to help prevent connector mis-

mating, an anti-snag design, and a locking mechanism to help secure

connections when the cap and plug latch together. For additional reliability,

an optional connector position assurance device helps to prevent the connector from being mistakenly disengaged.

GRACE INERTIA: No current when half-mated

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APPLICATIONS• Washing machines • Air conditioners • Refrigerators • Vending machines • Control cabinets • Industrial controls and machinery

FEATURES• Lanceless contacts prevent snagging or

entanglement • Four keying methods and colours • Dual-beam contact design provides good

contact and durability • Optional double-lock plates for terminal

position assurance• Operating-temperature range: -30°C to

105°C

APPLICATIONS• Home appliances• Commercial building equipment

FEATURES• Low insertion force• Optional terminal position assurance

device • Tin-plated copper alloy contacts• Compliant with glow-wire test

requirements• Operating-temperature range: -55°C to 105°C





High-current connectors comply with flammability standards

10A power key connectors provide for easy assembly

TE Connectivity’s (TE) economy power and economy power II wire-to-board connectors are widely used in power circuits which have a large current-carrying capacity.

The TE Connectivity (TE) power key connectors are wire-to-board connectors with a 5.0mm centreline for power circuits with a maximum current up to 10A. The connector system, which uses housing lances to prevent tangling of wired contacts, consists of plug housings for wires, and compact PCB header assemblies.

TE CONNECTIVITY

TE CONNECTIVITY

APPLICATIONS• Household appliances • Industrial machinery • Lighting • Heating, ventilation and air-conditioning

equipment• Commercial and building equipment • Vending machines • Coin changers

FEATURES• 3.96mm, 5.08mm and 7.92mm centreline

options • Voltage rating: • 250V AC for economy power range • 600V AC for economy power II range• Wire-to-board, shrouded and unshrouded

header configurations • Operating-temperature range: • -25°C to 105°C for economy power

range • -55°C to 105°C for economy power II

range• Models complying with GWEPT 750°C

and UL94 V-0 flammability standards • UL recognised

APPLICATIONS• Household appliances • Gas appliances • Power-cord applications• Control boards

FEATURES• 300V AC voltage rating • Maximum current rating: 10A with AWG

16 wire and two contacts• Operating-temperature range: -30°C to

105°C • Wire sizes: AWG 24 to AWG 16• UL recognised• Some models compliant with Glow Wire

Test and UL 94 V-0 flammability standard

The economy power connectors are rated for a continuous current of up to 7.5A. In the economy power II series, this maximum current value rises to 11A.

Terminal Position Assurance (TPA) devices are available in the economy power II series. TPA helps to ensure that the contacts are fully seated in the housing.

This helps to avoid downtime and costly service calls to repair equipment failures that

are due to a backed-out contact. In addition, a latch helps to prevent unintended disconnection.

The two connector families offer a variety of housing and header styles and configurations in Glow Wire-compatible material.

The design of the TE power key connectors provides for assured contact seating and proper mating to the PCB header. In addition, special design features permit the release of bubbles created by the PCB potting process.

Once mated, the connector system has a height of just 20.7mm. It is easy to assemble, and a clear clicking sound provides aural confirmation that a contact insertion has been properly made.

The power key connectors are available in various colours and keys to help prevent mating errors. Double-lock plates which function as Terminal Position Assistance (TPA) devices are also available.

TE’s economy power connectors: Latch helps prevent unintended disconnection TE Connectivity and GRACE INERTIA are trademarks.

TE Connectivity and POWER TRIPLE LOCK are trademarks.Power key from TE: Various colour and key options

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Centreline (mm)

Current Rating

(A)

Voltage Rating (V AC)

Wire Sizes (AWG)

Positions Configurations

3.3 4 250 20 4, 6, 8, 10, 12 Wire-to-board

3.5 7 300 26-18 2, 3, 4, 6 Wire-to-wire

6.0 10 600 24-16 2, 3 Wire-to-board

6.2 20 600 16-12 1, 2, 3 Wire-to-wire

6.5 10 300 24-16 3 Wire-to-board

7.92 10 300 24-16 2 Wire-to-board

9.0 20 600 16-12 3 Wire-to-board

12.4 20 600 16-12 2 Wire-to-board

D E S I G N N O T E

S E E P R E V I O U S I S S U E S O F F T M AT W W W. M Y- F T M . C O M 7

Design consideration in the use of SiC MOSFETs: on-resistance and the gate-drive circuit

Silicon Carbide (SiC) MOSFETs are being used more commonly in certain power-switching applications at voltages higher than 500V, especially in those that benefit from the higher switching speeds that SiC devices can support when compared to an equivalent Silicon (Si) MOSFET.

In fact, there are many similarities between SiC MOSFETs and Si MOSFETs: both are enhancement-mode devices with body diodes, and they are much faster than IGBTs. In addition, the on-resistance of a SiC MOSFET increases with temperature just as the on-resistance of an Si MOSFET does, but not by as much.

And in both types of device, the switching speed is governed mostly by the speed at which the gate charge is removed or added. The speed limit is determined by the output capacitance and the ability of the devices to source high currents.

There are, though, important differences between SiC and Si MOSFETs:• SiC MOSFETs have a lower on-resistance than Si MOSFETs. They are

normally driven at a higher gate voltage, in the range -5V to +20V, to keep on-resistance to a minimum and increase switching speed.

• The body diode of a SiC MOSFET has a high voltage drop of around 4V, but a low minority carrier lifetime. They have a significantly faster recovery time and a lower recovery charge than those of silicon MOSFETs.

• The output switching current, dI/dt, is considerably higher in SiC MOSFETs than in Si MOSFETs. This affects DC bus ringing, EMI, and output-stage losses.

• The slew rate at the output of a SiC half-bridge can be much higher than when using a Si MOSFET. SiC power stages can easily switch at a dV/dt of 30-50kV/µs. This should be considered in the design of the gate drive’s signal isolation, gate power isolation, and EMI mitigation.

SiC MOSFETs, then, offer considerable benefits in the operation of high-voltage and high-speed power-conversion circuits. Two particular aspects of a SiC MOSFET-based circuit’s operation are discussed in this Design Note.

The effect of temperature on on-resistanceFigures 1-3 show the different effects of temperature on on-resistance in SiC and Si MOSFETs. The behaviour of electron mobility in Si MOSFETs is dominated by thermal scattering. Figure 1 shows that, from 25°C to 150°C, on-resistance increases by around 2.7 times.

Figure 2 is typical of a Microsemi 1,200V SiC MOSFET. There are two scattering mechanisms affecting electron mobility, with the resulting benefit that from 25°C to 175°C, on-resistance only varies typically

from about 1.5 to 1.8. A Microsemi 700V SiC MOSFET’s behaviour is slightly different, as shown in Figure 3.

MICROSEMIThis behaviour means that parallel operation of SiC MOSFETs is possible. A positive on-resistance slope, almost flat for the 700V devices, makes it easier to share current in parallel operation. Consideration of the behaviour from -50°C to 25°C and simulation of the sharing process will show that, at lower ambient temperatures, the device temperatures will diverge more than at higher temperatures. The divergence, however, is less than the absolute temperature resulting from the lower ambient temperature. For this reason it is almost impossible to create a situation where the negative temperature coefficient will impair a circuit’s reliability as long as the circuit is designed for a maximum operating temperature of greater than 25°C.

Fig. 1: The change in on-resistance over temperature in a typical Si MOSFET

Fig. 2: The change in on-resistance over temperature in a Microsemi 1,200V SiC MOSFET

Fig. 3: The change in on-resistance over

temperature in a Microsemi 700V SiC

MOSFET




High power-density PN rectifier offers a 400V rating

Tiny low-voltage comparator for space-constrained applications

The PNS40010ER is a 400V, 1A PN rectifier in a small surface-mount package from Nexperia, a discrete power components manufacturer recently spun-off from NXP Semiconductors.

The TS985 from STMicroelectronics is a single-channel, low-voltage comparator which combines battery-friendly performance with enhanced dynamic range and high-speed operation.

Housed in a six-bump chip-scale package with a footprint of less than 1mm², it is ideal for use in portable products in which board space is severely limited.

NEXPERIA

STMICROELECTRONICS

APPLICATIONS• General rectification applications• Reverse polarity protection

FEATURES• Standard switching time• Low forward voltage• Low reverse current• Low-inductance package• Package height typically 1mm• AEC-Q101 qualified

APPLICATIONS• Smart watches• Digital cameras• IoT devices• Portable test equipment• Battery-powered and portable devices• Low-voltage applications

FEATURES• Rail-to-rail inputs and push-pull outputs • 60µA supply current at 1MHz switching

frequency • Low output-saturation voltage • Internal hysteresis • Operating-temperature range:

-40°C to 85°C • 2kV ESD tolerance on the human body

model

The PNS40010ER, which benefits from high-efficiency planar technology, is notable for its high power density. It carries a maximum continuous forward current of 1.4A and withstands a maximum reverse voltage of 400V. Its average forward current rating is 1A at a switching frequency of 20kHz and an ambient temperature of up to 115°C.

These superior power ratings are provided by a device which is packaged in a small, SOD123W surface-mount housing with flat

leads. The device is able

to withstand junction temperatures up to 175°C. Thermal resistance from junction to solder point is 15K/W.

The TS985 can operate from a supply voltage ranging from as low as 1.8V up to 5V, while typically drawing a current of just 14µA. While maintaining this low-power performance, it still achieves high speed, boasting a propagation delay of just 300ns.

The TS985 offers an input-offset voltage of 0.5mV, a value which drifts over temperature at a rate of just 4.5µV/°C. Input bias current is 14nA.

PNS40010ER rectifier: Small surface-mount housing with flat leads

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Gate drive considerationsThe design of a SiC MOSFET gate driver is much like the design of a standard IGBT or Si MOSFET driver. Most of the features and practices are the same: • Asymmetrical high gate drive current keeps switching losses to a

minimum• Secondary-side power monitoring and short-circuit protection might

both be useful

Due to the higher speed of SiC MOSFETs, the capacitance of the gate-drive interface should be kept to a minimum. At 50V/ns, 5pF of interface capacitance results in 250mA current pulses. On the control side, these current pulses should be directed away from cables or control electronics by bypassing to a chassis or other filtering structure.

The power supply that supplies the gate-drive power should be rated for at least 50V/ns. Most are not, but a good option is RECOM’s RxxP22005D series of DC-DC power supplies, which are intended for use with SiC MOSFETs. The gate driver itself should support bipolar operation, and should also support >50V/ns speeds.

More detail on this, and on other aspects of the use of SiC MOSFETs, may be found in Microsemi’s Full Application Note 1826, available at www.microsemi.com from February 2017.

D E S I G N N O T E



Understanding the latest changes to the laws governing external power supplies

People today are familiar with the challenges associated with our use of energy, and in particular the need to control greenhouse gas emissions and to use energy efficiently. Anyone placing a hand on a notebook computer’s warm power adapter will immediately be aware of the effect of wasted energy: such power losses have a direct impact on the environment.

In line with government policies aimed at minimizing the harm to the planet caused by greenhouse gas emissions, legislators have been constantly increasing pressure on equipment suppliers to deliver

CUI INCproducts which use less and less power and which operate more and more efficiently. In February 2016, the US Department of Energy (DoE) enacted legislation requiring external power adapters marketed in the US to comply with international Level VI eco-design specifications. The dust has barely settled, and yet already the European Union (EU) is now tightening the screw by publishing its new Code of Conduct (CoC) Tier 2 efficiency standards.

There is some history behind this leapfrog-style progress in environmental legislation. About two years ahead of the US move to Level VI, the EU in 2014 introduced CoC Tier 1 as a voluntary standard. CoC Tier 1 specifies efficiency and power limits that are only slightly less stringent than Level VI, but also requires an extra efficiency measurement to be taken at 10% of full load. This presents a tough challenge to designers, as power supplies are known to exhibit their poorest efficiency at such low loads. CoC Tier 1 is currently under review by EU legislators, with the expectation that it will become mandatory during 2017. In

2018 CoC Tier 2 is expected to come into force, further tightening the no-load power, average efficiency and 10% load specifications, and effectively setting the bar higher than Level VI.

Efficiency standards: a brief historyFor the full story of the regulations governing external power supplies, it is necessary to look back to the early 1990s and the US ENERGY STAR initiative. ENERGY STAR began as a voluntary labelling programme for products such as computer peripherals and white goods. A short while later, a University of California Berkeley Laboratory study found that stand-by operation of domestic appliances accounted for 5% of the nation’s residential electricity consumption.

At the time, the external power supply was considered a prime culprit, and it was estimated that there were more than one billion external power supplies active in the US alone. The operating efficiency of the linear technology used then was often as low as 50%. Worse still, power continued to be drawn even when the end equipment was turned off or disconnected. Researchers feared that the growing use of such external supplies could see this wasteful power use account for as much as 30% of all electrical energy consumption, if nothing was done to reduce the losses. Legislation was considered necessary to require equipment manufacturers to respond adequately. Accordingly, in 2004, the California Energy Commission became the first to implement mandatory energy-efficiency standards.

Since that time, various authorities around the world have introduced a succession of standards, some voluntary and others mandatory, which impose tighter and tighter requirements on the efficiency of external power supplies. Figure 1 illustrates the sequence of events. It not only brings us to the present but also shows what OEMs should be expecting in 2017 and 2018.

Challenges faced by OEMsWhile these standards might benefit the consumer and the environment, they present a considerable challenge to both the manufacturer of the external power supply and the OEM which pairs it with its end-product. For the power-supply manufacturer, the technical challenge of meeting the latest efficiency specifications becomes ever-more complex with each successive regulation. For the OEM, the compliance effort in the countries where the power supply is used involves a number of logistical and supply-chain challenges. These difficulties are amplified because, despite attempts to harmonise standards across the globe, their development and adoption has in reality proved to be a game of leapfrog as countries or regions seek to catch up with and then surpass their neighbours.

In practice this means that OEMs which want to avoid the complexity of maintaining different product configurations for different geographic markets need to ensure their external power supplies meet the latest and most stringent standards worldwide. EPS manufacturers, for their part, must employ leading-edge design techniques to comply with evolving standards and keep their product lines ahead of the wave of changes.

CoC Tier 2 regulationsThe CoC Tier 2 standard significantly lowers the already tight limits set by the DoE’s Level VI standards. A supply with a nameplate rating between 49W and 250W, which has a maximum no-load power of 210mW under Level VI rules and 250mW under CoC Tier 1, will have to consume less than 150mW to satisfy the requirements of CoC Tier 2. Figures 2 and 3 present a comprehensive list of the Tier 2 specifications. Here, average efficiency is the mean of active efficiency measured at 25%, 50% and 75% of full load; low-load efficiency is measured at 10% of full load.

Changes to be expected in futureGlobally, it is expected that other nations will soon follow the lead set by the DoE Level VI standard. It should also be expected that countries with existing efficiency regulations previously in line with the US, such as Canada, will move to harmonise with the newer US and European standards.

The US Environmental Protection Agency estimates that external power-supply efficiency regulations implemented over the past decade have reduced energy consumption by 32 billion kilowatts, saving

$2.5bn annually and reducing CO2 emissions

by more than 24 million tonnes per year. Furthermore, many OEMs are now starting to demand greener power supplies as a way to differentiate their end-products, pushing efficiencies continually higher.

OEMs therefore need to future-proof their power supplies to ensure that they meet these new CoC Tier 2 standards. CUI has already done everything needed to adapt its circuit topologies to meet efficiency requirements at all load levels, using advanced devices, high-efficiency topologies and reduced switching frequencies under light and no-load conditions.

The company has further qualified the majority of its Level VI line to also conform to the more stringent CoC Tier 2 standards. In the future, CUI will continue to implement the latest energy-saving technologies into its external power supplies in order to comply with current and future standards as the regulatory landscape continues to evolve.

Fig. 1: The history of the efficiency regulations governing external power supplies

Fig. 2: CoC Tier 2 efficiency specifications for basic-voltage external adapters

Fig. 3: CoC Tier 2 efficiency specifications for low-voltage external adapters

Fig. 4: CUI has already qualified the majority of its external wall plug and desktop adapters to comply with the proposed CoC Tier 2 standards

D E S I G N N O T E

F O L L O W U S N O W – S E A R C H F T M B O A R D C L U B O N8

CoC Tier 2 Single-voltage External AC-DC Power Supply, Basic Voltage

Nameplate Output Power (Pout )

Minimum Average Efficiency in Active Mode (expressed as a decimal)

10% Load Average Efficiency in Active Mode (expressed as a decimal)

Minimum Power in No-load Mode (W)

0.3W ≤ Pout ≤ 1W ≥ 0.50 x Pout + 0.169 ≥ 0.50 x Pout + 0.060 ≥ 0.075

1W < Pout ≤ 49W ≥ 0.071 x In (Pout ) – 0.00115 x Pout + 0.670

≥ 0.071 x In (Pout ) – 0.00115 x Pout + 0.570 ≥ 0.075

49W < Pout ≤ 250W ≥ 0.890 ≥ 0.790 ≥ 0.150

Pout > 250W N/A N/A N/A

CoC Tier 2 Single-voltage External AC-DC Power Supply, Low Voltage

Nameplate Output Power (Pout )

Minimum Average Efficiency in Active Mode (expressed as a decimal)

10% Load Average Efficiency in Active Mode (expressed as a decimal)

Minimum Power in No-load Mode (W)

0.3W ≤ Pout ≤ 1W ≥ 0.517 x Pout + 0.091 ≥ 0.517 x Pout ≥ 0.075

1W < Pout ≤ 49W ≥ 0.0834 x In (Pout ) – 0.0011 x Pout + 0.609

≥ 0.0834 x In (Pout ) – 0.00127 x Pout + 0.518 ≥ 0.075

49W < Pout ≤ 250W ≥ 0.880 ≥ 0.780 ≥ 0.150

Pout > 250W N/A N/A N/A

A P P L I C A T I O N S P O T L I G H T – P O W E R


40V, 0.5A Schottky barrier rectifier has a low forward voltage

The NCD5700 is a high-current, stand-alone IGBT gate driver for high-power applications which helps designers to realise a cost-effective system by eliminating the need for many external components.

The PMEG4005CEA from Nexperia, the discrete power components business recently spun-off from NXP Semiconductors, is a planar Schottky barrier rectifier with a low forward voltage. This makes it suitable for low-voltage rectification and for applications in which power-conversion losses must be kept to a minimum.

It integrates multiple protection features including an accurate under-voltage lock-out function, an Enable input and an Active Low fault output. The NCD5700’s active Miller clamp prevents spurious gate turn-on events. In addition, its desaturation protection includes a programmable delay.

The device features an accurate 5.0V output. Separate high and low driver outputs ease system design. A high current output of +4A/-6A at IGBT Miller Plateau voltages reduces switching losses and keeps switching times short.

The driver is designed to accommodate a wide range of bias voltages including unipolar and bipolar inputs.

The PMEG4005CEA is housed in a SOD323 (SC-76) surface-mount plastic package which has a footprint of just 1.8mm x 1.35mm. It features an integrated guard ring for stress protection.

The rectifier is rated for a maximum reverse voltage of 40V, and an average forward current of up to 0.5A at a switching frequency of 20kHz and a temperature of up to 135°C. Typical forward voltage is just 550mV, measured at a pulsed forward current of 500mA and a junction temperature of 25°C.

ON SEMICONDUCTOR

NEXPERIA

NCD5700 gate driver: Suited to use in solar inverters

11

APPLICATIONS• Low-voltage rectification• High-efficiency DC-DC conversion• Switch-mode power supplies• Reverse-polarity protection• Low-power applications• Automotive applications

FEATURES• 1.5µA reverse current • 1.8ns reverse-recovery time• 150°C maximum junction temperature• Ambient-temperature range:

-55°C to 150°C• 45K/W thermal resistance from junction to

solder point• AEC-Q101 qualified




Power controller for LED lighting offers high power factor, efficiency and reliability

600V and 650V MOSFETs feature low-inductance package

Operating directly from the rectified mains, STMicroelectronics’ HVLED001A quasi-resonant controller for LED lighting integrates both high- and low-voltage circuitry on the same chip, eliminating the cost of external high-voltage components.

Vishay Intertechnology has extended its offering of 600V and 650V E series power MOSFETs with three N-channel devices in the compact, surface-mount PowerPAK® SO-8L package.

Offering a high power factor greater than 0.9, low total harmonic distortion of less than 10%, and high conversion efficiency of more than 90%, the HVLED001A helps lighting equipment manufacturers to comply with stringent standards governing lighting fixtures.

ST’s HVLED001A is an enhanced peak current-mode controller capable of controlling flyback or buck-boost topologies in LED drivers that have an output power of up to 150W. Other topologies, such as buck, boost and SEPIC, can also be implemented.

ST’s innovative high-voltage silicon technology allows for direct connection of the

The 600V SiHJ8N60E and 650V SiHJ6N65E and SiHJ7N65E MOSFETs provide a space-saving and reliable alternative to MOSFETs in the TO-252 (DPAK) package. The devices benefit from reduced package inductance.

Measuring just 5mm x 6mm, the SiHJ8N60E, SiHJ6N65E, and SiHJ7N65E

STMICROELECTRONICS

VISHAY

HVLED001A to the input voltage to start-up the device and to monitor the input voltage, without the need for external components.

The device embeds advanced features to control either the output voltage or the output current precisely and reliably using few, mainly passive components. It also controls operation of the power circuit under abnormal conditions such as an open circuit, output short-circuit, input over-voltage or under-voltage, open loop or over-current.

occupy only half as much board space as TO-252 devices, and are half as high. Also, the gullwing leads of the PowerPAK SO-8L package result in better board-level reliability when subjected to temperature cycling than MOSFETs in leadless DFN packages.

Based on Vishay’s energy-efficient E series superjunction technology, the SiHJ8N60E, SiHJ6N65E, and SiHJ7N65E feature a low product of gate charge and on-resistance, a key figure of merit for MOSFETs used in power-conversion applications. The MOSFETs produce extremely low conduction and switching losses, helping designers to reduce power consumption in PFC, flyback and two-switch forward converters, and in hard-switched topologies for High-Intensity Discharge (HID) and LED lighting.

HVLED001A: Controls LED drivers with output up to 150W

E series MOSFETs withstand temperature cycling

PMEG4005CEA rectifier: AEC-Q101 qualified

10

APPLICATIONS• Single-stage LED drivers supporting loads

up to 75W • Two-stage LED drivers supporting loads

up to 150W

FEATURES• Low start-up and quiescent currents• Programmable minimum Off time• Input-voltage detection for high power

factor and to trigger protection function• Smart auto-reload timer provides for latch-

free operation• Compatible with 0-10V and PWM

dimming schemes• Remote Control pin

APPLICATIONS• Switch-mode power supplies• Flyback converters• High-Intensity Discharge (HID) lamps• Fluorescent ballast lighting• Consumer devices• External power adaptors

FEATURES• Low input capacitance• Low switching and conduction losses• Avalanche energy-rated




The STEVAL-ILL074V1 provides a stable and insulated 52V bus suitable for secondary-side circuitry such as LED current sources. It can support loads of up to 60W while operating from a wide input-voltage range.

Orderable Part Number: STEVAL-ILL074V1

Part NumberMaximum

Drain-source Voltage (V)

Gate-source Voltage (V)

Maximum Continuous

Drain Current (A) @ 25°C

Maximum On-resistance (Ω)

@ 10V

Gate Charge (nC) @ 10V

SiHJ8N60E 600 ±30 8.0 0.520 22

SiHJ6N65E 650 ±30 5.6 0.868 16

SiHJ7N65E 650 ±30 7.9 0.598 22

IGBT gate driver integrates multiple protection features

APPLICATIONS• Solar inverters • Uninterruptible power supplies• Motor-control systems

FEATURES• Low output-voltage impedance • Short propagation delays • Direct interface to optocoupler for isolated

drives• Tight under-voltage lock-out thresholds for

bias flexibility




110W AC-DC power supplies offer superior EMC performance and high surge immunity

Boost LED driver features programmable dimming function

SL Power Electronics has introduced the new TB110 series of internal power supplies, part of its comprehensive range of power solutions for noise-sensitive test and measurement equipment.

The new AL3050 from Diodes Inc., is a current-mode boost LED driver for portable devices which offers a programmable dimming control function.

The new TB110 series models offer up to 90% efficiency, and are available in a small 2.0” x 4.0” x 1.4” form factor, ideal for use in 1U chassis applications. They comply with the strictest requirements of the EN61000-4-x standards, to enable designers to readily implement power systems that comply with EMC regulations. They meet the Class B requirements for conducted EMI with a 6dB margin, and for radiated EMI with a 3dB

margin. The products also offer 4kV surge immunity.

Long life and reliability are other notable features of the TB110 series. Mean time before failure at a temperature of 50°C is calculated to be longer than 1 million hours. In addition, capacitor life is rated at longer than 15 years at an ambient temperature of 40°C.

Operating from an input-voltage range of 90V-264V AC, the TB110 products supply up to 110W of output power with airflow, and 80W when convection-cooled.

Featuring an integrated 30V power MOSFET and Schottky diode, the AL3050 can drive as many as eight LEDs in series. The implementation of a complete driver circuit based on the ASL3050 only requires the addition of four external components, which means that the total system footprint is small.

The driver operates at a high efficiency of up to 85%, and this, combined with its small size, make it ideal for LED backlighting systems in portable equipment powered by a single lithium-ion cell.

SL POWER

DIODES INCORPORATED

They are available in versions with outputs of 12V, 24V or 48V. All models are CE-marked for compliance with the low-voltage directive and approved to the ITE standards of CSA/EN/IEC/UL60950-1, 2nd Edition, Amendment 2.

Brightness control is implemented by the AL3050 via either PWM or single-wire digital dimming, giving accurate LED current control from one pin.

The AL3050 offers under-voltage lock-out, over-voltage, over-current and thermal protection functions.

TB110 series power supplies fit in a 1U chassis

AL3050: PWM or digital dimming

13

APPLICATIONS• Signal analysers• Signal generators• Analysis instruments • IT equipment

FEATURES• ESD protection: 15kV for air discharges,

8kV for contact discharges• DC OK signal• Power Good signal• Class I and II input models• Three-year warranty

APPLICATIONS• Internet of Things end nodes• Portable media players• Mobile devices• GPS receivers• Backlights for small LCD displays

FEATURES• 28V open-LED protection for up to eight

LEDs• 200mV reference accurate to ±3% • 750kHz switching frequency• Up to 100:1 PWM dimming ratio• Integrated loop compensation• Soft start• Operating-temperature range:

-40°C to 85°C





High-performance buck regulators aimed at high-voltage applications

Microstepping motor control and driver in a single package

Semtech has announced an extension to its high-voltage power-management platform with the introduction of the TS3004x family of integrated switching buck regulators.

STMicroelectronics’ powerSTEP01 is a system-in-package which combines digital motion-control and driver functions for stepper motors.

The new product family is aimed at high-performance applications that operate from an input voltage of up to 40V, in markets such as industrial, telecoms and consumer equipment.

The TS3004x product family is comprised of the TS30041 and the TS30042 DC-DC synchronous switching regulators. The TS30041 has a maximum continuous output-current rating of 1A, and the TS30042 is rated for 2A. The devices are available with a range of fixed output-voltage choices: 1.5V, 1.8V, 2.5V, 3.3V and 5V, all with ±2% output tolerance.

It integrates eight N-channel MOSFETs for stepper motors operating at up to 85V and a microstepping motor controller which is programmable over a high-speed Serial Peripheral Interface (SPI).

The MOSFETs, which feature low on-resistance of 16mΩ, are configured in two full bridges with non-dissipative programmable over-current protection. The device can drive stepper motors through patented voltage-mode control or advanced current-mode control algorithms, as required by the needs of the application.

The digital control core can generate user-defined motion profiles. Acceleration, deceleration, speed and target positions are easily programmed through a dedicated registers set. All application commands and data registers, including those used to set

SEMTECH

STMICROELECTRONICS

There is also an adjustable version which provides an output voltage ranging from 0.9V up to 1V lower than the input voltage. All the TS3004x products, which implement current-mode PWM control, have integrated power switches and robust fault-protection features. They run in pulse-frequency mode for improved efficiency at light loads.

The TS3004x regulators help designers to realise compact power-management designs, as they are housed in a small 16-pin QFN package with a 3mm x 3mm footprint.

analogue values such as the current-protection trip point, dead time and PWM frequency, are transmitted via SPI.

The powerSTEP01 also features a full set of protection functions to prevent damage attributable to high temperatures, low voltages or excessive currents or voltages.

In addition, the device features a diagnostic register which collects information about the status of the system, allowing the control core to perform real-time diagnostics. The conditions detected include enabled/disabled power stage, real-time motor status, and over-current and under-voltage events.

Semtech’s TS3004x family: Maximum input voltage is 40V

powerSTEP01: Dedicated register set for motor control

12

APPLICATIONS• Industrial power supplies • Telecoms equipment• Factory automation equipment • Automotive

FEATURES• Input-voltage range: 4.5V to 40V • Up to 95% efficiency • 1MHz fixed switching frequency • High efficiency up to 95% • Soft start • Over-current, over-temperature and over-

voltage protection• Less than 10µA current in stand-by mode • Low external component count

APPLICATIONS• Pick-and-place machines• Textile and sewing machines• Stage lighting• Surveillance systems

FEATURES• Operating-voltage range: 7.5V to 85V • 10A maximum output current • Adjustable output slew rate • Sensorless stall detection • Integrated voltage regulators • Low quiescent stand-by current




The EVLPOWERSTEP01 demonstration board is a microstepping motor driver supported by the STEVAL-PCC009V2 communication board and evaluation software supplied by ST.

Orderable Part Number: EVLPOWERSTEP01

Part Number Minimum Input Voltage

Maximum Input Voltage

Maximum Output Voltage LED Current Quiescent

Current

AL3050 2.7V 5.5V 26V 0.7A 0.3mA



40V N-channel logic-level MOSFET has low leakage current

High-voltage superjunction MOSFET offers low 19.5Ω on-resistance

The PSMN1R0-40YLD from Nexperia, the discrete power components business recently spun-off from NXP Semiconductors, is a 40V logic-level MOSFET which is notable for its soft switching and low leakage current.

The FCH023N65S3L4 from ON Semiconductor is a SuperFET® III 650V MOSFET which uses advanced superjunction technology to achieve extremely low on-resistance and low gate charge.

An N-channel gate-drive MOSFET in an LFPAK56 package, the PSMN1R0-40YLD benefits from Nexperia’s NextPower-S3 technology, which provides for very fast switching with soft recovery. It features a Schottky-Plus body diode, a device which provides the soft-switching characteristics of a conventional Schottky diode without the high leakage current that Schottky diodes draw.

The effect of the ON Semiconductor SuperFET III technology is to minimise conduction losses and provide superior switching performance. It also means that the device can withstand extreme transient voltage events up to 100V/ns.

On-resistance in the FCH023N65S3L4 is rated at just 19.5mΩ. At the same time, typical gate charge for the device is a low 222nC at a gate-source voltage of 10V. The maximum gate threshold voltage is 4.5V.

The FCH023N65S3L4 can handle a continuous drain current of 75A at a case temperature of 25°C. At a case temperature of 100°C, this drain current value falls to 65.8A.

NEXPERIA

ON SEMICONDUCTOR

Compared to a logic-level MOSFET built without NextPower-S3 technology, the PSMN1R0-40YLD causes lower power losses and helps power-system designers to achieve higher overall efficiency. This advantage is reinforced by the device’s low reverse-recovery charge and gate charge, factors which also help users to produce designs marked by low levels of EMI.

PSMN1R0-40YLD 40V MOSFET: Suitable for server power supplies

FCH023N65S3L4: Efficient operation in UPS products

15

APPLICATIONS• Synchronous rectification• DC-DC converters• High-performance server power supplies• Motor-control systems• Power ORing

FEATURES• Optimised for 4.5V gate-drive applications • 150°C maximum junction temperature• Exposed leads can be wave soldered• Low parasitic inductance and resistance

APPLICATIONS• Telecoms equipment• Server power supplies• Industrial power supplies• Uninterruptible power supplies• Solar energy-generation equipment

FEATURES• 1.98nF effective output capacitance • 100% avalanche tested • 2.025J maximum single pulsed avalanche

energy• Operating-temperature range:

-55°C to 150°C• 0.21°C/W junction-to-case thermal

resistance





6A synchronous buck regulator features wide input-voltage range

The SiC462 from Vishay is a synchronous buck regulator with integrated high-side and low-side power MOSFETs. Its power stage is capable of supplying a continuous current of 6A at a switching frequency of up to 1MHz.

The regulator produces an adjustable output voltage as low as 0.8V from a wide input-voltage range of 4.5V-60V.

The SiC462’s architecture provides for ultra-fast response to voltage transients with a small requirement for output capacitance. Tight ripple regulation is maintained at very light loads.

VISHAYThe device is stable with any capacitor, and no external ESR network is required for loop stability. The SiC462 also incorporates a power-saving scheme which significantly increases light-load efficiency.

The regulator offers a full set of protection functions, including output over-voltage protection, output under-voltage protection and thermal shut-down.

Vishay’s SiC462: High efficiency at light loads

14

APPLICATIONS• Point-of-load power supplies in telecoms

servers• Industrial products • Industrial computing equipment• Consumer electronics devices

FEATURES• Switching frequency selectable in a range

from 100kHz to 1MHz • 95% peak efficiency• <10µA shut-down current• <250µA operating current when enabled

but not switching• User-programmable soft start• Cycle-by-cycle current limit





New digital controller for wireless battery-charger transmitters

New 48V DC-DC converter modules offer very high power density

The STWBC-WA from STMicroelectronics, a digital controller IC for wireless battery-charger transmitters, has been optimised for use in wearable devices.

Vicor has extended its family of DCM™ DC-DC converter modules in a VIA package, offering new options which have a 36-75V input-voltage range and a maximum output power of 320W.

The STWBC-WA, which has a rated input-voltage range of 3V-5.5V, is ideally suited for operation from the 5V USB power supply which wearable device chargers use. It is suitable for charging applications using less than 3W.

The power transmitter unit is responsible for controlling the transmitting coil and generating the correct amount of power requested by the receiver unit. This ensures the highest possible level of end-to-end efficiency, keeping power losses to a minimum. It also helps the charging system to maintain a low operating temperature.

The digital wireless battery transmitter can adapt to the amount of energy transferred by the coil by modulating the frequency, duty cycles or coil input voltage.

Each module in the DCM family is a rugged, efficient DC-DC converter operating from an unregulated, wide input-voltage range, producing an isolated and regulated output with much higher power density than competing products.

STMICROELECTRONICS

VICORThe three new modules are housed in a 3414 VIA package which measures 3.38in x 1.40in x 0.37in. They offer power density of up to 183W/in3. The VIA package offers flexible thermal management options with very low top- and bottom-side thermal impedance values.

The highly integrated modules incorporate EMI filtering, transient protection, in-rush current limiting, and a secondary-referenced control interface for trim, enable and remote-sensing functions. Configurations are available to support either board mounting or chassis mounting.

STWBC-WA: Charges low-power devices such as fitness bands

17

APPLICATIONS• Smart watches • Wearable devices• Internet of Things sensors • Healthcare equipment• Remote controls

FEATURES• Active presence detector• Turnkey firmware available• 32kbytes of Flash programme memory• 1kbyte of EEPROM data memory• 6kbytes of RAM• Operating-temperature range:

-40°C to 105°C

APPLICATIONS• Industrial equipment• Process control• Automotive systems• Heavy equipment

FEATURES• 92.4% peak efficiency• High-frequency zero-voltage switching• Tight regulation over all line and load

conditions• Over-voltage protection• Under-voltage protection• Short-circuit protection• Thermal protection





SiC MOSFET offers size and efficiency benefits in auxiliary power supplies

The BUK9M5R2-30E from Nexperia, the discrete power components business which was recently spun-off from NXP Semiconductors, is an N-channel logic-level MOSFET housed in a compact LFPAK33 (Power33) package.

ROHM Semiconductor has announced a new 1,700V Silicon Carbide (SiC) MOSFET intended for industrial applications, including manufacturing equipment and high-voltage inverters.

Qualified to the AEC-Q101 standard, it is intended for use in high-performance automotive applications. Featuring a maximum junction temperature of 175°C, it is able to withstand the most thermally demanding environments, including automotive lamps and motors.

The BUK9M5R2-30E is rated for a maximum drain-source voltage of 30V, and a maximum drain current of 70A. Low on-state resistance of 4.3mΩ at a gate-source voltage of 5V and a drain current of 25A ensures that conduction losses are kept to a minimum.

The SCT2H12NZ combines a high breakdown voltage with low on-resistance of 1.15Ω, which is some eight times lower than that of a typical equivalent silicon MOSFET. This results in dramatically reduced conduction losses in high-power applications and greatly improved energy efficiency. In addition, the device’s TO-3PFM package offers the creepage distance required in industrial equipment.

In many applications, the SiC MOSFET’s low losses and the consequent reduction in waste heat generated enable users to eliminate the heat-sink that would be required in a circuit based on the use of a silicon MOSFET.

NEXPERIA

ROHM SEMICONDUCTORROHM is expecting particularly high demand for the SCT2H12NZ in auxiliary power-supply designs in industrial equipment such as motor drives and the inverters in photovoltaic (PV) energy generators. By combining the SCT2H12NZ with ROHM’s BD7682FJ-LB power controller, as featured on page 21, designers can realise an auxiliary supply unit which offers robust performance and which improves efficiency by up to 6% compared to systems based on silicon MOSFET power switches.

The SCT2H12NZ is featured in the Technical View on page 26.

BUK9M5R2-30E: 175°C rating for use in engine bay

SCT2H12NZ: Very low conduction losses

16

APPLICATIONS• 12V automotive systems• Motors• Lamps • Solenoid control• Transmission control• Power switching

FEATURES• Withstands repetitive avalanche events• 9.7nC gate-drain charge• 1.58K/W thermal resistance from junction

to mounting base• 1.7V gate-source threshold voltage• 21.8ns reverse-recovery time

APPLICATIONS• Factory automation equipment • Solar and industrial inverters• Manufacturing equipment

FEATURES• 14nC gate charge at a gate-source

voltage of 18V • 2.6A maximum continuous drain current at

a case temperature of 100°C• 35W maximum power dissipation at a

case temperature of 25°C• 175°C maximum junction temperature• 2.8V gate threshold voltage





The STEVAL-ISB038V1 is a reference-design evaluation kit for a wireless battery charger. It provides for 1W wireless power transfer, using a half-bridge topology and a 20mm coil on the transmitter side, and an 11mm coil and STWLC04 wireless power receiver on the receiver side.

Orderable Part Number: STEVAL-ISB038V1

The AC-DC Converter Evaluation Board from ROHM features the BD7682FJ-LB controller and the SCT2H12NZ SiC power MOSFET in a power-converter design either operating from a mains input ranging from 210V to 690V AC or from the DC portion of the power supply.

Orderable Part Number: BD7682FJ_EVK_30x_1609

Input Voltage

VIA Package

Input-voltage Range

Output Voltage

5V 12V 15V 24V 28V 48V

300V 3714 200-420V 400W 600W 500W

270V 3714 160-420V 500W 500W

28V 3414 16-50V 180W 320W 320W 320W 320W

48V 3414 36-75V 320W 320W 320W

30V N-channel logic-level MOSFET for automotive systems

ROHM’s BD7682F: page 21



New switching regulator supplies digital components from 4-20mA loop

50A power relays switch high lighting and motor loads

RECOM has launched the R420-1.8/PL switching regulator, which is intended to be used to supply microprocessors and microcontrollers from a 4-20mA loop.

The DJ-H series from Panasonic are latching power relays which have a current rating of 50A and which are suitable for lighting and motor loads.

The benefits of the flat module include its very low stand-by power consumption, and its high conversion efficiency in normal operation.

The analogue 4-20mA loop is commonly used in process and control technology, because of its simple two-wire topology, which is reliable and easy to install. The unused portion of the loop current may be used to supply digital components. This calls for regulation to step the input from the 4-20mA loop down to the level required by a digital component.

The relays are able to handle high in-rush currents, such as TV-20 class tungsten lighting loads, and NEMA410 standard electronic ballast loads. They are also suitable for use

RECOM

PANASONIC

Conventional switching regulators, which offer high efficiency at full load, are unsuitable as their poor conversion efficiency at low loads means that they are incapable of meeting the output-power requirements from a 4mA input.

Linear regulators are also unsuitable: their poor efficiency decreases the power available from the 4-20mA supply by a factor of around three compared to switching regulators.

To solve this problem, RECOM developed the R420-1.8/PL switching regulator, which draws a stand-by current of just 100µA while

RECOM’s R420-1.8/PL: Draws 100µA in stand-by mode

DJ-H relays: Flux-resistant 39mm x 30mm x 15mm package

18

APPLICATIONS• Industrial equipment• Process-control systems• Factory-automation equipment

FEATURES• Open-frame, surface-mount unit• Adjustable output-voltage range: 1.8V-5V• Short-circuit protection• Operating-temperature range:

-40°C to 105°C • Three-year warranty

APPLICATIONS• Smart home equipment• Shutter and blind controls• Lighting controls

FEATURES• 480V AC maximum switching voltage at

25A• Reinforced insulation • >10mm clearance/creepage distances

between coil and contact• 12kV surge breakdown voltage• 1W activation control power in single-coil

type




Part Number

Rated Voltage (V DC)

Number of Coils

Manual Switching

ADJH21005 5 1 NoADJH21012 12 1 NoADJH21024 24 1 NoADJH23005 5 2 NoADJH23012 12 2 NoADJH23024 24 2 NoADJH21105 5 1 YesADJH21112 12 1 YesADJH21124 24 1 YesADJH23105 5 2 YesADJH23112 12 2 YesADJH23124 24 2 Yes

maintaining the rated output voltage. For example, from a 24V DC input sourcing less than 3.5mA, the R420 can provide a 10mA output at 3.3V. This is enough to supply a sensor alongside an MCU and HART modem without affecting the loop’s functionality or the accuracy of the measurement instrument connected to it.

Vishay’s TrenchFET: page 20 Nexperia’s PMV28UNEA: page 25

with capacitive loads which comply with the IEC 60669-1 standard.

The DJ-H relays are housed in a flux-resistant package measuring 39mm x 30mm x 15mm. They are supplied in single-coil and double-coil versions, and in Standard and Manual Switch types with voltage ratings of 5V, 12V or 24V DC.

The single-coil versions have a power rating of 1W and the double-coil versions have a power rating of 2W.



Quasi-resonant power controller enables soft switching at high frequency

1,200V SiC MOSFET provides stable, efficient performance at up to 200°C

ROHM Semiconductor’s BD768xFJ is a series of DC-DC controllers which operate in quasi-resonant mode to provide for soft switching and low EMI.

The SCT50N120 Silicon Carbide (SiC) power MOSFET extends the STMicroelectronics family of robust and efficient SiC power semiconductors. It features a maximum breakdown voltage of 1,200V and a maximum continuous-current capability of 65A at a case temperature of 25°C, and 50A at 100°C.

When incorporated into power-converter designs with an external MOSFET power switch and current-sense resistor, a BD768xFJ device offers the user a great deal of flexibility to match the performance of the circuit to the requirements of the application.The BD768xFJ controllers can switch an external MOSFET at frequencies up to 120kHz, and go into burst-mode operation at light loads in order to enhance efficiency and conserve power. In addition, the controller itself draws just 19µA in stand-by mode.

The BD768xFJ series has been specifically designed to drive Silicon Carbide (SiC) MOSFETs, which are becoming an increasingly popular choice for the power-switch function in power converters with a high AC or DC input voltage. The ROHM controller includes a gate-clamp circuit for

The high efficiency of the SCT50N120 is due in large part to its low on-resistance, which is rated at 59mΩ at a junction temperature of 150°C when sinking 40A. Switching performance is also consistent, benefitting from highly stable turn-off energy and gate charge over the full temperature range up to the maximum junction temperature of 200°C. The resulting low conduction and switching losses, combined with ultra-low leakage current, simplify thermal management and improve the reliability of the circuit.

ROHM SEMICONDUCTOR

STMICROELECTRONICS

optimal driving of SiC MOSFETs, and a valley-detection function to keep switching losses and electro-magnetic emissions to a minimum.

A built-in brown-out function monitors the input voltage level.

The BD768xFJ is featured in the Technical View on page 26.

As well as lowering energy losses, ST’s SiC MOSFETs also enable power systems to use switching frequencies up to three times higher than is possible with similarly rated silicon IGBTs. This means that designers can specify smaller external components and save size, weight and bill-of-materials costs. The SCT50N120’s high-temperature capability also helps to simplify the design of the cooling system in applications such as power modules for electric vehicles.

BD768xFJ: Suited to SiC MOSFET driver circuits

21

APPLICATIONS• Industrial equipment• AC power adapters• Household appliances

FEATURES• Under-voltage drop-out protection• Over-voltage protection• Over-current protection • Soft start

APPLICATIONS• Solar inverters• Uninterruptible power supplies• Motor drives• High-voltage DC-DC converters• Switch-mode power supplies

FEATURES• Very tight variation of on-resistance over

temperature • Slight variation of switching losses over

temperature • Very fast and robust intrinsic body diode • Low capacitance





New technology lowers on-resistance to 1.35mΩ in low-voltage MOSFETs

Power MOSFET features low on-resistance and gate charge

Vishay’s TrenchFET® Gen IV series of low-voltage MOSFETs features advanced transistor technology which produces very attractive energy-saving characteristics for designers striving to increase the efficiency of power-conversion applications.

ON Semiconductor’s NTMFS5H600NL is a 60V N-channel power MOSFET which is capable of supplying a continuous drain current of 250A at a case temperature of 25°C.

The TrenchFET Gen IV MOSFETs are particularly notable for their low on-resistance. In the SiRA00DP 30V N-channel MOSFET, for instance, on-resistance is rated at a maximum 1.35mΩ at a gate-source voltage of 4.5V, when sinking a current of 15A. When the gate-source voltage rises to 10V and the current to 20A, this on-resistance value falls even further, to 1.00mΩ.

The devices in the TrenchFET Gen IV series also offer very low gate charge

The NTMFS5H600NL’s low on-resistance of 1.3mΩ helps to keep conduction losses to a minimum in the power-conversion applications for which it is intended, such as point-of-load modules, high-performance DC-DC converters and secondary synchronous rectification circuits.

In addition, low total gate charge of 40nC at a gate-source voltage of 4.5V and a drain current of 50A reduces losses in the MOSFET driver circuit.

The device is housed in a compact five-terminal dual flat no-lead package with a 5mm x 6mm SO-8 footprint.

VISHAY

ON SEMICONDUCTOR

values: in the SiRA00DP, total gate charge is just 66nC at a gate-source voltage of 4.5V and a drain current of 20A. In addition, the ratio of gate-source charge to gate-drain charge is as low as 0.3 in TrenchFET Gen IV MOSFETs. This low ratio can help to prevent shoot-through by lowering gate-induced voltages.

The PowerPAK® packages in which TrenchFET Gen IV devices are housed offers excellent thermal characteristics, and allows for the design of systems with high power density.

TrenchFET Gen IV: Combines low gate charge and low on-resistance

NTMFS5H600NL: 5mm x 6mm footprint

20

APPLICATIONS• Computer peripherals• Servers • Telecoms equipment • Games consoles• Inverters • DC-DC converter modules• ORing circuits• Point-of-load power supplies

FEATURES (SiRA00DP)• 100A maximum continuous drain current• 11.7nF input capacitance• 3.3nF output capacitance• 1.2°C/W maximum junction-to-case

thermal resistance• Operating junction-temperature range:

-55°C to 150°

APPLICATIONS• Network equipment • Telecoms equipment• Servers• AC power adapters• Handheld power tools

FEATURES• 2.0V maximum gate threshold voltage• 6.68nF input capacitance• 1.23nF output capacitance• 30pF reverse transfer capacitance• 0.8°C/W junction-to-case thermal

resistance



Part Number Feedback Overload Protection Mechanism Over-voltage Protection Mechanism

BD7682FJ Auto-restart Latching

BD7683FJ Latching Latching

BD7684FJ Auto-restart Auto-restart

BD7685FJ Latching Auto-restart

The MOSFET benefits from ST’s thermally-efficient HiP247™ package, which allows reliable operation at up to 200°C while maintaining compatibility with the industry-standard TO-247 footprint.

ROHM’s SCT2H12NZ: page 16

Panasonics’ DJ-H: page 18 Nexperia’s PMV28UNEA: page 25



100V, 8A Schottky barrier rectifier operates at up to 175°C

Regulated 6W DC-DC converters offer high power density

The PMEG100V080ELPD from Nexperia, the discrete power components business recently spun-off from NXP Semiconductors, is a Schottky barrier rectifier and a member of Nexperia’s Maximum Efficiency General Application (MEGA) family of power devices.

RECOM’s new RS6 series of 6W-rated DC-DC converter modules is intended for use in space-constrained applications which require high power density.

AEC-Q101 qualified, the PMEG100V080ELPD is intended for use in automotive applications.

It is housed in a CFP15 (SOT1289) surface-mount plastic package with flat leads. It has a footprint of 5.8mm x 4.3mm and is 0.78mm high. Thermal resistance from junction to solder point is 3K/W. The device is rated for a maximum junction temperature of 175°C.

The PMEG100V080ELPD can handle average forward currents of up to 8A, and is able to withstand reverse voltages up to 100V. A low forward voltage means that the PMEG100V080ELPD can be used in applications requiring low system power consumption.

The modules feature power density of 2.7W/cm³, and will operate at full load across a wide temperature range from -40°C to 75°C. Output accuracy is rated at ±1%.

The new RS6 DC-DC converters have a 2:1 input-voltage range at nominal voltages of 5V, 12V, 24V and 48V DC. Housed in a 21.8mm x 9.2mm x 11.1mm package, they are pin-compatible with the RSO, RS and RS3 models, providing for easy upgrading without the need to change the PCB design.

The RS6 module is available in versions with a single 3.3V, 5V, 12V

NEXPERIA

RECOMor 15V DC output. Dual-output versions rated at ±5V, ±12V and ±15V DC are also available. A Trim pin allows for accurate matching of the output voltage to the load requirement.

The RS6 series devices offer high efficiency at both full and low loads. At full load, conversion efficiency is up to 88%. Even at 30% load, efficiency can be as high as 80%.

PMEG100V080ELPD: For use in cars’ LED lamps

RECOM DC-DC converter: Single or dual outputs

23

APPLICATIONS• Low-voltage rectification• Automotive LED lighting• DC-DC converters• Switch-mode power supplies• Reverse-polarity protection• Low-power applications

FEATURES• Clip-bonding technology and heat-sink

give high power capability• 160A non-repetitive peak forward current• 10ns reverse-recovery time• 535mV peak forward recovery voltage

APPLICATIONS• Industrial equipment• Test and measurement equipment• Battery-powered products

FEATURES• Overload protection• Short-circuit protection• 50mVp-p output ripple and noise• 2kV DC isolation• Remote on/off• Certified to EN 62368-1 Certification

Bodies scheme• Conforms to IEC/EN 60950-1 standard• Three-year warranty





Isolated DC-DC converters in a rugged package operate at high efficiency

Miniature rechargeable NiMH button cells suited to battery back-up applications

CUI Inc has added to its line of isolated DC-DC converters with the introduction of three new encapsulated models with power outputs ranging from 10W to 30W.

VARTA Microbattery offers four series of rechargeable Nickel Metal Hydride (NiMH) button cells, giving designers a choice of energy-storage devices optimised for robustness, high-temperature operation at up to 85°C, or high power output.

The 10W PDQ10-D, 15W PDQ15-D and 30W PDQ30-D are supplied in an industry-standard 1” x 1” encapsulated package, enabling users to save space in end-product designs by replacing equivalent 1” x 2” modules. The converters’ low-profile, rugged DIP package has a five-sided, shielded metal case.

The PDQ modules are available in versions which provide a single regulated output voltage of 3.3V, 5V, 12V or 15V DC or dual regulated output voltages of ±5V, ±12V or

The smaller NiMH cells are particularly well suited for use as a battery back-up for the Real-Time Clock (RTC) device found in many types of electronic systems. For instance, the small V 6 HR cell is highly reliable, offers a nominal capacity of 6mAh, and at just 2.15mm high easily fits on space-constrained circuit boards alongside low-profile surface-mount semiconductor components. Tolerant of a 0.18mA continuous over-charge current, the V 6 HR enables the designer to implement a simple charging circuit which continuously trickle-charges the cell.

CUI INC

VARTA MICROBATTERY

±15V DC, and with an input-voltage range of either 9V-36V DC or 18V-75V DC. Typical conversion efficiency is as high as 90%.

Featuring a broad operating-temperature range of -40°C to 105°C, the PDQ-D series is suitable for convection-cooled equipment and may be used in harsh environments.

All PDQ-D models offer input-to-output isolation of 1,500V DC, while the single-output models also offer output-voltage trimming which allows for a ±10% adjustment of the nominal output.

All VARTA NiMH button cells include a built-in pressure vent to guarantee safe operation in the event of mistreatment. The cells also have a low rate of self-discharge, which means that they are ready for use without charging or special handling procedures even after an extended period of storage.

It is an inherent property of batteries that their capacity declines with use: the VARTA NiMH button cells have an extended product lifetime of more than 1,000 cycles.

The four series of NiMH button cells are:• V..H series – robust cells with a discharge

capability of up to 2CA. • V..HT series – robust cells with high-

temperature capability. Discharge capability of up to 2CA.

• V..HR series – high-rate button cell with a discharge capability of up to 5CA.

• V..HRT series – high-rate, high-temperature button cell with a discharge capability of up to 5CA.

All cells are UL recognised.

CUI’s PDQ modules: Shielded metal case

VARTA’s NiMH cells: Built-in pressure vent

22

APPLICATIONS• Industrial products• Telecoms equipment• Remote sensor systems • Portable electronics devices

FEATURES• Over-voltage, under-voltage lock-out and

short-circuit protection functions• Remote on/off control• ±1.5% voltage accuracy• Recovery time from 75% to 100% step

load change: • 250µs for PDQ15-D and PDQ30-D • 500µs for PDQ-10D• All models conform to EN 55022 Class

A standard for conducted emissions (external capacitor and inductor required)

• PDQ10-D also conforms to EN 55022 Class B

APPLICATIONS• RTC battery back-up • Battery-backed memory• Industrial equipment• Healthcare equipment• Automotive systems• Wireless headsets and headphones

FEATURES• Tolerates deep discharge • Patented crimp sealing system eliminates

risk of leakage• No memory effect




To apply for these free boards go to: www.my-boardclub.com/ftmTerms and conditions apply. Visit www.my-boardclub.com/about_us for details

20V N-channel trench MOSFET supports very fast switching

Motor-control development board supports sensored and sensorless designs

The PMV28UNEA from Nexperia, the discrete power components business recently spun-off from NXP Semiconductors, is an N-channel trench MOSFET in a small SOT23 (TO-236AB) surface-mount plastic package measuring 3.0mm x 1.4mm.

The FRDM-KV10Z from NXP Semiconductors is a development platform for users of the Kinetis® V1x series of microcontrollers. The KV1x MCUs, which are based on the ARM® Cortex®-M0+ processor core, have the features and performance required to implement sensored or sensorless control of a Brushless DC (BLDC) motor or a Permanent Magnet Synchronous Motor (PMSM).

AEC-Q101 qualified, the PMV28UNEA is intended for use in automotive applications. It is rated for operation at junction and ambient temperatures ranging from -55°C to 150°C, and can handle a drain current of up to 4.7A at an ambient temperature of 25°C. On-state resistance under these conditions is 24mΩ, and total gate charge is 6.2nC.

The FRDM-KV10Z hardware features a 75MHz MKV10Z32VLF7 MCU which includes 32kbytes of Flash, 8kbytes of SRAM, a 16-bit ADC and FlexTimers with a quadrature decoder for motor and power control. The board also includes a six-axis FXOS8700CQ sensor combining an accelerometer and magnetometer.

As part of the FRDM-KV10Z platform, NXP provides OpenSDA, the open-source embedded serial and debug adapter device running an open-source bootloader. This circuit offers several options for serial communication, Flash programming and run-control debugging. The FRDM-KV10Z is also supported by a range of NXP and third-party development software.

Future Electronics’ Board Club: supporting innovative electronics design

Europe’s electronics industry thrives on the application of innovation and creativity, and an essential innovator’s tool in design projects is the development board. The Board Club website is a Future Electronics resource for users of development boards. Here, and only here, Board Club members can gain access to exclusive free development boards and development board offers.If you would like to register for membership, please visit: www.my-boardclub.com/register.php

NEXPERIA

NXP SEMICONDUCTORS

It is capable of supporting very fast switching operations. Turn-on delay time is rated at 8ns, and rise time at 35ns. The turn-off delay time is 39ns and the fall time is 14ns.

The PMV28UNEA features a gate-source threshold voltage of 0.7V, and maximum drain leakage current of 1µA. The device’s breakdown voltage is rated at a minimum of 20V.

PMV28UNEA MOSFET: 3.0mm x 1.4mm package

25


Orderable Part Numbers:FRDM-KV10Z with FRDM-MC-LVBLDC motor-control kit

APPLICATIONS• Relay driver• High-speed line driver• Low-side load switch• Switching circuits

FEATURES• >2kV ESD protection according to the

human body model• 21K/W thermal resistance from junction to

solder point• 7Ω gate resistance at a switching

frequency of 1MHz

APPLICATIONS• BLDC motor control • Power management

FEATURES• Three-colour user LEDs• User-controlled push-button switches• Thermistor • USB or external power-supply options





Rugged DC-DC converter modules suitable for military applications

AC-DC converter IC helps users comply with tough light-load power regulations

NetPower offers various series of rugged DC-DC converter modules which are intended for use in harsh environments.

The VIPer01 from STMicroelectronics is a high-voltage converter which includes a logic-level 800V avalanche-rugged power MOSFET and a PWM current-mode controller.

The rugged converters offer input:output conversion ratios of 8:1, 4:1 and 2:1, and provide power outputs up to 1kW. The modules are available in sizes ranging from a thirty-second brick to full brick.

One of the NetPower series of DC-DC converters is the EYRS1, a one-eighth brick which offers an input-voltage range of 9V-36V. Four variants of the product are available offering an output voltage of 5V, 12V, 15V or 28V.

Heat distribution inside the encapsulated package is carefully managed to ensure

The logic-level power MOSFET technology enables the VIPer01 to operate from a supply of just 4.5V and enables the design of ultra-efficient power supplies with a 5V output. Moreover the 800V technology allows the device to handle a very high AC input voltage.

The VIPer01 is suitable for use in end-products which have to comply with the most stringent energy-saving standards, as it has very low power consumption and operates in pulse-frequency modulation mode when supplying light loads. Power consumption can

NETPOWER

STMICROELECTRONICS

even and sufficient heat dissipation. The standard operating-temperature range is -40°C to 100°C, but an extended temperature range is also available, providing for operation at temperatures as low as -55°C.

The NetPower converter modules all offer built-in protection against input under-voltage, output over-voltage, over-current and short-circuits, and over-temperature.

be less than 10mW at 230V AC in a no-load condition, and less than 400mW at 230V AC when supplying a 250mW load.

The VIPer01 is ideal for power-supply applications requiring a 5V output and supplying a load of up to 4W over a wide input-voltage range of 85V-265V AC, and at ambient temperatures up to 60°C.

The VIPer01 supports the flyback, buck and buck-boost converter topologies. Integrating a high-voltage start-up circuit, a sense FET, error amplifier and oscillator, it enables the user to realise a compact power supply with a small number of external components.

NetPower DC-DC converters: Even heat distribution

24

APPLICATIONS• Military equipment• Aerospace• Railway equipment• High-reliability telecoms equipment• Industrial products

FEATURES• No minimum load requirement • Output remote sense • Fixed-frequency operation • 2,250V DC input-to-output isolation • Flanged baseplate available • Complies with IEC 60950-1 2nd edition • Qualified/screened for IPC-9592,

MIL-STD-810, MIL-STD-883

APPLICATIONS• Auxiliary power supplies for industrial and

consumer equipment• Low-power adapters

FEATURES• Self-supply option eliminates need for

auxiliary winding or bias components • Jittered switching frequency reduces EMI

filter cost • Pulse-skip mode reduces start-up peak

current • Over-voltage, short-circuit and thermal

shut-down protection functions




The STEVAL-ISA177V1 evaluation board implements an AC-DC converter using a non-isolated flyback topology, producing a 0.85A output at 5V. The STEVAL-ISA178V1 board implements an AC-DC converter using a non-isolated buck topology, producing a 0.2A output at 5V.

Orderable Part Numbers:STEVAL-ISA177V1 and STEVAL-ISA178V1

Panasonics’ DJ-H: page 18 Vishay’s TrenchFET: page 20

The FRDM-KV10Z kit is supplied with a KV10Z MCU-based development board, a quick reference card and a USB A-to-MicroB cable. Alongside the FRDM-KV10Z kit, developers can use NXP’s FRDM-MC-LVBLDC, a three-phase BLDC motor kit for the Freedom platform. It includes a board and a Linix 45ZWN24-40 motor with wiring for the three motor phases and Hall-effect sensor signals.

See the KV series Star Part on page 3.

T E C H N I C A L V I E W


Fig. 2: Top and bottom views of the ROHM AUX evaluation board

Fig. 3: Circuit schematic of the ROHM AUX Evaluation Board

Fig. 5: Efficiency of the AUX Evaluation Board under various load and input-voltage conditions


How to use a SiC MOSFET operating in quasi-resonant mode to cut the size and cost of auxiliary power supplies

A power converter used in an industrial system such as a photovoltaic (PV) inverter, Uninterruptible Power Supply (UPS) or industrial motor drive will normally include an auxiliary supply unit which supplies power to system peripherals such as a microprocessor, LCD display, sensors and fans, as well as to the gate drivers inside the main power circuit.

Auxiliary supply units commonly support loads of up to 40W, and provide an output at a low DC voltage. The standard topology used in these circuits is flyback, and in three-phase systems they will typically operate from an input voltage of up to 480V AC or 900V DC.

Such a system places considerable demands on the auxiliary supply unit’s power switch. Taking into account the reflected voltage in the primary side, which is added during the blocking state, a power switch with a breakdown voltage of more than 1,500V is normally required. The use of standard silicon MOSFETs for this application entails considerable problems. The designer is faced with one of two undesirable options: • either to connect several lower-voltage devices in series, which

increases the system’s complexity, size and component count • or to use a 1,500V silicon MOSFET, a device type which suffers from

high power losses which require a bulky and expensive heat-sink

The adoption of a high-voltage Silicon Carbide (SiC) MOSFET in place of a single silicon MOSFET eliminates these drawbacks. SiC MOSFETs with a 1,700V rating are available now from ROHM Semiconductor in surface-mount (TO-268-2L) and fully moulded, isolated (TO-3PFM) packages, as shown in Figure 1. The devices feature an extended creepage distance of 5mm and 5.45mm respectively.

To show the superior characteristics of an auxiliary supply unit based on a SiC MOSFET, ROHM has developed an evaluation board which may be used to supply peripheral devices in a power converter, and which supports loads up to 40W at an output voltage of 12V. Based on the flyback topology, this AUX Evaluation Board includes the SCT2H12NZ, a 1,700 SiC MOSFET, as the main switch, and the BD7682FJ-LB, a quasi-resonant flyback controller. This controller’s operation helps to keep the dynamic losses in the SiC MOSFET to a minimum, thus reducing its operating temperature.

The board operates from both AC and DC inputs, drawing power either directly from the mains or from the DC portion of the power supply, such as after the PFC stage. For mains-supplied designs, the input-voltage range is wide: from 210V to 690V AC. This is useful in UPS and industrial drives, which commonly supply the auxiliary power unit from the mains.

For DC-fed systems, the input range is 300V-900V DC. In PV inverters, this enables the auxiliary supply unit to draw power directly from the solar panels, or after the boost-conversion stage.

The BD7682FJ-LB quasi-resonant controller used in the AUX Evaluation Board is a compact and effective solution intended to meet the requirements of a SiC MOSFET. It operates at a variable frequency of up to 120kHz; the frequency is adjusted in response to the load conditions. The benefit of this can be seen in Figure 4, which shows the drain-source voltage at various output-power levels.

The turn-on time is dynamically modified to ensure that the switch turns on in an oscillation valley. This minimises the switching losses in the

SiC MOSFET, reducing its operating temperature and increasing system efficiency. When there is no load, the controller goes into burst mode to keep energy losses low.

Simple to use and housed in a compact SOP8-J8 package, the BD768xFJ-LB offers many functions and protection features: • Current sense, implemented via a shunt resistor in

series with the SiC MOSFET• Overload protection configured by the current-

sense resistor• Mask function: avoids erroneous sensing of the

voltage over the auxiliary winding• Quasi-resonant control for low dynamic losses and EMI • Frequency-reduction mode to increase efficiency at light loads• Burst operation in no-load conditions for low-current stand-by

operation• Output over-voltage protection• Soft start• Input brown-out protection• Integrated SiC MOSFET driver

Measured system performanceFigure 5 shows the performance of the AUX Evaluation Board when operating at three DC input voltages: 300V, 600V and 900V. In each case, efficiency was measured across an output-power range from zero to the system’s maximum rated power of 40W. At the lowest 300V input voltage, overload protection was activated above 30W.

At an input voltage of 300V, efficiency peaks at 87%. At higher input voltages, dissipation across the resistor dividers used in the circuit increases. This means that efficiency declines slightly as the input voltage increases. Nonetheless, efficiency remains above 80% across nearly all load conditions.

Over the entire load range at all three input-voltage values, the highest temperature measured at the MOSFET’s case was 80°C. The SCT2H12NZ’s maximum junction temperature is 175°C, so no heat-sink was required for the operation of the test circuit.

Fig. 1: ROHM’s 1,700V SiC MOSFET offers a choice of two package styles

T E C H N I C A L V I E W

F O L L O W U S N O W – S E A R C H F T M B O A R D C L U B O N26

READ THIS ARTICLE TO FIND OUT ABOUT:

• The efficiency and cost drawbacks of existing approaches to the design of auxiliary power supplies

• How the thermal and electrical characteristics of SiC MOSFETs affect auxiliary power-supply design

• The high efficiency of an auxiliary power-supply reference design developed by ROHM Semiconductor

Part Number On-resistance Package

SCT2750NY 0.75Ω TO-268-2L

SCT2H12NY 1.15Ω TO-268-2L

SCT2H12NZ 1.15Ω TO-3PFM

Fig. 4: Drain-source voltage measurements at various load conditions. Each division marks a span of 200V.

ROHM Semiconductor


Orderable Part Number: BD7682FJ_EVK_30x_1609

Component Focus: Pages 3-6 - Welcome to FTM Board Club · 2017-02-23 · Component Focus: Pages 3-6...

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