Super High Efficiency SHE Telecom Rectifier Provides Record Efficiency With Cost Effective GaN Based Power Conversion

Erik Myhre, Eltek

Eric Persson, Infineon Technologies

12019-03-07

Agenda• Motivation

• Fully bridgeless totem pole PFC topology details

• GaN device selection

• Eltek SHE Rectifier Performance, Robustness

• SHE System reliability testing

• SHE Field Quality and Reliability

• What is next for GaNin datacenter/telecom applications?

22019-03-07

ACLINE

EMI Filter

Q1

Q2

Q3

Q4

Q5

Q6

GaN enables hard switching in half bridge topologies

Electricity ranks high in operating costs

Q3

400 V

AC IN

Q4

L1

Q1

Q2 System cost pays back in reduced operating costs

TOTEM POLE topologies allows:

› Very high efficiency

› Smaller footprint

› System costs reduction

No bridge rectifier, lower losses

GaN features leveraged:

› No reverse recovery charge

› Low R(on) x Area FOM

Motivation: Why use GaN in Datacenter/Telecom?

32019-03-07 Copyright © Infineon Technologies AG 2019. All rights reserved.

CCM FullBridge TOTEMPOLE PFC

Q3

+400 V

0 V

AC IN

Q4

L1

Q1

Q2

Fully-bridgeless totem-pole PFC topology details

• Simple topology. No diodes, only switches in conduction path

• Input current is always flowing through one CoolGaN and one CoolMOS

• Operating frequency is kept low to minimize switching loss (45 kHz)

Single inductor

High-frequency half-bridge

Low-frequency half-bridge

for half-cycle commutation

Why GaN is best forhigh-frequency half-bridge:

› Zero Qrr

› Small Eoss

› Small Qg, fast switching

42019-03-07

GaN device selection

PG-DSO-20-87 package for GaN• Surface mount technology• Low parasitic inductance• Heat slug orients upward

allowing top side cooling

CoolGaNTM 600V, 70 mOhm GaN• Normally off• Robust gate structure• Application specific qualification• Reliability rated for hard switching

52019-03-07

Hybrid Drain-GITnormOFF GaN

Fp2 3kW SuperHE: Key Specifications

• The Flatpack2 48/2000 Super HE is contributing to setting the new industry standard in the DC power market, with efficiency of 97.8%.

• The Super HE is a premium rectifier particularly suitable for markets and applications where energy is costly

• In grid connected applications the payback time is down to 2 years compared to standard HE rectifier, and in hybrid applications even faster.

62019-03-07

Fp2 3kW SuperHE: key specifications (2/2)

• This system is designed for use in Telecom and Wireless applications such as Radio base station/Cell sites, LTE/4G/WiMAX, Mobile switching centers (MCS)

• It is also suitable for use in Telecom Fixed applications such as Central office, telephony servers/switches, Fiber optics, Microwave, Broadband, Broadcast and datacenters.

• The Eltek Super High Efficiency (SHE) telecom rectifier achieves record levels of efficiency (approaching 98%) in a cost effective manner through use of CoolGaNTM

Gallium Nitride power transistors from Infineon Technologies.

72019-03-07

Telecom

FP2 3kW SuperHE pays for itself in lower costs

82019-03-07

Robustness: GaN Device breaks down at higher voltage than Si FET’sand is more robust in lightning strike test

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 100 200 300 400 500 600 700 800 900 1000

Id in

mA

Vds in V

25°C, typ

ID = 250µA

VDS = 910V

VBDSS criterion: Id = 250µA

IDSS Characteristic

› GaN can withstand much higher voltage stress than silicon

› …but lifetime at such high voltage is limited

GaN device

incurs

dielectric

breakdownSilicon device goes into

avalanche breakdown

92019-03-07

Robustness: Handling peak currents• Normal and abnormal peak currents must be limited to stay within GaN max ratings

• During normal operational transients, this is managed by the controller current-loop

• During abnormal operation, protection diodes help• Re-rush current after line-cycle dropout

• Differential-mode lightning-strike surge test Surge Current

Protection Diodes

102019-03-07

System Reliability testing

HTOB testing

• Performed according to IPC9592 revB.

• Duration: 1000 hours at ambient +45C

• Output power cycling 0-100%-0% 10 times during the first 30 minutes

• The input voltage is cycled between 264Vac and 200Vac

• Input Power cycled 10 times with 1min. on and 1min. off.

• 10 minutes off in the end of the cycle

• Test passed without failures

112019-03-07

FP2 3kW SuperHE: Field Quality, Reliability

• >20,000 systems in the field (40,000 CoolGaNTM

devices)

• GaN devices have not caused any field failures; MTBF > 30 X 106 Hours (limited by current operating hours)

• This complements Infineon Technologies cumulative equivalent of 26 x109 Device hours of biased life operation

• Devices were qualified to Infineon’s comprehensive GaN qualication criteria www.infineon.com/gan>Documents>Whitepaper

122019-03-07

Telecom

Next up for GaN: GaN for DCDC converters

› 10 times lower charges than Si (Qoss, Qg, Qrr)

› Higher frequency operation

› Higher efficiency

› Smaller designs for the same Pout

› More power for the same footprint

› Lower system costs

GaN: Enabler for higher power density

LLC

132019-03-07

Advantages

The future is GaN in datacenter/telecom applications

INCREASING THE EFFICIENCY INCREASING THE POWER DENSITY

IMPROVING THE RELIABILITY REDUCING THE COST

• PFC: Reliable and cost efficient totem poleLow ohmic transistors

• LLC: Lower and lower RDS(ON) devices

• Synchronous Rectification: continue to reduce parasitics, very low RDS(ON)

• GaN allows increased switching frequency

• Smaller inductors and capacitors

• Less filtering

• GaN costs will lower towards silicon

• GaN allows increased switching frequency

• Smaller inductors and capacitors

• Less filtering

• No steep (avalanche) breakdown voltage of the device

• Behaves more like a ceramic capacitor

• Less susceptible to cosmic radiation than Silicon devices

GaN

142019-03-07

the new power paradigm:ultimate efficiency and reliability

CoolGaN™ 600 V + GaN EiceDRIVER™: In volume production now!

› The most reliable GaN solution delivering highest performance amongst all available GaN devices

› Manufacturing expertise throughout the entire supply chain

› Global application design support

› Broad portfolio including drivers

› Volume capability

› Attractive price projection

152019-03-07 Copyright © Infineon Technologies AG 2019. All rights reserved.

Summary

• Fully bridgeless totem-pole boost PFC topology leverages GaN performance to achieve very high efficiency in a system cost effective manner

• SHE Rectifier family achieves 97.8% efficiency at 2kW and 3kW.

• 3 key features of GaN transistors enable this high performance:

• Zero reverse recovery charge, so half-bridge can operate hard-switched

• Low Qg and Qoss enabling fast switching transitions, thus low loss

• Low RD(ON) x Area

• >20,000 systems in the field and growing, no GaN failures

• More robust (lightning strike) than Silicon based systems

• GaN is poised to enable high density in the data center as well

162019-03-07