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EXPERT SYSTEMS AND SOLUTIONS

Email: expertsyssol@gmail.com

expertsyssol@yahoo.com

Cell: 9952749533

www.researchprojects.info

PAIYANOOR, OMR, CHENNAI

Call For Research Projects Finalyear students of B.E in EEE, ECE, EI,

M.E (Power Systems), M.E (Applied

Electronics), M.E (Power Electronics)

Ph.D Electrical and Electronics.

Students can assemble their hardware in our

Research labs. Experts will be guiding the

projects.

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OPAMPAPPLICATIONS

Session-12PRAKASH BISWAGAR

Asst.Professor, E&C Dept.

RV College of Engg.

Bangalore

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AGENDA Recap

Active filters

DAC ADC

Regulators

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ACTIVE FILTERS

Filters are frequency selective networks

Used in Communications

Can be active or passive

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CLASSIFICATION OFFILTERS

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FILTERS BASED ON

FREQUENCY

(i) Low pass filter(LPF)

(ii) High pass filter(HPF)

(iii)Band pass filter(BPF)

(iv) Band stop filter(BSF)

(v) All pass filter

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Frequency Response offilters

Ideal

Practical

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REALIZATION OF FILTERS

1. Butterworth filters2. Chebyshev filters

3. Elliptic filters

4. Bessel filters

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BUTTERWORTH FILTERS

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CHEBYSHER FILTERS

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BUTTERWORTH FILTERS

Named after the inventor BUTTERWORTH

No ripple in the pass/stop band

Have large transition width Filter characterized by system transfer function

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Where Pn(S) = Butterworth polynomial

S = Complex variable = +j

Order of the polynomial indicates the order ofthe filter

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BUTTERWORTH POLYNOMIALS

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I-ORDER LPF

BUTTERWORTH TYPE

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RCN/W used for filtering action

R1 & R1 used for gain adjustment

OPAMP is configured in non-inverting model

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D TO A CONVERTERS

Analog o/pDigital

I/P

DAC

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DAC SPECIFICATIONS

Resolution

Linearity

Accuracy Settling time

Output time

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Types of DAC

1.Binary weighted DAC

2.R-2R ladder type DAC

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BINARY WEIGHTED DAC

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LIMITATIONS OFBINARY WEIGHTED RESISTORS

(1) As the resolution increases, the resistor value

increases(2) The accuracy is low, since depends on

resistor values.

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R-2R LADDER TYPE DAC

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R-2R LADDER TYPE DAC

Uses only two values of resistors

Overcomes the limitations of Binary weighted

DAC

OPAMP is connected in inverting mode

Each digital input is applied through R-2R

network and VRef

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ERRORS IN DAC

1.Linearity error

2.Offset error3.Gain error

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ADCs Converts analog signal into digital data

Used in Data acquisition systems & Digitalinstruments etc

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TYPES OF ADC

1.Counter type ADC

2.Successive approximation ADC

3.Flash or parallel converter type ADC4.Integrated type ADCs

(Single slope & dual slope)

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COUNTER TYPE ADC

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COUNTER TYPE ADC

Initially the counter is cleared

The analog signal is applied to one of theinputs of the comparator

Counter o/p is converted into analog, by theDAC

The DACO/P is compared with the incoming

signal Conversion stops when digital O/P >Incoming

signal

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SUCCESSIVE APPROXIMATION

ADC

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SAR ADC

Widely used

Similar to Counter type ADC except that ,a

SA

R is used SAR acts as programmable Up/Down counter

Completion of conversion , triggered by a

change in the state of the comparator Much faster than the counter type

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FLASH ADC

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FLASH ADC For n-bit digital word, 2n-1 comparators are

required

The analog sample is simultaneously appliedto one input of all the comparators

Other input to the comparator is a DC voltage

derived from the pot. dividerN/W

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QUANTIZATION ERRORS

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REGULATORS

Block diagram of a RPS

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CLASSIFICATION OFREGULATORS

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BASIC REGULATOR

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MAIN PARTS OF A

MONOLITHIC REGULATOR

Reference voltage circuit ErrorAmplifier

Series pass element

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PRACTICAL REGULATOR

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3-TERMINAL REGULATORS

(FIXED O/P)

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3-TERMINAL REGULATORS(SDJUSTABLE O/P)

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3-TERMINAL REGULATOR

(ADJUSTABLE)

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DESIGN OF V.R.USING 78XX

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