The document discusses different types of isolation amplifiers, which provide electrical isolation and safety barriers between input and output circuits. There are three main types: transformer coupling uses a transformer to couple supplies; optical isolation converts signals to light; and capacitive coupling uses a differential capacitive barrier and separate supplies. Transformer coupling is commonly used and offers medium isolation voltage and gain stability. Optical isolation provides low-cost isolation but lower voltage ratings. Capacitive coupling has the highest isolation resistance and gain stability but also the highest cost. Isolation amplifiers have applications in medical equipment, industrial processes, and other areas requiring electrical isolation.

2.  Isolation amplifiers provide electrical
isolation and an electrical safety barrier.
 They protect the patients from leakage
currents.
 They break the ohmic continuity of electrical
signals between input and output.
 Isolated power supplies are provided for both
the input and output stages.
 Used to amplify low level signals.

3. GENERAL PIN
CONFIGURATION OF
ISOLATION AMPLIFIER

4. TYPES
Three types of methods are used to design
isolation amplifier
 Transformer isolation
 Optical isolation
 Capacitive isolation

5. TRANSFORMER COUPLED
ISOLATION AMPLIFIER

6.  It uses either frequency modulated or a
pulse width modulated carrier signal.
 Internally it has 20KHz oscillator,
transformer, rectifier and filter to provide
supplies for each isolated stages.
 Rectifier- input to primary OPAMP.
 Transformer- couples the supply.
 Oscillator – input to secondary OPAMP.
 A low pass filter is used to remove the
other frequency components.

7. Advantages
 High common mode rejection ratio
 High linearity
 High accuracy

9. applications
 MEDICAL
Patient Monitoring and Diagnostic
Instrumentation
 INDUSTRIAL
Ground Loop Elimination and
Off-ground Signal Measurement
 NUCLEAR
Input/output/Power Isolation

10. Optically isolated isolation
amplifier

11.  The biological signal is converted into a
light signal by LED for further process.
 It has patient circuit which is the input
circuit and a phototransistor which
forms the output circuit.
 Each circuit is battery driven.
 The input circuit converts the signal to
light and the output circuit converts the
light back to signal.

13. advantages
 Original frequency and amplitude is
obtained.
 High linearity.
 No modulator or demodulator is needed as
it couples optically.
 Improves patient safety

14. Application
 INDUSTRIAL PROCESS CONTROL
 DATAACQUISITION
 INTERFACE ELEMENT
 BIOMEDICAL MEASUREMENTS
 PATIENT MONITORING
 TEST EQUIPMENT
 CURRENT SHUNT MEASUREMENT
 GROUND-LOOP ELIMINATION
 SCR CONTROLS

15. Capacitively coupled isolation
amplifier

16.  It uses digital encoding of the input
voltage and frequency modulation.
 The input voltage is converted to
proportional charge on the switched
capacitor.
 It has modulator and demodulator circuits.
 The signals are sent across a differential
capacitive barrier.
 Separate supplies are given for both sides.

18. advantages
 Ripple noises are removed.
 It avoids device noise, radiated noise and
conducted noise.
 High immunity to magnetic noises.
 Useful for analog systems.
 Has high gain stability and linearity.

19. applications
 DATAACQUISITION
 INTERFACE ELEMENT
 PATIENT MONITORING
 ECG
 EEG

20. Comparative study
 Commonly used
Transformer isolation amplifier
 Cost
Optical- low cost due to less
components
Transformer
Capacitor coupled- high cost
 Isolation voltage
Optical- low (800V)
Transformer- medium (1200V)

21.  Isolation resistance
Optical- 10^12
Transformer- 10^10
Capacitance- 10^12
 Gain stability and Linearity
Optical- 0.02%
Transformer- between 0.005% and
0.02%
Capacitance- 0.005% (best)

22. VECTOR CARDIOGRAPHY
(VCG)

23. ANGULAR VIEWS

24. VCG WAVEFORM