Isolation amplifier

1. ISOLATION AMPLIFIER
BY
S.SHAMEERA BANU
115011013907
B.TECH II-YEAR (ECE)

2. ISOLATION AMPLIFIER :
1 Isolation amplifiers provides electrical
isolation & an electrical safety barrier
2 They protect the patients from leakage
currents
3
They break the ohmic continuity of
electrical signals b/w input & output
Isolated power supplies are provided for both
the i/p & o/p4
5 Use to amplify low level signals

3. PIN DIAGRAM :

4. THREE TYPES OF METHODS ARE USED TO
DESIGN ISOLATION AMPLIFIER :
Transformer
isolation
1
Optical
amplifier
2
Capacitive
isolation
3

5. TRANSFORMER COUPLED
ISOLATION AMPLIFIER :
1
Internally it
has 20KHz
oscillator,
transforer,
Rectifier &
filter to
provide
supplies for
each
isolated
stages.
R
2
Rectifier-
input to
primary
op-amp
3
Transfor
mer –
couples
the
supply
4
Oscillator -
input to
secondary
op-amp
5
A low pass
filter is
used to
remove
the other
frequency
componen
ts

6. ADVANTAGES:
2
High
linearity
1
High
common
mode
rejection
ratio
3
High
accuracy

7. APPLICATIONS :
MEDICAL
Patient
monitoring &
diagnostic
instrumentation.
INDUSTRIAL
Ground loop
elimination &
off-ground
signal
measurement
NUCLEAR
Input /
output /
power
isolation.

8. OPTICALLY ISOLATED ISOLATION
AMPLIFIER :
The biological signal is converted into a
light signal by LED for future process.1
It has patient circuit which is the i/p ckt &
a phototransitor which forms the o/p ckt2
Each circuit is battery driven3
The i/p ckt converts the signal to light & the
o/p ckt converts the light back to signal.
4

9. ADVANTAGES :
2
High
linearity
1
Original
frequency &
amplitude is
obtained.
3
No
modulator/
demodulator
is needed as
it couples
4
Improves
patient
safety

10. APPLICATIONS :
Industrial
process
control
Data
acquisition
Interface
element
Biomedical
measurements
Patient
monitoring
Test
equipment
Current
shunt
measurement
Ground
loop
elimination
SCR
Controls

11. CAPACITIVELY COUPLED
ISOLATION AMPLIFIER :
It uses digital encoding of the i/p voltage & frequency modulation.1
The i/p voltage is converted to proportional charge on the
switched capacitor.
2
It has modulator & demodulator circuits.3
The signals are sent across a differential capacitive barrier4
Separate supplies are given for both sides5

12. APPLICATIONS & ADVANTAGES :
APPLICATIONS:
Data acquisition
Interface Element
Patient monitoring
ECG
EEG ADVANTAGES:
Ripple noises are
removed
It avoids radiated noise
High immunity to
Magnetic noises
Useful for analog
systems
Has high gain stability
& linearity

13. THANK YOU