EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101:...

66
EE101: Op Amp circuits (Part 4) M. B. Patil [email protected] www.ee.iitb.ac.in/~sequel Department of Electrical Engineering Indian Institute of Technology Bombay M. B. Patil, IIT Bombay

Transcript of EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101:...

Page 1: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

EE101: Op Amp circuits (Part 4)

M. B. [email protected]

www.ee.iitb.ac.in/~sequel

Department of Electrical EngineeringIndian Institute of Technology Bombay

M. B. Patil, IIT Bombay

Page 2: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Half-wave rectifier

Consider a diode rectifier:

slope=1

DR

VoVi

Vi

Vo

VD

If Vi � VD , the diode drop can be ignored.

However, if Vi is small, e.g., Vi = 0.2 sin ωt V , then the circuit does not rectify, andVo(t) = 0 V .

Precision rectifier circuits overcome this drawback.

M. B. Patil, IIT Bombay

Page 3: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Half-wave rectifier

Consider a diode rectifier:

slope=1

DR

VoVi

Vi

Vo

VD

If Vi � VD , the diode drop can be ignored.

However, if Vi is small, e.g., Vi = 0.2 sin ωt V , then the circuit does not rectify, andVo(t) = 0 V .

Precision rectifier circuits overcome this drawback.

M. B. Patil, IIT Bombay

Page 4: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Half-wave rectifier

Consider a diode rectifier:

slope=1

DR

VoVi

Vi

Vo

VD

If Vi � VD , the diode drop can be ignored.

However, if Vi is small, e.g., Vi = 0.2 sin ωt V , then the circuit does not rectify, andVo(t) = 0 V .

Precision rectifier circuits overcome this drawback.

M. B. Patil, IIT Bombay

Page 5: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Half-wave precision rectifier

DR

Vi

Vo

R

VDVi

Vo1

Vo

iR

i−iD

slope=1

Vi

Vo

Consider two cases:

(i) D is conducting: The feedback loop is closed, and the circuit looks like (exceptfor the diode drop) the buffer we have seen earlier.

Since the input current i− ≈ 0, iR = iD .

Further, V+ − V− =Vo1

AV=

Vo + 0.7 V

AV≈ 0 V → Vo = Vi .

This situation arises only if iD > 0 (since the diode can only conduct in theforward direction), i.e., Vo > 0→ Vi = Vo > 0 V .

M. B. Patil, IIT Bombay

Page 6: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Half-wave precision rectifier

DR

Vi

Vo

R

VDVi

Vo1

Vo

iR

i−iD

slope=1

Vi

Vo

Consider two cases:

(i) D is conducting: The feedback loop is closed, and the circuit looks like (exceptfor the diode drop) the buffer we have seen earlier.

Since the input current i− ≈ 0, iR = iD .

Further, V+ − V− =Vo1

AV=

Vo + 0.7 V

AV≈ 0 V → Vo = Vi .

This situation arises only if iD > 0 (since the diode can only conduct in theforward direction), i.e., Vo > 0→ Vi = Vo > 0 V .

M. B. Patil, IIT Bombay

Page 7: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Half-wave precision rectifier

DR

Vi

Vo

R

VDVi

Vo1

Vo

iR

i−iD

slope=1

Vi

Vo

Consider two cases:

(i) D is conducting: The feedback loop is closed, and the circuit looks like (exceptfor the diode drop) the buffer we have seen earlier.

Since the input current i− ≈ 0, iR = iD .

Further, V+ − V− =Vo1

AV=

Vo + 0.7 V

AV≈ 0 V → Vo = Vi .

This situation arises only if iD > 0 (since the diode can only conduct in theforward direction), i.e., Vo > 0→ Vi = Vo > 0 V .

M. B. Patil, IIT Bombay

Page 8: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Half-wave precision rectifier

DR

Vi

Vo

R

VDVi

Vo1

Vo

iR

i−iD

slope=1

Vi

Vo

Consider two cases:

(i) D is conducting: The feedback loop is closed, and the circuit looks like (exceptfor the diode drop) the buffer we have seen earlier.

Since the input current i− ≈ 0, iR = iD .

Further, V+ − V− =Vo1

AV=

Vo + 0.7 V

AV≈ 0 V → Vo = Vi .

This situation arises only if iD > 0 (since the diode can only conduct in theforward direction), i.e., Vo > 0→ Vi = Vo > 0 V .

M. B. Patil, IIT Bombay

Page 9: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Half-wave precision rectifier

DR

Vi

Vo

R

VDVi

Vo1

Vo

iR

i−iD

slope=1

Vi

Vo

Consider two cases:

(i) D is conducting: The feedback loop is closed, and the circuit looks like (exceptfor the diode drop) the buffer we have seen earlier.

Since the input current i− ≈ 0, iR = iD .

Further, V+ − V− =Vo1

AV=

Vo + 0.7 V

AV≈ 0 V → Vo = Vi .

This situation arises only if iD > 0 (since the diode can only conduct in theforward direction), i.e., Vo > 0→ Vi = Vo > 0 V .

M. B. Patil, IIT Bombay

Page 10: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Half-wave precision rectifier

DR

Vi

Vo

R

ViVo1

Vo

Vi

Vo

Vo = 0

(ii) D is not conducting → Vo = 0 V .

What about Vo1?

Since the Op Amp is now in the open-loop configuration, a very small Vi isenough to drive it to saturation.

Note that Case (ii) occurs when Vi < 0 V . Since V+ − V− = Vi − 0 = Vi isnegative, Vo1 is driven to −V sat.

M. B. Patil, IIT Bombay

Page 11: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Half-wave precision rectifier

DR

Vi

Vo

R

ViVo1

Vo

Vi

Vo

Vo = 0

(ii) D is not conducting → Vo = 0 V .

What about Vo1?

Since the Op Amp is now in the open-loop configuration, a very small Vi isenough to drive it to saturation.

Note that Case (ii) occurs when Vi < 0 V . Since V+ − V− = Vi − 0 = Vi isnegative, Vo1 is driven to −V sat.

M. B. Patil, IIT Bombay

Page 12: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Half-wave precision rectifier

DR

Vi

Vo

R

ViVo1

Vo

Vi

Vo

Vo = 0

(ii) D is not conducting → Vo = 0 V .

What about Vo1?

Since the Op Amp is now in the open-loop configuration, a very small Vi isenough to drive it to saturation.

Note that Case (ii) occurs when Vi < 0 V . Since V+ − V− = Vi − 0 = Vi isnegative, Vo1 is driven to −V sat.

M. B. Patil, IIT Bombay

Page 13: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Half-wave precision rectifier

DR

Vi

Vo

R

ViVo1

Vo

Vi

Vo

Vo = 0

(ii) D is not conducting → Vo = 0 V .

What about Vo1?

Since the Op Amp is now in the open-loop configuration, a very small Vi isenough to drive it to saturation.

Note that Case (ii) occurs when Vi < 0 V . Since V+ − V− = Vi − 0 = Vi isnegative, Vo1 is driven to −V sat.

M. B. Patil, IIT Bombay

Page 14: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Half-wave precision rectifier

DR

Vi

Vo

R

ViVo1

Vo

Vi

Vo

Vo = 0

(ii) D is not conducting → Vo = 0 V .

What about Vo1?

Since the Op Amp is now in the open-loop configuration, a very small Vi isenough to drive it to saturation.

Note that Case (ii) occurs when Vi < 0 V . Since V+ − V− = Vi − 0 = Vi isnegative, Vo1 is driven to −V sat.

M. B. Patil, IIT Bombay

Page 15: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Half-wave precision rectifier

superdiode

D

2

0

−2

−4

−6

−8

−10

−12

D onD off

t (ms) 1 2 0

R

Vo1 Vo

Vi

Vo

Vo = 0

Vo = Vi

Vi

Vo

Vi

−Vsat

Vo1

* The circuit is called a “superdiode” (i.e., a diode with zero Von).

* Note that the Op Amp needs to come out of saturation when Vi changes fromnegative to positive values. This is a relatively slow process, and it limits thespeed of this circuit.

SEQUEL file: precision half wave 1.sqproj

M. B. Patil, IIT Bombay

Page 16: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Half-wave precision rectifier

superdiode

D

2

0

−2

−4

−6

−8

−10

−12

D onD off

t (ms) 1 2 0

R

Vo1 Vo

Vi

Vo

Vo = 0

Vo = Vi

Vi

Vo

Vi

−Vsat

Vo1

* The circuit is called a “superdiode” (i.e., a diode with zero Von).

* Note that the Op Amp needs to come out of saturation when Vi changes fromnegative to positive values. This is a relatively slow process, and it limits thespeed of this circuit.

SEQUEL file: precision half wave 1.sqproj

M. B. Patil, IIT Bombay

Page 17: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Half-wave precision rectifier

superdiode

D

2

0

−2

−4

−6

−8

−10

−12

D onD off

t (ms) 1 2 0

R

Vo1 Vo

Vi

Vo

Vo = 0

Vo = Vi

Vi

Vo

Vi

−Vsat

Vo1

* The circuit is called a “superdiode” (i.e., a diode with zero Von).

* Note that the Op Amp needs to come out of saturation when Vi changes fromnegative to positive values. This is a relatively slow process, and it limits thespeed of this circuit.

SEQUEL file: precision half wave 1.sqproj

M. B. Patil, IIT Bombay

Page 18: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Half-wave precision rectifier

superdiode

D

2

0

−2

−4

−6

−8

−10

−12

D onD off

t (ms) 1 2 0

R

Vo1 Vo

Vi

Vo

Vo = 0

Vo = Vi

Vi

Vo

Vi

−Vsat

Vo1

* The circuit is called a “superdiode” (i.e., a diode with zero Von).

* Note that the Op Amp needs to come out of saturation when Vi changes fromnegative to positive values. This is a relatively slow process, and it limits thespeed of this circuit.

SEQUEL file: precision half wave 1.sqproj

M. B. Patil, IIT Bombay

Page 19: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Improved half-wave precision rectifier

iR2

iR1iD2

iD1

R

Vo

iR

R1

R2

D2

D1

ViVo1

R

Vi > 0

VoR1

D2

D1

ViVo1

R2

R

Vi < 0

VoR1

D2

D1

ViVo1

R2

(i) D1 conducts: V− = V+ = 0 V , Vo1 = −VD1 ≈ −0.7 V .

D2 cannot conduct (show that, if it did, KCL is not satisfied at Vo).→ iR2 = 0, Vo = V− = 0 V .

iR1 = iD1 which can only be positive ⇒ Vi > 0 V .

(ii) D1 is off; this will happen when Vi < 0 V .

In this case, D2 conducts and closes the feedback loop through R2.

Vo = V− + iR2R2 = 0 +

„0− Vi

R1

«R2 = −R2

R1Vi .

M. B. Patil, IIT Bombay

Page 20: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Improved half-wave precision rectifier

iR2

iR1iD2

iD1

R

Vo

iR

R1

R2

D2

D1

ViVo1

R

Vi > 0

VoR1

D2

D1

ViVo1

R2

R

Vi < 0

VoR1

D2

D1

ViVo1

R2

(i) D1 conducts: V− = V+ = 0 V , Vo1 = −VD1 ≈ −0.7 V .

D2 cannot conduct (show that, if it did, KCL is not satisfied at Vo).→ iR2 = 0, Vo = V− = 0 V .

iR1 = iD1 which can only be positive ⇒ Vi > 0 V .

(ii) D1 is off; this will happen when Vi < 0 V .

In this case, D2 conducts and closes the feedback loop through R2.

Vo = V− + iR2R2 = 0 +

„0− Vi

R1

«R2 = −R2

R1Vi .

M. B. Patil, IIT Bombay

Page 21: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Improved half-wave precision rectifier

iR2

iR1iD2

iD1

R

Vo

iR

R1

R2

D2

D1

ViVo1

R

Vi > 0

VoR1

D2

D1

ViVo1

R2

R

Vi < 0

VoR1

D2

D1

ViVo1

R2

(i) D1 conducts: V− = V+ = 0 V , Vo1 = −VD1 ≈ −0.7 V .

D2 cannot conduct (show that, if it did, KCL is not satisfied at Vo).→ iR2 = 0, Vo = V− = 0 V .

iR1 = iD1 which can only be positive ⇒ Vi > 0 V .

(ii) D1 is off; this will happen when Vi < 0 V .

In this case, D2 conducts and closes the feedback loop through R2.

Vo = V− + iR2R2 = 0 +

„0− Vi

R1

«R2 = −R2

R1Vi .

M. B. Patil, IIT Bombay

Page 22: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Improved half-wave precision rectifier

iR2

iR1iD2

iD1

R

Vo

iR

R1

R2

D2

D1

ViVo1

R

Vi > 0

VoR1

D2

D1

ViVo1

R2

R

Vi < 0

VoR1

D2

D1

ViVo1

R2

(i) D1 conducts: V− = V+ = 0 V , Vo1 = −VD1 ≈ −0.7 V .

D2 cannot conduct (show that, if it did, KCL is not satisfied at Vo).→ iR2 = 0, Vo = V− = 0 V .

iR1 = iD1 which can only be positive ⇒ Vi > 0 V .

(ii) D1 is off; this will happen when Vi < 0 V .

In this case, D2 conducts and closes the feedback loop through R2.

Vo = V− + iR2R2 = 0 +

„0− Vi

R1

«R2 = −R2

R1Vi .

M. B. Patil, IIT Bombay

Page 23: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Improved half-wave precision rectifier

iR2

iR1iD2

iD1

R

Vo

iR

R1

R2

D2

D1

ViVo1

R

Vi > 0

VoR1

D2

D1

ViVo1

R2

R

Vi < 0

VoR1

D2

D1

ViVo1

R2

(i) D1 conducts: V− = V+ = 0 V , Vo1 = −VD1 ≈ −0.7 V .

D2 cannot conduct (show that, if it did, KCL is not satisfied at Vo).→ iR2 = 0, Vo = V− = 0 V .

iR1 = iD1 which can only be positive ⇒ Vi > 0 V .

(ii) D1 is off; this will happen when Vi < 0 V .

In this case, D2 conducts and closes the feedback loop through R2.

Vo = V− + iR2R2 = 0 +

„0− Vi

R1

«R2 = −R2

R1Vi .

M. B. Patil, IIT Bombay

Page 24: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Improved half-wave precision rectifier

iR2

iR1iD2

iD1

R

Vo

iR

R1

R2

D2

D1

ViVo1

R

Vi > 0

VoR1

D2

D1

ViVo1

R2

R

Vi < 0

VoR1

D2

D1

ViVo1

R2

(i) D1 conducts: V− = V+ = 0 V , Vo1 = −VD1 ≈ −0.7 V .

D2 cannot conduct (show that, if it did, KCL is not satisfied at Vo).→ iR2 = 0, Vo = V− = 0 V .

iR1 = iD1 which can only be positive ⇒ Vi > 0 V .

(ii) D1 is off; this will happen when Vi < 0 V .

In this case, D2 conducts and closes the feedback loop through R2.

Vo = V− + iR2R2 = 0 +

„0− Vi

R1

«R2 = −R2

R1Vi .

M. B. Patil, IIT Bombay

Page 25: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Improved half-wave precision rectifier

iR2

iR1iD2

iD1

R

Vo

iR

R1

R2

D2

D1

ViVo1

R

Vi > 0

VoR1

D2

D1

ViVo1

R2

R

Vi < 0

VoR1

D2

D1

ViVo1

R2

(i) D1 conducts: V− = V+ = 0 V , Vo1 = −VD1 ≈ −0.7 V .

D2 cannot conduct (show that, if it did, KCL is not satisfied at Vo).→ iR2 = 0, Vo = V− = 0 V .

iR1 = iD1 which can only be positive ⇒ Vi > 0 V .

(ii) D1 is off; this will happen when Vi < 0 V .

In this case, D2 conducts and closes the feedback loop through R2.

Vo = V− + iR2R2 = 0 +

„0− Vi

R1

«R2 = −R2

R1Vi .

M. B. Patil, IIT Bombay

Page 26: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Improved half-wave precision rectifier

iR2

iR1iD2

iD1

R

Vo

iR

R1

R2

D2

D1

ViVo1

R

Vi > 0

VoR1

D2

D1

ViVo1

R2

R

Vi < 0

VoR1

D2

D1

ViVo1

R2

(i) D1 conducts: V− = V+ = 0 V , Vo1 = −VD1 ≈ −0.7 V .

D2 cannot conduct (show that, if it did, KCL is not satisfied at Vo).→ iR2 = 0, Vo = V− = 0 V .

iR1 = iD1 which can only be positive ⇒ Vi > 0 V .

(ii) D1 is off; this will happen when Vi < 0 V .

In this case, D2 conducts and closes the feedback loop through R2.

Vo = V− + iR2R2 = 0 +

„0− Vi

R1

«R2 = −R2

R1Vi .

M. B. Patil, IIT Bombay

Page 27: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Improved half-wave precision rectifier

1 k

1 k

R

VoR1

D2

D1

Vi

Vo1

R2

Vo

Vi

Vo = 0

−R2

R1Vi

2

1

0

−1

t (ms) 1 2 0

VoVi

Vo1

* Note that the Op Amp does not enter saturation since a feedback path isavailable for Vi > 0 V and Vi < 0 V .

SEQUEL file: precision half wave.sqproj

M. B. Patil, IIT Bombay

Page 28: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Improved half-wave precision rectifier

1 k

1 k

R

VoR1

D2

D1

Vi

Vo1

R2

Vo

Vi

Vo = 0

−R2

R1Vi

2

1

0

−1

t (ms) 1 2 0

VoVi

Vo1

* Note that the Op Amp does not enter saturation since a feedback path isavailable for Vi > 0 V and Vi < 0 V .

SEQUEL file: precision half wave.sqproj

M. B. Patil, IIT Bombay

Page 29: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Improved half-wave precision rectifier

1 k

1 k

R

VoR1

D2

D1

Vi

Vo1

R2

Vo

Vi

Vo = 0

−R2

R1Vi

2

1

0

−1

t (ms) 1 2 0

VoVi

Vo1

* Note that the Op Amp does not enter saturation since a feedback path isavailable for Vi > 0 V and Vi < 0 V .

SEQUEL file: precision half wave.sqproj

M. B. Patil, IIT Bombay

Page 30: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Improved half-wave precision rectifier

1 k

1 k

R

VoR1

D2

D1

Vi

Vo1

R2

Vo

Vi

Vo = 0

−R2

R1Vi

2

1

0

−1

t (ms) 1 2 0

VoVi

Vo1

* Note that the Op Amp does not enter saturation since a feedback path isavailable for Vi > 0 V and Vi < 0 V .

SEQUEL file: precision half wave.sqproj

M. B. Patil, IIT Bombay

Page 31: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Improved half-wave precision rectifier

1 k

1 k

R

VoR1

D2

D1

Vi

Vo1

R2

Vo

Vi

Vo = 0

−R2

R1Vi

2

1

0

−1

t (ms) 1 2 0

VoVi

Vo1

* Note that the Op Amp does not enter saturation since a feedback path isavailable for Vi > 0 V and Vi < 0 V .

SEQUEL file: precision half wave.sqproj

M. B. Patil, IIT Bombay

Page 32: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Improved half-wave precision rectifier

R

VoR1

D2

D1

Vi

Vo1

R2

Vi

Vo = 0

Vo

−R2

R1Vi

The diodes are now reversed.

By considering two cases: (i) D1 on, (ii) D1 off, the Vo versus Vi relationship shown inthe figure is obtained (show this).

SEQUEL file: precision half wave 2.sqproj

M. B. Patil, IIT Bombay

Page 33: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Improved half-wave precision rectifier

R

VoR1

D2

D1

Vi

Vo1

R2

Vi

Vo = 0

Vo

−R2

R1Vi

The diodes are now reversed.

By considering two cases: (i) D1 on, (ii) D1 off, the Vo versus Vi relationship shown inthe figure is obtained (show this).

SEQUEL file: precision half wave 2.sqproj

M. B. Patil, IIT Bombay

Page 34: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Improved half-wave precision rectifier

R

VoR1

D2

D1

Vi

Vo1

R2

Vi

Vo = 0

Vo

−R2

R1Vi

The diodes are now reversed.

By considering two cases: (i) D1 on, (ii) D1 off, the Vo versus Vi relationship shown inthe figure is obtained (show this).

SEQUEL file: precision half wave 2.sqproj

M. B. Patil, IIT Bombay

Page 35: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

AM demodulation using a peak detector

AMsignal

Superdiode

filter

−0.15

0

0.15

t (ms) 1 2 0

Vo2

Vi

Vo1

Vo1

* charging through superdiode, discharging through resistor

* The time constant (RC) needs to be carefully selected.

SEQUEL file: super diode.sqproj

M. B. Patil, IIT Bombay

Page 36: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

AM demodulation using a peak detector

AMsignal

Superdiode

filter

−0.15

0

0.15

t (ms) 1 2 0

Vo2

Vi

Vo1

Vo1

* charging through superdiode, discharging through resistor

* The time constant (RC) needs to be carefully selected.

SEQUEL file: super diode.sqproj

M. B. Patil, IIT Bombay

Page 37: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

AM demodulation using a peak detector

AMsignal

Superdiode

filter

−0.15

0

0.15

t (ms) 1 2 0

Vo2

Vi

Vo1

Vo1

* charging through superdiode, discharging through resistor

* The time constant (RC) needs to be carefully selected.

SEQUEL file: super diode.sqproj

M. B. Patil, IIT Bombay

Page 38: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

AM demodulation using a peak detector

AMsignal

Superdiode

filter

−0.15

0

0.15

t (ms) 1 2 0

Vo2

Vi

Vo1

Vo1

* charging through superdiode, discharging through resistor

* The time constant (RC) needs to be carefully selected.

SEQUEL file: super diode.sqproj

M. B. Patil, IIT Bombay

Page 39: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Full-wave precision rectifier

Half−waverectifier(inverting)

x (−1)

x (−2)Vo1 Vo

Vi

Vi

Vo1

Vi

VB

Vi

VA

Vi

Vo

VA

VB

(SEQUEL file: precision_full_wave.sqproj)

R

R/2

R

inverting summerinverting half−wave rectifier

VoR1

D2

D1

R1

ViVo1

−2

−1

0

1

2

t (ms) 1 2 0

ViVo

M. B. Patil, IIT Bombay

Page 40: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Full-wave precision rectifier

Half−waverectifier(inverting)

x (−1)

x (−2)Vo1 Vo

Vi

Vi

Vo1

Vi

VB

Vi

VA

Vi

Vo

VA

VB

(SEQUEL file: precision_full_wave.sqproj)

R

R/2

R

inverting summerinverting half−wave rectifier

VoR1

D2

D1

R1

ViVo1

−2

−1

0

1

2

t (ms) 1 2 0

ViVo

M. B. Patil, IIT Bombay

Page 41: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Full-wave precision rectifier

Half−waverectifier(inverting)

x (−1)

x (−2)Vo1 Vo

Vi

Vi

Vo1

Vi

VB

Vi

VA

Vi

Vo

VA

VB

(SEQUEL file: precision_full_wave.sqproj)

R

R/2

R

inverting summerinverting half−wave rectifier

VoR1

D2

D1

R1

ViVo1

−2

−1

0

1

2

t (ms) 1 2 0

ViVo

M. B. Patil, IIT Bombay

Page 42: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

D

A

R

i

R′

R0

−V0

V0 V

D off

A

R

i

R′

R0

−V0

V0 V

D on

A

R

i

R′

R0

−V0

V0 V

Von

i

V

Vbreakslope = R0 ‖ R

slope = R0

When D is off, VA is (by superposition),

VA = VR′

R + R′ − V0R

R + R′ .

For D to turn on, VA = Von ≈ 0.7 V → V ≡ Vbreak =R

R′ (V0 + Von) + Von .

When D is on,

i =V

R0+

V − Von

R+−V0 − Von

R′

= V

»1

R0+

1

R

–+ (constant)

i.e., V = (R0 ‖ R) i + (constant) .

M. B. Patil, IIT Bombay

Page 43: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

D

A

R

i

R′

R0

−V0

V0 V D off

A

R

i

R′

R0

−V0

V0 V

D on

A

R

i

R′

R0

−V0

V0 V

Von

i

V

Vbreakslope = R0 ‖ R

slope = R0

When D is off, VA is (by superposition),

VA = VR′

R + R′ − V0R

R + R′ .

For D to turn on, VA = Von ≈ 0.7 V → V ≡ Vbreak =R

R′ (V0 + Von) + Von .

When D is on,

i =V

R0+

V − Von

R+−V0 − Von

R′

= V

»1

R0+

1

R

–+ (constant)

i.e., V = (R0 ‖ R) i + (constant) .

M. B. Patil, IIT Bombay

Page 44: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

D

A

R

i

R′

R0

−V0

V0 V D off

A

R

i

R′

R0

−V0

V0 V

D on

A

R

i

R′

R0

−V0

V0 V

Von

i

V

Vbreakslope = R0 ‖ R

slope = R0

When D is off, VA is (by superposition),

VA = VR′

R + R′ − V0R

R + R′ .

For D to turn on, VA = Von ≈ 0.7 V → V ≡ Vbreak =R

R′ (V0 + Von) + Von .

When D is on,

i =V

R0+

V − Von

R+−V0 − Von

R′

= V

»1

R0+

1

R

–+ (constant)

i.e., V = (R0 ‖ R) i + (constant) .

M. B. Patil, IIT Bombay

Page 45: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

D

A

R

i

R′

R0

−V0

V0 V D off

A

R

i

R′

R0

−V0

V0 V

D on

A

R

i

R′

R0

−V0

V0 V

Von

i

V

Vbreakslope = R0 ‖ R

slope = R0

When D is off, VA is (by superposition),

VA = VR′

R + R′ − V0R

R + R′ .

For D to turn on, VA = Von ≈ 0.7 V → V ≡ Vbreak =R

R′ (V0 + Von) + Von .

When D is on,

i =V

R0+

V − Von

R+−V0 − Von

R′

= V

»1

R0+

1

R

–+ (constant)

i.e., V = (R0 ‖ R) i + (constant) .

M. B. Patil, IIT Bombay

Page 46: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

D

A

R

i

R′

R0

−V0

V0 V D off

A

R

i

R′

R0

−V0

V0 V

D on

A

R

i

R′

R0

−V0

V0 V

Von

i

V

Vbreakslope = R0 ‖ R

slope = R0

When D is off, VA is (by superposition),

VA = VR′

R + R′ − V0R

R + R′ .

For D to turn on, VA = Von ≈ 0.7 V → V ≡ Vbreak =R

R′ (V0 + Von) + Von .

When D is on,

i =V

R0+

V − Von

R+−V0 − Von

R′

= V

»1

R0+

1

R

–+ (constant)

i.e., V = (R0 ‖ R) i + (constant) .

M. B. Patil, IIT Bombay

Page 47: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

D

A

R

i

R′

R0

−V0

V0 V D off

A

R

i

R′

R0

−V0

V0 V

D on

A

R

i

R′

R0

−V0

V0 V

Von

i

V

Vbreakslope = R0 ‖ R

slope = R0

When D is off, VA is (by superposition),

VA = VR′

R + R′ − V0R

R + R′ .

For D to turn on, VA = Von ≈ 0.7 V → V ≡ Vbreak =R

R′ (V0 + Von) + Von .

When D is on,

i =V

R0+

V − Von

R+−V0 − Von

R′

= V

»1

R0+

1

R

–+ (constant)

i.e., V = (R0 ‖ R) i + (constant) .

M. B. Patil, IIT Bombay

Page 48: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

D

A

R

i

R′

R0

−V0

V0 V D off

A

R

i

R′

R0

−V0

V0 V

D on

A

R

i

R′

R0

−V0

V0 V

Von

i

V

Vbreakslope = R0 ‖ R

slope = R0

When D is off, VA is (by superposition),

VA = VR′

R + R′ − V0R

R + R′ .

For D to turn on, VA = Von ≈ 0.7 V → V ≡ Vbreak =R

R′ (V0 + Von) + Von .

When D is on,

i =V

R0+

V − Von

R+−V0 − Von

R′

= V

»1

R0+

1

R

–+ (constant)

i.e., V = (R0 ‖ R) i + (constant) .

M. B. Patil, IIT Bombay

Page 49: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

D

A

R

i

R′

R0

−V0

V0 V D off

A

R

i

R′

R0

−V0

V0 V

D on

A

R

i

R′

R0

−V0

V0 V

Von

i

V

Vbreakslope = R0 ‖ R

slope = R0

When D is off, VA is (by superposition),

VA = VR′

R + R′ − V0R

R + R′ .

For D to turn on, VA = Von ≈ 0.7 V → V ≡ Vbreak =R

R′ (V0 + Von) + Von .

When D is on,

i =V

R0+

V − Von

R+−V0 − Von

R′

= V

»1

R0+

1

R

–+ (constant)

i.e., V = (R0 ‖ R) i + (constant) .

M. B. Patil, IIT Bombay

Page 50: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

i

0 V

R0

V

i

V

D1B R1B

R1B

i

−V0

0 V

R0

Vi

V

D2B R2B

R2B

i

V

D1A R1A

R1A

V0

i

V

D2A R2A

R2A

i

V

D1B

D2B

D2A

D1A

R1A

R2A

R1B

R2B

R1B

R2B

RL

Vo

i

R2A

R1A

i

V0

Ra

−V0

R0

Vi

Ra = 5 k

R0 = 20 k

R1A = R1B = 15 k

R2A = R2B = 5 k

R1A′ = R1B′ = 60 k

R2A′ = R2B′ = 10 k

V0 = 15 V

−100 5−5

−5

0

5

10

Vi (V)

Vo

(V)

20 4 6 8

10

−10

0

time (msec)

Vi

Vo

Since Vi = −Ra i , the Vo versus Vi plot is similar to the V versus i plot, except for the (−Ra) factor.

SEQUEL file: ee101 wave shaper.sqproj

M. B. Patil, IIT Bombay

Page 51: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

i

0 V

R0

Vi

V

D1B R1B

R1B

i

−V0

0 V

R0

Vi

V

D2B R2B

R2B

i

V

D1A R1A

R1A

V0

i

V

D2A R2A

R2A

i

V

D1B

D2B

D2A

D1A

R1A

R2A

R1B

R2B

R1B

R2B

RL

Vo

i

R2A

R1A

i

V0

Ra

−V0

R0

Vi

Ra = 5 k

R0 = 20 k

R1A = R1B = 15 k

R2A = R2B = 5 k

R1A′ = R1B′ = 60 k

R2A′ = R2B′ = 10 k

V0 = 15 V

−100 5−5

−5

0

5

10

Vi (V)

Vo

(V)

20 4 6 8

10

−10

0

time (msec)

Vi

Vo

Since Vi = −Ra i , the Vo versus Vi plot is similar to the V versus i plot, except for the (−Ra) factor.

SEQUEL file: ee101 wave shaper.sqproj

M. B. Patil, IIT Bombay

Page 52: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

i

0 V

R0

Vi

V

D1B R1B

R1B

i

−V0

0 V

R0

V

i

V

D2B R2B

R2B

i

V

D1A R1A

R1A

V0

i

V

D2A R2A

R2A

i

V

D1B

D2B

D2A

D1A

R1A

R2A

R1B

R2B

R1B

R2B

RL

Vo

i

R2A

R1A

i

V0

Ra

−V0

R0

Vi

Ra = 5 k

R0 = 20 k

R1A = R1B = 15 k

R2A = R2B = 5 k

R1A′ = R1B′ = 60 k

R2A′ = R2B′ = 10 k

V0 = 15 V

−100 5−5

−5

0

5

10

Vi (V)

Vo

(V)

20 4 6 8

10

−10

0

time (msec)

Vi

Vo

Since Vi = −Ra i , the Vo versus Vi plot is similar to the V versus i plot, except for the (−Ra) factor.

SEQUEL file: ee101 wave shaper.sqproj

M. B. Patil, IIT Bombay

Page 53: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

i

0 V

R0

Vi

V

D1B R1B

R1B

i

−V0

0 V

R0

Vi

V

D2B R2B

R2B

i

V

D1A R1A

R1A

V0

i

V

D2A R2A

R2A

i

V

D1B

D2B

D2A

D1A

R1A

R2A

R1B

R2B

R1B

R2B

RL

Vo

i

R2A

R1A

i

V0

Ra

−V0

R0

Vi

Ra = 5 k

R0 = 20 k

R1A = R1B = 15 k

R2A = R2B = 5 k

R1A′ = R1B′ = 60 k

R2A′ = R2B′ = 10 k

V0 = 15 V

−100 5−5

−5

0

5

10

Vi (V)

Vo

(V)

20 4 6 8

10

−10

0

time (msec)

Vi

Vo

Since Vi = −Ra i , the Vo versus Vi plot is similar to the V versus i plot, except for the (−Ra) factor.

SEQUEL file: ee101 wave shaper.sqproj

M. B. Patil, IIT Bombay

Page 54: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

i

0 V

R0

Vi

V

D1B R1B

R1B

i

−V0

0 V

R0

Vi

V

D2B R2B

R2B

i

V

D1A R1A

R1A

V0

i

V

D2A R2A

R2A

i

V

D1B

D2B

D2A

D1A

R1A

R2A

R1B

R2B

R1B

R2B

RL

Vo

i

R2A

R1A

i

V0

Ra

−V0

R0

Vi

Ra = 5 k

R0 = 20 k

R1A = R1B = 15 k

R2A = R2B = 5 k

R1A′ = R1B′ = 60 k

R2A′ = R2B′ = 10 k

V0 = 15 V

−100 5−5

−5

0

5

10

Vi (V)

Vo

(V)

20 4 6 8

10

−10

0

time (msec)

Vi

Vo

Since Vi = −Ra i , the Vo versus Vi plot is similar to the V versus i plot, except for the (−Ra) factor.

SEQUEL file: ee101 wave shaper.sqproj

M. B. Patil, IIT Bombay

Page 55: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

i

0 V

R0

Vi

V

D1B R1B

R1B

i

−V0

0 V

R0

Vi

V

D2B R2B

R2B

i

V

D1A R1A

R1A

V0

i

V

D2A R2A

R2A

i

V

D1B

D2B

D2A

D1A

R1A

R2A

R1B

R2B

R1B

R2B

RL

Vo

i

R2A

R1A

i

V0

Ra

−V0

R0

Vi

Ra = 5 k

R0 = 20 k

R1A = R1B = 15 k

R2A = R2B = 5 k

R1A′ = R1B′ = 60 k

R2A′ = R2B′ = 10 k

V0 = 15 V

−100 5−5

−5

0

5

10

Vi (V)

Vo

(V)

20 4 6 8

10

−10

0

time (msec)

Vi

Vo

Since Vi = −Ra i , the Vo versus Vi plot is similar to the V versus i plot, except for the (−Ra) factor.

SEQUEL file: ee101 wave shaper.sqproj

M. B. Patil, IIT Bombay

Page 56: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

i

0 V

R0

Vi

V

D1B R1B

R1B

i

−V0

0 V

R0

Vi

V

D2B R2B

R2B

i

V

D1A R1A

R1A

V0

i

V

D2A R2A

R2A

i

V

D1B

D2B

D2A

D1A

R1A

R2A

R1B

R2B

R1B

R2B

RL

Vo

i

R2A

R1A

i

V0

Ra

−V0

R0

Vi

Ra = 5 k

R0 = 20 k

R1A = R1B = 15 k

R2A = R2B = 5 k

R1A′ = R1B′ = 60 k

R2A′ = R2B′ = 10 k

V0 = 15 V

−100 5−5

−5

0

5

10

Vi (V)

Vo

(V)

20 4 6 8

10

−10

0

time (msec)

Vi

Vo

Since Vi = −Ra i , the Vo versus Vi plot is similar to the V versus i plot, except for the (−Ra) factor.

SEQUEL file: ee101 wave shaper.sqproj

M. B. Patil, IIT Bombay

Page 57: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

i

0 V

R0

Vi

V

D1B R1B

R1B

i

−V0

0 V

R0

Vi

V

D2B R2B

R2B

i

V

D1A R1A

R1A

V0

i

V

D2A R2A

R2A

i

V

D1B

D2B

D2A

D1A

R1A

R2A

R1B

R2B

R1B

R2B

RL

Vo

i

R2A

R1A

i

V0

Ra

−V0

R0

Vi

Ra = 5 k

R0 = 20 k

R1A = R1B = 15 k

R2A = R2B = 5 k

R1A′ = R1B′ = 60 k

R2A′ = R2B′ = 10 k

V0 = 15 V

−100 5−5

−5

0

5

10

Vi (V)

Vo

(V)

20 4 6 8

10

−10

0

time (msec)

Vi

Vo

Since Vi = −Ra i , the Vo versus Vi plot is similar to the V versus i plot, except for the (−Ra) factor.

SEQUEL file: ee101 wave shaper.sqproj

M. B. Patil, IIT Bombay

Page 58: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

i

0 V

R0

Vi

V

D1B R1B

R1B

i

−V0

0 V

R0

Vi

V

D2B R2B

R2B

i

V

D1A R1A

R1A

V0

i

V

D2A R2A

R2A

i

V

D1B

D2B

D2A

D1A

R1A

R2A

R1B

R2B

R1B

R2B

RL

Vo

i

R2A

R1A

i

V0

Ra

−V0

R0

Vi

Ra = 5 k

R0 = 20 k

R1A = R1B = 15 k

R2A = R2B = 5 k

R1A′ = R1B′ = 60 k

R2A′ = R2B′ = 10 k

V0 = 15 V

−100 5−5

−5

0

5

10

Vi (V)

Vo

(V)

20 4 6 8

10

−10

0

time (msec)

Vi

Vo

Since Vi = −Ra i , the Vo versus Vi plot is similar to the V versus i plot, except for the (−Ra) factor.

SEQUEL file: ee101 wave shaper.sqproj

M. B. Patil, IIT Bombay

Page 59: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

i

0 V

R0

Vi

V

D1B R1B

R1B

i

−V0

0 V

R0

Vi

V

D2B R2B

R2B

i

V

D1A R1A

R1A

V0

i

V

D2A R2A

R2A

i

V

D1B

D2B

D2A

D1A

R1A

R2A

R1B

R2B

R1B

R2B

RL

Vo

i

R2A

R1A

i

V0

Ra

−V0

R0

Vi

Ra = 5 k

R0 = 20 k

R1A = R1B = 15 k

R2A = R2B = 5 k

R1A′ = R1B′ = 60 k

R2A′ = R2B′ = 10 k

V0 = 15 V

−100 5−5

−5

0

5

10

Vi (V)

Vo

(V)

20 4 6 8

10

−10

0

time (msec)

Vi

Vo

Since Vi = −Ra i , the Vo versus Vi plot is similar to the V versus i plot, except for the (−Ra) factor.

SEQUEL file: ee101 wave shaper.sqproj

M. B. Patil, IIT Bombay

Page 60: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

i

0 V

R0

Vi

V

D1B R1B

R1B

i

−V0

0 V

R0

Vi

V

D2B R2B

R2B

i

V

D1A R1A

R1A

V0

i

V

D2A R2A

R2A

i

V

D1B

D2B

D2A

D1A

R1A

R2A

R1B

R2B

R1B

R2B

RL

Vo

i

R2A

R1A

i

V0

Ra

−V0

R0

Vi

Ra = 5 k

R0 = 20 k

R1A = R1B = 15 k

R2A = R2B = 5 k

R1A′ = R1B′ = 60 k

R2A′ = R2B′ = 10 k

V0 = 15 V

−100 5−5

−5

0

5

10

Vi (V)

Vo

(V)

20 4 6 8

10

−10

0

time (msec)

Vi

Vo

Since Vi = −Ra i , the Vo versus Vi plot is similar to the V versus i plot, except for the (−Ra) factor.

SEQUEL file: ee101 wave shaper.sqproj

M. B. Patil, IIT Bombay

Page 61: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

i

0 V

R0

Vi

V

D1B R1B

R1B

i

−V0

0 V

R0

Vi

V

D2B R2B

R2B

i

V

D1A R1A

R1A

V0

i

V

D2A R2A

R2A

i

V

D1B

D2B

D2A

D1A

R1A

R2A

R1B

R2B

R1B

R2B

RL

Vo

i

R2A

R1A

i

V0

Ra

−V0

R0

Vi

Ra = 5 k

R0 = 20 k

R1A = R1B = 15 k

R2A = R2B = 5 k

R1A′ = R1B′ = 60 k

R2A′ = R2B′ = 10 k

V0 = 15 V

−100 5−5

−5

0

5

10

Vi (V)

Vo

(V)

20 4 6 8

10

−10

0

time (msec)

Vi

Vo

Since Vi = −Ra i , the Vo versus Vi plot is similar to the V versus i plot, except for the (−Ra) factor.

SEQUEL file: ee101 wave shaper.sqproj

M. B. Patil, IIT Bombay

Page 62: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

i

0 V

R0

Vi

V

D1B R1B

R1B

i

−V0

0 V

R0

Vi

V

D2B R2B

R2B

i

V

D1A R1A

R1A

V0

i

V

D2A R2A

R2A

i

V

D1B

D2B

D2A

D1A

R1A

R2A

R1B

R2B

R1B

R2B

RL

Vo

i

R2A

R1A

i

V0

Ra

−V0

R0

Vi

Ra = 5 k

R0 = 20 k

R1A = R1B = 15 k

R2A = R2B = 5 k

R1A′ = R1B′ = 60 k

R2A′ = R2B′ = 10 k

V0 = 15 V

−100 5−5

−5

0

5

10

Vi (V)

Vo

(V)

20 4 6 8

10

−10

0

time (msec)

Vi

Vo

Since Vi = −Ra i , the Vo versus Vi plot is similar to the V versus i plot, except for the (−Ra) factor.

SEQUEL file: ee101 wave shaper.sqproj

M. B. Patil, IIT Bombay

Page 63: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

i

0 V

R0

Vi

V

D1B R1B

R1B

i

−V0

0 V

R0

Vi

V

D2B R2B

R2B

i

V

D1A R1A

R1A

V0

i

V

D2A R2A

R2A

i

V

D1B

D2B

D2A

D1A

R1A

R2A

R1B

R2B

R1B

R2B

RL

Vo

i

R2A

R1A

i

V0

Ra

−V0

R0

Vi

Ra = 5 k

R0 = 20 k

R1A = R1B = 15 k

R2A = R2B = 5 k

R1A′ = R1B′ = 60 k

R2A′ = R2B′ = 10 k

V0 = 15 V

−100 5−5

−5

0

5

10

Vi (V)

Vo

(V)

20 4 6 8

10

−10

0

time (msec)

Vi

Vo

Since Vi = −Ra i , the Vo versus Vi plot is similar to the V versus i plot, except for the (−Ra) factor.

SEQUEL file: ee101 wave shaper.sqproj

M. B. Patil, IIT Bombay

Page 64: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes

i

0 V

R0

Vi

V

D1B R1B

R1B

i

−V0

0 V

R0

Vi

V

D2B R2B

R2B

i

V

D1A R1A

R1A

V0

i

V

D2A R2A

R2A

i

V

D1B

D2B

D2A

D1A

R1A

R2A

R1B

R2B

R1B

R2B

RL

Vo

i

R2A

R1A

i

V0

Ra

−V0

R0

Vi

Ra = 5 k

R0 = 20 k

R1A = R1B = 15 k

R2A = R2B = 5 k

R1A′ = R1B′ = 60 k

R2A′ = R2B′ = 10 k

V0 = 15 V

−100 5−5

−5

0

5

10

Vi (V)

Vo

(V)

20 4 6 8

10

−10

0

time (msec)

Vi

Vo

Since Vi = −Ra i , the Vo versus Vi plot is similar to the V versus i plot, except for the (−Ra) factor.

SEQUEL file: ee101 wave shaper.sqproj

M. B. Patil, IIT Bombay

Page 65: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes: spectrum

0

510

−10

0

Vi

20 4 6 8

10

−10

0

time (msec) N0 2 4 6 8 10

0

10

Vo

M. B. Patil, IIT Bombay

Page 66: EE101: Op Amp circuits (Part 4) - Indian Institute of ...sequel/ee101/ee101_opamp_4.pdf · EE101: Op Amp circuits (Part 4) M. B. Patil mbpatil@ee.iitb.ac.in sequel Department of Electrical

Wave shaping with diodes: spectrum

0

510

−10

0

Vi

20 4 6 8

10

−10

0

time (msec) N0 2 4 6 8 10

0

10

Vo

M. B. Patil, IIT Bombay