Amplifier circuit with overshoot suppression

Patent metadata

Field	Value
Publication number	US-9837967-B2
Application number	US-201514751152-A
Country	US
Kind code	B2
Filing date	Jun 26, 2015
Priority date	Oct 29, 2009
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

An amplifier circuit with an overshoot suppress scheme is provided. The amplifier circuit includes an input amplifier, an output amplifier and a diode device. The output amplifier is coupled to the input amplifier and outputs an output voltage. The diode device is coupled between an output end and an input end of the output amplifier. When a voltage difference between the output end and the input end of the output amplifier is greater than a barrier voltage of the diode device, the diode device is turned on, and an overshoot of the output voltage is reduced.

First claim

What is claimed is:

1. An amplifier circuit, comprising:
an input amplifier;
an output amplifier, comprising:
a PMOSFET having a gate electrode serving as a first input end and a drain coupled to an output end; and
an NMOSFET having a gate electrode serving as a second input end and a drain coupled to the output end, wherein the output amplifier outputting an output voltage at the output end and coupled to the input amplifier via at least one of the first and second input ends; and

a diode device coupled between the output end and the at least one of the first and second input ends of the output amplifier, wherein when a voltage difference between the output end and the at least one of the first and second input ends of the output amplifier is greater than a barrier voltage of the diode device, the diode device is turned on, and an overshoot of the output voltage is reduced.

2. The amplifier circuit as claimed in claim 1 , wherein the diode device comprises a diode, an anode of the diode is coupled to the output end of the output amplifier, and a cathode of the diode is coupled to the at least one of the first and second input ends of the output amplifier.

3. The amplifier circuit as claimed in claim 1 , wherein the diode device comprises a diode, an anode of the diode is coupled to the at least one of the first and second input ends of the output amplifier, and a cathode of the diode is coupled to the output end of the output amplifier.

4. The amplifier circuit as claimed in claim 1 , wherein the diode device comprises a plurality of diodes, the diodes are coupled in series to form a diode string, an anode of the diode string is coupled to the at least one of the first and second input ends of the output amplifier, and a cathode of the diode string is coupled to the output end of the output amplifier.

5. The amplifier circuit as claimed in claim 1 , wherein the diode device comprises a plurality of diodes, the diodes are coupled in series to form a diode string, an anode of the diode string is coupled to the output end of the output amplifier, and a cathode of the diode string is coupled to the at least one of the first and second input ends of the output amplifier.

6. The amplifier circuit as claimed in claim 1 , wherein the diode device comprises:
a diode; and
a variable resistor, a first end of the variable resistor coupled to a first end of the diode, a second end of the diode serving as one of the first and the second ends of the diode device, and a second end of the variable resistor serving as the other one of the first and the second ends of the diode device.

7. The amplifier circuit as claimed in claim 1 , wherein the diode device comprises:
a plurality of diodes coupled in series to form a diode string; and
a variable resistor, a first end of the variable resistor coupled to a first end of the diode string, a second end of the diode string serving as one of the first and the second ends of the diode device, and a second end of the variable resistor serving as the other one of the first and the second ends of the diode device.

8. The amplifier circuit as claimed in claim 1 , wherein the diode device comprises:
a first diode;
a second diode; and
a variable resistor, a first end of the variable resistor coupled to a first end of the first diode, a second end of the variable resistor coupled to a first end of the second diode, a second end of the first diode serving as one of the first and the second ends of the diode device, and a second end of the second diode serving as the other one of the first and the second ends of the diode device.

9. The amplifier circuit as claimed in claim 1 , further comprising another diode device, wherein a first end of the another diode device is coupled to the output end of the output amplifier, and a second end of the another diode device is coupled to another input end of the output amplifier.

10. The amplifier circuit as claimed in claim 9 , wherein the another diode device comprises a diode, an anode of the diode is coupled to the output end of the output amplifier, and a cathode of the diode is coupled to the another input end of the output amplifier.

11. The amplifier circuit as claimed in claim 9 , wherein the another diode device comprises a diode, an anode of the diode is coupled to the another input end of the output amplifier, and a cathode of the diode is coupled to the output end of the output amplifier.

12. The amplifier circuit as claimed in claim 9 , wherein the another diode device comprises a plurality of diodes, the diodes are coupled in series to form a diode string, an anode of the diode string is coupled to the another input end of the output amplifier, and a cathode of the diode string is coupled to the output end of the output amplifier.

13. The amplifier circuit as claimed in claim 9 , wherein the another diode device comprises a plurality of diodes, the diodes are coupled in series to form a diode string, an anode of the diode string is coupled to the output end of the output amplifier, and a cathode of the diode string is coupled to the another input end of the output amplifier.

14. The amplifier circuit as claimed in claim 9 , wherein the another diode device comprises:
a diode; and
a variable resistor, a first end of the variable resistor coupled to a first end of the diode, a second end of the diode serving as one of the first and the second ends of the another diode device, and a second end of the variable resistor serving as the other one of the first and the second ends of the another diode device.

15. The amplifier circuit as claimed in claim 9 , wherein the another diode device comprises:
a plurality of diodes coupled in series to form a diode string; and
a variable resistor, a first end of the variable resistor coupled to a first end of the diode string, a second end of the diode string serving as one of the first and the second ends of the another diode device, and a second end of the variable resistor serving as the other one of the first and the second ends of the another diode device.

16. The amplifier circuit as claimed in claim 9 , wherein the another diode device comprises:
a first diode;
a second diode; and
a variable resistor, a first end of the variable resistor coupled to a first end of the first diode, a second end of the variable resistor coupled to a first end of the second diode, a second end of the first diode serving as one of the first and the second ends of the another diode device, and a second end of the second diode serving as the other one of the first and the second ends of the another diode device.

17. The amplifier circuit as claimed in claim 1 , wherein the amplifier circuit is an operational amplifier, the input amplifier is an input stage of the operational amplifier, and the output amplifier is an output stage of the operational amplifier.

18. The amplifier circuit as claimed in claim 1 , wherein
a source of the PMOSFET is coupled to a first voltage, and
a source of the NMOSFET is coupled to a second voltage.

19. The amplifier circuit as claimed in claim 18 , wherein the first voltage is a system voltage, and the second voltage is a ground voltage.

20. The amplifier circuit as claimed in claim 1 , wherein the output end of the output amplifier is coupled to a non-inverting input end of the input amplifier.

21. The amplifier circuit as claimed in claim 1 , wherein the input amplifier has an output pair and outputs two output voltages in phase to the output amplifier via

Assignees

• Novatek Microelectronics Corp

Inventors

• Su Chia-Wei
• Huang Ju-Lin
• Liang Keko-Chun

Classifications

• H03F2203/45654

  the LC comprising one or more extra diodes not belonging to mirrors · CPC title

• H03F2203/45658

  the LC comprising two diodes of current mirrors · CPC title

• H03F3/45475

  using IC blocks as the active amplifying circuit · CPC title

• H03F2200/153

  Feedback used to stabilise the amplifier · CPC title

• H03F1/52

  Circuit arrangements for protecting such amplifiers {(monitoring arrangements G01R31/28; increasing reliability in communication systems, e.g. using redundancy H04B1/74)} · CPC title