Amplifier circuit

Patent metadata

Field	Value
Publication number	US-11736070-B2
Application number	US-202117406248-A
Country	US
Kind code	B2
Filing date	Aug 19, 2021
Priority date	Nov 11, 2020
Publication date	Aug 22, 2023
Grant date	Aug 22, 2023

Abstract

An amplifier circuit includes a multistage amplifier, a first feedback circuit and a second feedback circuit. The multistage amplifier includes a first-staged amplifier, a last-staged amplifier and at least one middle-staged amplifier cascaded between the first-staged amplifier and the last-staged amplifier. The first feedback circuit is configured to couple a positive output end of the last-staged amplifier to a positive input end of the at least one middle-staged amplifier, or is configured to couple a negative output end of the last-staged amplifier to a negative input end of the at least one middle-staged amplifier. The second feedback circuit is configured to couple the positive output end of the last-staged amplifier to a positive input end of the last-staged amplifier, or is configured to couple the negative output end of the last-staged amplifier to a negative input end of the last-staged amplifier.

First claim

What is claimed is:

1. An amplifier circuit, comprising:
a multistage amplifier comprising a first-staged amplifier, a last-staged amplifier and at least one middle-staged amplifier cascaded between the first-staged amplifier and the last-staged amplifier;
a first feedback circuit configured to couple a positive output end of the last-staged amplifier to a positive input end of the at least one middle-staged amplifier, or configured to couple a negative output end of the last-staged amplifier to a negative input end of the at least one middle-staged amplifier; and
a second feedback circuit configured to couple the positive output end of the last-staged amplifier to a positive input end of the last-staged amplifier, or configured to couple the negative output end of the last-staged amplifier to a negative input end of the last-staged amplifier,
wherein the first feedback circuit comprises a first compensating resistor and a first compensating capacitor, and the second feedback circuit comprises a second compensating capacitor,
if the first compensating resistor is coupled between the first compensating capacitor and the positive output end of the last-staged amplifier, and the first compensating capacitor is coupled between the first compensating resistor and the positive input end of the at least one middle-staged amplifier, the second compensating capacitor will be coupled between the positive input end of the last-staged amplifier and a node between the first compensating resistor and the first compensating capacitor; and
if the first compensating resistor is coupled between the first compensating capacitor and the negative output end of the last-staged amplifier, and the first compensating capacitor is coupled between the first compensating resistor and the negative input end of the at least one middle-staged amplifier, the second compensating capacitor will be coupled between the negative input end of the last-staged amplifier and a node between the first compensating resistor and the first compensating capacitor.

2. The amplifier circuit of claim 1 , wherein the second feedback circuit further comprises a second compensating resistor.

3. The amplifier circuit of claim 2 , wherein the second compensating resistor is coupled between the second compensating capacitor and the positive output end of the last-staged amplifier, and the second compensating capacitor is coupled between the second compensating resistor and the positive input end of the last-staged amplifier.

4. The amplifier circuit of claim 2 , wherein the second compensating resistor is coupled between the second compensating capacitor and the negative output end of the last-staged amplifier, and the second compensating capacitor is coupled between the second compensating resistor and the negative input end of the last-staged amplifier.

5. The amplifier circuit of claim 1 , further comprising:
a third feedback circuit configured to couple the positive output end of the last-staged amplifier to the negative input end of the at least one middle-staged amplifier, or configured to couple the negative output end of the last-staged amplifier to the positive input end of the at least one middle-staged amplifier.

6. The amplifier circuit of claim 5 , wherein the third feedback circuit comprises a third compensating resistor and a third compensating capacitor.

7. The amplifier circuit of claim 6 , wherein the third compensating resistor is coupled between the third compensating capacitor and the positive output end of the last-staged amplifier, and the third compensating capacitor is coupled between the third compensating resistor and the negative input end of the at least one middle-staged amplifier.

8. The amplifier circuit of claim 6 , wherein the third compensating resistor is coupled between the third compensating capacitor and the negative output end of the last-staged amplifier, and the third compensating capacitor is coupled between the third compensating resistor and the positive input end of the at least one middle-staged amplifier.

9. The amplifier circuit of claim 1 , further comprising:
a fourth feedback circuit configured to couple the positive output end of the last-staged amplifier to the negative input end of the last-staged amplifier, or configured to couple the negative output end of the last-staged amplifier to the positive input end of the last-staged amplifier.

10. The amplifier circuit of claim 9 , wherein the fourth feedback circuit comprises a fourth compensating resistor and a fourth compensating capacitor.

11. The amplifier circuit of claim 10 , wherein the fourth compensating resistor is coupled between the fourth compensating capacitor and the positive output end of the last-staged amplifier, and the fourth compensating capacitor is coupled between the fourth compensating resistor and the negative input end of the last-staged amplifier.

12. The amplifier circuit of claim 10 , wherein the fourth compensating resistor is coupled between the fourth compensating capacitor and the negative output end of the last-staged amplifier, and the fourth compensating capacitor is coupled between the fourth compensating resistor and the positive input end of the last-staged amplifier.

13. An amplifier circuit, comprising:
a multistage amplifier comprising a first-staged amplifier, a last-staged amplifier and at least one middle-staged amplifier cascaded between the first-staged amplifier and the last-staged amplifier;
a negative feedback circuit coupled to an output end of the last-staged amplifier and configured to provide a negative feedback to an input end of the at least one middle-staged amplifier and to an input end of the last-staged amplifier; and
a positive feedback circuit coupled to the output end of the last-staged amplifier and configured to provide a positive feedback to the input end of the at least one middle-staged amplifier,
wherein each of the negative feedback circuit and the positive feedback circuit comprises a first feedback circuit and a second feedback circuit, each of the first feedback circuits comprises a first compensating resistor and a first compensating capacitor, and each of the second feedback circuits comprises a second compensating capacitor,
if the first compensating resistor is coupled between the first compensating capacitor and a positive output end of the last-staged amplifier, and the first compensating capacitor is coupled between the first compensating resistor and a positive input end of the at least one middle-staged amplifier, the second compensating capacitor will be coupled between a positive input end of the last-staged amplifier and a node between the first compensating resistor and the first compensating capacitor; and
if the first compensating resistor is coupled between the first compensating capacitor and a negative output end of the last-staged amplifier, and the first compensating capacitor is coupled between the first compensating resistor and a negative input end of the at least one middle-staged amplifier, the second compensating capacitor will be coupled between a negative input end of the last-staged amplifier and a node between the first compensating resistor and the first compensating capacitor.

14. The amplifier circuit of claim 13 , wherein the positive feedback circuit is further configured to provide the positive feedback to the input end of the last-staged amplifier.

15. An amplifier circuit, comprising:
a multistage amplifier comprising a first-staged amplifier, a last-staged amplifier and at least one middle-staged amplifier cascaded between the first-staged amplifier and the la

Assignees

• Realtek Semiconductor Corp

Inventors

• Tu Chih-Chan
• Chen Chih-Lung
• Chan Ka-Un

Classifications

• H03F1/38 Primary

  Positive-feedback circuit arrangements without negative feedback · CPC title

• H03F1/34

  Negative-feedback-circuit arrangements with or without positive feedback (H03F1/02 - H03F1/30, H03F1/38 - H03F1/50, H03F3/50 take precedence {; for rejection of common mode signals H03F3/45479}) · CPC title

• H03F3/45

  Differential amplifiers (differential sense amplifiers G11C7/062) · CPC title

• H03F2200/153

  Feedback used to stabilise the amplifier · CPC title

• H03F2200/408

  the output amplifying stage of an amplifier comprising three power stages · CPC title