Audio amplifier with duty ratio control

Patent metadata

Field	Value
Publication number	US-12088267-B2
Application number	US-202217585606-A
Country	US
Kind code	B2
Filing date	Jan 27, 2022
Priority date	Jan 27, 2022
Publication date	Sep 10, 2024
Grant date	Sep 10, 2024

Abstract

An audio amplifier with duty ratio control is provided. The audio amplifier comprises a pulse width modulation modulator, a power stage, and a voltage converter. The pulse width modulation modulator is configured to receive an input signal for generating a pulse width modulation signal. The power stage is configured to output an output signal according to a supply voltage and the pulse width modulation signal. The voltage converter is configured to adjust voltage level of the supply voltage according to the pulse width modulation signal. The audio amplifier is configured to adjust the voltage level of the supply voltage when duty ratio of the pulse width modulation signal is greater than a duty ratio threshold.

First claim

What is claimed is:

1. An audio amplifier with duty ratio control, comprising:
a pulse width modulation modulator configured to receive an input signal for generating a pulse width modulation signal;
a power stage configured to output an output signal according to a supply voltage and the pulse width modulation signal; and
a voltage converter configured to adjust voltage level of the supply voltage according to the pulse width modulation signal;
wherein the audio amplifier is configured to adjust the voltage level of the supply voltage when duty ratio of the pulse width modulation signal is greater than a duty ratio threshold.

2. The audio amplifier according to claim 1 , further comprising:
a pulse width modulation detector, electrically coupled between the power stage and the voltage converter, for outputting an indication signal to the voltage converter, wherein the indication signal indicates whether the duty ratio of the pulse width modulation signal is greater than the duty ratio threshold and the voltage converter is configured to adjust the voltage level of the supply voltage according to the indication signal.

3. The audio amplifier according to claim 2 , wherein the pulse width modulation detector is configured to output the indication signal according to the pulse width modulation signal and the duty ratio threshold.

4. The audio amplifier according to claim 2 , wherein the voltage converter is configured to adjust the voltage level of the supply voltage when the indication signal indicates that the duty ratio of the pulse width modulation signal is greater than the duty ratio threshold.

5. The audio amplifier according to claim 1 , wherein the audio amplifier is configured to limit the duty ratio of the pulse width modulation signal to a percentage based on the duty ratio threshold.

6. The audio amplifier of claim 1 , wherein a closed loop is formed between the power stage and the voltage converter.

7. An audio amplifier with duty ratio control, comprising:
a pulse width modulation modulator for generating a pulse width modulation signal;
a power stage coupled to the pulse width modulation modulator; and
a voltage converter coupled to the power stage and configured to output a supply voltage to the power stage, wherein the voltage converter is configured to adjust a voltage level of the supply voltage according to duty ratio of the pulse width modulation signal.

8. The audio amplifier according to claim 7 , further comprising:
a pulse width modulation detector, electrically coupled between the power stage and the voltage converter, for outputting an indication signal to the voltage converter, wherein the indication signal indicates whether the duty ratio of the pulse width modulation signal is greater than a duty ratio threshold and the voltage converter adjusts the voltage level of the supply voltage according to the indication signal.

9. The audio amplifier according to claim 8 , wherein the pulse width modulation detector is configured to output the indication signal according to the pulse width modulation signal and the duty ratio threshold.

10. The audio amplifier according to claim 8 , wherein the voltage converter is configured to adjust the voltage level of the supply voltage when the indication signal indicates that the duty ratio of the pulse width modulation signal is greater than the duty ratio threshold.

11. The audio amplifier according to claim 7 , wherein the audio amplifier is configured to limit the duty ratio of the pulse width modulation signal to a percentage based on the duty ratio threshold.

12. The audio amplifier of claim 7 , wherein a closed loop is formed between the power stage and the voltage converter.

Assignees

• Elite Semiconductor Microelectronics Technology Inc

Inventors

• Hsu Che-Wei
• Yu Wun-Long

Classifications

• H03F3/2178

  using more than one switch or switching amplifier in parallel or in series (H03F3/2173, H03F3/2175 take precedence) · CPC title

• H02M3/1582

  Buck-boost converters (H02M3/1584 takes precedence) · CPC title

• H03F2200/351

  Pulse width modulation being used in an amplifying circuit · CPC title

• H02M3/158

  including plural semiconductor devices as final control devices for a single load · CPC title

• H03F1/0227

  using supply converters · CPC title