# US 10,312,879 B2 · Audio control circuit

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- Number: US 10,312,879 B2
- Document ID: US10312879B2
- Status: Granted
- Kind: B2
- Application number: 15/432,351
- Filed: 2017-02-14
- Published: 2018-05-31
- Granted: 2019-06-04
- Earliest claimed: 2016-11-28
- Assignees: Anpec Electronics Corporation
- Applicants: Anpec Electronics Corporation
- Inventors: Che-Chang Chang
- Web page: https://patentgrep.com/patent/US10312879B2

## CPC

- H03G 7/004: {using continuously variable impedance devices}
- H03G 3/3005: {in amplifiers suitable for low-frequencies, e.g. audio amplifiers (H03G3/32, H03G3/34 take precedence)}
- H03G 3/301: {the gain being continuously variable}
- H04R 29/004: {for microphones (H04R29/007 takes precedence)}
- H04R 2430/01: Aspects of volume control, not necessarily automatic, in sound systems
- H03G: CONTROL OF AMPLIFICATION
- H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K)

## Abstract

An audio control circuit is provided in the present disclosure. The audio control circuit includes an input module, a volume signal detecting module and a volume adjusting module. The input module is used for receiving an audio signal. The volume signal detecting module is used for receiving a volume control signal and generates a volume adjusting signal according to the volume control signal. The volume adjusting module is used for receiving the audio signal and the volume adjusting signals and generates an amplified audio signal according to the audio signal and the volume adjusting signal. The volume control signal is a pulse width modulation signal.

## Claims

### Claim 1

An audio control circuit, comprising:
an input module configured to receive an audio signal;
a volume control signal detecting module configured to receive an audio control signal, and including:
a duty cycle calculating unit;
a sampling unit configured to sample the audio control signal according to a clock signal, wherein a frequency value of the clock signal is greater than a frequency value of the audio control signal;
a high level counting unit configured to calculate a high level signal time of each period of the audio control signal; and
a low level counting unit configured to calculate a low level signal time of each period of the audio control signal, wherein the duty cycle calculating unit calculates a duty cycle percentage of each period of the audio control signal according to the high level signal time and the low level signal time, the volume control signal detecting module generating a volume adjusting signal according to the duty cycle percentage of each period of the audio control signal; and
a volume adjusting module configured to receive the audio signal and the volume adjusting signal, and to generate an adjusted audio signal according to the audio signal and the volume adjusting signal;
wherein the audio control signal is a pulse width modulation signal.

### Claim 2 (depends on 1)

The audio control circuit according to claim 1, wherein the audio control circuit further comprises:
a processing module configured to process a plurality of audio characteristics of the adjusted audio signal, and to output the processed adjusted audio signal; and
an output module configured to receive the processed adjusted audio signal from the processing module and to output the processed adjusted audio signal.

### Claim 3 (depends on 1)

The audio control circuit according to claim 1, wherein the volume control signal detecting module further includes:
a clock signal providing unit configured to provide the clock signal to the sampling unit.

### Claim 4 (depends on 3)

The audio control circuit according to claim 3, wherein the clock signal providing unit includes a plurality of clock signals, the plurality of clock signals including different frequency values respectively.

### Claim 5 (depends on 1)

The audio control circuit according to claim 1, wherein the volume control signal detecting module further includes:
a reset unit, configured to reset the high level counting unit, the low level counting unit and the duty cycle calculating unit, according to a high level signal value detected by the high level counting unit or a low level signal value detected by the low level counting unit.

### Claim 6 (depends on 1)

The audio control circuit according to claim 1, wherein a frequency value of the audio control signal is greater than 20 KHz.

### Claim 7

A volume adjusting method adopted for an audio control circuit, comprising:
receiving an audio control signal and an audio signal;
sampling the audio control signal according to a clock signal;
calculating a high level signal time and a low level signal time of each period of the audio control signal, calculating a duty cycle percentage of each period of the audio control signal according to the high level signal time and the low level signal time, and providing a plurality of volume adjusting values corresponding to the duty cycle percentage of each period of the audio control signal; and
adjusting a volume of the audio signal according to the volume adjusting values;
wherein the audio control signal is a pulse width modulation signal.