Automatic gain control circuit used for D-class audio power amplifier chip
A technology of automatic gain control and power amplifier chip, which is applied in the direction of gain control, amplification control, electrical components, etc., can solve the problems of wasting battery power, etc., and achieve the effects of stable power supply voltage, prolonging the use time, and easing over-temperature treatment
Active Publication Date: 2016-06-22
JIAXING HEROIC ELECTRONICS TECH
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Problems solved by technology
This wastes some of the battery power
[0005] Therefore, those skilled in the art are committed to developing an automatic gain control circuit for class D audio power amplifier chips, eliminating the phenomenon of sudden stop and sudden sound caused by over-temperature treatment in the prior art, and improving battery efficiency
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[0036] The invention is used for a Class D audio power amplifier chip, which is used in audio equipment such as earphones, has a temperature protection circuit, and receives power from a battery in the equipment.
[0037] Such as figure 2 As shown, the automatic gain control circuit for a class D audio power amplifier chip of the present invention includes an automatic gain controller, a variable gain amplifier, a comparator and a threshold comparison voltage generating module 10 . Wherein, the threshold comparison voltage generation module 10 receives the voltage of the battery, and outputs a threshold comparison voltage that changes with the change of the battery voltage according to the battery voltage. Its specific structure and working process will be described in detail later. The comparator CMP has two input terminals, the first input terminal of which receives the threshold comparison voltage output by the threshold comparison voltage generating module 10, and the sec...
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The invention discloses an automatic gain control circuit used for a D-class audio power amplifier chip. The circuit includes an automatic gain controller, a variable gain amplifier, a comparator and a threshold comparison voltage generation module, wherein the threshold comparison voltage generation module outputs a threshold comparison voltage which is variable with the voltage of a battery to the comparator, and the comparator compares output of the variable gain amplifier with the threshold comparison voltage; and the automatic gain controller has four working states, a current working state is determined according to received over-temperature signal, previous working state and output of the comparator, and an enable signal is correspondingly output to the variable gain amplifier, so as to control the gain of the variable gain amplifier. The automatic gain control circuit fuses over-temperature treatment in a gain adjustment link, and realizes uninterrupted output of sound during over-temperature and quick gain recovery after over-temperature is over; and realizes reduction of output power of the audio chip when electric quantity of a battery is relatively low, and effectively prolongs usage time of the battery.
Description
technical field [0001] The invention relates to the technical field of audio power amplifiers, in particular to an automatic gain control circuit for a Class D audio power amplifier chip. Background technique [0002] Class D audio power amplifier chip (also referred to as: Class D power amplifier chip) is more and more favored by people due to its high energy utilization rate and small application circuit area. It is gradually widely used in portable multimedia devices and becomes an audio power amplifier circuit part. mainstream configuration. [0003] When class D power amplifier chips are used in portable devices, for reasons of saving space and cost, heat sinks are often omitted, so class D power amplifier chips are generally equipped with a temperature protection circuit. Such as figure 1 The shown class D power amplifier chip with an automatic gain control circuit, wherein the automatic gain control circuit includes an automatic gain controller AGC, a variable gain ...
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Login to View More IPC IPC(8): H03G3/30
CPCH03G3/3026H03G2201/708
Inventor 胡建鹏黄武康代军杨志飞姚远李晓江
Owner JIAXING HEROIC ELECTRONICS TECH