CN210780689U

CN210780689U - High-power full-balance D-type power amplifier with low EMI (electro-magnetic interference) characteristic

Info

Publication number: CN210780689U
Application number: CN201921714390.3U
Authority: CN
Inventors: 杜江; 黄虎; 张�成; 陆正煜
Original assignee: 3g Audio Technology Co ltd
Current assignee: 3g Audio Technology Co ltd
Priority date: 2019-10-12
Filing date: 2019-10-12
Publication date: 2020-06-16
Anticipated expiration: 2029-10-12

Abstract

A high-power full-balance D-type power amplifier with low EMI characteristics is connected between a signal source and a load and comprises two paths of signal unit configurations and a spread spectrum clock source, wherein the spread spectrum clock source is connected to the signal unit configurations, and each path of signal unit configuration comprises an amplifier, a signal modulation module, a driving unit module, a signal filtering module, a first negative feedback circuit and a second negative feedback circuit. The input end of the amplifier is connected to a signal source, the output end of the amplifier is connected to the input end of the signal modulation module, the output end of the signal modulation module is connected to the input end of the driving unit module, the output end of the driving unit module is connected to the input end of the signal filtering module, and the output ends of the signal filtering modules configured by the two paths of signal units are respectively connected to the positive end and the negative end of a load. The utility model discloses do not reduce complete machine efficiency and can reduce EMI emission intensity from the source, reduce the external EMI interference of complete machine by a wide margin.

Description

High-power full-balance D-type power amplifier with low EMI (electro-magnetic interference) characteristic

Technical Field

The utility model relates to an audio frequency device especially relates to a high-power full-balance D class power amplifier of low EMI characteristic.

Background

Class D power amplifiers refer to class D audio power amplifiers (sometimes also referred to as digital power amplifiers). By controlling ON/OFF of the switching unit, an amplifier for driving a speaker is called a class D amplifier. Class D amplifiers were first proposed in 1958 and have become increasingly popular in recent years. Compared with the general linear AB class power amplifier circuit, the D class power amplifier has the characteristics of high efficiency, small volume and the like.

Class D power amplifiers are an amplification mode in which the amplifying element is in a switched state of operation. The amplifier is in the off state when no signal is input, and no power is consumed. When the power supply works, the transistor is enabled to enter a saturation state by means of an input signal, and the transistor is equivalent to a switch which is switched on, so that the power supply is directly switched on with a load. The ideal transistor does not consume power because of no saturation voltage drop, and in fact the transistor always consumes a small saturation voltage drop and consumes part of electric energy. The power consumption is only related to the characteristics of the tube and is not related to the size of the signal output, so that the power consumption is particularly beneficial to occasions with ultrahigh power. Ideally, the efficiency of class D power amplifiers is 100%, the efficiency of class B power amplifiers is 78.5%, and the efficiency of class a power amplifiers is only 50% or 25% (depending on the load mode).

With the continuous development and improvement of the technology, the conventional class D power amplifier has the characteristics of high distortion and high EMI, and cannot meet the requirements of users, so that improvement of the conventional class D power amplifier is urgently needed.

SUMMERY OF THE UTILITY MODEL

In view of the above, there is a need to provide a high power fully balanced class D power amplifier with uniform conductivity and low EMI characteristics.

The high-power fully-balanced D-type power amplifier with the low EMI characteristic is connected between a signal source and a load and comprises two paths of signal unit configurations and a spread spectrum clock source, wherein the spread spectrum clock source is connected to the signal unit configurations, and each path of signal unit configuration comprises an amplifier, a signal modulation module, a driving unit module, a signal filtering module, a first negative feedback circuit and a second negative feedback circuit. The input end of the amplifier is connected to a signal source, the output end of the amplifier is connected to the input end of the signal modulation module, the output end of the signal modulation module is connected to the input end of the driving unit module, the output end of the driving unit module is connected to the input end of the signal filtering module, and the output ends of the signal filtering modules configured by the two paths of signal units are respectively connected to the positive end and the negative end of a load.

The utility model discloses the high-power full-balance D class power amplifier's of low EMI characteristic beneficial effect lies in: by adding a spread spectrum clock source, the clock frequency generated by the spread spectrum clock source is expanded to two sides repeatedly by taking the fundamental frequency as the center, the larger the expanded range is, the better the EMI inhibition effect is, and the expanded range is usually between 0.5% and 2.5%. The utility model discloses can reduce 5 ~ 18 dB's EMI interference amplitude, especially the effect at EMI's high frequency channel is especially obvious. The utility model discloses have small, with low costs, do not reduce complete machine efficiency and can reduce EMI emission intensity from the source, reduce the external EMI interference of complete machine by a wide margin.

Drawings

Fig. 1 is a schematic connection diagram of a high power fully balanced class D power amplifier with low EMI characteristics according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

As shown in fig. 1, the utility model provides a high-power fully balanced class D power amplifier of low EMI characteristic, it is connected between signal source and load 30, the high-power fully balanced class D power amplifier of low EMI characteristic includes two way signal unit configurations 10 and spread spectrum clock source 20, and the signal source sends the same positive signal or negative signal respectively to two way signal unit configurations 10.

Each path of signal unit configuration 10 includes an amplifier 11, a signal modulation module 12, a driving unit module 13, a signal filtering module 14, a first negative feedback circuit 15, and a second negative feedback circuit 16. The input end of the amplifier 11 is connected to a signal source, the output end of the amplifier 11 is connected to the input end of the signal modulation module 12, the output end of the signal modulation module 12 is connected to the input end of the driving unit module 13, the output end of the driving unit module 13 is connected to the input end of the signal filtering module 14, and the output ends of the signal filtering modules 14 of the two-way signal unit configuration 10 are respectively connected to the positive end and the negative end of the load 30. The first negative feedback circuit 15 is connected to the output end of the driving unit module 13 and the input end of the signal modulation module 12, respectively, and the second negative feedback circuit 16 is connected to the output end of the signal filtering module 14 and the input end of the amplifier 11, respectively.

The spread spectrum clock source 20 includes a plurality of output terminals, and the output terminals of the spread spectrum clock source 20 are respectively connected to the signal modulation modules 12 in different paths.

During operation, the amplifier 11 amplifies a signal of a signal source, the spread spectrum clock source 20 sends a spread spectrum signal to the signal modulation module 12, the signal modulation module 12 modulates the signal in combination with the spread spectrum signal of the spread spectrum clock source 20, the driving unit module 13 converts a change of an input voltage into a change of an output current, and the change of the output current is processed by the signal filtering module 14 and then input to the load 30.

The utility model discloses the high-power full-balance D class power amplifier's of low EMI characteristic beneficial effect lies in: by adding a spread spectrum clock source 20, the clock frequency generated by the spread spectrum clock source is expanded to both sides repeatedly by taking the fundamental frequency as the center, the larger the expanded range is, the better the EMI inhibition effect is, and the expanded range is usually between 0.5% and 2.5%. The utility model discloses can reduce 5 ~ 18 dB's EMI interference amplitude, especially the effect at EMI's high frequency channel is especially obvious. The utility model discloses have small, with low costs, do not reduce complete machine efficiency and can reduce EMI emission intensity from the source, reduce the external EMI interference of complete machine by a wide margin.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, many variations and modifications can be made without departing from the spirit of the invention, and these are within the scope of the invention. Therefore, the protection scope of the utility model patent should be subject to the appended claims.

Claims

1. A high-power fully-balanced D-type power amplifier with low EMI characteristics is connected between a signal source and a load, and is characterized in that the high-power fully-balanced D-type power amplifier with low EMI characteristics comprises two paths of signal unit configurations and a spread spectrum clock source, wherein the spread spectrum clock source is connected to the signal unit configurations, and each path of signal unit configuration comprises an amplifier, a signal modulation module, a driving unit module, a signal filtering module, a first negative feedback circuit and a second negative feedback circuit; the input end of the amplifier is connected to a signal source, the output end of the amplifier is connected to the input end of the signal modulation module, the output end of the signal modulation module is connected to the input end of the driving unit module, the output end of the driving unit module is connected to the input end of the signal filtering module, and the output ends of the signal filtering modules configured by the two paths of signal units are respectively connected to the positive end and the negative end of a load.

2. The low EMI characterized high power fully balanced class D power amplifier of claim 1, wherein: the spread spectrum clock source comprises a plurality of output ends, and the output ends of the spread spectrum clock source are respectively connected to the signal modulation modules on different paths.

3. The low EMI characterized high power fully balanced class D power amplifier of claim 1, wherein: the first negative feedback circuit is respectively connected with the output end of the driving unit module and the input end of the signal modulation module, and the second negative feedback circuit is respectively connected with the output end of the signal filtering module and the input end of the amplifier.