分立元件数字功放设计

UM10155

Discrete Class D High Power Audio Amplifier

UM10155：分立元件D类大功率音频功放

Keywords ：Class D Audio Amplifier, Universal Class D, UcD, PWM Audio Amplifier,

High Power Audio.

关键词：D类音频放大器，全D类（UcD）, PWM功放，大功率功放

Abstract ：This user manual describes the operating instructions and the most important background information of the Philips Semiconductor Discrete Class D High Power Audio Amplifier Demonstrator Board. With proper heatsinking of the Power MOSFETs and a well dimensioned power supply, the PWM amplifier is capable of supplying 200 W of high quality audio power into a 4 Ω loudspeaker.

内容摘要：本用户手册描述了飞利浦半导体分立D类高功率音频放大器演示板的操作方法和最

重要的背景资料。在适当的功率管散热器的和很好的供电情况下，这台PWM放大器能提供200 W 高质量音频输出给一个4 Ω的扬声器。

1. Introduction简介

The Universal Class D (UcD) version 1.00 demonstrator board implements a 200 W true RMS (into a 4 Ω load) high quality audio power amplifier on a very compact printed-circuit board. The amplifier is built-up of discrete components only, and makes use of Philips patent WO 03/090343.

这个1.0版本的全D类功放(UcD)示范板是一个在非常紧凑的PCB板上输出200 W真有效功率(4 Ω负载)的高质量音频功放。

Fig 1. General view001aaf148 2. Circuit diagram电路原理图The demonstrator board is intended to illustrate the capability of Philips Power MOSFETs in discrete high-end PWM audio amplifier applications. The board is self-contained and only requires a simple (non-stabilized) dual power supply, an audio source (e.g. function generator, CD player) and a loudspeaker to demonstrate its capabilities. For evaluation at high output power a provision is made to attach an appropriate heatsink to the MOSFETs on the board.

本演示板意欲图解说明飞利浦功率MOSFET在分立高档PWM音频放大器上的应用能力。

本板自我包含了齐全的功能，只需要简单的正负电源（非稳压），加上音源和扬声器即可示范其性能。为评价在大功率下的性能，需要附上一个适当的散热片到MOSFET上。

Table 1. Connections 表一：连接器

Connector

Function Remarks J1

audio in - signal use together with J2 J2

audio in - ground use together with J1 J3

amplifier enable the amplifier is enabled when connected to ground (J4) J4

ground use together with J3 J5 positive supply voltage 30 V to 45 V (no need for a

stabilized power supply)

J6 positive current sense can optionally be used in an

overcurrent protection scheme

J7 power supply ground 0 V

J8 negative current sense can optionally be used in an

overcurrent protection scheme

J9 negative supply voltage −30 V to −45 V (no need for a

stabilized power supply)

J10 loudspeaker output use together with J11

J11 loudspeaker ground use together with J10

J1 和J2用于音频输入；J3 和J4用于控制功放是否启用；J5 和J9是30 V 至45 V 正负供电，不需稳压； J6 和J8是电流感应端，用于设计功放保护；J7是电源的地；J10 和J11是输出端，用于接扬声器。

译者为了说明电路工作原理，作了一个示意原理图，参

见左图：运放输出的信号经28uH 电感和680nF 电容后

有延迟，对某些频率来讲，延迟的时间正好使信号反相，

这个信号反馈到运放的负输入端，与其它元件配合，即

形成一个400kHz 的方波振荡器，且运放正输入端的音

频能调制这个振荡器，从运放输出输出一个PWM 信号，

经28uH 电感和680nF 电容滤波后送给扬声器放大了的

模拟音频功率信号。

译者认为，原作者的这个电路的确非常巧妙。