H类功率放大器 - 电子线路设计及应用室 - 声学楼论坛

老兵哥,可否说说市面流行的专业功放(H类功放)的一些具体情况吗?如市场需求,性价比,可靠性,工作原理等.

对不住了,从来就没看到这个帖子.
看日期是一年多前的帖子啊.

虽然从来就没触及H类功率放大器,还是争取回答些吧.

http://www.patentstorm.us/patents/5453717.html

能不能看到呢?

US Patent 5453717 - H-bridge type power amplifier and its blocking means

US Patent Issued on September 26, 1995

Abstract

The invention concerns H-bridge type power amplifiers and their blocking
means.
The memory effect of the capacitive impedance of control inputs of each of
the two blocking transistors-in the H-bridge is used to block and unblock
the amplifier synchronously with the amplifier input signal: a first
switch and a semi-conductor element are placed in parallel with each
other, in series with each of these control inputs, such that the blocking
of the blocking transistor necessitates the opening of the first switch
under the control of the blocking signal, and is dependent on the sign of
the charge carried by said capacitive impedance; a second switch
controlled by the half periods of the input signal only enables the first
switch to close and therefore unblocking of the considered blocking
transistor for half periods that are not amplified by this blocking
transistor.

http://www.freepatentsonline.com/4581565.html

H-bridge power amplifier and method for controlling the same

Document Type and Number:

United States Patent 4581565

Abstract:

An improved H-bridge power amplifier for controllably driving a dc motor is presented. The motor is connected in the center of the H-bridge in conventional manner. The H-bridge includes a current sense resistor placed between the power supply and a common tie point of the upper transistors of the bridge. Free wheeling diodes are connected from the motor directly to the power supply. This arrangement allows current to flow through the current sense resistor only when one of the upper transistors is on. The power amplifier is operated by selecting an appropriate pair of upper and lower transistors on opposite sides of the bridge so as to cause the current to flow through the motor in a desired direction. Both the upper and lower transistors of the selected pair are held ON until the current as sensed in the current sense resistor equals or exceeds a specified value, typically a desired current level. When this occurs, the upper transistor is turned OFF for a fixed off-time period, during which time the lower transistor is maintained ON. The motor current thereby decays through a path comprising the ON lower transistor, one of the free wheeling diodes, and the motor, which decay path significantly reduces the ripple associated with the motor current. At the end of the fixed off-time, the upper transistor is turned ON, and the process repeats itself. If braking is desired to slow the motor down, a plug inhibit mode is enabled wherein the lower transistor is turned off and the upper transistor is alternately turned ON and OFF.

http://www.axemusic.com/product.asp?numPageStartPosition=1&PT_ID=240&P_ID=14250
http://www.directproaudio.com/product.cfm?directid=57044

这两个链接也应该浏览一下,
第一个是EV的产品,
第二个是CREST的产品,

两个都是名牌吧,
EV的是

EV CP3000S Compact Precision Series Class H Power Amplifier - 2x1100watts @ 4ohms $1,794.44 EA

CREST的是
CC4000功率放大器,

8 Ohm Stereo - 800 Watts
4 Ohm Stereo - 1350 Watts
2 Ohm Stereo - 2000 Watts
4 Ohm Bridged - 4000 Watts
1100美元.

先引用这些,......

新H类音频功率放大器

上海奉贤开源电器厂 徐耀忠供稿

发表于-1997年6月8号第23期第12版 电子报

PWN功放（D类功放）的理论效率为100%，实际整机效率在扣除开关管压降、过度消耗、LC低通滤波器及电源部分或输出变压器消耗后还约为85%，这是很了不起的效率指标。D类功放的瞬态响应失真及电磁兼容性能一直是困扰设计者的难题，为此我厂几年前开发了新的H类功率放大器，并把该技术用于收放扩多用途JK275-1F扩音机产品（专利授权公告号：CN1020227C）。

在图2中，放大器采用V_L、V_R两档高低值不同的电源， R_L为功放的负载电阻。Q1为担任功率放大用的功率管，本文称工作管，Q2为补偿Q1管压降用的功率发大管，称补偿管。IC为Q1管压降取样和放大器件。当Q1有讯号输入时，Q1开始导通，输出电流在负载电阻上产生输出电压V_RL。此时功放电能由V_L提供。随着输入信号增大，输出电压也线性增大。当Q1管压降到某一较小的设定值是时，IC开始工作，输出电压进一步线性增大。此时功放的电能由V_R提供。接着Q2先饱和，Q1继续线性工作，直至Q1饱和。电声行业中称此种采用高低两档电源电压，使功率放大器始终处于较小管压降的放大器为H类功放。显而易见，H类功放效率较高。

本厂发明的新H类功放特点在于功放高电压V_R接入的检测信号来自发大管的瞬态管压降，而不是取自功放的瞬时输出电压。这样的改进产生以下效果：1.高电压V_R的加入具有负反馈性质，由原来的开关加入变为补偿加入。功放的末级组态可以是共集电路也可以是工发电路；2.新H类功放具有更高的效率；3.高电压加入科采用PWM方式，组成开关-线性功放；4.新H类功放末级可设计成高效率A类功放。

由于H类功放的两档电压V_L、V_R可根据功放实际工作状态取优化值，比如用于400Hz等副正选波放大，可取V_L=0.5V_H。用于扩声，由于输出峰值电压几率相对较小，可取V_L=0.5V_H。不同的V_L、V_R将会影响功放电源利用效率。H类功放的最高正弦波理论效率为88%。

仙鹤JK275-1F扩音机原理见图1.图中Q3、Q4是推挽功率放大管。由于输入信号是加在栅源之间，故末级组态看似共漏输出，其实是共源输出。Q6、Q7组成管压降取样或门电路，图中稳压管电压取0.1V_L约15伏，当Q3、Q4中某一个管子导通后的压降低于15伏时，Q6、Q7中就相应有一个导通。电路的其他部分较好理解，在此不赘述。本功放电路只要把图中的虚线部分改成图3的PWM方式，并为Q3，Q4增设偏流电源，此新H类功放即可改变成开关-线性功放，使效率达到90%以上。其最妙处还在于放大器的工作过程由PWM完成放大波形的粗调，再由线性原件完成负反馈细调。故功放的效果接近PWM方式，整机的实际效率可达80%，而输出特征于常规功放相仿。

图4至图7是新H类功放的各点波形，其中图4、图5是功率管Q3 、Q4漏源电压波形，图6是Q5的电流波形，图7是功放的输出波形。观察各处波形光滑而无有害的突峰，说明功放输出失真很小。且高次谐波量很小。本功放在管子选配及仪器调试良好时能达到的技术指标为频响40kHz-16kHz，失真2%。考虑到实际使用要求和批量生产，我厂把该机定位国标定压功放二级机；频响80Hz-8kHz，失真5%。功放的整机效率75%。实际使用时因为本功放功率管偏置电路电路性能良好，大小功率输出均不出现交越失真，功放开环失真小于10%，闭环失真中频区为1.5%。当扩音机语言扩声及中波收音时声音清晰，无可闻噪声。播放高音质磁带、FM收音或外接CD音源并配备良好输送变压器及组合音箱时更觉得音质优美和丰满。

严格地讲,是应该称为H桥放大器.

http://www.eetchina.com/ART_8800544816_617703_TA_58a60f46.HTM
http://smartway.blog.dianyuan.com/u/42/1150871425.pdf

中文文献,有兴趣者可参考.

主题：H类功率放大器

US Patent 5453717 - H-bridge type power amplifier and its blocking means

Abstract

EV CP3000S Compact Precision Series Class H Power Amplifier - 2x1100watts @ 4ohms $1,794.44 EA