Class D amp discussion

gogowatch

The ucd patent document should help too.

Cheers,

kunkun

  傻了吧:

millwood

gogowatch: thanks for your reply.

1) how do you like the ti driver? I just order some and am waiting to receive it and ucc27201. I would appreciate your experience with it, vs. other drivers (ir2011, and the onsemi one (ncp5181?)). I have used lm5101 and it is too fragile.

2) the diy thread. it sounds quite interesting. I would 2nd their view on fdp3682. I have had a few of them and they blew up so easily where my irf540 have lasted long long time.

gogowatch

1. I have experience with LM5101, UCC27201 and HIP2101 only.  LM5101 and UCC27201 are powerful driver chips and I blew up all my available one before I can make careful measurement from them.  I believe they will work as good as it is specified in the datasheet.  My advise is that you have to be extremely careful when probing the live circuit or you will have a result as shown in the attached picture.  I saw a bright spark on the chip between pin 7 and 8 and a small mushroom cloud was developed by the time it was blew up.  You can imagine how powerful the driver chip is.  I use HIP2101 in my experiment now because it is less powerful and I can get it from taobao.  I got LM5101 and UCC27201 as samples from manufacturer.

2. How do you generate the dead time and the level shift?  I did dead time generation as shown in http://users.tkk.fi/~jwagner/electr/pwm-deadtime-gen and level shift simply by a pair of PNP transistor.

Cheers

millwood

gogowatch: thanks for your reply and tips.

I rely on the driver chips to manage deadtime. I don't use chips that have too much deadtime (common for smps drivers), or no shoot-through detection.

lately i am thinking of using independent high side and low side deivers but have yet to make any progress on that. If i do, I will go your route as well.

in my version of the UcD, the input is upside down from Bruno's AES paper and Phillips' application note. so that the output is all referenced to the negative rail, and the driver chip sits on the negative rail.

音响DSP

To Dear Millwood:
能否把下面的TDA8931T应用电路图做个简要分析,因为有些元件看不太懂.谢谢。

millwood

I will give it a shot.

the chip is a half-bridge construction. the application here is powered by a single rail so you will need to block the DC output.

R1/C1/C2 forms the power supply conditioning circuitry for power (Vp) and analog power (Vpa). R1/C2 and pin 6 forms the soft power on circuitry for the chip.


the low pass filter is L1 / C14, with C13/R10 being the typical zobel network.

HVP provides the 1/2 of Vp (see table 6, pin 13 of the datasheet). this is where I think Phillips is so dumb: they used two power mosfet to generate a dc voltage but they could have easily integrated two gate drivers and get a real full bridge application here. Anyway, HVP outputs 1/2 of Vp and C15 is the filter / DC blocking capacitor (otherwise, HVP would have been shorted to ground).

C12 is the typical bootstrap capacitor to provide the highside driver its supply voltage. table 6, pin 17 shows that the boot capacitor is powered up from STABI (12v internally regulated supply) through a fast recovery diode (in serial with a resistor). c9/r8 is the snobber network to get rid of any overshot on the front of the pwm waveform.

r7/c8/c10 snobs the output as well. r2/r3/r4 and c3 forms the feedback network. when OUT goes high, C3 snobs it and prevents it from showing up on INN (negative input end of the comparator) for a short period of time. As C3 is charged up, OUT stays hi to bring the audio output up through L1/C14. After C3 is charged up, OUT shows up at INN, and begins to surpass the audio input on INP, and the comparator flips, driving OUT to lo, and the cycle continues.

because this is a single rail operation, the chip also uses a pair of mosfet (table 6, pin 19) to form a 1/2 Vpa. that is the HVPI pin. C6 is the snobber on that pin and to feed 1/2 Vpa to the INN and INP. C4/C7 are the snobbers there. this is conceptually similar to how you would do to use opamp on single rail supplies.

C11 is the DC blocking input capacitor.

C16 stablizes STABI (the internal 12v regulator's output pin). R12 / S1 allows for disabling of the chip through pin 7 - if you didn't have R12, closing S1 would short STABI to ground. also please pay close attention to the logic on EN and POWERUP.

the particular set up does not use the over voltage protection pin (pin 12).

Hopefully this helps.

=====here is the translation, courtesy of Yahoo.=====

我将尝试。

芯片是应用这里由唯一路轨供给动力的一半桥梁建筑因此您将需要阻拦DC 产品。

R1/C1/C2 形成电源适应的电路为力量(Vp) 并且模式力量(Vpa) 。R1/C2 和别住6 个形式软的力量在电路为芯片。

低通滤波器是L1/C14, 用C13/R10 是典型的zobel 网络。

HVP 提供1/2 Vp (参见表6, 别针13 datasheet) 。这是我认为的地方菲利普是很沉默寡言的: 他们使用二力量mosfet 引起直流电压但他们能容易地集成了二个门司机和得到一种真正的充分的桥梁应用这里。无论如何, HVP 输出1/2 Vp 并且C15 是过滤器/DC 阻拦的电容器(否则, HVP 会短缺研) 。

C12 是典型的引导电容器提供highside 司机它的电源电压表6, 别住17 表示, 起动电容器从STABI 供给动力(12v 内部调控了供应) 通过一个快速的补救二极管(在连续与电阻器) 。c9/r8 是snobber 网络摆脱任何超越在pwm 信号波形的前线。

r7/c8/c10 snobs 产品和r2/r3/r4 和c3 一样好形成反馈网络当去高, C3 snobs 它和防止它出现在旅店(比较器的消极输入末端) 一个短的时期。如同C3 被充电, 在逗留之外高提出音频输出通过L1/C14。在C3 被充电之后, 出现在旅店, 和开始超过音像输入在INP, 并且比较器翻转, 驾驶到低, 并且周期继续。

因为这是唯一路轨操作, 芯片并且使用一对mosfet (表6, 别针19) 形成1/2 Vpa. 是HVPI 别针。C6 是snobber 在那个别针和哺养1/2 Vpa 对旅店和INP 。这与的C4/C7 是snobbers 那里怎样是概念性地相似您会做使用opamp 在唯一路轨供应。

C11 是DC 阻拦输入电容器。

C16 stablizes STABI (内部12v regulator's 产品别针) 。R12/S1 考虑到失去能力芯片通过别针7 - 如果您didn't 有R12, 关闭的S1 会短缺STABI 并且研取乐对逻辑的薪水密切的关注在EN 和POWERUP 。

特殊设定不使用结束电压保护别针(别针12) 。

有希望地这帮助。

Biglee_163

my god!
seams you don't konw chinese at all

scooby

Individual Class D power amplifier or feel good. High efficiency heating small. Also power-saving. Not many applications before, but now technology is mature. The scope of application or many. He still has the characteristics! Before listening to a friend said Class D power amplifier can ever heard. We have the opportunity to listen to ... estimated themselves to be a not very poor.

Biglee_163

原帖由 scooby 于 2007-10-29 20:49 发表
Individual Class D power amplifier or feel good. High efficiency heating small. Also power-saving. Not many applications before, but now technology is mature. The scope of application or many. He ...

这段英文我实在是看不懂了

gogowatch

I have built a power amp using Hypex UCD180.  It sounds great.

Cheers,

FUMAC

Individual Class D power amplifier or feel good. High efficiency heating small. Also power-saving.
Not many applications before, but now technology is mature.
The scope of application or many.
He still has the characteristics! Before listening to a friend said Class D power amplifier can ever heard. We have the opportunity to listen to ... estimated themselves to be a not very poor.

有部分D类功放感觉还是不错的, 高效率,低热量, 节省能源,
在此之前,并没有很多成熟的产品出现,但是现在不一样了,技术已经很成熟.可以适应不同的用途.
D类是有他自己独特的特点.
在听D类之前, 曾经听过一个朋友有说起,
我们有机会听了后发现d类功放并不是很糟糕.

大概这个意思,只做翻译,不代表本人观点,翻译错误请指正,本人在学英语

FUMAC

will give it a shot.

the chip is a half-bridge construction. the application here is powered by a single rail so you will need to block the DC output.
-------------
这个是一个半桥的结构, 这个电路使用单电源,所以加入了一个隔直电容

R1/C1/C2 forms the power supply conditioning circuitry for power (Vp) and analog power (Vpa).
--------------
R1/C1/C2 为供电滤波

R1/C2 and pin 6 forms the soft power on circuitry for the chip.
--------------
R1/C2 和pin 6 组成软启动电路

the low pass filter is L1 / C14, with C13/R10 being the typical zobel network.
---------L1/C4为低通滤波器, C13/R10是一个销振网络.

HVP provides the 1/2 of Vp (see table 6, pin 13 of the datasheet).
this is where I think Phillips is so dumb: they used two power mosfet to generate a dc voltage but they could have easily integrated two gate drivers and get a real full bridge application here.
Anyway, HVP outputs 1/2 of Vp and C15 is the filter / DC blocking capacitor (otherwise, HVP would have been shorted to ground).

---------
HVP 提供1/2电压   (请看 table 6, pin 13 of the datasheet).
个人认为飞利浦在这里非常愚蠢,他们使用两个MOSFET去产生直流电压,但是如果做多两个驱动,那么他就可以得到一个全桥的D类芯片.(fumac个人认为,全桥并不是一个理想的结构,500w以下,半桥结构可以做的很好,以下为广告时间:比如FUMAC 的 MHZ class-d 500w还是半桥结构 ,).

继续: HVP输出半电压,C15隔直电容,否则HVP就短路对地了(FUMAC的理解,此电容除了隔直外,另一个作用是HVP的滤波电容,呵呵,很古怪的做法)


C12 is the typical bootstrap capacitor to provide the highside driver its supply voltage. table 6, pin 17 shows that the boot capacitor is powered up from STABI (12v internally regulated supply) through a fast recovery diode (in serial with a resistor).
--------
c12 是标准的自举电容, 用于上臂驱动电路供电. 表6说明:17脚, 此电容供电通过一个快恢复二极管串联一个电阻后连接到内部12v稳压输出口 STABI

c9/r8 is the snobber network to get rid of any overshot on the front of the pwm waveform.
-------
C9R8是阻尼网络,用于消除PWM过冲的干扰

欲知后事如何,请看下回分解

millwood

fumac, are you selling your module? it would be quite marketable.

FUMAC

yes, i'm also finding a agent at usa, i'm selling my modules and compelete one. ;)

FUMAC

r7/c8/c10 snobs the output as well.
----
r7/c8/c10输出销振电路

r2/r3/r4 and c3 forms the feedback network. when OUT goes high, C3 snobs it and prevents it from showing up on INN (negative input end of the comparator) for a short period of time. As C3 is charged up, OUT stays hi to bring the audio output up through L1/C14. After C3 is charged up, OUT shows up at INN, and begins to surpass the audio input on INP, and the comparator flips, driving OUT to lo, and the cycle continues.
----------
r2/r3/r4 and c3 是反馈电路, 当输出为高的时候,  C3 将充电,在此极短时间,阻止了信号进入比较器的反向输入口(INN),当C3充电完成后, 输出信号进入INN,引起比较器的反转,于是输出为低电平,如此往复,电路就正常工作了


because this is a single rail operation, the chip also uses a pair of mosfet (table 6, pin 19) to form a 1/2 Vpa. that is the HVPI pin. C6 is the snobber on that pin and to feed 1/2 Vpa to the INN and INP. C4/C7 are the snobbers there. this is conceptually similar to how you would do to use opamp on single rail supplies.
------------
因为这个是一个单电源回路, 芯片采用双MOS输出半电压(前面说过),C6 是输入端基准电压的滤波, 这个基准电压由HVPI引脚提供,这个和OP工作在但电压电路上类似的结构(其实OP和比较器原理上区别不大,侧重点不同. fumac注)

C11 is the DC blocking input capacitor.
-----
C11输入端隔直电容

C16 stablizes STABI (the internal 12v regulator's output pin). R12 / S1 allows for disabling of the chip through pin 7 - if you didn't have R12, closing S1 would short STABI to ground. also please pay close attention to the logic on EN and POWERUP.
--------
C16是内部12v稳压输出的滤波电容.(stabi). R12 / S1组成芯片的使能控制,如果没有R12将会让内部稳压输出对地短路,同时,应该注意EN和上电的逻辑关系.



the particular set up does not use the over voltage protection pin (pin 12).
----------
这个电路并没有使用过压保护功能(pin12)
fumac:过压保护一般并不需要,因为功放设计的时候,成熟的工程师都充分考虑到电压的波动,
但是对于DIY 最好还是加上过压保护吧,因为diyer手头上的变压器参差不齐,电压也不一定完全符合安全设计的要求..
以下为广告时间:FUMAC的MCD都有过压保护,

----下次不干翻译了,累!

音响DSP

嘿嘿，有广告时间给你去给大家普及下这里讨论的迟滞振荡，而不是常规见到的三角波做基准，输入正弦波，通过比较器输出PWM波的。
我也早在2年前就看过TDA8931T的应用电路图，觉得有点不完善。现在有TFA9810T，我也会把它的应用电路和内部结构贴出来让大家再对比，多对比，大脑有思考，才不会觉得累和迷惘。
TFA9810内部结构简图

应用电路，比TDA8931T的简单多了。

younglee

Class D 虽然是开关电路，但技术的成熟会慢慢好听起来的！

scooby

In the past, read the book. Class D power amplifier protection are very good. Personal opinion. Protection circuit or necessary.

younglee

LM4682 - 10 Watt Stereo CLASS D Audio Power Amplifier with Stereo Headphone Amplifier and DC Volume Control
Parametric Table     expand
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Parametric Table    collapse
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Power@ 8Ohms, 1% THD 6 Watt
Power@ 8Ohms, 10% THD 8 Watt
THD 0.2 %
PSRR 94 dB
Channels 2 Channels
THD Conditions Po=6W/channel,fin=1kHz
PSRR Conditions Vrip=200mVpp, 1kHz,Vin=0,input referred,f=60Hz

Power@ 8Ohms, 1% THD 6 Watt
Power@ 8Ohms, 10% THD 8 Watt
THD 0.2 %
PSRR 94 dB
Channels 2 Channels
THD Conditions Po=6W/channel,fin=1kHz
PSRR Conditions Vrip=200mVpp, 1kHz,Vin=0,input referred,f=60Hz
User Supply 12 Volt
Shut down Yes
Shutdown Type Low
Supply Range +9 - +14V
Temperature Min -40 deg C
Temperature Max +85 deg C
View Using Catalog



Typical Performance


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