some question about IR2110

[titanchen68]

This is my circuit in the file
This designed i have using ir2011 to work well.
I try to using ir2110 to work..But
I got one problem , when i remove the feedback resistor R39=47k
The output waveform is 1Vpp sine wave.
But got some DC offset about 500mV.
The waveform after feedback Low-pass filter , It looks like triangle-wave , 40Vpp.
When i reconnect the feedback resistor R39 .
The output of error amp , become 5v output.
Let the output of LT1016 going to saturated.

I connect the -40v to ir2110's Vcc , serise a R33=10ohm.
I saw some designe connect the 10ohm between -40v and Vdd not Vcc.
which way is correct ??

When i remove the feedback R , R33 , the ir2110 burn out easily.
Always see the R33 burned.

I have fix the circuit for 3 days.
Does anyone has any suggestion.???

[edl]

Hi,

Try this:
Give +5V to Vdd.
For Vcc let's give -40V with a 10ohm resistor. Let's put a 1uF folcap to the ground from Vcc.

Regards,

[analogspiceman]

The power supply of your schematic is drawn impossibly wrong and the labels don't match.  Please check this carefully and repost your actual circuit if you are serious about asking for help.

Regards -- analogspiceman

[phase_accurate]

Does R33 really have to be there ? The supply voltage of such a driver should be as "stiff" as possible IMO in order to work reliably. Or is there a cap between Vcc and COM in the App note ?

Regards

Charles

Edit: What is your switching frequency BTW ?

[titanchen68]

Thanks for all...

1. I see the datasheet of ir2110 , said , -0.3 < Vdd < Vss+25
If i connect Vdd to +5V , It will higher than Vss+25.
Is that right?

2. I'm sorry , I lost to modify the output voltage label.
I have modify it .

3. could you tell me , what is IMO ??
No , i didn't have cap between Vcc and Com.
Is that effect my whole circuit wrong ??
I will add it and try again ...
The sw freq is 200kHz , but now i search for the LF357.
now , i using tl084 to generate , but the waveform not good.

4. I saw a circuit created by Pierre , he use a IR2113.
He connect the 12vbias direct to Vcc , and serise a 10ohm to connect to Vdd.
which way is right??

[phase_accurate]

3. could you tell me , what is IMO ??

= In My Opinon

Apart from the things already mentioned - your C28 is a little large with 1n if your switching frequency is really 200 kHz. This will give you a pole in the feedback loop of 160 kHz approx.

Regards

Charles

[titanchen68]

160KHz too high ???
doesn't the purpose of the feedback low-pass filter is to reduce the high frequency noise ???
so , we have to set the limit freq slightly lower than s.w freq.
am i getting something wrong ???

[phase_accurate]

160KHz too high ???

No - toooooooooo low !

Theoretically the feedback signal should be as accurate as possible. i.e. not filtered at all with this carrier-based topology. I.e. it's bandwidth shouldn't be restricted.

But there will always be overshoot etc from the switching stage that the feedback loop can't cope with and these should be filtered out. So one uses a first-order lowpass as a compromise. But this one shouldn't have a too low cutoff frequency.

Regards

Charles

[SSassen]

Titan,

Upon first glance I see a missing capacitor, you need a ~1uF cap between Vcc and Com, and the bootstrap capacitor should be between 0.1 ~ 0.33uF, yours is too large. No need for a 4.7-ohm resistor in series with the diode either, just omit that. You mosfet gate resistors are very different, the low side being 10x the value of the high side, this will not work well.

I suggest you study the IR2110 and IR2011 datasheets a bit closer and take a look at the IRDAMP reference design, that should give you some pointers.

Best regards,

Sander Sassen
http://www.hardwareanalysis.com

[titanchen68]

1. My s.w freq= 200KHz , the cutoff-freq = 160KHz
If it too low , how many is suitable for me ??

2. 1uF bootstartp cap is too large ???
so , i only need a 100n for it ???
If i remove 4.7ohm , did i have to remove the 10ohm either ??

3. yes , i have read the IRDAMP reference yet .
and i also read many diyaudio member's designe.
It have many different bootstrape cap using.
So , i 'm not really sure what value is correct .

4. I'm sorry , my circuit's gate resistor get some wrong.
I forget to correct the circuit gate value.