IR2110 Low Channel Problem

[Khaled Farag]

Hello,
I am implementing a half-bridge converter as shown in the figure.



The problem is that the low side channel has been blown many times (LO pin becomes short-circuited with VCC pin). The circuit works properly without problems at first, but when I stopped it and touched the IR2110 for checking its temperature and switched ON the circuit again , I found the aforementioned problem. This happens many times. So, any suggestions will be highly appreciated.

Note: I use IGBT (G20N60B3D) as the power switch and the switching frequency is 500 Hz and of course there is a dead time between the switching devices.

Thanks

 

[Easy peasy]

sounds like the wiring is flakey...

 

[AdamsN]

use 2 zenners (15V) in each mosfet, between the gate and sourse, to clamp and protect your IC and your mosfet.

You should also tell us, your load? This happens in an open circuit situation or you have inductive load?

 

[c_mitra]

I guess (wild guess indeed) that the two diodes (D2 and D3) are rather slow. Because your switching frequency is rather low, you can afford to have slow turn-on and slow turn-off. Just get rid of D2 and D3.

 

[Khaled Farag]

Thanks for your reply.

If the wiring is flakey, may it cause this problem many times??

- - - Updated - - -

Thanks AdamsN for your reply.

This happens in an open circuit situation without any load.

 

[Khaled Farag]

Thanks c_mitra for your reply.

The circuit works well and I switched it OFF and ON again many times without any problem. Then as I said I touched the IR2110 with my finger, after that I found this problem.
Note:In every time I switched it ON, I let it running for about 20 minutes without problems. So, what would have happened to the IC by touching it ??

Thanks

 

[Warpspeed]

Only thing I can see there, is that pin 3 is not bypassed, and that supplies power to the bit that is blowing up.

How about another 22uF and 100nF between pins 2 and 3 ?

The problem could just as easily be on the ground side as the +12v side, but a bit of strong very direct power supply decoupling is not going to hurt.

*edit*

Thinking about it a bit more, the reverse recovery current of D1 could be spiking pin 3 upwards enough to be damaging, depending on physical layout.
Bypassing pins 2 and 3 should fix that.

 

[Khaled Farag]

Thanks for your reply Easy peasy
If the wiring is flakey, could that cause this problem many times?


Thanks for your reply AdamsN
This happens in an open circuit situation without any load. The circuit works well, the problem happens when I touched it.


Thanks c_mitra for your reply
OK I will try that. But the problem is that the circuit works well at first before I have touched it.
Note: I switched it OFF and ON many times without any problem and I let it run for about 20 minutes in every time. So, what would have happened to the IC by touching it??


Thanks for your reply Tony
OK I will try that, but it works well before I have touched it, and I have also seen many posts in many forums that present a working circuit without doing this bypassing. So, what could be my problem??

 

[Easy peasy]

show us a pic of the setup - that will likely expose the problem, your power supply could be flicking up to high volts when you turn it off (or on later) - try putting 2200uF on the 5V and 12V to limit this effect along with some 5W zeners, 5v6 and 15V say, respectively...

 

[saeedmns68]

Are U sure to put R4 and R3 resistors?without them IGBTs may turn on with out any control