Huge problem with l6203

[black-code]

hello all,..

I faced a very huge problem with l6203 in my project and i don't know any solution ,i hope someone can help me to overcome it.

I connected l6203 with atmega32 microcontroller to make a speed control for a dc motor with a two batteries 12 v connected in series to give 24 volt.

The microcontroller takes it's 5 v from a simple regulator 7805.

Here is the schematic :

**broken link removed**

I used the above circuit for two motors with two h-bridges (l6203) and two microcontrollers each motor has it's microcontroller and h-bridge ( GND and VCC are common for all the circuit).

On connecting the power to the circuit the motors runs normally then suddenly one of the two bridges becomes very hot and then blowing out !!!!! Crying or Very sad

WHAT IS THE REASON PLEAAASE ??

I am very depressed for that because i don't want the reason for that.
I read l6203 datasheet, i found that there is a table saying that vref taking 13.5 volts typ. is this means that i must connect vref to 13.5 external voltage or what ??


Thanks.

 

[Pommie]

Your schematic isn't showing. I looked at it anyway and see that you have no bootstrap capacitors. Without these the mosfets can't turn on fully and burn out. You will also (probably) need a snubber circuit. This is all explained in the data sheet.

Mike.

 

[black-code]

Thanks mike for help.

So I must put the bootstrap capacitors at pins 4 and 8, is this the reason for that damage ??

Do you mean l6505 by a snubber circuit, i think that i can use the microcontroller instead !!

In the datasheet i read that vref takes 13.5v in electrical characteristics table, so should i connect vref pin to 13.5 v or just connect it with 0.22uf to gnd ??

THANKS.

 

[black-code]

Any help ??

 

[Pommie]

Is your question different from the original question?

Mike.