h bridge driver 's switching effects battery supply

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Hi all , I utilize the attached circuit and the switching part is working correct but it effects the battery supply (+12v) and drops it to 10v in minimum case of switching and brings it up to 14v in maximum one I know if I utilize another power supply for h-bridge part other than the digital part which produces PWM , the problem is solved But how can I use just one power supply and the problem would be solved Thanks in advanced

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Last Edited: Sun. Dec 14, 2014 - 01:30 PM
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The current has to go somewhere. Use a series diode and an electrolytic cap to decouple the supply.

Where's the h bridge? I can only see a single ended mosfet driver.

Last Edited: Sun. Dec 14, 2014 - 12:34 PM
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Sorry I can't get it

Would you please explain more ?

BTW , The attached may be the diode you mentioned ?

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Your schematic seems to have little relationship to how a TC4422 should be connected

Tom Pappano
Tulsa, Oklahoma

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It is not clear what you are trying to accomplish.  If you close the loop on the PWM by monitoring the output with ADC, then you can work around the supply voltage variation.

 

The TC4422 can withstand 18V supply.  You could limit to that with a shunt zener, if necessary.  A series pass regulator does not hold back if the output is pumped up by the boost of the LC, when PWM value is decreased.

 

It would be helpful to know the PWM profile used, and the load.  The regen pumping can be desirable for energy efficiency when driving PZT loads, and supply bulk capacitor bank sized accordingly.

It all starts with a mental vision.

Last Edited: Sun. Dec 14, 2014 - 07:52 PM
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Thanks
The carrier frequency is 125 khz and the output voltage is 300v peak to peak
I seperated the +12v of the digital parts of the board including the micro-controller which generates the PWM with the +12v of the tc4422 but the problem persists yet !!!

Even when I power off the +12v of tc4422 while +12v of the digital parts is still connected , the problem still persists !

 

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I still cannot see a h bridge. Where is it? What you describe is not very clear - the energy has to come from somewhere. Maybe from your bread made with radium flour to keep it warm?

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The 2 attachments are the whole circuit to produce a 125khz - 300v p2p sine wave

I connected the ground of the tc4422 dirrectly to power supply and disconnected it from the digital part of the board and the problem got solved

It seems the reverse current from the tc4422 which flows back to digital part was the problem

 

Now another point

When I disconnected the +12v and GND of tc442 from the digital part and connected them directly to power supply , the board worked fine for some time

but the tc4422 corrupted

When cutting the VCC and GND , the capacitor and diode which was common in digital and tc4422 was remained in the digital part and power supply dirrectly connected to the tc4422 circuit

Exactly the same as the picture in my first post

Can this corrupt the tc4422 ?!

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Just add more  bread, sounds  like the heater is working. :)

It all starts with a mental vision.

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Kartman wrote:

The current has to go somewhere. Use a series diode and an electrolytic cap to decouple the supply.

can you explain more or say where to place the cap and diode exactly ?

When I utilize a 100Uf cap between +12v and GND of the picture in my first post the voltage level decreases to 30v p2p instead of 300v p2p

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The tc4422 was not working for more than 3 seconds and it was corrupted
I don't know why
maybe feedimg PWM while +12V was not yet stable caused the problem ?

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Corrupted as in failed? Since you have no protection for inductive kickback, then it is not surprising what is more surprising is that there was enough energy coupled through from the pwm signal.

FYI it is a totem pole or push-pull driver. You need two of these for a H bridge.

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What can I do for the inductive kickback ?

This circuit is designed by a well known company (I don't say what it is cause this site is Atmel board)

How can I find a circuit which is industrial and working properly ?

 

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I think you need to understand how TC4422 switches as a half bridge, and what happens in the switched L-C circuit.

 

A review of your training in L-C switched circuits may help.

It all starts with a mental vision.

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Thanks
I'm working to find an industrial driver