High frequency H-bridge

[559 nanon]

Hi every one,

I've designe an H-bridg (refer to the schematic). the h-bridge is meant to work at:

1. 100K Hz (from a fucntion generator; low 0 and high 5)
2. 15A -18A
3. drive a load (an inductor in series with 6 ohm resistor)
4. Vcc = 12V
5. C1= C2 =0.47 uF ; C3=C4= 2.2 uF.
6. the Mosfet driver is IR2104

there are some issues that I really need to understand; these are:

1. when one MOSFET is defected the MOSFET drivers' ICs also break down (and they say unbreakable)

2. I used two power supplies (from the lab). one is for the power and the other one for the Vcc for all ICs. When I truned the power on (15V) and Vcc was 12V, the Vcc power supplies jump to 27V without I touched the knob. (it seems they add up; 12+15) huh?

really like to share ideas with you.

thanx

 

[darla1]

make sure that all grounds connectd properly,i have observed in schematics, there is isolation, so need to connet gorunds properly.

 

[559 nanon]

Thank you darla 1 for you reply. the problem was the heat sink which was connecting (short circuit) the drains of two mosfets

thank you again