HIP4081 PWM issue

[gv260ea]

Hi, Recently i've been developing a motor driver bıard with the HIP4081. I'm applying PWM to the BHI pin and 3.3V to the ALI pin. My mosfets are IRFS7437 and there is a 15ohm resistor between their gates and the driver pins. I do not get the pwm out of the mosfet. The first photo is the output pin under load and the second pin is the gate pin of the mosfet. Notice that there is an offset in the gatepin which the square wave doesn't go to GND. What is causing this issue and how can i solve it. I have also attached the schematic of the board.

View attachment Schematic.pdf

 

[KlausST]

Hi,

Maybe the bootstrap circuit can not wirk, because you don't switch the low side fet on.
Fet drivers with bootstrap circuit need a minimum duty cycle at the low side fet.

Look into datasheet and/or application notes.

Klaus