Hello everyone,
I'm having strange problem with the design of a high voltage MOSFET driver. I'm using 4 N-channel MOSFETs in H-bridge setup, so the two high side FETs are controlled with a bootstrapping (please have a look at the attached circuit of the high side driver).
The problem is as I increase the Vin (the voltage switched by the FET) the driver stops working. At 80V of Vin it's all working allright and having 200V makes the gate signal blurry on the high side (I believe the FET can't really be turned on) by unknown reason. I'm testing only the high side FET, using a 10K capacitor connected from its source to ground.
Some details on the parts I'm using:
- FET - IRF740
- Bootstrap capacitor - 0.1 uF
- Vcc - 15V
- Control signal - 8kHz 50% duty
All help and tips are highly appreciated.
I'm having strange problem with the design of a high voltage MOSFET driver. I'm using 4 N-channel MOSFETs in H-bridge setup, so the two high side FETs are controlled with a bootstrapping (please have a look at the attached circuit of the high side driver).
The problem is as I increase the Vin (the voltage switched by the FET) the driver stops working. At 80V of Vin it's all working allright and having 200V makes the gate signal blurry on the high side (I believe the FET can't really be turned on) by unknown reason. I'm testing only the high side FET, using a 10K capacitor connected from its source to ground.
Some details on the parts I'm using:
- FET - IRF740
- Bootstrap capacitor - 0.1 uF
- Vcc - 15V
- Control signal - 8kHz 50% duty
All help and tips are highly appreciated.
Attachments
-
25.7 KB Views: 723