Hi EPC support team,
I designed a high voltage switch circuit with EPC2036 based on a half bridge circuit. The circuit can work well under 35V, but when high voltage increase to 40V, both high side and low side GaNFet EPC2036 were broken. I checked the damaged epc2036, all GS and DS are short circuit. It looks like EPC2036 can not support the voltage higher than 35V when they are used in a half bridge circuit.
EPC2036 can operate up to at least 80V in half bridge configuration without problems, and the devices are fully guaranteed to 100V rating.
We have a half-bridge board for the EPC2036: EPC9050 (epc-co.com), there are some waveforms in the quick start guide, and this could be a board you could test to compare to your own design.
In particular we use 1Ohm turn ON and OFF, while I noticed you use 0Ohm: since EPC2036 is a very small device this can result in ringing on both the gate and drain.
The next thing to check would be the layout. The board above can be a good reference, and we have resources here: GaN Designs Schematic & Recommended Layout | GaN 1st Time Right |EPC (epc-co.com)
I also wonder: what topology are you using? What is the output RC for?
Thank you for your reply and suggestions.
Let me detail our setting and hope you can provide more suggestions.
I am using this half bridge circuit to control high voltage turn-on/off for a LiDar short pulse discharging. My target voltage is 65V. R22,R23 are charging resistors and C43, C44 are discharging capacitors.
I am using a PWM (2KHz 98% duty cycle) to keep the HV_2 voltage as HV+. There is a 10us time to turn-on U21 (low end GaNFet), during this time, Vds of U21 is HV_2.
When HV_2 is below 35V, the whole circuits work well. But when I increased HV_2 to 40~45V, U21 exploded.
I think the reason of U21’s explosion is EPC2036 Vds can not support a 45V 10us.
I can only find the minimum low state input pulse width of pwm signal is 200ns. Do you have the parameter of maximum low state input pulse width?
May I have any mathod to keep U2 on and don’t need to “refresh” high side bootstrap supply voltage?
EPC2036 can support up to 100V indefinitely, so we need to understand in more detail the circuit operation. Could you share some waveforms measured across U21? We can also continue the conversation off line if you write to me firstname.lastname@example.org