# VOM1271 as isolated power supply for gate driver

When looking for a gate driver to drive a FET with 65nC gate capacity at 10V with a frequency of 100 Hz I found the VOM1271. Unfortunately it seems like with such a high gate capacity it is impossible for this part to switch fast enough, I calculated the switching time to be over 1 millisecond. So I was wondering if I could use the VOM1271 as an always on isolated power supply to constantly charge a capacitor and then just put an isolated gate driver next to it to control the FET?

Does that sound feasible for such a low switching frequency?

• "to switch fast enough" -- how fast? This seems to be your assumption, but what justification could you provide to support it? Examples: device and load ratings, allowable power dissipation, required efficiency, minimum pulse width, etc. Commented Jul 18, 2023 at 14:38
• There are MOSFETs with much more than 65nC of gate charge, and they can be switched very quickly (microseconds) as long as a suitably high-current driver is used (Amperes of current.) Could you expand on exactly how the VOM1271 is being driven by showing a schematic? Commented Jul 18, 2023 at 14:45
• @rdtsc The VOM1271 is only able to supply about 50uA though. That's why I wanted to use a faster driver, but I need to supply an isolated voltage for it. Commented Jul 18, 2023 at 14:50
• Calculate how much power or current you need to switch 65 nC at 100 Hz and 10 V. Can the VOM1271 supply it? As @rdtsc said, it will be easier to find a different MOSFET. Commented Jul 18, 2023 at 14:57
• @TimWilliams This is for an inverter circuit, I need it to switch as fast as possible to keep the THD low. It will be 50% on and 50% off from a 50 Hz sine wave. I can "wait" until it is fully switched before supplying voltage to the circuit to reduce switching losses, but 1 millisecond is a little too long. Something in the 10uS range would probably be my goal. Commented Jul 18, 2023 at 14:59