EPC90147 5kHz low frequency limit


We are using EPC90147 board and we want to use it below 5 kHz. Is this limit due to the bootstrap? If so, can we bypass it using a circuit like the one in the picture?

Best regards,

thank you for your question.
There are two low frequency limits, one is due to the bootstrap, which puts limits to the maximum HS FET turn on / turn off time and to the duty cycle, since the charge of the bootstrap capacitor is less effective at extreme low or high duty cycle.
The second one is inherent in the design of our GaN IC EPC23102. We have a limit of maximum Ton and Toff of 200 us, which defines the minimum Fsw as 5 kHz, regardless of duty. Please see the below section of the datasheet. This internal limit cannot be overcome, and there is no workaround.

Hope this helps.

Best regards