Hi Shimizu,
Ideally the device can work at 100% duty cycle which means long time high side gate voltage sustain. So 7 Hz should be fine. Please make sure there is no external GS path even high resistance path.
But I think we don't have to go such low PWM frequency, we can alway has constant high PWM frequency but with low frequency modulation for the 3 or 6 PWM inputs. Such as 1% or 99% to replace the constant LOW and HIGH control.
Best regards,
