Originally Posted by 7500rpm
You must turn on the high side FET's hard ( no pwm ) the low side is the only ones you pwm. The gate voltage on the high side must be approx 10-15 volts higher than Vcc to turn on the FETs properly.
That would be true for a BLDC ESC. Pulsing the low side drivers is what pumps the boot strap circuits and I guess more pulses would be better. Although at WOT both the high and low side drivers are not PWM and the commutation switching does the pumping.
For the circuit in question here, the low side driver is connected to a different driver module and does not pump the boot strap circuit for the high side driver. Ignoring everything else but the boot strap circuit, it is irrelevant whether the low side driver is on hard or pulsed