I got some Hip4081 . If I using it only for turn on/off motor , not for PWM in controll motor , is my MOSFET in high side going to turn off because charge pump capacitor for Hip fully discharge . But sometime I use my motor in PWM mode . Is it ok ?
i don't think so, but I can't say for sure - I'd have to see your circuit. The HIP4081 has an internal charge pump that should be able to hold your FET on. I suggest you review the datasheet, especially page 4 under the section titled "Upper Bias Supply Circuit Design". The link to the datasheet is here: **broken link removed**