Part Number:DRV8844
I am seeing a 6V p-p ripple at the VCP pin that is in sync with the PWM drive frequency. The Voltage at the VCP varies from 37V to 43V and the supply voltage to the H-bridge is 28VDC. Then the H-bridge high side is turned on the VCP voltage drops sags to 37V and when the high side is turned off the VCP voltage charges to 43V. At the same time the high side output sags from 27.5V to 24.5V. I would think that 37V is enough to fully turn on the high side FET based on a 28V supply (9V). Can anyone tell me why the high side FET output is sagging and/or how to remove the ripple in the charge pump output? PNG picture is attached.
