I am currently bringing up a new design that is using the TPS62750 as the main PMIC. The application is a USB device that has a 470mF supercap (not shown) and we are using the TPS62750 to bring down the 5V input voltage to 3.85V that is both charging the supercapacitor and supplying our system load.
When we disconnect the input power source, we are seeing the input voltage remain high from what seems to be back driving from the output supercap into the input voltage. We are seeing a 550mV drop, likely the forward voltage of High Side MOSFET body diode. Due to this and the voltage being sufficiently high to keep the enable pin high, the output capacitor discharge function isn't activated either. Green waveform is input voltage and Yellow waveform is output voltage.
Has anyone had a similar experience with this IC? Any way to avoid this?