Energy recovery when braking is a requirement for some motor-driving applications. If the battery is fully charged and both charge and discharge MOSFETs are off, the PACK side can have a high voltage, damaging the BQ769x2 if the PIN voltage is higher than 85 V. One easy way to block high voltage is to add a series diode D29 between the discharge MOSFET and TOP_DSG, but the diode also blocks the sink current to turn off discharge MOSFET. A resister R166 is connected in parallel with D29 to supply a current path to turn on Q49 when turning off the discharge MOSFET. D20 and R155 protect TOP_LD voltage over the maximum limitations of the top BQ769x2. D20 is also helpful to limit the TOP_DSG voltage because the DSG pin is always driven toward LD pin when turning the discharge MOSFET off. For the other high-voltage pins of both the top BQ769x2 and bottom BQ769x2, the Zeners and resisters are always helpful to limit the voltages within the absolute maximum values. But if these high-voltage pins are used for voltage measurement, further calibrations are normally required to secure good accuracy with the protective Zeners and resisters.