A slew rate control circuit in output driver of switching circuit to prevent power ground undershoot is introduced. The gate capacitance of lower power transistor is first fast discharged to ensure the operation of the output signal. The gate capacitance of lower power transistor is then slowly discharged to limit OUT SLEW RATE. The gate capacitance of lower power transistor is further slowly discharged when the power ground level is below common ground. With above controlling, the gate voltage slew rate of lower power transistor is reduced when the lower power transistor is almost fully turned OFF. Therefore, undershoot at the power ground is avoided. Similar slew rate control circuit can also be derived in output driver of switching circuit to prevent PVCC overshoot.