Described is an apparatus which comprises: a low-side switch coupled to an output node for providing regulated voltage supply; and a first driver operable to cause the low-side switch to turn off when the output node rises above a first transistor threshold voltage. Described is also a voltage regulator which comprises: a signal generator to generate a pulse-width modulated (PWM) signal; a bridge having a low-side switch coupled to an output node for providing regulated voltage supply according to the PWM signal; a first driver operable to cause the low-side switch to turn off when the output node rises above a first transistor threshold voltage; and a bridge controller to provide control signals to the first driver. The voltage regulator may operate without diode clamps and its operation is self-timed. The voltage regulator also provides tolerance against process variation.