For charging a bootstrap capacitor in a voltage converter, a circuit is provided for wider bandwidth to eliminate the feedback stability issue and pin out for compensation circuit. A pair of transistors are connected in series between a power input and the bootstrap capacitor, the first transistor is switched synchronously with a low-side transistor of the voltage converter, and a comparator compares a feedback voltage drawn from a feedback node between the pair of transistors with a reference voltage, to control the second transistor to determine to charge the bootstrap capacitor.