A bootstrap circuit integrated to a voltage converter integrated circuit (IC) and a voltage converter IC for a switch mode voltage regulator. The bootstrap circuit is used to provide a bootstrap voltage signal for driving a high side switch of the voltage converter IC. The bootstrap circuit has a pre-charger and a bootstrap capacitor. The pre-charger provides a first bootstrap signal to pre-charge a control terminal of the high side switch, and the bootstrap capacitor provides a second bootstrap signal to enhance the charge of the control terminal of the high side switch.