Bootstrap circuit and method for controlling the same

A bootstrap circuit, applying to a voltage converter, for charging a bootstrap capacitor, comprising:

• a charging voltage source;
• a charging diode, including an anode coupled to the charging voltage source;
• a high-voltage transistor, including a channel coupled between a cathode of the charging diode and a bootstrap capacitor, and a control terminal switching the channel of the high-voltage transistor to be on or off;
• a logic control circuit, including a logic input, a first logic output, and a second logic output, wherein the logic input is used for receiving a charging command signal, the charging command signal is used to control the bootstrap circuit whether to charge the bootstrap capacitor by the bootstrap circuit, the first logic output is used to output a signal non-inverting with the signal in the logic input, the second logic output is used to output a signal inverting with the signal in the logic input;
• a high-voltage control transistor, having a control terminal and a channel coupled between the charging voltage source and the control terminal of the high-voltage transistor;
• a cut-off resistor, coupled between the control terminal of the high-voltage transistor and the control terminal of the high-voltage control transistor;
• a charging control transistor, including a channel coupled between the control terminal of the high-voltage control transistor and a ground terminal and a control terminal coupled to the second logic output;
• and
• a control capacitor, coupled between the control terminal of the high-voltage transistor and the first logic output.