Patent ID: 7471121

Claim:
A transistor drive circuit of a power converter, comprising: an input terminal to receive a supply voltage; an output terminal to output a switching signal for driving a transistor of the power converter; an N-type high-side transistor having a drain terminal coupled to the input terminal, a source terminal of the N-type high-side transistor coupled to the output terminal; a P-type high-side transistor having a source terminal coupled to the input terminal, a drain terminal of the P-type high-side transistor coupled to the output terminal; an N-type low-side transistor having a drain terminal coupled to the output terminal, a source terminal of the N-type low-side transistor coupled to a ground; a first control circuit coupled to control the gate terminal of the N-type high-side transistor and the gate terminal of the P-type high-side transistor; a second control circuit coupled to control the gate terminal of the N-type low-side transistor; and a detection circuit coupled to the supply voltage to generate a disable signal in response to the voltage level of the supply voltage, wherein the disable signal is transmitted to the first control circuit to disable the P-type high-side transistor once the voltage level of the supply voltage is higher than a threshold voltage.