US Patent 7969206 Semiconductor element drive circuit

A drive circuit for driving a semiconductor element according to an input signal includes an output stage, a clamp circuit, a comparator, and a clamp control circuit. The output stage includes a series circuit of two transistors. A node between the transistors is coupled to a control terminal of the semiconductor element. One of the transistors is turned on when the input signal indicates that the semiconductor element is driven. The clamp circuit clamps a potential of the control terminal to a level enough to drive the semiconductor element when the one of the transistors is turned on. The comparator compares a power supply voltage of the drive circuit with a threshold voltage. The clamp control circuit disables the clamp circuit when the power supply voltage is less than the threshold voltage.