Patent ID: 8664997

Claim:
A method to achieve a fast switchable high voltage power transistor driver circuit, comprising the following steps: (1) providing a circuit comprising a port for a high voltage supply voltage, a port for a low voltage supply voltage, an input stage comprising only one high voltage output power transistor, an output port, and a port for a digital input signal, and a control stage to achieve a constant gate-source voltage of the only one high voltage output power transistor; (2) limiting the gate-source voltage of the high voltage output power transistor using a voltage drop of a first reference current across a resistive load if the digital input signal is high, wherein time constants for switching on and off the high voltage output power transistor are reduced by adding two high voltage transistors of the same type as the high voltage output power transistor to the circuit in parallel to the input stage in order to increase the operation frequency of the circuit, wherein each of both additional transistors is smaller than the high voltage power transistor; (3) pulling the gate of the high voltage power transistor to the level of the high voltage supply voltage if the digital input signal is low; and (4) generating a second reference current, which is controlled by a reference voltage via a differential amplifier, wherein the second reference current is mirrored to the first reference current in order to establish an accurate gate source voltage of the high voltage.