Patent ID: 6940703
Filing Date: 2005-09-06
Classification: H02H

Abstract:
1. An amplifier, comprising: amplifier circuitry for amplifying an input signal; and overvoltage protection circuitry for interposing between an input voltage and an amplifier supply voltage, the amplifier supply voltage providing power to the amplifier circuitry, the overvoltage protection circuitry comprising; switch circuitry connected to and passing current between an input voltage node and an amplifier supply voltage node, the input voltage node corresponding to the input voltage and the amplifier supply voltage node corresponding to the amplifier supply voltage; and switch control circuitry for sensing the amplifier supply voltage and regulating current flow through the switch circuitry in response thereto, wherein the switch control circuitry comprises a three terminal bucking DC voltage regulator configured as a voltage controlled current source for providing a control signal to the switch circuitry; wherein an output of the voltage regulator is coupled to the supply voltage node such that a change in the supply voltage varies an output current from the voltage regulator, and thereby varies an input current to the voltage regulator from which the control signal is generated.