System and method of protecting a low voltage capacitor of an error amplifier operating in a higher voltage domain

Abstract

An error amplifier including a differential pair circuit, a resistive device, a low voltage capacitor, and a protection device. The differential pair circuit is coupled between an upper supply node and a lower supply node with first and second intermediate nodes and is responsive to a difference between a reference voltage and a feedback voltage for driving a control voltage developed on the second intermediate node. The resistive device is coupled between the second intermediate node and a low voltage node, and the low voltage capacitor and the protection device are coupled between the low voltage node and the lower supply node. The protection device is dynamically controlled by the first intermediate node to prevent the low voltage node from exceeding a predetermined maximum level. The protection device may be a transistor having size parameters based on voltage characteristics of the first intermediate node during expected operating conditions.