Patent ID: 7230806
Filing Date: 2007-06-12
Classification: H01L

Abstract:
1. A power supply clamp circuit comprising: a switchable current sinking circuit connected to a power supply node, the switchable current sinking circuit having a plurality of series coupled transistors; a control circuit connected to a control node of the switchable current sinking circuit, the control circuit adapted to couple the control node to a ground potential such that during an electrostatic discharge event on the power supply node a voltage drop from the control node to the ground potential is less than a threshold voltage of an n-type load transistor within the control circuit; a voltage divider circuit connected to the power supply node and adapted to provide a reference voltage to the control circuit; a voltage follower circuit adapted to present a low output resistance to the voltage divider circuit and connected to the control circuit at the control node of the switchable current sinking circuit; and a differential amplifier circuit adapted to set a required voltage drop across the voltage follower through a negative feedback.