Patent ID: 9171834
Filing Date: 2015-10-27
Classification: H01L,H02H,Y10T

Abstract:
1. An integrated circuit that provides over voltage protection for a thin oxide load circuit, the integrated circuit comprising: a substrate having a thick oxide portion and a thin oxide portion; a load circuit disposed on the thin oxide portion, wherein the load circuit has a first end that is coupled to a first supply node and a second end that is directly connected to a virtual supply node; a current source circuit disposed on the substrate, the current source circuit having an input coupled to a control signal node and an output directly connected to the virtual supply node, wherein the current source circuit is operable to provide a voltage at the virtual supply node, which is based on a control signal coupled to the control signal node; a protection circuit disposed on the substrate and disconnected from the control signal node of the current source circuit, the protection circuit comprising a sensing portion coupled to a protection portion, wherein the sensing portion is directly connected to the virtual supply node and is operable to sense the voltage at the virtual supply node and, when the sensed voltage meets an intrinsic or extrinsic reference voltage value, to activate the protection portion, which is external to the current source circuit, wherein the protection circuit is coupled to the sensing portion and is operable in response to feedback from the sensing portion of the sensed voltage, to clamp a difference in voltage between the voltage at the virtual supply node and a second voltage at the first supply node to a first maximum voltage value that is established by the second voltage at the first supply node and the control signal, the magnitude of which is set by a source external to the protection circuit.