Patent ID: 6118640
Filing Date: 2000-09-12
Classification: H01L,H02H

Abstract:
An electro-static-discharge (ESD) protection circuit comprising:a first power-supply input for coupling to a first power supply;a second power-supply input for coupling to a second power supply, the first power supply not being directly connected to the second power supply by metal lines on an integrated circuit containing the ESD protection circuit;an ESD switch, coupled to conduct current between the first power-supply input and the second power-supply input, the ESD switch controlled by a gate node;an active control circuit, coupled to the first power-supply input and the second power-supply input, for driving an enable voltage onto the gate node to enable the ESD switch and for driving a disable voltage onto the gate node to disable the ESD switch;wherein the disable voltage is driven to the gate node when the first or second power-supply inputs are powered up;a first filter network, coupled to the first power-supply input, for coupling a rapid voltage rise from an ESD pulse applied to the first power-supply input to the gate node to generate the enable voltage on the gate node, the enable voltage causing the ESD switch to conduct the ESD pulse to the second power-supply input when the enable voltage is applied; anda first discharge path, in the first filter network, coupled between the gate node and the second power-supply input, for gradually discharging the enable voltage to the second power-supply input through a first resistor,whereby the ESD switch is actively disabled and enabled.