Circuit for electrostatic discharge protection

摘要

A circuit (100) ensures electrostatic discharge (ESD) protection during an ESD event. The ESD circuit (100) has a current shunting device (135), a RC trigger circuit (125) and a RC delay circuit (130). The shunting device (135) is connected between two IC power supply rails, and provides the primary current path for a positive ESD event referenced from one power supply rail (VDD 105) to the other (Vss 110). The trigger circuit (125) initially activates the shunting device into a low resistance conductive state in response to an ESD event. The RC delay circuit (130) serves to maintain the shunting device in the conductive state, initially produced by the trigger circuit (125), for the remaining duration of the ESD event. A large capacitor required to achieve the delay time in this RC circuit may be eliminated by utilizing the gate-to-body capacitance in the existing shunting device (135).