ELECTROSTATIC DISCHARGE PROTECTION CIRCUIT

摘要

PURPOSE: An electrostatic discharge protection circuit is provided to increase the endurance against electrostatic discharge by using NPN bipolar transistors as well as NMOS transistor as circuit components. CONSTITUTION: The electrostatic discharge protection circuit includes a pad(10), a main chip(20), a bipolar transistor(T1) and a MOS transistor(T2). The bipolar transistor as well as the MOS transistor are coupled between the pad and the main chip and are coupled with each other in parallel. The bipolar transistor and the MOS transistor protects the circuit from electrostatic discharge as well as from CDM(charged device model). Alternatively, the circuit further includes a resistor, the first MOS transistor, a controller and the second MOS transistor. The resistor is coupled between the pad and the main chip. The first MOS transistor is coupled with the pad and the resistor. The controller controls the operation of the first MOS transistor. The second MOS transistor is coupled between the resistor and the main chip and is grounded.