| 摘要 |
An electrostatic discharge protection circuit is provided to prevent NMOS(N-channel Metal Oxide Semiconductor) transistors from being broken due to a CDM(Charged Device Model) electric charge by turning on CDM transistors before the NMOS transistors respectively. In an electrostatic discharge protection circuit, an output driver includes a pull down driver(331) connected between an input node of an input/output pad(301) and a first ground voltage line(302) and a pull up driver(332) connected between a first power voltage line(303) and the input node of the input/output pad(301). A pull down driver control unit(360) connected between a second power voltage line(305) and a second ground voltage line(304) turns on the pull down driver(331) or off by using a signal of an inner circuit(390) of a semiconductor device. A first CDM transistor is connected between an input node of the pull down driver(331) and the first ground voltage line(302). A first CDM resistance(306) is connected between the input node of the pull down driver(331) and an output node of the pull down driver control unit(360). A second CDM transistor(380b) is connected between an output node of the pull down driver control unit(360) and the second ground voltage line(304). A pull up driver control unit(370) connected between the second power voltage line(305) and the second ground voltage line(304) turns the pull up driver(332) on or off by using a signal of the inner circuit(390) of the semiconductor device. A third CDM transistor(380c) is connected between an input node of the pull up driver(332) and the first power voltage line(303). A second CDM resistance(307) is connected between the input node of the pull up driver(332) and an output node of the pull up driver control unit(370). And, a fourth CDM transistor(380d) is connected between an output node of the pull up driver control unit(370) and the second ground voltage line(304).
|
