| 摘要 |
An electrostatic discharge protection circuit is provided to reduce the turn-on resist of a control unit which controls operation of a transmission unit dividing an input and output pad and the internal circuit when static electricity is applied by coupling resistor with capacitance at each gate of NMOS and PMOS transistors. An electrostatic discharge protection circuit comprises a discharge unit(310), a transmission unit(320), and a control unit(330). The discharge unit includes diodes(312,314). One diode is connected between an input and output pad and a power voltage terminal(VDD). The other diode is direct connected between the input and output pad and a ground voltage terminal(VSS). The discharge unit discharge ESD current coming from the input and output pad to the power voltage terminal or the ground voltage terminal. The transmission unit includes a transfer transistor(PG1), and first and second resisters(R5,R6). The transfer transistor is installed between the input and output pad and internal circuit. The first resister is installed between the power voltage terminal and a gate of an NMOS transistor(N3) of the transfer transistor. The second resister is installed between the ground voltage terminal and a gate of a PMOS transistor(P4) of the transfer transistor. The transmission unit turns on the transfer transistor and transfers signals coming through the input and output pad to the internal circuit in a regular operation. The transmission unit turns off the transfer transistor, and shuts off the input and output pad and the internal circuit, when ESD current is applied.
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