ESD protection control circuit and system
An electrostatic discharge (ESD) protection control circuit for an output pad of an integrated circuit includes an output driver and a control switch. The output driver, coupled to the output pad, includes a first output transistor for outputting power or signals to the output pad. The control switch, for improving ESD protection on the output pad when closed, includes a first connection terminal, coupled to a gate terminal of the first output transistor; a second connection terminal, coupled to a ground terminal; and a control terminal, coupled to a first power supply terminal.
1. An electrostatic discharge (ESD) protection control circuit for an output pad of an integrated circuit (IC), the ESD protection control circuit comprising:
an output driver, coupled to the output pad, comprising a first output transistor for outputting power or signals to the output pad; and
a control switch, for improving ESD protection on the output pad, comprising:
a first connection terminal, coupled to a gate terminal of the first output transistor;
a second connection terminal, coupled to a ground terminal; and
a control terminal, electrically connected to a first power supply terminal;
wherein the control switch comprises a P-type metal oxide semiconductor transistor.
2. The ESD protection control circuit of claim 1 , wherein the P-type metal oxide semiconductor transistor comprises:
a source terminal, connected to the gate terminal of the first output transistor;
a drain terminal, connected to the ground terminal; and
a gate terminal, connected to the first power supply terminal.
3. The ESD protection control circuit of claim 1 , wherein the control switch comprises an N-type metal oxide semiconductor transistor, which comprises:
a drain terminal, connected to the gate terminal of the first output transistor;
a source terminal, connected to the ground terminal; and
a gate terminal, coupled to the first power supply terminal via an inverter.
4. The ESD protection control circuit of claim 1 , wherein the first output transistor is an N-type metal oxide semiconductor transistor, and the first power supply terminal controls the control switch to be closed when the IC is power-off and controls the control switch to be open when the IC is power-on.
5. The ESD protection control circuit of claim 1 , wherein the first power supply terminal supplies power to a previous stage coupled to the output driver.
6. The ESD protection control circuit of claim 1 , wherein the output pad is connected to an ESD protection cell.
7. The ESD protection control circuit of claim 1 , wherein the output driver further comprises a second output transistor, which receives power from a second power supply terminal.
8. The ESD protection control circuit of claim 7 , wherein the second power supply terminal is connected to an ESD protection cell.
9. The ESD protection control circuit of claim 1 , wherein the first output transistor is a power supply transistor, and the output pad is a power output pad.
10. An electrostatic discharge (ESD) protection system for an output pad of an integrated circuit (IC), the ESD protection system comprising:
an output driver, coupled to the output pad, comprising an output transistor for outputting power or signals to the output pad;
a previous stage, coupled to the output driver, for receiving power from a power supply terminal;
an ESD protection cell, coupled to the output pad; and
a control switch, for improving ESD protection on the output pad, comprising:
a first connection terminal, coupled to a gate terminal of the first output transistor;
a second connection terminal, coupled to a ground terminal; and
a control terminal, electrically connected to the power supply terminal;
wherein the control switch comprises a P-type metal oxide semiconductor transistor.