一种CMOS功率开关反向电压保护电路

A CMOS Power Switch Reverse-Voltage Protection Circuit

接口电路通常采用CMOS功率开关作为输出缓冲电路,在实际应用中经常受到反向电压的冲击,因此,必须设计相应的反向电压保护电路,以保证CMOS功率开关的安全。提出了一种新型的反向电压保护电路,能够在反向电压冲击CMOS功率开关时提供合理的衬底电压和栅极电压,抑制反向电流,保障器件安全。该电路简洁有效,不影响电路的输出驱动能力和瞬态响应特性。采用0.6μm CMOS工艺,制作了一个包含保护电路的接口电路,测试结果表明,该保护电路能够在+12V反向电压下为功率开关提供良好保护。

In interface circuits,CMOS power switches are usually used as output buffers,which is subject to attack by reverse voltage in practical applications.Therefore,it is necessary to design a reverse-voltage protection circuit to ensure the safety of power switches.A novel protection circuit was put forward,which automatically selected proper substrate voltage and gate bias voltages to suppress reverse-voltage when it attacked CMOS power switch.The circuit was simple and efficient,it had no effect on output drive capability and transient characteristics of the circuit.An interface IC containing the protection circuit was fabricated using 0.6 μm CMOS process.Test result showed that the circuit was capable of providing protection for power switch against 12 V reverse voltage.