Output driver with back-powering prevention

摘要

A back-power prevention circuit is provided that protects a buffer transistor from back-power during a back-power condition by charging a signal lead coupled to a gate of the buffer transistor to a pad voltage and by charging a body of the buffer transistor to the pad voltage.

主权项

1. An integrated circuit, comprising:
a pad configured to receive a voltage signal from a remote integrated circuit; a power supply rail; a first buffer transistor having a first terminal coupled to the pad and having a second terminal coupled to the power supply rail; a pre-driver configured to drive a gate of the first buffer transistor through a first control path; a first switch coupled between the first control path and the pad, the first switch being configured to switch on in response to a power down of the power supply rail; and a control signal generator configured to respond to an assertion of the voltage signal while the power supply rail is powered down by coupling a body of the first buffer transistor to the pad.