Level shift circuit

摘要

There is provided a level shift circuit free from malfunction. The level shift circuit converts a signal of a first power supply voltage of a first supply terminal, which is supplied to an input terminal, into a signal of a second power supply voltage of a second supply terminal and outputs the converted signal to an output terminal. The level shift circuit has a control circuit that detects when the first power supply voltage reduces below a predetermined voltage. The voltage of the output terminal of the level shift circuit is fixed to the second power supply voltage or a ground voltage according to a detection signal of the control circuit.

主权项

1. A level shift circuit adapted to convert a signal of a first power supply voltage of a first supply terminal, which is supplied to an input terminal, into a signal of a second power supply voltage of a second supply terminal and outputs the converted signal to an output terminal, the level shift circuit comprising:
a control circuit configured to detect whether the first power supply voltage is above a predetermined voltage, a first transistor configured to set a voltage of the output terminal to the second power supply voltage when the signal supplied to the input terminal is below a threshold; a first switch connected in parallel to the first transistor; a second transistor configured to set the voltage of the output terminal to the ground voltage when the signal supplied to the input terminal is above the threshold; and a second switch connected between the second transistor and the output terminal, wherein the first switch and the second switch are controlled by a detection signal of the control circuit, and wherein a voltage of the output terminal of the level shift circuit is fixed to one of the second power supply voltage or a ground voltage according to the detection signal of the control circuit.