Level shift circuit

摘要

The invention provides a level shift circuit which uses a low supply voltage level shift circuit as a first level shift element and a high supply voltage level shift circuit as a second level shift element and which is configured to switch these level shift circuits in accordance with supply voltage. The low supply voltage level shift circuit is in an operating state with its power supply turned ON when supply voltage is low and in a shut-down state with the power supply turned OFF to ensure the breakdown voltages of the elements when supply voltage is high. The high supply voltage level shift circuit is in a shut-down state with its power supply turned OFF when supply voltage is low and comes into an operating state with the power supply turned ON while ensuring the breakdown voltages of elements when supply voltage is high.

主权项

1. A level shift circuit comprising:
a signal input terminal for receiving an input signal to be level shifted; a first level shift circuit; a second level shift circuit; a comparator circuit; and a reference voltage supply, wherein: the signal input terminal is connected to a first VIN terminal of the first level shift circuit and a second VIN terminal of the second level shift circuit, the first level shift circuit is connected, at its first power supply terminal, to a first high potential side power supply, connected, at its second power supply terminal, to a second high potential side power supply and connected, at its earth terminal, to a low potential side power supply, the second level shift circuit is connected, at its first power supply terminal, to the first high potential side power supply, connected, at its second power supply terminal, to the second high potential side power supply and connected, at its earth terminal, to the low potential side power supply, a power supply ON/OFF operation of the first level shift circuit and a power supply ON/OFF operation of the second level shift circuit are controlled in accordance with an output from the comparator circuit, and the comparator circuit is configured to compare a second high potential side power supply voltage inputted from outside with an output voltage of the reference voltage supply.