Cypress Semiconductor Corporation

Xiaohu Zhang

Tao Peng

George M Ansel

An improved interface circuit is provided herein for translating a relatively high input voltage into a relatively low output voltage using only low voltage transistors and a single, low voltage power supply. According to one embodiment, the interface circuit includes a power supply, a pair of input transistors with source terminals coupled together for receiving a relatively low voltage from the power supply, and a current sense amplifier with a pair of input terminals, each coupled to a drain terminal of a different one of the pair of input transistors for receiving a pair of differential currents and for generating a pair of differential voltages therefrom.

Low voltage interface circuit

A driver circuit is provided herein. In general, the driver circuit includes a driver portion, a common mode feedback portion and a current replication portion. The feedback portion receives a common mode voltage (vcm) from the driver portion and an alternative common mode voltage (vcm_alt) from the current replication portion. The feedback portion selects one of the common mode voltages for comparison with a reference voltage and generates a feedback bias signal (vcmfb) based on a voltage difference there between. When the driver circuit is enabled, the actual common mode voltage (vcm) is used to maintain the output common mode voltage around the reference voltage. When the driver circuit is disabled, the alternative common mode voltage (vcm_alt) is used to keep the bias signal (vcmfb) from drifting away.

Growing community of inventors

Starkville, MS, United States of America

Xiaohu Zhang