Method and apparatus for biasing body voltages

摘要

An apparatus for biasing a body voltage of a silicon-on-insulator transistor includes an operational amplifier that generates an output voltage that is proportional to the voltage difference between a desired gate-source threshold voltage and a reference voltage. A reference biasing transistor has a gate that is electrically coupled to the output. A reference mirror transistor has both a gate and a drain that are electrically coupled to the current source node, and also has a body that is electrically coupled to the drain of the reference biasing transistor. A device biasing transistor has a gate that is electrically coupled to the output voltage and has a drain that is electrically coupled to the body of the silicon-on-insulator transistor. The device biasing transistor maintains a voltage at the body of the silicon-on-insulator transistor so that it has a gate-source threshold voltage within a predetermined range of the desired gate-source threshold voltage.