High output swing operational amplifier using low voltage devices

摘要

A power efficient high output swing operational ("HOOP") amplifier for integrated circuit analog signal processing is described. The operational amplifier includes a differential input stage and an output stage. The differential input stage is powered by a regular power supply while the output stage is powered by a voltage multiplier which results in a high voltage output swing without sinking significant power from the voltage multiplier. The high output voltage (e.g., 23 volts) is achieved using low voltage MOS devices. An output isolation technique is utilized to prevent possible latchup and contention. The operational amplifier also features a bias boot scheme to achieve a faster settling time from power up. In addition, the present invention provides realization of frequency compensation with highest possible breakdown and reduced noise coupling. A bias arrangement between input and output stages of the operational amplifier is used to further help reduce the power drawn from the voltage multiplier and decrease the settling time.