Patent ID: 10566933

Abstract:
A class AB amplifier with improved DC gain. An amplifier includes an input stage and an output stage. The output stage is configured to amplify an output of the input stage. The output stage includes output transistors, class AB amplifier circuitry, minimum selector circuitry, and gain boost amplifier circuitry. The class AB amplifier circuitry includes a first transistor and a second transistor connected as a differential amplifier. The minimum selector circuitry is configured to control bias current in the output transistors by driving a control input of the first transistor. The gain boost amplifier circuitry is coupled to the class AB amplifier circuitry. The gain boost amplifier circuitry is configured to drive a common mode signal onto the control input of the first transistor and a control input of the second transistor, the common mode signal based on the output of the input stage.