In described examples, a charge pump includes an output, first and second transistors, a control circuit, a multiplexer, and a calibration circuit. The first transistor's drain is coupled to the output. The second transistor's drain is part of a current path separate from a current path that includes the first transistor's drain. The control circuit generates a control signal in response to voltages at the gates of the first and second transistors. First and second inputs of the multiplexer are respectively coupled to sources of the first and second transistors. A control input of the multiplexer is coupled to receive the control signal. A first input of the calibration circuit is coupled to an output of the multiplexer. A second input of the calibration circuit receives a reference voltage. First and second outputs of the calibration circuit are respectively coupled to body terminals of the first and second transistors.