A system includes a charge pump system having a plurality of enable signal input terminals and an output terminal, the charge pump system configured to provide an output voltage at the output terminal; and a detection circuit connected to the enable terminals and the output terminal of the charge pump system, the detection circuit configured to compare the charge pump system output voltage to a plurality of predefined input detection voltage levels, and to selectively output a plurality of enable signals to the charge pump system enable signal input terminals in response to the comparison.