A method of adaptively controlling a charge pump including coupling the charge pump to a control node, toggling a clock input between supply voltage levels to charge an a charge pump output, monitoring the charge pump output, maintaining the control node at a supply voltage level when a supply voltage magnitude does not exceed a threshold level, and adjusting the control node to maintain the charge pump output at a limit level when the supply voltage magnitude exceeds the threshold level. A positive charge pump embodiment charges the output to twice the positive supply voltage up to no more than a limit level. A negative charge pump embodiment charges the output to the same magnitude with opposite polarity as the positive supply voltage, and decreases the output magnitude if the positive supply voltage is above the threshold level. A Zener diode and controlled current mirror may be used for control.