A voltage doubler and an oscillating control signal generator controlling a charge pump (powered by a first voltage to provide a second voltage) of the voltage doubler are disclosed. The oscillating control signal generator includes a first input terminal receiving a fundamental oscillation signal, a second input terminal receiving a comparison result showing whether the second voltage is greater than a target value, a third input terminal operative to obtain an electric current consumption status at an output terminal of the charge pump, and an output terminal outputting an oscillating control signal for the control of the charge pump. Further, the oscillating control signal generator includes a logic circuit. The logic circuit generates the oscillating control signal by selectively blocking status changes of the fundamental oscillation signal according to the comparison result and the electric current consumption status.