Abstract: A control system for controlling an operating voltage of an electronic device is presented. The electronic device includes a timing event detector responsive to timing events, such as errors, related to operation of the electronic device. The control system includes a controller for decreasing the operating voltage when the rate of timing events is below a target level and for increasing the operating voltage when the rate of timing events exceeds the target level to search for a threshold voltage that is the smallest operating voltage at which the rate of timing events is substantially at the target level. The control system further includes a controllable clock signal generator for producing a clock signal for operating the electronic device so that the clock frequency is according to an increasing function of the operating voltage. Thus, it is possible to find a voltage-frequency operating point where the energy consumption is minimized.