Dynamic voltage and frequency scaling

Abstract

An integrated circuit comprises an oscillator which outputs a clock signal, a logic circuit portion, a detection circuit portion for detecting signal propagation delay relative to clock frequency, and a power supply which provides a configurable supply voltage. The detection circuit comprises a latch circuit portion, a delay circuit portion and a comparison circuit portion. The latch circuit portion outputs an alternating signal which changes state in dependence on the clock signal. This is received by the delay circuit portion which outputs first and second delayed signals respectively subject to first and second propagation delays each dependent on the supply voltage. The comparison circuit portion compares the alternating signal with the delayed signals, and outputs respective comparison signals if said signals indicate that the respective propagation delay is smaller than the clock signal period. A control circuit portion controls the supply voltage in dependence on the comparison signals.