A low-area, low-power programmable frequency multiplier for DLL based clock synthesizers

A simple low-area and low-power clock frequency multiplier is proposed for Delay Locked Loop (DLL) based clock synthesizers. In this circuit, 2n voltage controlled delay lines (VCDL) are used to multiply the input frequency of a clock signal by n. This frequency multiplier is less susceptible to jitter- accumulation as it is a DLL-based design. The proposed circuit can operate at a substantially low supply voltage. Simulation results show that the proposed frequency multiplier dissipates about 10% to 50% less power than similar clock multiplier circuits. In addition, an architecture for programmable frequency multiplication has been proposed in this paper.