Publication

Abstract : In this paper, we present a new design of phase frequency detector (PFD) without reset, such that the blind zone and dead zone issues in the phase locked loop are annihilated. The PFD is designed using transmission gate-based latches, which produce UP and DOWN pulses only when there is a distinct phase difference between the reference and divided frequencies. Thus, the continuous pulses that get produced by the conventional NAND gate-based latches are avoided, leading to reduced power consumption of the PFD. The charge pump makes use of an op-amp used as a buffer, to reduce the current mismatch. The loop filter used is of second order, and the voltage-controlled oscillator is of conventional current-starved type. The divider makes use of true single-phase clock latches. It was found that the phase locked loop with new design of PFD, compared with the conventional design, consumes 27% lesser power, and the lock time is decreased by 79%. In addition, it was found that the control voltage swing is reduced by 71%, which leads to much lesser spur content at the output of the voltage-controlled oscillator.