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A faster phase frequency detector using transmission gate–based latch for the reduced response time of the PLL

Publication Type : Journal Article

Publisher : International Journal of Circuit Theory and Applications

Source : International Journal of Circuit Theory and Applications, Volume 46, Number 4, p.842-854 (2018)

Url : https://onlinelibrary.wiley.com/doi/abs/10.1002/cta.2449

Keywords : blind zone, charge pump (CP), dead zone, Divider, Loop filter, phase frequency detector (PFD), voltage-controlled oscillator (VCO)

Campus : Bengaluru

School : School of Engineering

Department : Electronics and Communication

Year : 2018

Abstract : Summary 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.

Cite this Research Publication : A. Koithyar and Dr. T. K. Ramesh, “A faster phase frequency detector using transmission gate–based latch for the reduced response time of the PLL”, International Journal of Circuit Theory and Applications, vol. 46, pp. 842-854, 2018.

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