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A faster phase frequency detector using transmission gate–based latch for the reduced response time of the PLL
Author(s) -
Koithyar Aravinda,
Ramesh T.K.
Publication year - 2018
Publication title -
international journal of circuit theory and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.364
H-Index - 52
eISSN - 1097-007X
pISSN - 0098-9886
DOI - 10.1002/cta.2449
Subject(s) - phase locked loop , phase frequency detector , voltage controlled oscillator , delay locked loop , phase detector , transmission gate , pll multibit , reset (finance) , nand gate , control theory (sociology) , voltage , dead time , power (physics) , charge pump , electronic engineering , swing , engineering , electrical engineering , physics , computer science , logic gate , transistor , phase noise , capacitor , acoustics , quantum mechanics , artificial intelligence , financial economics , control (management) , economics
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.