An Energy-Efficient Asynchronous Hybrid-Searching Algorithm for Auto Frequency Calibration in IEEE 802.11ax Applications

• Published in: IEEE International Symposium on Circuits and Systems proceedings pp. 1 - 5
• Main Authors: Wang, Zijie, Wu, Lianbo, Zhang, Patrick, Zhang, Hui
• Format: Conference Proceeding
• Language: English
• Published: IEEE 21.05.2023
• Subjects: asynchronous hybrid search; Auto frequency calibration; Calibration; Energy efficiency; frequency hopping; IEEE 802.11ax Standard; Power demand; System-on-chip; Time-frequency analysis; Ultra-high speed TSPC; VCO calibration; Voltage-controlled oscillators
• ISSN: 2158-1525
• DOI: 10.1109/ISCAS46773.2023.10181790

Modern totally on-chip systems now demand that phase-locked loops are designed with auto frequency calibration (AFC) circuits for multi-band voltage controlled oscillators (VCO). This paper proposes an energy-efficient asynchronous hybrid searching algorithm for high-speed integrated AFC. Asynchronous architecture breaks the minimum limit of searching time. Hybrid method overcomes non-monotonic variation of frequency errors in binary search. A true-single-phase-clock(TSPC)-based high-speed digital counter accelerates AFC further by directly quantizing frequency from VCO. Designed in a 55nm CMOS technology, the proposed AFC achieves a calibration time of 1.5-3.5\mu\mathrm{s} across required tuning range by IEEE-802.11ax standard, with a Figure-of-Merit(FoM) of 0.8.