Frequency detector with self-adjusted detecting time based on resembling state-machine controller

SHEN Ya-dan， HE Le-nian， YE Yi-die
（College of Electronic Engineering， Zhejiang University， Hangzhou 310027， China）

Abstract： Aiming at providing precision and response speed in SOC system，a frequency detector（FD）based on a resembling state-machine controller（RSMC）was investigated. After comparison and analysis of exited FD structures，a RSMC was proposed in the FD. With a RSMC，both precision and response speed can be improved without external components. Self-adjust function of detecting time in accordance with the frequency of the detected signals was also achieved. SMIC18pf process，which has four metal layers and one poly layer，was taken in the design. A silicon area of 0.071 mm2（without pads and ESD） was obtained. The results indicate that the detecting frequency variation is -15%~+20% for low frequency edge at center frequency of [FL]=2 MHz and -12%~+20% for high frequency edge at center frequency of [FH]=7.5 MHz. The detecting time is [TL]=15.53 μs for [FL]=2 MHz and [TH]=2.3 μs for [FH]=7.5 MHz. The 3.3 V analog power dissipation is 59.8 μW while the 1.8 V digital power dissipation is 6.4 μW. The total power dissipation is 66.2 μW.
Key words： frequency detector； improved analog detecting method； resembling state-machine controller（RSMS）； frequency- programmable circuit； self-adjusted detecting time； no external components