Title :
Level-Shifting variable current charging technique for high-speed Comparator-Based Switched-Capacitor circuits
Author :
Wong, Kim-Fai ; Sin, Sai-Weng ; U, Seng-Pan ; Martins, R.P.
Author_Institution :
Analog & Mixed-Signal VLSI Lab., Univ. of Macau, Macao, China
Abstract :
The utilization of variable current sources, in Comparator-Based Switched-Capacitor (CBSC) circuits, instead of the traditional constant current sources, reveals itself as one of the effective ways to increase speed while maintaining the accuracy. In this paper, a Level-Shifting Variable Current Charging Technique is proposed to implement variable current sources for CBSC circuits. The CBSC gain stage obtained with the proposed technique is applied to a 2-1 Cascaded Multi-Stage (MASH) ΔΣ modulator implemented in 90 nm CMOS for WCDMA applications. Simulation results show that the modulator achieves 75 dB of dynamic range while consuming 2.7 mW.
Keywords :
CMOS analogue integrated circuits; current comparators; delta-sigma modulation; switched capacitor networks; CBSC circuits; CMOS process; WCDMA; cascaded multistage ΔΣ modulator; constant current sources; high-speed comparator-based switched-capacitor circuits; level-shifting variable current charging technique; power 2.7 mW; size 90 nm; CMOS technology; Charge transfer; Circuit simulation; Complexity theory; Dynamic range; Sampling methods; Switched capacitor circuits; Switching circuits; Timing; Voltage;
Conference_Titel :
Circuits and Systems (MWSCAS), 2010 53rd IEEE International Midwest Symposium on
Conference_Location :
Seattle, WA
Print_ISBN :
978-1-4244-7771-5
DOI :
10.1109/MWSCAS.2010.5548889
