Design of Monolithic CMOS LDO Regulator With D-2 Coupling and Adaptive Transmission Control for Adaptive Wireless Powered Bio-Implants

作者：Zheng Chen^*; Ma Dongsheng

来源：IEEE Transactions on Circuits and Systems I-Regular Papers, 2011, 58(10): 2377-2387.

DOI：10.1109/TCSI.2011.2123650

• Adaptive transmission control
• adaptive wireless powered bio-implants
• direct dynamic coupling
• dynamic voltage scaling
• low drop-out regulator

This paper presents a monolithic CMOS low drop-out regulator for adaptive wireless powered bio-implants. A dual-loop control scheme is proposed to enhance load/DVS transient response, without a filter capacitor. The inner loop employs a direct dynamic coupling technique to improve transient response by directly detecting voltage variations through a capacitive coupling high-pass filter. Meanwhile, the outer loop adopts an adaptive transmission control to improve the regulator's large-signal transient response. The regulator is intrinsically stabilized without frequency compensation. Both small-signal and large-signal analysis are provided as design guidelines. The proposed regulator was fabricated with a 0.35-mu m CMOS process, with an active die area of 0.35 mu m(2). Experimental results demonstrate a 1.6-s V down-tracking and 2.2-mu s V up-tracking speed for DVS reference tracking, with undershoot/overshoot voltages controlled below 90 mV. Without a filter capacitor, the output voltage of the regulator recovers within 2.0 mu s for 100-mA load change, with less than 90-mV variation. The current/power efficiency stays above 93/78% over the entire interested load current range, with a peak value of 99.96/91.1%, respectively.

• 出版日期2011-10