A CMOS/SOI Single-input PWM Discriminator for Low-voltage Body-implanted Applications

JADER A. DE LIMA ； SIDNEI F. SILVA ； ADRIANO S. CORDEIRO ； MICHEL VERLEYSEN

《VLSI Design》 2002卷 (2002/12) Pp. 469-476

https://doi.org/10.1080/1065514021000012075

摘要

A CMOS/SOI circuit to decode Pulse-Width Modulation (PWM) signals is presented as part of a bodyimplanted neurostimulator for visual prosthesis. Since encoded data is the sole input to the circuit, the decoding technique is based on a novel double-integration concept and does not require low-pass filtering. Non-overlapping control phases are internally derived from the incoming pulses and a fastsettling comparator ensures good discrimination accuracy in the megahertz range. The circuit was integrated on a 2 μm single-metal thin-film CMOS/SOI fabrication process and has an effective area of 2mm^2. Measured resolution of encoding parameter a is better than 10% at 6MHz and V_(DD) = 3:3V: Idle-mode consumption is 340 μW. Pulses of frequencies up to 15MHz and a =10% can be discriminated for 2:3V ≤ V_(DD) ≤ 3:3V: Such an excellent immunity to V_(DD) deviations meets a design specification with respect to inherent coupling losses on transmitting data and power by means of a transcutaneous link.

關鍵字

PWM decoder ； SOI design ； Low-voltage comparators ； Implanted circuits ； Visual prosthesis