Title :
An energy management IC for bio-implants using ultracapacitors for energy storage
Author :
Sanchez, William ; Sodini, Charles ; Dawson, Joel L.
Author_Institution :
Microsyst. Technol. Labs., Massachusetts Inst. of Technol., Cambridge, MA, USA
Abstract :
We present the first known energy management IC to allow low-power systems, such as biomedical implants, to optimally use ultracapacitors instead of batteries as their chief energy storage elements. The IC, fabricated in a 0.18 μm CMOS process, consists of a switched-capacitor DC-DC converter, a 4 nW bandgap voltage reference, a high-efficiency rectifier to allow wireless recharging of the capacitor bank, and a switch matrix and digital control circuitry to govern the stacking and unstacking of the ultracapacitors. The stacking procedure allows for more than 98% of the initial energy stored in the capacitors to be removed before the output voltage drops unsuitably low. The DC-DC converter achieves a peak efficiency of 51% for loads between 10 and 100 μW, operates for input voltages between 1.25 and 2.5 V.
Keywords :
CMOS integrated circuits; DC-DC power convertors; digital control; low-power electronics; prosthetic power supplies; prosthetics; reference circuits; supercapacitors; switched capacitor networks; CMOS process; bandgap voltage reference; bioimplants; biomedical implants; capacitor bank; digital control circuit; energy management IC; energy storage; high efficiency rectifier; low power system; power 10 muW to 100 muW; size 0.18 mum; stacking procedure; switch matrix; switched-capacitor DC-DC converter; ultracapacitors; voltage 1.25 V to 2.5 V; wireless recharging; Biomedical measurements; Converters; Integrated circuits; Stacking; Supercapacitors; Switches;
Conference_Titel :
VLSI Circuits (VLSIC), 2010 IEEE Symposium on
Conference_Location :
Honolulu, HI
Print_ISBN :
978-1-4244-5454-9
DOI :
10.1109/VLSIC.2010.5560271
