Abstract
We present an adaptive reconfigurable active voltage doubler (VD)/rectifier (REC) (VD/REC) in standard CMOS, which can adaptively change its topology to either a VD or a REC by sensing the output voltage, leading to more robust inductive power transmission over an extended range. Both active VD and REC modes provide much lower dropout voltage and far better power conversion efficiency (PCE) compared to their passive counterparts by adopting offset-controlled high-speed comparators that drive the rectifying switches at proper times in the high-frequency band. We have fabricated the active VD/REC in a 0.5-μm 3-metal 2-poly CMOS process, occupying 0.585 mm2 of chip area. In an exemplar setup, VD/REC extended the power transmission range by 33% (from 6 to 8 cm) in relative coil distance and 41.5% (from 53° to 75°) in relative coil orientation compared to using the REC alone. While providing 3.1-V dc output across a 500-$\Omega$ load from 2.15- (VD) and 3.7-V (REC) peak ac inputs at 13.56 MHz, VD/REC achieved measured PCEs of 70% and 77%, respectively.
Original language | English |
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Article number | 6236106 |
Pages (from-to) | 481-485 |
Number of pages | 5 |
Journal | IEEE Transactions on Circuits and Systems II: Express Briefs |
Volume | 59 |
Issue number | 8 |
DOIs | |
Publication status | Published - 2012 |
Externally published | Yes |
Bibliographical note
Funding Information:Manuscript received January 30, 2012; revised May 23, 2012; accepted June 12, 2012. Date of publication July 10, 2012; date of current version August 10, 2012. This work was supported in part by the National Institutes of Health under Grants 1R01NS062031 and 5R21EB009437 and in part by the National Science Foundation under Award ECCS-824199. This brief was recommended by Associate Editor G. Wang.
Keywords
- Active rectifier (REC)
- active voltage doubler (VD)
- adaptive control
- high-speed comparators
- implantable microelectronic devices (IMDs)
- inductive power transmission
- near field
ASJC Scopus subject areas
- Electrical and Electronic Engineering