TY - JOUR
T1 - A 570-kbps ASK demodulator without external capacitors for low-frequency wireless bio-implants
AU - Wang, Chua Chin
AU - Lee, Tzung Je
AU - Chio, U. Fat
AU - Hsiao, Yu Tzu
AU - Chen, Jia Jin J.
N1 - Funding Information:
The authors would like to express their deepest gratefulness to CIC (Chip Implementation Center) of NAPL (National Applied Research Laboratories), Taiwan, for their thoughtful chip fabrication service. Moreover, this research was partially supported by National Health Research Institutes under Grant NHRI-EX95-9319EI and NHRI-EX97-9732EI. The authors also like to thank “Aim for Top University Plan” project of NSYSU and Ministry of Education, Taiwan, for partially supporting the research.
PY - 2008/1
Y1 - 2008/1
N2 - This paper proposes a novel structure of ASK (amplitude shift keying) demodulators, which requires no external capacitors, for implantable micro-stimulators. By using a traditional β multiplier reference to detect the signal envelope, followed by a Schmitt trigger and a load driver, the large off-chip capacitor in traditional ASK demodulators is not required any more. Therefore, the proposed circuit possesses small area to be integrated in an SOC (system-on-chip). Besides, due to the lack of the large capacitor, the proposed circuit can operate with a higher data rate using lower frequency carriers. The proposed circuit is integrated in an implantable micro-stimulator on silicon using 0.35 μ m 2P4M CMOS process. The area of the proposed circuit occupies merely 0.039 mm2 with a maximum power dissipation of less than 12 mW (including the power consumption of the analog circuits of the micro-stimulator) by measurement results on silicon. Moreover, the measurement results verify that the proposed ASK demodulator can detect the ASK modulated signal up to 570 kbps data rate at 2 MHz carrier frequency when the modulation index is 10%.
AB - This paper proposes a novel structure of ASK (amplitude shift keying) demodulators, which requires no external capacitors, for implantable micro-stimulators. By using a traditional β multiplier reference to detect the signal envelope, followed by a Schmitt trigger and a load driver, the large off-chip capacitor in traditional ASK demodulators is not required any more. Therefore, the proposed circuit possesses small area to be integrated in an SOC (system-on-chip). Besides, due to the lack of the large capacitor, the proposed circuit can operate with a higher data rate using lower frequency carriers. The proposed circuit is integrated in an implantable micro-stimulator on silicon using 0.35 μ m 2P4M CMOS process. The area of the proposed circuit occupies merely 0.039 mm2 with a maximum power dissipation of less than 12 mW (including the power consumption of the analog circuits of the micro-stimulator) by measurement results on silicon. Moreover, the measurement results verify that the proposed ASK demodulator can detect the ASK modulated signal up to 570 kbps data rate at 2 MHz carrier frequency when the modulation index is 10%.
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U2 - 10.1016/j.mejo.2007.10.010
DO - 10.1016/j.mejo.2007.10.010
M3 - Article
AN - SCOPUS:38049014847
VL - 39
SP - 130
EP - 136
JO - Microelectronics Journal
JF - Microelectronics Journal
SN - 0959-8324
IS - 1
ER -