TY - GEN
T1 - 80dB dynamic range 100KHz bandwidth inverter-based ΣΔ ADC for CMOS image sensor
AU - Tang, Fang
AU - Wang, Bo
AU - Bermak, Amine
PY - 2012
Y1 - 2012
N2 - A sigma delta (ΣΔ) ADC for sensing application is presented in this paper. Several techniques are adopted to implement a low power high dynamic range ADC. Firstly, a single-stage inverter replaces the commonly used differential amplifier, in order to reduce the static current. Secondly, the normal NMOS transistor in the inverter stage is replaced by a high threshold device. As a result, with the same transistor size and supply voltage, the gain of the inverter can be enhanced while the short circuit current can be reduced. Thirdly, the charge leakage due to the forward-based parasitic diode is eliminated by using a charge protection switch and rearranged reference scheme. The proposed ΣΔ ADC is implemented and fabricated using TSMC 0.18μm technology. The simulation result shows that for a 1.8V supply, 25MHz sampling frequency and 125 oversampling ratio, the power consumption is 63.7μW and 116μW, dynamic range is 80dB and 83dB, the ENOB is 11.5 and 11.7bit for a single-ended and a pseudo-differential configurations, respectively. The presented ADC scheme can be applied in a Full HD image sensor running at up to 50 frames/s.
AB - A sigma delta (ΣΔ) ADC for sensing application is presented in this paper. Several techniques are adopted to implement a low power high dynamic range ADC. Firstly, a single-stage inverter replaces the commonly used differential amplifier, in order to reduce the static current. Secondly, the normal NMOS transistor in the inverter stage is replaced by a high threshold device. As a result, with the same transistor size and supply voltage, the gain of the inverter can be enhanced while the short circuit current can be reduced. Thirdly, the charge leakage due to the forward-based parasitic diode is eliminated by using a charge protection switch and rearranged reference scheme. The proposed ΣΔ ADC is implemented and fabricated using TSMC 0.18μm technology. The simulation result shows that for a 1.8V supply, 25MHz sampling frequency and 125 oversampling ratio, the power consumption is 63.7μW and 116μW, dynamic range is 80dB and 83dB, the ENOB is 11.5 and 11.7bit for a single-ended and a pseudo-differential configurations, respectively. The presented ADC scheme can be applied in a Full HD image sensor running at up to 50 frames/s.
KW - high dynamic range
KW - inverter-based
KW - low power
KW - ΣΔ ADC
UR - https://www.scopus.com/pages/publications/84866594019
U2 - 10.1109/ISCAS.2012.6271975
DO - 10.1109/ISCAS.2012.6271975
M3 - Conference contribution
AN - SCOPUS:84866594019
T3 - ISCAS 2012 - 2012 IEEE International Symposium on Circuits and Systems
SP - 3094
EP - 3097
BT - ISCAS 2012 - 2012 IEEE International Symposium on Circuits and Systems
PB - IEEE Computer Society
T2 - 2012 IEEE International Symposium on Circuits and Systems, ISCAS 2012
Y2 - 20 May 2012 through 23 May 2012
ER -