Name
Title | ||
|---|---|---|
A 10-Bit Column-Parallel Single Slope ADC Based on Two-Step TDC with Error Calibration for CMOS Image Sensors. |
Abstract | ||
|---|---|---|
This paper presents a 10-bit column-parallel single slope analog-to-digital converter (SS ADC) with a two-step time-to-digital converter (TDC) to overcome the long conversion time problem in conventional SS ADC for high-speed CMOS image sensors (CIS). The time interval proportional to the input signal is generated by a ramp generator and a comparator, which is digitized by a two-step TDC consisting of coarse and fine conversions to achieve a high-precision time-interval measurement. To mitigate the impact of propagation delay mismatch, a calibration circuit is also proposed to calibrate the delay skew within -T/2 to T/2. The proposed ADC is designed in 0.18 mu m CMOS process. The power dissipation of each column circuit is 232 mu W at supply voltages of 3.3V for the analog circuits and 1.8V for the digital blocks. The post simulation results indicate that the ADC achieves a SNDR of 60.89 dB (9.82 ENOB) and a SFDR of 79.98 dB at a conversion rate of 2 MS/s after calibration, while the SNDR and SFDR are limited to 41.52 dB and 67.64 dB, respectively before calibration. The differential nonlinearity (DNL) and integral nonlinearity (INL) without calibration are +15.80/-15.29 LSB and +1.68/-15.34 LSB while they are reduced down to +0.75/-0.25 LSB and +0.76/-0.78 LSB with the proposed calibration. |
Year | DOI | Venue |
|---|---|---|
2015 | 10.1142/S0218126615500541 | JOURNAL OF CIRCUITS SYSTEMS AND COMPUTERS |
Keywords | Field | DocType |
CMOS image sensor,column-parallel single-slope ADC,time-to-digital converter,high conversion speed,error calibration | Integral nonlinearity,Comparator,Differential nonlinearity,Control theory,Computer science,Spurious-free dynamic range,Electronic engineering,CMOS,Effective number of bits,Ramp generator,Time-to-digital converter,Electrical engineering | Journal |
Volume | Issue | ISSN |
24 | 4 | 0218-1266 |
Citations | PageRank | References |
2 | 0.38 | 6 |
Authors | ||
4 | ||
Name | Order | Citations | PageRank |
|---|---|---|---|
| Jiangtao Xu | 1 | 74 | 18.98 |
| Jing Yu | 2 | 2 | 0.38 |
| Fujun Huang | 3 | 2 | 0.38 |
| Kaiming Nie | 4 | 35 | 8.77 |