• 강이구 (극동대학교 정보통신학부) ;
• 한득창 (극동대학교 정보통신학부) ;
• 홍승우 (고려대학교 전기공학과) ;
• 이종석 (고려대학교 전기공학과) ;
• 성만영 (고려대학교 전기공학과)
• Published : 2006.09.01

#### Abstract

To enhance the conversion speed more fast, we separate the determination process of MSB and LSB with the two independent ADC circuits of the Incremental Sigma Delta ADC. After the 1st Incremental Sigma Delta ADC conversion finished, the 2nd Incremental Sigma Delta ADC conversion start while the 1st Incremental Sigma Delta ADC work on the next input. By determining the MSB and the LSB independently, the ADC conversion speed is improved by two times better than the conventional Extended Counting Incremental Sigma Delta ADC. In processing the 2nd Incremental Sigma Delta ADC, the inverting sample/hold circuit inverts the input the 2nd Incremental Sigma Delta ADC, which is the output of switched capacitor integrator within the 1st Incremental Sigma Delta ADC block. The increased active area is relatively small by the added analog circuit, because the digital circuit area is more large than analog. In this paper, a 14 bit Extended Counting Incremental Sigma-Delta ADC is implemented in $0.25{\mu}m$ CMOS process with a single 2.5 V supply voltage. The conversion speed is about 150 Ksamples/sec at a clock rate of 25 MHz. The 1 MSB is 0.02 V. The active area is $0.50\;x\;0.35mm^{2}$. The averaged power consumption is 1.7 mW.

#### References

1. C. Jansson, 'A high resolution, compact, and low-power DC suitable for array implementation in standard CMOS', IEEE T. Circuits and Systems II, Vol. 45, No. 4, p. 904, 1995
2. A. Bertl, 'A high precision ADC system for instrumentation', IEE, Advanced A-D and D-A Conversion Techniques and their Applications, Vol. 4, No. 393, p. 60, 1994
3. J. C. Candy and G. C. Temes, 'Oversampled methods for A/D and D/A conversion', in Oversampled Delta-Sigma Data Converters, IEEE Press, p. 1, 1992
4. J. C. Candy and G. C. Temes, 'Oversampling method for data conversion', IEEE Pacific Rim Conference on Communication, Computer And Signal Processing, Vol. 1, p. 168, 1996
5. J. Robert, G. C. Temes, R. Dessoulavy, and P. Deval, 'A 16-bit low-voltage CMOS A/D converter', IEEE Jour. Solid-State Circuits, Vol. SC-22, No.2, p. 157, 1987