A Continuous Time Sigma Delta Modulators Using CMOS Current Conveyors

In this paper, a alternative structure method for continuous time sigma delta modulator is presented. In this modulator for implementation of integrators in loop filter second generation current conveyors are employed. The modulator is designed in CMOS technology and features low power consumption (<2.8mW), low supply voltage (±1.65), wide dynamic range (>65db), and with 180khZ bandwidth. Simulation results confirm that this design is suitable for data converters.

Authors:

• E. Farshidi
• N. Ahmadpoor

Keywords:

• Current Conveyor
• continuous
• sigma delta
• MOS
• modulator

References:

[1] E. Di Gioia and H. Klar "A 11-bit, 12.5 MHzv low power low voltage
continuous-time Sigma-Delta modulator, in Mixed Design of
Integrated Circuits and Systems (MIXDES), 2010 Proceedings of the
17th International Conference, pp. 176-181.
[2] G. Mitteregger, C. Ebner, C. Mechnig, T. Blon, C. Holuigue, E. Romani,
A. Melodia and V. Melini, "A 14b 20mW 640MHz CMOS CT Delta-
Sigma ADC with 20MHz Signal Bandwidth and 12b ENOB, in Solid-
State Circuits Conference, 2006. ISSCC 2006. Digest of Technical
Papers. IEEE International, pp. 131-140.
[3] E. Prefasi, L. Hernandez, S. Paton, A. Wiesbauer, R. Gaggl and E. Pun,
" A 0.1 mm Wide Bandwidth Continuous-Time ADC Based on a Time
Encoding Quantizer in 0.13 ╬╝m CMOS, Solid-State Circuits, IEEE
Journal of 2009. vol. 44, pp. 2745-2754, Oct. 2009.
[4] H. Aboushady," Design for reuse of current-mode continuous-time
sigma-delta analog-to-digital converters. Ph. D. thesis 2002, University
of Paris VI, Department of Electronics Communications and Computer
Science.
[5] A.A. Khan, K.K. Dey and S.S. Roy, "Novel RC sinusoidal oscillator
using second-generation current conveyor. Instrumentation and
Measurement, IEEE Transactions on, vol. 54, pp. 2402-2406, Dec.
2005.
[6] F. Kacar and H. Kuntman, "A new fully differential second generation
current conveyor and its application, in Optimization of Electrical and
Electronic Equipment, 2008. OPTIM 2008. 11th International
Conference on 2008, pp. 3-8.
[7] H. Moradzadeh and S.J. Azhari, " Low-voltage low-power rail-to-rail
low-Rx wideband second generation current conveyor and a single
resistance-controlled oscillator based on it. Circuits, Devices &
Systems IET, vol. 5, pp. 66-72, January 2011.
[8] E. Arslan and A. Morgul, "Wideband self-biased CMOS CCII, in
Research in Microelectronics and Electronics, 2008. PRIME 2008. Ph.D,
pp. 217-220.
[9] T. Song, Z. Cao and S. Yan, " A 2.7-mW 2-MHz Continuous-Time ΣΔ
Modulator With a Hybrid Active-Passive Loop Filter. Solid-State
Circuits, IEEE Journal of, vol. 43, pp. 330-341, Feb. 2008.
[10] Y. Aiba, K. Tomioka, Y. Nakashima, K. Hamashita and B. Sup Song ,"A
Fifth-Order Gm-C Continuous-Time sigma delta Modulator With
Process-Insensitive Input Linear Range. Solid-State Circuits, IEEE
Journal of, vol. 44, pp. 2381-2391, Sept. 2009.
[11] K. Lee, M.R. Miller, G.C. Temes, " An 8.1 mW, 82 dB Delta-Sigma
ADC With 1.9 MHz BW and -98 dB THD. Custom Integrated
Circuits Conference, 2008. CICC 2008. IEEE, pp. 93-96.