Similar articles

Abstract: A low power high performance delta-Sigma modulator for portable measurement applications is presented. To reduce power consumption while maintaining high performance, a fully feedforward architecture with a comprehensive system-level design is implemented. As a key building block, a novel power efficient current mirror operational transconductance amplifier (OTA) with a fast-settling less-error switched-capacitor common-mode feedback (SC CMFB) circuit is introduced, and the effects of both gain nonlinearity and 1/f noise of OTA are discussed. A new method to determine the voltage gain of an OTA is also proposed. The bottom terminal parasitic effect of poly-insulator-poly (PIP) capacitors is considered. About an extra 20% of capacitance is added to the total capacitance load. A power and area efficient resonator is adopted to realize a coefficient of 1/90 for 50% power and 75% area reduction compared with conventional designs. The chip is implemented in a low cost 0.35 μm complementary metal oxide semiconductor (CMOS) process. The total power consumption is 20 μW with a 1.5 V supply, and the measured dynamic range (DR) is 95 dB over a 1 kHz bandwidth. Experimental results show that a high figure-of-merit (FOM) is achieved for the designed modulator in comparison with those from the literature.

[1]Chae, Y., Han, G., 2007. A Low Power Sigma-Delta Modulator Using Class-C Inverter. IEEE Symp. on VLSI Circuits, p.240-241.

[2]Chae, Y., Han, G., 2009. Low voltage, low power, inverter-based switched-capacitor Delta-Sigma modulator. IEEE J. Sol.-State Circ., 44(2):458-472.

[3]Choksi, O., Carley, L.R., 2003. Analysis of switched-capacitor common-mode feedback circuit. IEEE Trans. Circ. Syst. II, 50(12):906-917.

[4]Enz, C.C., Temes, G.C., 1996. Circuit techniques for reducing the effects of opamp imperfections: auto-zeroing, correlated double sampling, and Chopper stabilization. Proc. IEEE, 84(11):1584-1614.

[5]Fiorenza, J.K., Sepke, T., Holloway, P., Sodini, C.G., Lee, H.S., 2006. Comparator-based switched-capacitor circuits for scaled CMOS technologies. IEEE J. Sol.-State Circ., 41(12):2658-2668.

[6]Gharbiya, A., Johns, D.A., 2006. On the implementation of input-feedforward Delta-Sigma modulators. IEEE Trans. Circ. Syst. II, 53(6):453-457.

[7]Goes, J., Vaz, B., Monteiro, R., Paulino, N., 2006. A 0.9-V ΔΣ Modulator with 80-dB SNDR and 83-dB DR Using a Single-Phase Technique. IEEE Int. Solid-State Circuits Conf., p.191-200.

[8]Nagaraj, K., 1989. A parasitic-insensitive area-efficient approach to realizing very large time constants in switched-capacitor circuits. IEEE Trans. Circ. Syst., 36(9):1210-1216.

[9]Ou, W., Wu, X.B., 2008. High-consistency behavior modeling of switched-capacitor Sigma-Delta modulator in SIMULINK. J. Semicond., 29(11):2209-2217.

[10]Park, Y., Nam, K.Y., Su, D.K., Vleugels, K., Wooley, B.A., 2009. A 0.7-V 870-μW digital-audio CMOS Sigma-Delta modulator. IEEE J. Sol.-State Circ., 44(4):1078-1087.

[11]Peluso, V., Steyaert, M.S.J., Sansen, W., 1997. A 1.5-V-100-μW ΔΣ modulator with 12-b dynamic range using the switched-opamp technique. IEEE J. Sol.-State Circ., 32(7):943-951.

[12]Pun, K.P., Chatterjee, S., Kinget, P., 2006. A 0.5-V 74-dB SNDR 25-kHz CT ΔΣ Modulator with Return-to-Open DAC. IEEE Int. Solid-State Circuits Conf., p.181-190.

[13]Rabii, S., Wooley, B.A., 1997. A 1.8-V digital-audio Sigma-Delta modulator in 0.8-μm CMOS. IEEE J. Sol.-State Circ., 32(6):783-796.

[14]Rabii, S., Wooley, B.A., 1999. The Design of Low-Voltage, Low-Power Sigma-Delta Modulators. Kluwer Academic Publishers, Norwell, USA, p.59-60.

[15]Rajput, S.S., Jamuar, S.S., 2002. Low voltage analog circuit design techniques. IEEE Circ. Syst. Mag., 2(1):24-42.

[16]Roh, J., Byun, S., Choi, Y., Roh, H., Kim, Y.G., Kee, J.K., 2008. A 0.9-V 60-μW 1-bit fourth-order Delta-Sigma modulator with 83-dB dynamic range. IEEE J. Sol.-State Circ., 43(2):361-370.

[17]Sauerbrey, J., Tille, T., Schmitt-Landsiedel, D., Thewes, R., 2002. A 0.7V MOSFET-Only Switched-Opamp ΣΔ Modulator. IEEE Int. Solid-State Circuits Conf.

[18]Schreier, R., Temes, G.C., 2004. Understanding Delta-Sigma Data Converters. Wiley-IEEE Press, New York, p.112-113.

[19]Silva, J., Moon, U., Steensgaard, J., Temes, G.C., 2001. Wideband low-distortion Delta-Sigma ADC topology. Electron. Lett., 37(12):737-738.

[20]Xu, J., Zhao, M., Wu, X., Yan, X., 2007. Low Voltage Low Power Current Mirror OTA for Sigma-Delta Modulator. IEEE Conf. on Electron Devices and Solid-State Circuits, p.875-879.

[21]Yang, Y., Chokhawala, A., Alexander, M., Melanson, J., Hester, D., 2003. A 114-dB 68-mW Chopper-stabilized stereo multibit audio ADC in 5.62 mm². IEEE J. Sol.-State Circ., 38(12):2061-2068.

[22]Yao, L.B., Michiel, S.J., Steyaert, W.S., 2004. A 1-V 140-μW 88-dB audio Sigma-Delta modulator in 90-nm CMOS. IEEE J. Sol.-State Circ., 39(11):1809-1818.