[1] Erickson, R. W. and Maksimovic, D., Fundamentals of Power Electronics. New York: Kluwer Academic, 2004.Google Scholar

[2] Stratakos, A. J., Sanders, S. R., and Brodersen, R. W., “A low-voltage CMOS DC-DC converter for a portable battery-operated system,” in Proc. IEEE Power Electron. Specialists Conf., Jun. 1994, vol. 1, pp. 619–626.Google Scholar

[3] Ma, D., Ki, W.-H., and Tsui, C.-Y., “An integrated one-cycle control buck converter with adaptive output and dual loops for output error correction,” IEEE J. Solid-State Circuits, vol. 39, no. 1, pp. 140–149, Jan. 2004.CrossRefGoogle Scholar

[4] Lee, C. F. and Mok, P. K. T., “A monolithic current-mode CMOS DC-DC converter with on-chip current-sensing technique,” IEEE J. Solid-State Circuits, vol. 39, no. 1, pp. 3–14, Jan. 2004.CrossRefGoogle Scholar

[5] Siu, M., Mok, P. K. T., Leung, K. N., Lam, Y. H., and Ki, W.-H., “A voltage-mode PWM buck regulator with end-point prediction,” IEEE Trans. Circuits Syst. II, Exp. Briefs, vol. 53, no. 4, pp. 294–298, Apr. 2006.Google Scholar

[6] Ma, F.-F., Chen, W.-Z., and Wu, J.-C., “A monolithic current-mode buck converter with advanced control and protection circuits,” IEEE Trans. Power Electron., vol. 22, no. 5, pp. 1836–1846, Sep. 2007.CrossRefGoogle Scholar

[7] Lin, C.-H., Huang, H.-W., and Chen, K.-H., “Fast transient technique (FTT) in buck current-mode DC-DC converters for low-voltage SoC systems,” in Proc. IEEE Custom Integrated Circuits Conf., Sep. 2008, pp. 25–28.

[8] Chen, J.-J., Yang, F.-C., and Chen, C.-C., “A new monolithic fast-response buck converter using spike-reduction current-sensing circuits,” IEEE Trans. Ind. Electron., vol. 55, no. 3, pp. 1101–1111, Mar. 2008.Google Scholar

[9] Wu, P. Y., Tsui, S. Y. S., and Mok, P. K. T., “Area- and power-efficient monolithic buck converters with pseudo-type III compensation,” IEEE J. Solid-State Circuits, vol. 45, no. 8, pp. 1446–1455, Aug. 2010.CrossRefGoogle Scholar

[10] Fan, J., Li, X., Park, J., and Huang, A., “A monolithic buck converter using differentially enhanced duty ripple control,” in Proc. IEEE Custom Integrated Circuits Conf., Sep. 2009, pp. 527–530.

[11] Chan, M. P. and Mok, P. K. T., “Design and implementation of fully integrated digitally controlled current-mode buck converter,” IEEE Trans. Circuits Syst. I, Reg. Papers, vol. 58, no. 8, pp. 1980–1991, Aug. 2011.Google Scholar

[12] Chan, M. P. and Mok, P. K. T., “Fully integrated digital controller IC for buck converter with a differential-sensing ADC,” in Proc. IEEE Int. Conf. Electron Devices and Solid-State Circuits, Dec. 2008, pp. 1–4.

[13] Chan, M. P. and Mok, P. K. T., “On-chip digital inductor current sensor for monolithic digitally controlled DC-DC converters,” in Proc. IEEE Int. Symp. Circuits Syst., May 2012, pp. 962 –965.

[14] Xiao, J., Peterchev, A. V., Zhang, J., and Sanders, S. R., “A 4-µA quiescent-current dual-mode digitally controlled buck converter IC for cellular phone applications,” IEEE J. Solid-State Circuits, vol. 39, no. 12, pp. 2342–2348, Dec. 2004.Google Scholar

[15] Annema, A.-J., Nauta, B., Langevelde, R.van, and Tuinhout, H., “Analog circuits in ultra-deep-submicron CMOS,” IEEE J. Solid-State Circuits, vol. 40, no. 1, pp. 132–143, Jan. 2005.CrossRefGoogle Scholar

[16] Ki, W.-H., “Signal flow graph in loop gain analysis of DC-DC PWM CCM switching converters,” IEEE Trans. Circuits Syst. I, Fundam. Theory Appl., vol. 45, no. 6, pp. 644 –655, Jun. 1998.Google Scholar

[17] Ridley, R. B., “A new continuous-time model for current-mode control with constant frequency, constant on-time, and constant off-time, in CCM and DCM,” in Proc. IEEE Power Electron. Specialists Conf., 1990, pp. 382–389.

[18] Miller, N. R., “A digitally controlled switching regulator,” in Proc. IEEE Power Electron. Specialists Conf., Jun. 1977, pp. 142–147.

[19] Chui, M. Y. K., Ki, W.-H., and Tsui, C.-Y., “A programmable integrated digital controller for switching converters with dual-band switching and complex pole-zero compensation,” IEEE J. Solid-State Circuits, vol. 40, no. 3, pp. 772–780, Mar. 2005.CrossRefGoogle Scholar

[20] Rahman, N., Parayandeh, A., Wang, K., and Prodic, A., “Multimode digital SMPS controller IC for low-power management,” in Proc. IEEE Int. Symp. Circuits Syst., May 2006, pp. 5327–5330.

[21] Patella, B. J., Prodic, A., Zirger, A., and Maksimovic, D., “High-frequency digital PWM controller IC for DC-DC converters,” IEEE Trans. Power Electron., vol. 18, no. 1, pp. 438–446, Jan. 2003.CrossRefGoogle Scholar

[22] Soenen, E. G., Roth, A., Shi, J., Kinyua, M., Gaither, J., and Ortynska, E., “A robust digital DC-DC converter with rail-to-rail output range in 40nm CMOS,” in ISSCC Dig. Tech. Papers, Feb. 2010, pp. 198–199.

[23] Ahmad, H. H. and Bakkaloglu, B., “A 300mA 14mV-ripple digitally controlled buck converter using frequency domain ΔΣADC and hybrid PWM generator,” in ISSCC Dig. Tech. Papers, Feb. 2010, pp. 202–203.

[24] Syed, A., Ahmed, E., and Maksimovic, D., “Digital PWM controller with feed-forward compensation,” in Proc. IEEE Appl. Power Electron. Conf., Feb. 2004, vol. 1, pp. 60–66.Google Scholar

[25] Foong, H. C., Zheng, Y., Tan, Y. K., and Tan, M. T., “Fast-transient integrated digital DC-DC converter with predictive and feedforward control,” IEEE Trans. Circuits Syst. I, Reg. Papers, vol. 59, no. 7, pp. 1567–1576, Jul. 2012.CrossRefGoogle Scholar

[26] McCreary, J. L. and Gray, P. R., “All-MOS charge redistribution analog-to-digital conversion techniques. I,” IEEE J. Solid-State Circuits, vol. 10, no. 6, pp. 371–379, Dec. 1975.CrossRefGoogle Scholar

[27] Johns, D. A. and Martin, K., Analog Integrated Circuit Design. New York: John Wiley & Sons, 1997.Google Scholar

[28] Lee, K.-Y., Yeh, C.-A., and Lai, Y.-S., “Design and implementation of fully digital controller for non-isolated-point-of-load converter with high current slew rate,” in Proc. IEEE Industrial Electronics Conf., Nov. 2006, pp. 2605–2610.

[29] Peng, H. and Maksimovic, D., “Digital current-mode controller for DC-DC converters,” in Proc. IEEE Appl. Power Electron. Conf., Mar. 2005, vol. 2, pp. 899–905.Google Scholar

[30] Li, J. and Lee, F. C., “Digital current mode control architecture with improved performance for DC-DC converters,” in Proc. IEEE Appl. Power Electron. Conf., Feb. 2008, pp. 1087–1092.

[31] Trescases, O., Lukic, Z., Ng, W. T., and Prodic, A., “A low-power mixed-signal current-mode DC-DC converter using a one-bit ΣΔ DAC,” in Proc. IEEE Appl. Power Electron. Conf., Mar. 2006, pp. 700–704.

[32] Trescases, O., Rahman, N., Prodic, A., and Ng, W. T., “A 1V buck converter IC with hybrid current-mode control and a charge-pump DAC,” in Proc. IEEE Power Electron. Specialists Conf., Jun. 2008, pp. 1122–1128.

[33] Lam, H. Y. H., Ki, W.-H., and Ma, D., “Loop gain analysis and development of high-speed high-accuracy current sensors for switching converters,” in Proc. IEEE Int. Symp. Circuits Syst., May 2004, vol. 5, pp. V–828–V–831.Google Scholar

[34] Chen, M.-J., Gu, Y.-B., Huang, J.-Y., Shen, W.-C., Wu, T., and Hsu, P.-C., “A compact high-speed Miller-capacitance-based sample-and-hold circuit,” IEEE Trans. Circuits Syst. I, Fundam. Theory Appl., vol. 45, no. 2, pp. 198–201, Feb. 1998.Google Scholar

[35] Robert, P.-Y., Gosselin, B., Ayoub, A. E., and Sawan, M., “An ultra-low-power successive-approximation-based ADC for implantable sensing devices,” in Proc. IEEE Int. Midwest Symp. Circuits Syst., Aug. 2006, vol. 1, pp. 7–11.Google Scholar

[36] Ramirez-Angulo, J., Gupta, S., Padilla, I., et al., “Comparison of conventional and new flipped voltage structures with increased input/output signal swing and current sourcing/sinking capabilities,” in Proc. IEEE Int. Midwest Symp. Circuits Syst., Aug. 2005, vol. 2, pp. 1151–1154.Google Scholar

[37] Gray, P. R., Hurst, P. J., Lewis, H., and Meyer, R. G., Design of Analog Integrated Circuits. New York: John Wiley & Sons, 2001.Google Scholar

[38] Syed, A., Ahmed, E., Maksimovic, D., and Alarcon, E., “Digital pulse width modulator architectures,” in Proc. IEEE Power Electron. Specialists Conf., Jun. 2004, vol. 6, pp. 4689–4695.Google Scholar

[39] Wang, X., Zhou, X., Park, J., and Huang, A. Q., “Design and implementation of a 9-bit 8MHz DPWM with AMI06 process,” in Proc. IEEE Appl. Power Electron. Conf., Feb. 2009, pp. 540–545.

[40] Wang, K., Rahman, N., Lukic, Z., and Prodic, A., “All-digital DPWM/DPFM controller for low-power DC-DC converters,” in Proc. IEEE Appl. Power Electron. Conf., Mar. 2006, pp. 719–723.

[41] Trescases, O., Wei, G., and Ng, W. T., “A segmented digital pulse width modulator with self-calibration for low-power SMPS,” in Proc. IEEE Int. Conf. Electron Devices and Solid-State Circuits, Dec. 2005, pp. 367–370.

[42] Chow, H.-C. and Yeh, N. L., “A new phase-locked loop with high speed phase frequency detector,” in Proc. IEEE Int. Midwest Symp. Circuits Syst., Aug. 2005, vol. 2, pp. 1342–1345.Google Scholar

[43] Lukic, Z., Rahman, N., and Prodic, A., “Multibit Σ-Δ PWM digital controller IC for DC-DC converters operating at switching frequencies beyond 10 MHz,” IEEE Trans. Power Electron., vol. 22, no. 5, pp. 1693–1707, Sep. 2007.CrossRefGoogle Scholar

[44] Leong, P.-K., Yang, C.-H., Leng, C.-W., and Tsai, C.-H., “Design and implementation of sigma-delta DPWM controller for switching converter,” in Proc. IEEE Int. Symp. Circuits Syst., May 2009, pp. 3074–3077.

[45] Kelly, A. and Rinne, K., “High resolution DPWM in a DC-DC converter application using digital sigma-delta techniques,” in Proc. IEEE Power Electron. Specialists Conf., Jun. 2005, pp. 1458–1463.

[46] Martin, T. W. and Ang, S. S., “Digital control for switching converters,” in Proc. IEEE Int. Symp. Industrial Electronics, Jul. 1995, vol. 2, pp. 480–484.Google Scholar

[47] Duan, Y. and Jin, H., “Digital controller design for switchmode power converters,” in Proc. IEEE Appl. Power Electron. Conf., Mar. 1999, vol. 2, pp. 967–973.Google Scholar

[48] Prodic, A., Maksimovic, D., and Erickson, R. W., “Design and implementation of a digital PWM controller for a high-frequency switching DC-DC power converter,” in Proc. IEEE Ind. Electronics Soc. Conf., Nov. 2001, vol. 2, pp. 893–898.Google Scholar

[49] Prodic, A. and Maksimovic, D., “Design of a digital PID regulator based on look-up tables for control of high-frequency DC-DC converters,” in Proc. IEEE Workshop Computers Power Electronics, Jun. 2002, pp. 18–22.

[50] Guo, L., Hung, J. Y., and Nelms, R. M., “Experimental evaluation of a fuzzy controller using a parallel integrator structure for DC-DC converters,” in Proc. IEEE Int. Symp. Ind. Electron., Jun. 2005, vol. 2, pp. 707–713.Google Scholar

[51] Bae, H. S., Yang, J. H., Lee, J. H., and Cho, B.-H., “Digital state feedback current control using pole placement technique for the 42V/14V bi-directional DC-DC converter application,” in Proc. IEEE Appl. Power Electron. Conf., Feb. 2007, pp. 3–7.

[52] Trescases, O., Prodic, A., and Ng, W. T., “Digitally controlled current-mode DC-DC converter IC,” IEEE Trans. Circuits Syst. I, Reg. Papers, vol. 58, no. 1, pp. 219–231, Jan. 2011.CrossRefGoogle Scholar

[53] Prodic, A. and Maksimovic, D., “Digital PWM controller and current estimator for a low-power switching converter,” in Proc. IEEE Workshop Computers Power Electronics, Jul. 2000, pp. 123–128.

[54] Musunuri, S. and Chapman, P. L., “Improvement of light-load efficiency using width-switching scheme for CMOS transistors,” IEEE Power Electron. Lett., vol. 3, no. 3, pp. 105–110, Sep. 2005.CrossRefGoogle Scholar

[55] Trescases, O., Wei, G., Prodic, A., and Ng, W. T., “Predictive efficiency optimization for DC-DC converters with highly dynamic digital loads,” IEEE Trans. Power Electron., vol. 23, no. 4, pp. 1859–1869, Jul. 2008.CrossRefGoogle Scholar

[56] Chattopadhyay, S. and Das, S., “A digital current-mode control technique for DC-DC converters,” IEEE Trans. Power Electron., vol. 21, no. 6, pp. 1718–1726, Nov. 2006.CrossRefGoogle Scholar

[57] Dake, T. and Ozalevli, E., “A precision high-voltage current sensing circuit,” IEEE Trans. Circuits Syst. I, Reg. Papers, vol. 55, no. 5, pp. 1197–1202, Jun. 2008.CrossRefGoogle Scholar

[58] Du, M. and Lee, H., “An integrated speed- and accuracy-enhanced CMOS current sensor with dynamically biased shunt feedback for current-mode buck regulators,” IEEE Trans. Circuits Syst. I, Reg. Papers, vol. 57, no. 10, pp. 2804–2814, Oct. 2010.CrossRefGoogle Scholar

[59] Leung, C. Y., Mok, P. K. T., and Leung, K. N., “A 1-V integrated current-mode boost converter in standard 3.3/5-V CMOS technologies,” IEEE J. Solid-State Circuits, vol. 40, no. 11, pp. 2265–2274, Nov. 2005.Google Scholar

[60] Yuvarajan, S. and Wang, L., “Performance analysis and signal processing in a current sensing power MOSFET (SENSEFET),” in Proc. IEEE Industry Applications Society Annual Meeting, Oct. 1991, vol. 2, pp. 1445–1450.Google Scholar

[61] Forghani-zadeh, H. P. and Rincon-Mora, G. A., “Current-sensing techniques for DC-DC converters,” in Proc. IEEE Int. Midwest Symp. Circuits Syst., Aug. 2002, vol. 2, pp. II–577–II–580.Google Scholar

[62]Analog Devices. AD7478: 1MSPS, 8-Bit ADC in 6 lead SOT-23 datasheet [online]. Available at: http://www.analog.com/en/analog-to-digital-converters/ad-converters/ad7478/products/product.html.

[63]Linear Technology. LTC1196: 8-Bit, SO-8, 1Msps ADCs with auto-shutdown options datasheet [online]. Available at: http://www.linear.com/product/LTC1196.

[64]Maxim Integrated Products. MAX11120: 1Msps, low-power, serial 8-bit, 4-channel ADCs datasheet [online]. Available at: http://datasheets.maxim-ic.com/en/ds/MAX11120-MAX11128.pdf.

[65] Trescases, O., Wei, G., and Ng, W. T., “A low-power DC-DC converter with digital spread spectrum for reduced EMI,” in Proc. IEEE Power Electron. Specialists Conf., Jun. 2006, pp. 1–7.

[66]Samsung. Samsung Exynos 4 Quad user's manual [online]. Available at: http://www.samsung.com/global/business/semiconductor/file/product/Exynos_4_Quad_User_Manaul_Public_REV100-0.pdf.

[67]Texas Instruments. Multicore DSP+ARM KeyStone II system-on-chip data manual [online]. Available at: http://www.ti.com/product/66ak2e05#doctype6.

[68] Redl, R. and Sun, J., “Ripple-based control of switching regulators: an overview,” IEEE Trans. Power Electron., vol. 24, no. 12, pp. 2669–2680, Dec. 2009.CrossRefGoogle Scholar

[69] Su, F. and Ki, W.-H., “Digitally assisted quasi-V2 hysteretic buck converter with fixed frequency and without using large-ESR capacitor,” in ISSCC Dig. Tech. Papers, Feb. 2009, pp. 446–447, 447a.

[70] Dallago, E., Passoni, M., and Sassone, G., “Lossless current sensing in low-voltage high-current DC/DC modular supplies,” IEEE Trans. Ind. Electron., vol. 47, no. 6, pp. 1249–1252, Dec. 2000.Google Scholar

[71] Lei, H. and Shiguo, L., “Design considerations of time constant mismatch problem for inductor DCR current sensing method,” in Proc. IEEE Appl. Power Electron. Conf., Mar. 2006, pp. 1368–1374.

[72] Cheng, K.-Y., Yu, F., Lee, F. C., and Mattavelli, P., “Digital enhanced V2-type constant on-time control using inductor current ramp estimation for a buck converter with low-ESR capacitors,” IEEE Trans. Power Electron., vol. 28, no. 3, pp. 1241–1252, Mar. 2013.CrossRefGoogle Scholar

[73] Song, J., Yoon, G., and Kim, C., “An efficient adaptive digital DC-DC converter with dual loop controls for fast dynamic voltage scaling,” in Proc. IEEE Custom Integrated Circuits Conf., Sep. 2006, pp. 253–256.

[74] Shi, J., Hsu, Y.-C., Soenen, E., Roth, A., and Gaither, J., “A wide-range DC/DC converter with 2nd order digital compensation and direct battery connection in 40nm CMOS,” in Proc. IEEE Custom Integrated Circuits Conf., Sep. 2011, pp. 1–4.

[75] Chan, M. P. and Mok, P. K. T., “On-chip digital inductor current sensor for monolithic digitally controlled DC-DC converter,” IEEE Trans. Circuits Syst. I, Reg. Papers, vol. 60, no. 5, pp. 1232–1240, May 2013.CrossRefGoogle Scholar

[76] Oppenheim, A. V., Discrete-Time Signal Processing, . Upper Saddle River, NJ: Prentice Hall, 1999.Google Scholar