A Frequency-Hopping Based Pulse Width Modulator for Spur Reduction in Switching Buck Converters
Subject Areas : electrical and computer engineeringReza Inanlou 1 , Omid Shoaei 2
1 - University of Tehran
2 - University of Tehran
Keywords: Frequency hopping, spur reduction, switched mode convertor,
Abstract :
This paper presents an EMI reduction technique for switched-mode buck converters. To achieve this, the frequency hopping concept is utilized in asynchronous pulse width modulators (APWM) performing the power conversion with controlling the on-off time of the power switches. The modulator has an oscillatory behavior; such that its oscillation frequency depends on its internal loop delay. Making use of this property and randomly changing the loop delay between 8 distinct random values, its self-oscillation frequency is also changed between 8 different values. As a result, a spur-free spectrum is achieved at the output of the converter. To verify the usefulness of the proposed method, a model-based behavioral simulation was done using MATLAB-SIMULINK. The main advantage of the proposed method over previous works is that the switching frequency controlling mechanism is fully digital. Besides, it can be readily done without causing any disturbance in the carrier signal.
[1] L. Wang, et al., "A wireless biomedical signal interface system-on-chip for body sensor networks," IEEE Trans. Biomed. Circuits Syst., vol. 4, no. 2, pp. 112-117, Apr. 2010.
[2] A. Urso, et al., "A switched-capacitor DC-DC converter powering an LC oscillator to achieve 85% system peak power efficiency and -65 dBc spurious tones," IEEE Trans. on Circ. and Sys. I: Regular Papers, vol. 67, no. 11, pp. 3764-3777, Nov. 2020.
[3] C. Tao and A. A. Fayed, "A low-noise PFM-controlled buck converter for low-power applications," IEEE Trans. on Circ. and Sys. I: Regular Papers, vol. 59, no. 12, pp. 3071-3080, Dec. 2012.
[4] J. H. Chen, P. J. Liu, and Y. J. E. Chen, "A spurious emission reduction technique for power amplifiers using frequency hopping DC-DC converters," in Proc. IEEE Radio Freq. Integr. Circuits Symp., pp. 145-148, Boston, MA, USA, 7-9 Jun. 2009.
[5] M. W. Kim and J. J. Kim, "A PWM/PFM dual-mode DC-DC buck converter with load-dependent efficiency-controllable scheme for multi-purpose IoT applications," Energies, vol. 14, pp. 1-14, Feb. 2021.
[6] R. Inanlou, O. Shoaei, and M. Tamaddon, "An asynchronous pulse width modulator for DC-DC buck converter," International J. of Circuit Theory and Applications, vol. 48, no. 2, pp. 231-253, Feb. 2020.
[7] -, TPS7A49xx Series Data Sheet, Texas Instruments Incorp., 2010. [Online]. Available: www.ti.com › Power Management › Linear Regulator (LDO).
[8] A. V. Oppenheim, A. S. Willsky, and I. T. Young, Signals and Systems, Prentice Hall, NJ, 1983.
[9] H. S. Black, Modulation Theory, D. Van Nostrand Company, NY, 1953.
[10] W. A. Burklandn, C. Tao, and A. A. Fayed, "Output switching noise spectral analysis and modeling in buck regulators," Microelectronics J., vol. 44, no. 5, pp. 373-381, Mar. 2013.
[11] T. Hegarty, An Overview of Radiated EMI Specifications for Power Supplies, Texas Instruments, Jun. 2018. Available: www.ti.com/lit/wp/slyy142/slyy142.pdf
[12] Y. Choi, W. Tak, Y. Yoon, J. Roh, S. Kwon, and J. Koh, "A 0.018% THD+N, 88-dB PSRR PWM Class-D amplifier for direct battery hookup," IEEE J. Solid-State Circ., vol. 47, no. 2, pp. 454-463, Feb. 2012.
[13] S. K. Dunlap and T. S. Fiez, "A noise-shaped switching power supply using a delta-sigma modulator," IEEE TCAS-I, vol. 51, no. 6, pp. 1051-1061, Jun. 2004.
[14] Y. S. Hwang, et al., "A low-EMI continuous-time delta-sigma-modulation buck converter with transient response eruption techniques," IEEE Trans. on Ind. Electron., vol. 67, no. 8, pp. 6854-6863, Aug. 2020.
[15] J. J. Chen, et al., "A low-electromagnetic-interference buck converter with continuous-time delta-sigma-modulation and burst-mode techniques," IEEE Trans. on Ind. Electron., vol. 65, no. 9, pp. 6860-6869, Sep. 2018.
[16] J. J. Chen, Y. S. Hwang, J. H. Yu, Y. T. Ku, and C. C. Yu, "A low-EMI buck converter suitable for wireless sensor networks with spur-reduction techniques," IEEE Sensors J., vol. 16, no. 8, pp. 2588-2597, Apr. 2016.
[17] Y. S. Hwang, J. J. Chen, W. J. Hou, P. H. Liao, and Y. T. Ku, "A 10 μs transient recovery time low-EMI DC-DC buck converter with Δ–Ʃ modulator," IEEE Trans. Very Large Scale Integr. (VLSI) Sys., vol. 24, no.9, pp. 2983-2992, Mar. 2016.
[18] W. H. Yang, et al., "An enhanced-security buck DC-DC converter with true-random-number-based pseudo hysteresis controller for Internet-of-Everything (IoE) devices," in Proc. IEEE Int. Solid-State Circuits Conf., ISSCC'18, pp. 126-128, Feb. 2018.
[19] M. Nashed and A. A. Fayed, "A current-mode hysteretic buck converter with spur-free control for variable switching noise mitigation," IEEE Trans. Power Electronics, vol. 33, no. 1, pp. 650-664, Jan. 2018.
[20] L. Corradini, A. Bjeletic, R. Zane, and D. Maksimovic, "Fully digital hysteretic modulator for DC-DC switching converters," IEEE Trans. on Power Electronics, vol. 26, no. 10, pp. 2969-2979, Oct. 2011.
[21] M. Hoyerby and M. Andersen, "Carrier distortion in hysteretic self-oscillating class-D audio power amplifiers: analysis and optimization," IEEE Trans. Power Electron., vol. 24, no. 3, pp. 714-729, Mar. 2009.
[22] M. Tamaddon and M. Yavari, "An oscillatory noise‐shaped quantizer for time‐based continuous‐time sigma‐delta modulators," International J. of Circuit Theory and Applications, vol. 46, no. 3, pp. 384-400, Mar. 2018.
[23] W. Li, Y. Orino, S. Hirata, and M. K. Kurosawa, "Design of a self-oscillating PWM signal generator with a double integration loop," IEEE Trans. on Circ. and Sys. I (TCAS_I): Regular Papers, vol. 60, no. 8, pp. 2064-2073, Feb. 2013.
[24] H. G. Li, S. D. Gong, J. W. Liu, and D. L. Su, "CMOS-based chaotic PWM generator for EMI reduction," IEEE Trans. Electromagn. Compat., vol. 59, no. 4, pp. 1224-1231, Aug. 2017.
[25] M. L. Chiu, T. H. Yang, and T. H. Lin, "A high accuracy constant-on-time buck converter with spur-free on-time generator," in Proc. IEEE Int. Symp. on Circuits and Systems, ISCAS'19, 4 pp., Sapporo, Japan, 26-29 May 2019.
[26] C. Tao and A. A. Fayed, "A buck converter with reduced output spurs using asynchronous frequency hopping," IEEE Trans. on Circ. and Sys. II: Express Briefs, vol. 58, no. 11, pp. 709-713, Nov. 2011.
[27] H. Li, J. Shang, B. Zhang, X. Zhao, N. Tan, and C. Liu, "Stability analysis with considering the transition interval for PWM DC-DC converters based on describing function method," IEEE Access, vol. 6, pp. 48113-48124, Jul. 2018.
