Journal of Power Electronics

The Korean Institute of Power Electronics (전력전자학회)
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Buck converter with switched capacitor charge compensation for fast transient response

  • Wanxin Zhou (State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China) ;
  • Kezhu Song (State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China) ;
  • Chuan Wu (State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China) ;
  • Chengyang Zhu (State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China) ;
  • Dongyi Xie (State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China)
  • Received : 2023.10.25
  • Accepted : 2024.04.25
  • Published : 2024.08.20
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Abstract

As microprocessor currents exceed 500 A and slew rate reaches 1000 A/㎲, increasing the decoupling capacitance on the motherboard to ensure normal operation of the microprocessor is inevitable because of the limited response capability of the voltage regulator. However, the area of the motherboard used for capacitors is usually narrow. To reduce the required capacitance, a novel buck converter with an auxiliary circuit for charge compensation using switched capacitors is proposed. The auxiliary circuit is not activated during the steady state. When the load current changes rapidly, the switched capacitors can quickly absorb or release charge to suppress voltage fluctuations. A 12 V-0.9 V buck converter has been built and tested under a 480 A load current step and a 960 A/㎲ current slew rate. The proposed scheme with 9.964 mF capacitance has an overshoot of 115 mV and an undershoot of 89 mV. Compared with the conventional PID scheme, the proposed scheme can save 58.4% of the capacitance for the same voltage fluctuations or suppress 39.5% of overshoot and 37.3% of undershoot with the same capacitance.

Keywords

Acknowledgement

This work was supported by the Shenzhen Science and Technology Program under Grant KQTD20170810111725321.

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