access icon openaccess Fixed-frequency hysteretic buck converter with novel adaptive window control and transient response improvement

This study presents a fixed-frequency hysteretic buck converter designed and fabricated using 0.18-µm complementary metal–oxide–semiconductor process. With a phase-locked loop (PLL)-based adaptive window control, the proposed buck converter can achieve a fixed switching frequency, and this frequency can be tuned within a certain range through a reference clock frequency. Concurrently, a novel auxiliary circuit is proposed to monitor the converter's output loading dynamics to reduce the converter's transient recovery time. It will also help to regulate the output voltage at the steady-state operation as well. With the supply voltage ranging from 3 to 4.2 V and an output voltage of 1.8 V, the simulated switching frequency is maintained at 10 MHz because of the PLL control. The transient response time is only 0.3 and 0.4 µs for a 400 mA step-up load and step-down load, respectively.

Inspec keywords: adaptive control; transient response; clocks; phase locked loops; switching convertors; voltage control; CMOS integrated circuits

Other keywords: fixed switching frequency; PLL control; output voltage; converter output loading dynamic monitoring; voltage 1.8 V; auxiliary circuit; steady-state operation; phase-locked loop-based adaptive window control; frequency 10.0 MHz; time 0.4 mus; complementary metal–oxide–semiconductor process; novel adaptive window control; size 0.18 mum; voltage 3.0 V to 4.2 V; output voltage regulation; converter transient response time; fixed-frequency hysteretic buck converter; transient response improvement; simulated switching frequency; current 400.0 mA; time 0.3 mus; reference clock frequency

Subjects: Voltage control; Self-adjusting control systems; Modulators, demodulators, discriminators and mixers; CMOS integrated circuits; Power electronics, supply and supervisory circuits

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http://iet.metastore.ingenta.com/content/journals/10.1049/joe.2018.5293
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