Chao, Yu LinYu LinChaoTsai, Chieh JuChieh JuTsaiHuang, Yi RongYi RongHuangLiu, Wen ChinWen ChinLiuMa, Sheng HsiangSheng HsiangMaCHING-JAN CHEN2024-02-172024-02-172023-01-0100939994https://scholars.lib.ntu.edu.tw/handle/123456789/639727This paper proposes a monolithic capacitor current mode adaptive on-time (CCAOT) controlled buck converter. A capacitor current-controlled modulation scheme ensures an ultra-fast load transient response. However, this scheme suffers from sensing circuit mismatch-induced instability, hence a concise passive ramp is proposed to mitigate the problem. The small signal model of the scheme is established to demonstrate the design standard of the system parameters. Moreover, a V2-loop eliminates the circuit delay caused on-time pulse error and achieves a pseudo constant frequency. Implemented in a 0.18μm CMOS process with a 4-MHz high switching frequency, this circuit occupies a total area of 1189 μm by 1199 μm in width and length including the pad ring. Finally, the experiment results show a fast load transient response, which is 42mV voltage drop and 1μs response time under the conditions of 1.1V output voltage and 1A load step-up with 1A/500ns slew rate. In addition, the frequency variation is 2% for a 1A load step and there is no instability issue in this work.Buck converters | capacitor current adaptive on-time (CCAOT) control | capacitor current-controlled modulation | Capacitors | dynamic on-time generator | fast load transient response | Inductors | Modulation | Oscillators | Sensors | Transient response | voltage regulator module (VRM)[SDGs]SDG7journal article10.1109/TIA.2023.33452562-s2.0-85182348479https://api.elsevier.com/content/abstract/scopus_id/85182348479