直流降壓式開關轉換器在同步導通模式下因操作頻率固定使得輕載效率大幅降低，一般而言可透過零電壓切換技術來減少切換損失。本篇論文提出以箝位三角形電流控制法(CL-TCM)之三階層降壓控制器達成零電壓切換，並結合漣波控制之固定導通模式和三階層降壓式轉換器架構的優點。控制策略使電路於輕載狀態下降低切換頻率，可減少切換損並提升效率。三階層轉換器架構降低功率開關及電感上之電壓應力，並使得轉換器切換頻率增加為為本二階層的兩倍，此舉可將電感電流漣波降為傳統二階層的四分之一倍，亦達到降低電感與電容等被動元件大小。
晶片製程使用TSMC 0.18m 1P6M 18HVG2製程，晶片面積大小為2.09×1.25 mm2。功率級輸入電壓為 12 V、輸出電壓為3.3V，切換頻率範圍為150k至700 kHz，電感與輸出電容分別為1.4 μH與27 μF，輸出負載範圍為200 mA至1200 mA。

關鍵詞：箝位三角形電流控制、三階層降壓式轉換器、固定導通模式、零電壓切換

In the synchronous conduction mode (SCM) of the dc-dc step-down switching power converter, the light load efficiency is greatly reduced due to the fixed operating frequency. Generally, Zero-voltage switching (ZVS) technology is used to reduce the switching loss. This thesis proposes the ZVS Modulation Clamp-switch TCM (CL-TCM) with Constant on-time (COT) control Three-level buck controller to achieve Zero-voltage switching, combining the advantages of a ripple-based controlled fixed on-time and Three-Level Buck converter architecture. The control strategy enables the circuit to drop the switching frequency under light load conditions. It can reduce switching loss and improve efficiency. The Three-level buck converter architecture reduces the voltage stress on the power switch and the inductor, and the frequency at the switching node is doubled, which can reduce the inductor current to a quarter, to further reduce the size of inductance and capacitance in circuit.

The chip is implemented with TSMC 0.18m 1P6M 18HVG2 process and the size of chip was 2.09×1.25 mm2. The power stage input voltage is 12 V. The output voltage is 3.3V, and the switching frequency is 150k to 700 kHz. The inductance and output capacitance are 1.4 μH and 27 μF respectively, and the output load range is 200 mA to 1200 mA.

Keywords: Clamp-switch TCM (CL-TCM), Three-level buck converter, Constant on-time (COT) control, Zero-voltage-switching (ZVS)

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