使用電感電流感測技術漣波式固定導通時間控制直流對直流降壓轉換器

Abstract

本論文實現了一個TSMC0.18um製程具有快速暫態反應的漣波式固定導通時間控制降壓轉換器。穩態量測結果顯示在系統切換頻率為一百萬赫茲時，輸入電壓為3.3伏特，輸出電壓為0.9伏特到1.8伏特，負載電流範圍為0.1安培到1安培，暫態量測結果在輸出為0.9伏特時，負載電流從0.1安培到1安培時回復時間為2.8微秒，下緩衝電壓為78毫伏，負載電流從1安培到0.1安培時回復時間為2.5微秒，上緩衝電壓為120毫伏。晶片面積0.922 mm2，最高效率為92.32%。本作品改善傳統電感電流斜坡補償技術，用精準的電流感測器來放大電感電流，提高系統穩定度及效率，採用負電感電流迴授路徑來增加系統暫態反應，透過電壓平方控制的雙迴路方式來消除輸出電壓的直流準位偏移。

This thesis implements a ripple-based constant on-time (RBCOT) buck converter with a fast transient response fabricated in TSMC 0.18 μm CMOS process. The steady-state measurement shows that this chip can regulate output voltage from 0.9V to 1.8V while the input voltage is 3.3V and the output load current is from 0.1A to 1A. The load transient response shows that when the output voltage is 0.9V, the undershoot voltage is 78mV and the overshoot voltage is 126mV. The settling time is 2.8μs for a step-up load and 2.5μs for a step-down load. The chip area is 0.922 mm2. The maximum efficiency is 92.32%. This work improves the traditional inductor current ramp compensation technique. Utilizing an accurate transconductance amplifier to amplify the inductor current to increase the system stability and efficiency. Adopting the negative inductor current feedback to improve the transient response. Through the V2 controlled dual loop structures to eliminate the output dc voltage offset issues.