一個在切換頻率中利用電流平均控制來減低暫態漣波的控制方法之直流降壓式轉換器

Abstract

本論文闡述一個切換頻率中利用電流平均控制來減低暫態漣波控制方法的直流電壓轉換器，並以台積電0.35-μm 2P4M 3.3V/5V Mixed Signal CMOS製程製作。當使用切換頻率技術時，由於電感的電流連續性，使得切換頻率前和切換頻率後所產生的電感電流交流值不同，在輸出電容產生出一暫態漣波電壓，此論文提出一個如何控制電感電流才能使之無此暫態漣波電壓，其方式為利用延長或縮短充電(放電)電流的時間來達到平均電感電流，此時間為切換頻率前後充電(放電)電感電流時間的平均值，實現方式是利用額外電路準確計算此時間後，以脈衝的型式插入原本的脈衝調變訊號。 依據量測的結果，本晶片的切換頻率設定在880k-3.4MHz，暫態漣波在頻域上改進14.1dB，時域上改進88%。跳頻技巧最多可使EMI降低23.55dB，功率效率最高為90%。晶片總面積占2.126mm2，而其它的量測結果也包含在本論文內。

This thesis presents an inductor current average control method for transient-ripple reduction in frequency hopping DC-DC converters and is implemented in a standard 0.35-μm 2P4M 3.3V/5V Mixed Signal CMOS process. When using the frequency-hopping technique, there is transient ripple on the output voltage due to the difference of inductor current between two different frequencies. This thesis proposes a method which predicts the average inductor current and inserts a calculated-width pulse between two frequencies to reduce the transient ripple on the output voltage. Measurement results are performed with the switching frequency of this chip operating between 0.88 MHz and 3.4 MHz. The transient ripple on the output voltage is reduced by 88% and the undesired spur is reduced by 14.1 dB. The frequency-hopping technique achieves 23.55 dB reduction of the EMI spur magnitude. The maximum power efficiency achieved 90%. The chip occupied 2.126 mm2, and the other detailed measurements are included in this thesis.