摘要:本文以Dickson電荷泵的基本原理出發點,研究了一種將正電壓輸入轉為負電壓輸出的開關電容電路。由于開關電容的充放電特點,為確定電容時間常數,采用非交疊(nonoverlapping)時鐘控制信號避免了由于時鐘交疊而造成的當電容充電還未完成即對下一級電容進行放電的現象。同時,參考功率MOSFET的電容模型通過增大驅動電路的電流減小了開關管的上升延時,提高了開關動作的速度,使轉換效率得到明顯提高。此電路結構簡單,性能優良,易于集成,可廣泛應用于輸出負電壓的電源產品中。
敘詞:功率MOSFET,開關電容,電荷泵, 轉換率
Abstract:In this paper we have developed a kind of charge pump, which can transform the positive voltage into the negative one according to the principles of Dickson charge pump. Because of the features of switch capacitor we should adopted nonoverlapping clock signal if we want to guarantee charge completely through the switching of power MOSFET. Furthermore, the drive currents of MOSFET have been improved to decrease the switching time and improve the efficiency of transform.
Keyword:Power MOSFET, Switch capacitor, Charge pump, Transform efficiency