基于CMOS的開關(guān)電容DC-DC降壓變換器
時(shí)間:2009-03-19 15:52:17來源:ronggang
導(dǎo)語:?采用兩個(gè)單端開關(guān)電容變換器反相并聯(lián)聯(lián)結(jié),降低了輸出電壓波紋。利用電路內(nèi)部節(jié)點(diǎn)電壓驅(qū)動(dòng)MOS開關(guān)管,避免了每個(gè)開關(guān)管都必須單獨(dú)驅(qū)動(dòng)
摘 要:在標(biāo)準(zhǔn)CMOS工藝的基礎(chǔ)上,分析了基本串并電容組合開關(guān)電容DC-DC降壓變換器的工作原理和集成方法。采用兩個(gè)單端開關(guān)電容變換器反相并聯(lián)聯(lián)結(jié),降低了輸出電壓波紋。利用電路內(nèi)部節(jié)點(diǎn)電壓驅(qū)動(dòng)MOS開關(guān)管,避免了每個(gè)開關(guān)管都必須單獨(dú)驅(qū)動(dòng)。用SPICE軟件對(duì)電路進(jìn)行了瞬態(tài)分析,給出了分析結(jié)果。
關(guān)鍵字:DC-DC變換器, CMOS開關(guān)電容網(wǎng)絡(luò),反相并聯(lián)結(jié)構(gòu)
Abstract: Working principle and integrating method of switched-capacitor DC-DC buck converters constructed by basic series-parallel capacitors was analyzed based on standard CMOS technology. Output voltage ripple was reduced by connecting two identical but opposite-phase SC converters in parallel. MOS transistors were driven by internal nodes voltage for avoiding the need for separate gate drivers. The circuit was analyzed transiently by SPICE and the results were given.
Keywords: DC-DC converters, CMOS switched-capacitor network, opposite-phase parallel configuration.
1.引言
開關(guān)電容(Switched-Capacitor)變換器是利用電容的充電、放電實(shí)現(xiàn)電荷轉(zhuǎn)移的原理構(gòu)成的一種開關(guān)網(wǎng)絡(luò),也稱作電荷泵變換器。這種變換器僅由功率開關(guān)和電容組成,不含磁性元件(如電感等),所以具有拓?fù)浣Y(jié)構(gòu)簡單、尺寸小、電磁干擾(EMI)低和轉(zhuǎn)換效率高等優(yōu)點(diǎn),十分適合于便攜式電子產(chǎn)品的電源設(shè)計(jì)。由于開關(guān)電容變換器是一種離散時(shí)間系統(tǒng),需要較高的輸入阻抗才能可靠地獲得存儲(chǔ)的電荷量,所以在混合集成時(shí),相對(duì)于其他工藝,在CMOS工藝中更容易實(shí)現(xiàn)。采用CMOS技術(shù)的開關(guān)電容變換器具有功耗低、集成度高和抗噪聲能力強(qiáng)等特點(diǎn)。
本文將CMOS技術(shù)引入到開關(guān)電容網(wǎng)絡(luò)中,分析了二階串并電容組合構(gòu)成的降壓型DC-DC變換器的基本工作原理,并在此基礎(chǔ)上設(shè)計(jì)了由MOS開關(guān)和MOS電容組成的、適合片上集成的開關(guān)電容降壓變換器。該變換器結(jié)構(gòu)并聯(lián)對(duì)稱,計(jì)算機(jī)仿真結(jié)果表明其工作性能優(yōu)于普通開關(guān)電容變換器。
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基于CMOS的開關(guān)電容DC-DC降壓變換器