建立一個(gè)交流/直流轉(zhuǎn)換器是易與PI Expert

　　交流電源供電的孤立的離線開(kāi)關(guān)需要在許多應(yīng)用中，從家用電器到適配器對(duì)電池充電。這些孤立的AC / DC轉(zhuǎn)換器從頭開(kāi)始設(shè)計(jì)可以壓倒一切，消耗更多的時(shí)間，并可以花費(fèi)更多。因此，為了使這項(xiàng)工作容易，靈活，成本效益，電源集成創(chuàng)造了一套工具和資源。除了幫助設(shè)計(jì)師開(kāi)發(fā)和建立這些離線AC / DC開(kāi)關(guān)在市場(chǎng)上有競(jìng)爭(zhēng)力的價(jià)格，電力集成的工具和資源，同時(shí)提高設(shè)計(jì)師在第一次嘗試通過(guò)監(jiān)管要求的機(jī)會(huì)，從而消除了開(kāi)發(fā)和交付的麻煩。

　　為了實(shí)現(xiàn)這一目標(biāo)，供應(yīng)商已經(jīng)準(zhǔn)備兩集成開(kāi)關(guān)IC的家庭，即電源轉(zhuǎn)換和TinySwitch III（TNY253 / 4 / 5和tny274gn或tny278gn），使電源設(shè)計(jì)人員的任何應(yīng)用程序在177 W而TinySwitch部分是專(zhuān)為需要25瓦或更少的輸出功率AC / DC開(kāi)關(guān)應(yīng)用的構(gòu)建AC / DC開(kāi)關(guān)，TOPSwitch的JX家族是專(zhuān)為AC / DC解決方案高達(dá)177 W和建設(shè)交流/直流使用這兩個(gè)系列的成員交換機(jī)的設(shè)計(jì)，電源集成了免費(fèi)設(shè)計(jì)的軟件稱(chēng)為PI Expert。

　　Low-power AC/DC solutions

　　However， before we start exploring the PI Expert design software; let’s take a look at the functionalities integrated on-chip for switcher ICs TinySwitch-III and TOPSwitch-JX. Since TinySwitch is tailored for AC/DC solutions below 25 W， we will first investigate the TinySwitch landscape. As shown in Figure 1， TinySwitch combines a 700 V power MOSFET， oscillator， high-voltage switched current source， current limit， and thermal shut-down circuitry on a single CMOS chip. As per the product data sheet， the start-up and run-on power is derived from the drain voltage， thereby eliminating the need for a transformer bias winding and its associated circuitry. It is rated to consume only about 80 mW at no load from 265 VAC input. A simple on/off control scheme also eliminates the need for loop compensation， according to the supplier.