發(fā)布時(shí)間：2019-01-14 10:18

【摘要】：日常生活中,AC/DC開(kāi)關(guān)電源有很廣泛的應(yīng)用,電源產(chǎn)生的諧波會(huì)給電網(wǎng)帶來(lái)諧波污染,從而影響到電網(wǎng)的安全。所以電網(wǎng)對(duì)負(fù)載提出了高功率因數(shù)的要求,對(duì)應(yīng)的功率因數(shù)校正技術(shù)應(yīng)運(yùn)而生,功率因數(shù)校正技術(shù)通過(guò)調(diào)節(jié)輸入電流的波形,使其隨輸入電壓的波形而變化,有效的降低了輸入電流的總諧波畸變率,從而減小電網(wǎng)諧波污染,增加了電網(wǎng)的安全性。隨著抑制電網(wǎng)諧波污染的國(guó)際標(biāo)準(zhǔn)的推行,PFC技術(shù)因其自身的優(yōu)點(diǎn)被廣泛應(yīng)用于AC/DC電源領(lǐng)域。本文設(shè)計(jì)一款具有單級(jí)PFC功能的恒流LED驅(qū)動(dòng)芯片,該芯片具有高功率因數(shù)、可實(shí)現(xiàn)調(diào)光、精確恒流輸出、無(wú)電解電容等特點(diǎn)。芯片的Rugulator模塊從內(nèi)部集成的功率MOSFET的漏極抽取電流給外接電容充放電來(lái)給整個(gè)芯片供電,芯片通過(guò)對(duì)輸出電流的采樣反饋,采用PWM和PFM兩種控制方法實(shí)現(xiàn)對(duì)驅(qū)動(dòng)信號(hào)占空比的控制,從而達(dá)到穩(wěn)定環(huán)路并使輸出電流恒定的目的。芯片的整個(gè)內(nèi)部反饋控制環(huán)路全部由用數(shù)字方法實(shí)現(xiàn),這樣就減小了由工藝偏差引入的誤差,從而實(shí)現(xiàn)精確恒流。內(nèi)部的狀態(tài)機(jī)模塊會(huì)產(chǎn)生周期為半個(gè)工頻周期的脈沖信號(hào),該信號(hào)用來(lái)對(duì)狀態(tài)機(jī)的狀態(tài)進(jìn)行更新,從而控制驅(qū)動(dòng)信號(hào)的導(dǎo)通時(shí)間和頻率在半個(gè)工頻周期內(nèi)不發(fā)生變化,符合單級(jí)PFC的核心思想,從而實(shí)現(xiàn)了PFC。芯片在輸入電壓220VAC,輸出電壓為16V且不調(diào)光的情況下,輸出電流平均值為350mA,芯片功率因數(shù)為0.91。在輸入電壓110VAC,輸出電壓為16V且不調(diào)光的情況下,輸出電流平均值為350mA,芯片功率因數(shù)為0.91。在輸入電壓220VAC,跳負(fù)載的情況下,完成對(duì)芯片動(dòng)態(tài)響應(yīng)性能的驗(yàn)證。在220VAC,90°調(diào)光的情況下,芯片的輸出電流平均值為250mA。仿真結(jié)果表明設(shè)計(jì)滿(mǎn)足預(yù)期的要求。
[Abstract]:In daily life, AC/DC switching power supply is widely used, the harmonic generated by the power supply will bring harmonic pollution to the power network, which will affect the security of the power grid. The power factor correction technology emerges as the times require. The power factor correction technology changes with the input voltage waveform by adjusting the waveform of input current. The total harmonic distortion rate of the input current is reduced effectively, which reduces the harmonic pollution and increases the security of the power network. With the implementation of international standards to suppress harmonic pollution, PFC technology has been widely used in the field of AC/DC power supply due to its own advantages. In this paper, a constant current LED driver chip with single stage PFC function is designed. The chip has the advantages of high power factor, dimming, accurate constant current output and no electrolytic capacitance. The Rugulator module of the chip extracts the current from the drain of the internally integrated power MOSFET to charge and discharge the external capacitor to supply the whole chip, and the chip supplies the whole chip by sampling and feedback of the output current. Two control methods, PWM and PFM, are used to control the duty cycle of the driving signal, so that the loop is stabilized and the output current is constant. The whole internal feedback control loop of the chip is realized by digital method, which reduces the error introduced by the process deviation and realizes the accurate constant current. The internal state machine module produces a pulse signal with half a power frequency cycle, which is used to update the state of the state machine so as to control the on-time and frequency of the driving signal to remain unchanged in half a power frequency cycle. It accords with the core idea of single level PFC, and realizes PFC.. When the input voltage is 220 V AC, the output voltage is 16 V and the light is not dimming, the average output current is 350 Ma, and the chip power factor is 0.91. When the input voltage is 110 V AC, the output voltage is 16 V and the light is not dimmed, the average output current is 350 Ma and the chip power factor is 0.91. When the input voltage is 220 VAC and load is skipped, the dynamic response performance of the chip is verified. In the case of 220 V AC 90 擄dimming, the average output current of the chip is 250 Ma. The simulation results show that the design meets the expected requirements.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：TM923.34

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相關(guān)期刊論文 前1條

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本文編號(hào)：2408604