一种带单级PFC的LED驱动芯片的设计
发布时间：2019-01-14 10:18
【摘要】：日常生活中,AC/DC开关电源有很广泛的应用,电源产生的谐波会给电网带来谐波污染,从而影响到电网的安全。所以电网对负载提出了高功率因数的要求,对应的功率因数校正技术应运而生,功率因数校正技术通过调节输入电流的波形,使其随输入电压的波形而变化,有效的降低了输入电流的总谐波畸变率,从而减小电网谐波污染,增加了电网的安全性。随着抑制电网谐波污染的国际标准的推行,PFC技术因其自身的优点被广泛应用于AC/DC电源领域。本文设计一款具有单级PFC功能的恒流LED驱动芯片,该芯片具有高功率因数、可实现调光、精确恒流输出、无电解电容等特点。芯片的Rugulator模块从内部集成的功率MOSFET的漏极抽取电流给外接电容充放电来给整个芯片供电,芯片通过对输出电流的采样反馈,采用PWM和PFM两种控制方法实现对驱动信号占空比的控制,从而达到稳定环路并使输出电流恒定的目的。芯片的整个内部反馈控制环路全部由用数字方法实现,这样就减小了由工艺偏差引入的误差,从而实现精确恒流。内部的状态机模块会产生周期为半个工频周期的脉冲信号,该信号用来对状态机的状态进行更新,从而控制驱动信号的导通时间和频率在半个工频周期内不发生变化,符合单级PFC的核心思想,从而实现了PFC。芯片在输入电压220VAC,输出电压为16V且不调光的情况下,输出电流平均值为350mA,芯片功率因数为0.91。在输入电压110VAC,输出电压为16V且不调光的情况下,输出电流平均值为350mA,芯片功率因数为0.91。在输入电压220VAC,跳负载的情况下,完成对芯片动态响应性能的验证。在220VAC,90°调光的情况下,芯片的输出电流平均值为250mA。仿真结果表明设计满足预期的要求。
[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 掳dimming, the average output current of the chip is 250 Ma. The simulation results show that the design meets the expected requirements.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM923.34
本文编号：2408604
[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 掳dimming, the average output current of the chip is 250 Ma. The simulation results show that the design meets the expected requirements.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM923.34
【参考文献】
相关期刊论文 前1条
1 曹太强;许建平;徐顺刚;;开关电源谐波的研究[J];电焊机;2007年05期
，本文编号：2408604
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