传统的开关型LED驱动电源中含有大电解电容和高频变压器,导致LED驱动电源的体积庞大且使用寿命较短。分段式线性恒流驱动电源可以避免使用大电解电容和高频变压器。设计了一种新型的分段线性恒流LED驱动电源,利用整流之后的高压脉动直...传统的开关型LED驱动电源中含有大电解电容和高频变压器,导致LED驱动电源的体积庞大且使用寿命较短。分段式线性恒流驱动电源可以避免使用大电解电容和高频变压器。设计了一种新型的分段线性恒流LED驱动电源,利用整流之后的高压脉动直流电压的变化,自适应地控制LED灯珠分阶段恒流工作。除整流桥和采样电阻外,整个驱动电路可实现单芯片集成,有效缩小了体积、延长了寿命。电路中还设计了智能拓展端口,可实现智能化控制。基于华虹宏力0.5μm 700 V BCD工艺对电路进行了仿真验证,在0~311 V周期脉动高电压输入条件下,驱动芯片分四阶段恒流工作,输出最大恒定电流可达97.17 m A,在恒流阶段,电流的瞬态精度误差仅为0.031%。仿真结果表明,该LED驱动电路各指标参数均满足预期要求。展开更多
随着世界各国LED照明产品应用越来越广泛,LED照明对健康的影响也越来越受到关注,而LED照明影响健康的一大因素即为"频闪"。近年来,随着光电一体化的发展,高压线性恒流芯片飞速发展,其性能表现决定了恒流模块以至于整个照明产...随着世界各国LED照明产品应用越来越广泛,LED照明对健康的影响也越来越受到关注,而LED照明影响健康的一大因素即为"频闪"。近年来,随着光电一体化的发展,高压线性恒流芯片飞速发展,其性能表现决定了恒流模块以至于整个照明产品的性能、安全及寿命的优劣。市场上大部分高压线性恒流驱动都存在着频闪问题。本文结合最新CEC Title 24要求,充分利用了高压线性恒流驱动芯片XR46084的外围元器件少、集成度高的特点,设计了1款无频闪的高压线性恒流驱动模组。展开更多
The influence of Ga and In on the electrochemical properties of Mg anode materials were investigated by the polarization and galvanostatic curve tests. The microstructure and the corroded surface of the Mg-In-Ga alloy...The influence of Ga and In on the electrochemical properties of Mg anode materials were investigated by the polarization and galvanostatic curve tests. The microstructure and the corroded surface of the Mg-In-Ga alloys were observed by scanning electron microscopy （SEM）. The corrosion product of the Mg-0.8%In （mass fraction） and Mg-0.8%Ga-0.3%In alloy were determined by X-ray diffraction. The results show that no second phase exists in the Mg-xIn （x=0-0.8%） allloys. Intergranular compounds containing Ga and In elements occur in the Mg-0.8%In-xGa （x=0-0.8%） alloys. The addition of In into Mg as well as the addition of 0.05%-0.5%Ga into Mg-In alloy promotes the corrosion resistance. The addition of Ga into Mg-In alloys also promotes the electrochemical activity. The Mg-0.8%In-0.8%Ga alloy has the most negative mean potential,-1.682 V, which is more negative than -1.406 V in AZ91D. The corrosion type of the Mg-In-Ga alloys is general corrosion and the corrosion product is Mg（OH）2.展开更多
In this paper, we investigate conservation laws of a class of partial differential equations, which combines the nonlinear telegraph equations and the nonlinear diffusion-convection equations. Moreover, some special c...In this paper, we investigate conservation laws of a class of partial differential equations, which combines the nonlinear telegraph equations and the nonlinear diffusion-convection equations. Moreover, some special conservation laws of the combined equations are obtained by means of symmetry classifications of wave equations uxx = H （x）utt.展开更多
文摘传统的开关型LED驱动电源中含有大电解电容和高频变压器,导致LED驱动电源的体积庞大且使用寿命较短。分段式线性恒流驱动电源可以避免使用大电解电容和高频变压器。设计了一种新型的分段线性恒流LED驱动电源,利用整流之后的高压脉动直流电压的变化,自适应地控制LED灯珠分阶段恒流工作。除整流桥和采样电阻外,整个驱动电路可实现单芯片集成,有效缩小了体积、延长了寿命。电路中还设计了智能拓展端口,可实现智能化控制。基于华虹宏力0.5μm 700 V BCD工艺对电路进行了仿真验证,在0~311 V周期脉动高电压输入条件下,驱动芯片分四阶段恒流工作,输出最大恒定电流可达97.17 m A,在恒流阶段,电流的瞬态精度误差仅为0.031%。仿真结果表明,该LED驱动电路各指标参数均满足预期要求。
文摘随着世界各国LED照明产品应用越来越广泛,LED照明对健康的影响也越来越受到关注,而LED照明影响健康的一大因素即为"频闪"。近年来,随着光电一体化的发展,高压线性恒流芯片飞速发展,其性能表现决定了恒流模块以至于整个照明产品的性能、安全及寿命的优劣。市场上大部分高压线性恒流驱动都存在着频闪问题。本文结合最新CEC Title 24要求,充分利用了高压线性恒流驱动芯片XR46084的外围元器件少、集成度高的特点,设计了1款无频闪的高压线性恒流驱动模组。
基金Project(20110162120051)supported by Specialized Research Fund for the Doctor Program of Higher Education,ChinaProject(51101171)supported by the National Natural Science Foundation of China
文摘The influence of Ga and In on the electrochemical properties of Mg anode materials were investigated by the polarization and galvanostatic curve tests. The microstructure and the corroded surface of the Mg-In-Ga alloys were observed by scanning electron microscopy （SEM）. The corrosion product of the Mg-0.8%In （mass fraction） and Mg-0.8%Ga-0.3%In alloy were determined by X-ray diffraction. The results show that no second phase exists in the Mg-xIn （x=0-0.8%） allloys. Intergranular compounds containing Ga and In elements occur in the Mg-0.8%In-xGa （x=0-0.8%） alloys. The addition of In into Mg as well as the addition of 0.05%-0.5%Ga into Mg-In alloy promotes the corrosion resistance. The addition of Ga into Mg-In alloys also promotes the electrochemical activity. The Mg-0.8%In-0.8%Ga alloy has the most negative mean potential,-1.682 V, which is more negative than -1.406 V in AZ91D. The corrosion type of the Mg-In-Ga alloys is general corrosion and the corrosion product is Mg（OH）2.
文摘In this paper, we investigate conservation laws of a class of partial differential equations, which combines the nonlinear telegraph equations and the nonlinear diffusion-convection equations. Moreover, some special conservation laws of the combined equations are obtained by means of symmetry classifications of wave equations uxx = H （x）utt.
