A digital controller IC for the flyback converter with primary-side feedback is proposed. The controller is used for adapter charger or LED driver applications. To obtain high accuracy for the primary-side feedback, a...A digital controller IC for the flyback converter with primary-side feedback is proposed. The controller is used for adapter charger or LED driver applications. To obtain high accuracy for the primary-side feedback, a digital primary-side sensing technology is adopted, which can auto-track the knee point of the primary auxiliary winding voltage. Furthermore, an internal digital compensator eliminates the need for external loop compensation components while achieving excellent line and load regulation. The controller could output both constant voltage and constant current depending on the load current. Pulse width modulation and pulse frequency modulation are used in constant voltage mode while quasi-resonant control is used in constant current mode. The digital controller is validated by using FPGA.展开更多
为了满足LED照明对低成本、小体积以及高功率因数的要求,采用了具有单级功率因数校正(PFC)和原边反馈(PSR)恒流控制功能的驱动电源方案。文章分析了在单级PFC拓扑下原边恒流控制的原理,提出一种新颖的去磁时间检测方法,并将其应用于芯片...为了满足LED照明对低成本、小体积以及高功率因数的要求,采用了具有单级功率因数校正(PFC)和原边反馈(PSR)恒流控制功能的驱动电源方案。文章分析了在单级PFC拓扑下原边恒流控制的原理,提出一种新颖的去磁时间检测方法,并将其应用于芯片G7102;同时推导了在准谐振工作模式下单级PFC拓扑的电流和功率因素λ值的计算公式,提出该工作条件下变压器的设计方法;最后制作了24 V 350 mA输出的LED驱动电源。实验证明,该方案在全电压范围内,电源效率η为85%以上,功率因数0.9以上,恒流精度达到2%,在小功率LED照明中具有很高的应用价值。展开更多
文摘A digital controller IC for the flyback converter with primary-side feedback is proposed. The controller is used for adapter charger or LED driver applications. To obtain high accuracy for the primary-side feedback, a digital primary-side sensing technology is adopted, which can auto-track the knee point of the primary auxiliary winding voltage. Furthermore, an internal digital compensator eliminates the need for external loop compensation components while achieving excellent line and load regulation. The controller could output both constant voltage and constant current depending on the load current. Pulse width modulation and pulse frequency modulation are used in constant voltage mode while quasi-resonant control is used in constant current mode. The digital controller is validated by using FPGA.
文摘为了满足LED照明对低成本、小体积以及高功率因数的要求,采用了具有单级功率因数校正(PFC)和原边反馈(PSR)恒流控制功能的驱动电源方案。文章分析了在单级PFC拓扑下原边恒流控制的原理,提出一种新颖的去磁时间检测方法,并将其应用于芯片G7102;同时推导了在准谐振工作模式下单级PFC拓扑的电流和功率因素λ值的计算公式,提出该工作条件下变压器的设计方法;最后制作了24 V 350 mA输出的LED驱动电源。实验证明,该方案在全电压范围内,电源效率η为85%以上,功率因数0.9以上,恒流精度达到2%,在小功率LED照明中具有很高的应用价值。
