原标题：Renesas R2A20134SP两种工作模式LED照明方案

　　Renesas公司的R2A20134SP是LED照明的控制IC,具有两种工作模式:临界导通模式(CRM)和固定开关频率模式.CRM模式能精确地控制LED电流和修正功率因素,具有高效率,而固定开关频率模式能大大地降低外接元件数量.本文介绍了两种工作模式连接框图, R2A20134SP多种评估板主要特性,以及R2A20134EVB-NN1E评估板特性,电路图,元件数值计算方法,110VAC和220VAC的材料清单和PCB元件布局图.

　　R2A20134SP is a control IC for LED lighting. It has two operation modes, Critical Conduction mode (CRM) and fixed switching frequency mode. User can choose one suitable mode for their purpose.

　　At Critical Conduction mode (CRM), this IC can control LED current precisely and correct power factor and achieve high efficiency by zero-current switching. At Fixed-Frequency mode, user can reduce the external components dramatically. AT Peak Current Control mode applying Fixed Switching Frequency Mode realized the minimum numbers of external components, smallest packaging and low BOM cost. Also this allows the isolated flyback operation.

　　图1.R2A20134SP临界导通模式(Rrt接地)框图

　　图2.R2A20134SP固定开关频率模式(Rrt接Vref)框图

　　图3.R2A20134SP峰值电流控制电路图

　　图4.R2A20134SP恒定ON时间控制(PFC)电路图

　　R2A20134SP多种评估板特一揽表:

　　图5. R2A20134EVB-NN1E评估板外形图

　　图6. R2A20134EVB-NN1E评估板电路图(误差放大器控制)

　　R2A20134EVB-NN1E评估板主要元件计算表:

　　R2A20134EVB-NN1E (误差放大器控制)材料清单(BOM):

　　Vin = AC85-132 V, Vf = 65 V, ILED = 100 mA

　　AC220 V input, VF = 35 V, ILED = 400 mA变更的元件数值:

　　图7. R2A20134EVB-NN1E评估板元件布局图:左:顶层;右:底层