The introduction of high brightness LED lighting reference design

Fairchild Semiconductor Company (FairchildSemiconductor) has a reference for the design of RD226 LED application design, no secondary side control circuit and optical coupler can implement AC input LED lighting system. RD226 is a general purpose input 12WLED lighting solution that is able to reduce the volume of Gao Liangdu (HB) LED lamps and save material list (BOM) costs. This reference design uses the flyback topology of the isolation of the primary side control off-line AC-DC converter, the general input voltage range of 85VRMS to 265VRMS, the line frequency is 50Hz to 60Hz. RD226 also provides 350mA and 700mA optional constant current output, the two largest output voltage is 17V. This reference design uses the Fairchild FAN102 device as the primary end control PWM controller to reduce the overall system cost and volume.

High brightness with AC power input (HB) LED applications need a circuit converts an AC input voltage for constant current, but in some applications, the load must be with the power supply input isolation, thus increasing the complexity of design. Traditional methods need to use flyback converter with constant current output. In most cases, the secondary side control circuit using an operational amplifier with a reference circuit, or with a special IC control to adjust current, and through an optical coupler transmitting PWM controller to the primary side control information. Fairchild innovative solutions that allow designers to achieve the AC input LED lighting system without secondary end control circuit and optocoupler.

Fairchild offers a wide range of reference design, can reduce board space, simplify the design, and ensure the reliability of the system and accelerate the speed to market. These ready to use designs can play an important role in making OEM vendors shorten design time and bring their applications to market more quickly.