This led driver electronic project is designed by Power Integrations using the LNK417EG high efficiency driver . This LNK417EG LED driver electronic project will provide a 30 volts output voltage at a maximum current of 500mA from an input voltage between 90 and 265 volts .
The LNK417EG integrated controller and 725 V MOSFET dramatically reduces the complexity and component count of the solution.
Inductor L2-L4, C1, R1, and R5 form the EMI filter and together with C9 (Y1 safety) capacitor allow the design to meet EN55015B conducted EMI limits. Capacitor C8 provides a low impedance path for the primary switching current. A small capacitor value is necessary to maintain a power factor of greater than 0.9.
Diode D1 and high-voltage SMD ceramic capacitors C11 and C10 detect the peak AC line voltage.
Diode D2 and VR1 clamp the drain voltage to below the BVDSS rating (725 V) of the internal power MOSFET in U1. Diode D5 is necessary to prevent reverse current from flowing through the LinkSwitch-PH device .
Diode D4, D6, C7, R3, R6 and R8 form the primary bias supply. This supplies the IC operating current into the BYPASS (BP) pin through D6 and R8 during normal operation.
Resistor R3 provides filtering to improve output regulation while R6 acts as a minimum load.
During start-up C13 is charged to ~6 V from an internal high-voltage current source tied to the device DRAIN (D) pin. Once charged the energy stored in C13 is used to run the device until the output and bias winding voltage rise and current is supplied via R8.
A disconnected load / overvoltage shutdown function is provided by D7, C14, R11, VR2, C12, R12 and Q1.
Diode D3 rectifies the secondary winding while ceramic capacitors C2, C3, C4, C5 and C6 filter the output.
Transformer used in this project can be a P-1031 type manufactured by Pin Shine or you can design your own transformer using the following electrical specifications .