Light driving apparatus and method thereof

摘要

A light driving apparatus includes a first rectifying unit for receiving AC power and rectifying the AC power into DC, a switching element controlled to turn on or off by a control signal, a transforming unit having a transformer and an inductor connected to a primary side of the transformer in parallel, a second rectifying unit for rectifying a secondary side output of the transforming unit and supplying an output voltage thereof to a LED unit, and a control unit provided in the primary side to give a constant-current control function so that a secondary side output is maintained consistently. According to the present disclosure, it is possible to simplify the circuit structure of the secondary side and improve the efficiency by controlling the secondary side current at the primary side without secondary side feedback information.

主权项

1. A light driving apparatus, comprising:
a first rectifying unit for receiving AC power and rectifying the AC power into DC power; a switching element; a transforming unit having a transformer for transforming the magnitude of an input voltage output from the first rectifying unit and an inductor connected to a primary side of the transformer in parallel, the transforming unit storing energy in the inductor when the switching element turns on and transferring the energy stored in the inductor to a secondary side when the switching element turns off; a second rectifying unit for rectifying a secondary side output of the transforming unit and supplying the secondary side output of the transforming unit to a LED unit; and a control unit for calculating a secondary side average current based on current and voltage of the primary side, obtained from the inductor included in the primary side of the transforming unit, and controlling the switching element to turn on or off according to a result of the calculation so that a constant driving current flows at the LED unit, wherein the control unit samples an input voltage applied to one end of the inductor and a difference value between the voltages at both ends of the inductor, divides the sampled input voltage by the sampled difference value, obtains a primary side average current by averaging a primary side output of the switching turn-on period, and obtains a secondary side average current by multiplying the obtained primary side average current and the output of the dividing operation.