| 摘要 |
PROBLEM TO BE SOLVED: To provide an LED driving device that improves accuracy of balance of current flowing in an LED.SOLUTION: The LED driving device has: a resonance-type power supply unit that has a series connection including a first transformer T2, first and second switching elements QH, QL, a primary winding Np, and a resonance capacitor Cri; a series circuit including first rectifying and smoothing circuits C1, D1 connected to the output of the power supply unit, a first LED group LD1 connected to the first rectifying and smoothing circuits and in which one or more LEDs are connected in series, and a first winding N1 connected between the power supply unit and the first rectifying and smoothing circuits; a series circuit including second rectifying and smoothing circuits C2, D2 connected to the output of the power supply unit, a second LED group LD2 connected to the second rectifying and smoothing circuits and in which one or more LEDs are connected in series, and a second winding S1 connected between the power supply unit and the second rectifying and smoothing circuits; and a control unit 1 for controlling switching frequencies of the QH and QL to a frequency higher than the resonance frequency of the power supply unit. First and second currents flowing in each series circuit are balanced on the basis of electromagnetic force generated in the first/second windings. |
