| 摘要 |
<p>The present invention relates to a power supply apparatus for a light emitting diode (LED) lamp capable of stably driving an LED lamp, while securing a long lifespan, by using an electroless capacitor. The power supply apparatus for an LED lamp according to the present invention comprises a rectifier rectifying commercial alternating current (AC) power; a first smoothing capacitor configured as an electroless capacitor to smooth a voltage rectified by the rectifier; a flyback-type DC-DC converter converting a ripple current smoothed through the first smoothing capacitor into a direct current (DC) voltage appropriate for driving an LED lamp; a second smoothing capacitor configured as an electroless capacitor to smooth an output voltage from the flyback-type DC-DC converter; and a pair of buck-type DC-DC converters connected in parallel between the second smoothing capacitor and the LED lamp and operating with mutually different switching frequencies (fsw1) and (fsw2) to supply a DC to the LCD lamp. In the foregoing constitution, the switching frequencies fsw1 and fsw2 satisfy the following equation: fsw1 is not equal to n x fsw2, where fsw1 is greater than fsw2 and n is an integer. A p-type filter including RLC elements to operate as a low frequency filter is interposed between the first smoothing capacitor and the DC-DC converter.</p> |
