At an exhibition held last week in Tokyo, the Japanese company Kaga Components Co Ltd exhibited a LED lighting power supply apparatus in which the electrolytic capacitor has been removed to get a lifetime extended to more than 100,000 hours as well as a smaller size.

As a new generation of light source, LED is expected to spread rapidly in the near future as people increasingly concerned about environmental issues. However, while the lifetime of LEDs is 30,000 to 40,000 hours, that of existing power supply apparatuses is as short as 10,000 hours, a spokesperson of Kaga Components said, which is attributed to the only 10,000 hours life of the electrolytic capacitor in power supply circuit.

"We can not disclose details of the circuit configuration because its patent is pending, but we could remove the electrolytic capacitor by improving the circuit configuration of the switching power supply," the company said.

The power supply circuit was also downsized through this improvement, with the apparatus measuring only 43 x 29 x 8mm.

Equipped with an ON/OFF control function and an output short-circuit protection function, the apparatus can be used with one to five series-connected LEDs and input powers of 100V and 200V at a maximum output of 20V DC 300mA.

Two types of input/output were offered by the company, an isolated type and a non-isolated type. The price "varies depending on the amount but ranges from ¥500 (approx US$5) to ¥600, which is almost equivalent to that of existing products," the company said.