Takeshi Kamoi

US Patent:

6914395, Jul 5, 2005

Filed:

Nov 26, 2002

Appl. No.:

10/473361

Inventors:

Tokushi Yamauchi - Hirakata, JP
Tsutomu Shiomi - Kitakatsuragi-gun, JP
Minoru Maehara - Matsubara, JP
Yutaka Iwahori - Kadoma, JP
Toshiaki Nakamura - Kadoma, JP
Takeshi Kamoi - Woburn MA, US

Assignee:

Matsushita Electric Works, Ltd. - Kadoma

International Classification:

H05B041/36

US Classification:

315308, 315224, 315291, 315360

Abstract:

An electronic ballast for a high intensity discharge lamp (HID) includes a power converters, a controller, and a lamp power switch. In the power converter, an input DC voltage is converted into a ballast output power for lighting the HID lamp. The controller has a function to control the power converter and change the ballast output power. The lamp power switch detects a lamp output parameter indicated after the HID lamp starts discharge, identifies a lamp power of the HID lamp according to the lamp output parameter, and gives an identification signal indicating the lamp power. In response to this identification signal, the power converter outputs the ballast output power which matches with the lamp power identified.

US Patent:

7109659, Sep 19, 2006

Filed:

Nov 19, 2004

Appl. No.:

10/991415

Inventors:

Takeshi Kamoi - Woburn MA, US

Assignee:

Matsushita Electric Works, Ltd. - Kadoma

International Classification:

H05B 39/10

US Classification:

315 88, 315 92, 315291, 315307, 362 13, 362 20

Abstract:

A high-intensity discharge lamp ballast includes a lamp operation unit configured to supply power from a power source to a high-intensity discharge lamp, a lamp voltage detector configured to detect a voltage applied to the high-intensity discharge lamp, a lamp status determination unit configured to determine whether the high-intensity discharge lamp is in a turned-on state, based on the voltage detected by the lamp voltage detector, an auxiliary lamp switching element configured to connect the power source and an auxiliary lamp having a rated voltage, and a controller configured to control the auxiliary lamp switching element so as to apply to the auxiliary lamp a voltage substantially equal to the rated voltage of the auxiliary lamp when the high-intensity discharge lamp is supplied with the power and the lamp status determination unit determines that the high-intensity discharge lamp is not in the turned-on state.