Title:
調光装置
Document Type and Number:
Japanese Patent JP4069482
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To surely prevent breakage of a relatively small switching element capable of reducing noise at a low cost even when an AC power supply is large, to quickly build up the light quantity to a desired value and to turn a lamp off when the switching element is broken. SOLUTION: A controller 90 can selectively control a main switch circuit 5 and an auxiliary switch circuit 6, turns off the operation of the switching element 8 of the auxiliary switch circuit 6 when an output current of the prescribed value Ith set in advance or above is detected by a current detecting means 10 during the operation of the auxiliary circuit switch 6, and ignites thyristors 3, 4 with the gate signal igniting the thyristors 3, 4 in the main switch circuit 5 synchronously with an AC power supply 1a. Even when the AC power supply 1a is large, an incandescent lamp 2 is prevented from being tuned on against a dimming action. A relatively small switching element 8 capable of reducing noise at a low cost is surely prevented from being broken, the light quantity is quickly built up to a desired value, and stable dimming control can be made.
Inventors:
Koji Umeda
Osamu Nakajima
Osamu Nakajima
Application Number:
JP35540697A
Publication Date:
April 02, 2008
Filing Date:
December 24, 1997
Export Citation:
Assignee:
Toshiba Lighting & Technology Corporation
International Classes:
F21V23/00; H05B39/08; F21S10/00; H05B37/02
Domestic Patent References:
| JP6338395A | ||||
| JP9298094A | ||||
| JP8507899A | ||||
| JP9259608A | ||||
| JP6290878A |
Attorney, Agent or Firm:
Susumu Ito