Title:
ELECTRODELESS DISCHARGE LAMP LIGHTING DEVICE
Document Type and Number:
Japanese Patent JP3387212
Kind Code:
B2
Abstract:
PURPOSE: To reduce the flickering of an electrodeless discharge lamp to prevent having a lower limit of dimming by detecting both end voltages of a high-frequency power supply coil or a current input to a high-frequency power supply means, and performing control so that a high voltage of the high-frequency power supply coil is generated.
CONSTITUTION: When a lighting signal for an electrodeless discharge lamp 7 is inputted to a dimmer circuit 6 at time t1, a direct input current I1 flows to a high-frequency power supply means from a DC input voltage E and high-frequency AC voltages appear at both ends of a high-frequency power supply coil 8, lighting the discharge lamp 7. Also, divided voltages are generated at the resistances R21, R22 of an output voltage detecting circuit 20. Voltages are input to the minus terminals of comparators IC21, IC31 from voltages V2, V1 after a slight delay from the time t1, so that the outputs of the comparators IC31 IC31 change from H to L while the base voltage of a TrQ11, remains L. The base voltage of the TrQ11 becomes H at time delayed from the time t1 and shortcircuits a resistance R2 in an oscillator circuit 1, the emitter voltage of Q1 drops, the output of the circuit 1 rises, and high voltages are generated at both ends of the coil 8 via amplifiers 2, 5 and a matching circuit 4.
Inventors:
Tomoyuki Nakano
Taishi Kido
Taishi Kido
Application Number:
JP11928494A
Publication Date:
March 17, 2003
Filing Date:
May 31, 1994
Export Citation:
Assignee:
MATSUSHITA ELECTRIC WORKS,LTD.
International Classes:
H05B41/24; (IPC1-7): H05B41/24
Domestic Patent References:
| JP591733A | ||||
| JP6240196A |
Attorney, Agent or Firm:
Junji Ando
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