US 7,023,146 B2 · Discharge lamp lighting apparatus

Abstract

A discharge lamp lighting apparatus has a problem that a microcomputer within the apparatus falls down into malfunction due to noises generated in an inside thereof. With such the structure of the discharge lamp lighting apparatus that an operation of a calculation processing circuit, which is built up with the microcomputer, etc., is stopped through stopping the supply of electric power to the calculation processing circuit or bringing it into a sleep mode, it is possible to protecting it from the malfunction, during a time period when high voltage is generated just after starting of lighting of the discharge lamp. Also, with applying a protection processing by means of the calculation processing circuit and also applying an analog protection circuit, in common with, thereby it is possible to ensure reliability thereof further.

Claims16

Dependent claims

A discharge lamp lighting apparatus, comprising:

an output electric power controlling circuit;
an alternating current converting circuit which converts an output of said output electric power controlling circuit into an alternating current;
an igniter circuit which amplifies an output of said alternating current converting circuit;
an output voltage detecting unit which detects an output voltage of said output electric power controlling circuit;
a driving current detecting unit which detects a discharge lamp driving current;
a calculation processing circuit which controls said output electric power controlling circuit depending upon detection is resulting from said output voltage detecting unit and said driving current detecting unit;
and
an electric power source which supplies electric power to said calculation processing circuit, wherein operation of said calculation processing circuit is stopped at least during a time period when high voltage is generated just after starting upon lighting of a discharge lamp.

5 more elements

A discharge lamp lighting apparatus, comprising:

an output electric power controlling circuit;
an alternating current converting circuit which converts an output of said output electric power controlling circuit into an alternating current;
an igniter circuit which amplifies an output of said alternating current converting circuit;
an output voltage detecting unit which detects an output voltage of said output electric power controlling circuit;
a driving current detecting unit which detects a discharge lamp driving current;
a calculation processing circuit which controls said output electric power controlling circuit depending upon detection results from said output voltage detecting unit and said driving current detecting unit;
and
an electric power source which supplies electric power to said calculation processing circuit;
an analog protection circuit which controls operation of said discharge lamp lighting apparatus upon basis of the detection result of said output voltage detecting unit;
and
an output current limit circuit for making such control that an output current of said discharge lamp is limited upon basis of the result of said driving current detecting unit, wherein said output electric power controlling circuit is controlled by said calculation processing circuit upon basis of the detection result of said output voltage detecting unit and the detection result of said driving current detecting unit, and also said output electric power controlling circuit is controlled by said analog protection circuit and said output current limit circuit when said calculation processing circuit malfunctions.

8 more elements

Dependencies are inferred from the claim text.

Discharge lamp lighting apparatus

Life of this patent

Discharge lamp lighting apparatus

Life of this patent

Abstract

Claims16