Lighting circuit

A lighting circuit drives a light source including N (N represents an integer of 2 or more) multiple light-emitting elements coupled in series. A bypass switch circuit includes N multiple bypass switches, each coupled in parallel to a corresponding light-emitting element. A constant current driving...

Ausführliche Beschreibung

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Bibliographische Detailangaben
Hauptverfasser: Muramatsu, Takao, Maruyama, Yuta, Murakami, Kentarou
Format: Patent
Sprache:eng
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Beschreibung
Zusammenfassung:A lighting circuit drives a light source including N (N represents an integer of 2 or more) multiple light-emitting elements coupled in series. A bypass switch circuit includes N multiple bypass switches, each coupled in parallel to a corresponding light-emitting element. A constant current driving circuit supplies a driving current stabilized to a target current to the light source. A light distribution controller controls the bypass switch circuit. For a given light distribution pattern, the duty ratio Di(%) is determined for each of the N multiple light-emitting elements. Multiple light-emitting elements are formed as control units having a sum total of duty ratios that is less than 100%. The light distribution controller controls the multiple bypass switches such that the multiple light-emitting elements included in the same control unit are not turned on at the same time.