Drive device for light-emitting element

A power converting unit supplies a predetermined current to each of light-emitting elements by controlling a duty ratio of a semiconductor switching element. A light-emitting-element selecting unit sequentially selects a light-emitting element to be supplied with the current from the power convertin...

Ausführliche Beschreibung

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Bibliographische Detailangaben
Hauptverfasser: YAMAMURO TAKAHIKO, URAKABE TAKAHIRO
Format: Patent
Sprache:eng
Schlagworte:
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Beschreibung
Zusammenfassung:A power converting unit supplies a predetermined current to each of light-emitting elements by controlling a duty ratio of a semiconductor switching element. A light-emitting-element selecting unit sequentially selects a light-emitting element to be supplied with the current from the power converting unit. A duty-ratio control unit controls the duty ratio of the semiconductor switching element based on a value obtained by multiplying a gain by a difference between an output current of the power converting unit and a target current. A gain selecting unit changes the gain according to selected light-emitting element.