To prevent generation of overshoot current when power is turned on.SOLUTION: A light-emitting element drive device 700 has: an output current drive section 710 performing constant current control of an output current Iout so that a feedback voltage Vfb1 (more accurately, a feedback voltage Vfb2 adjusted in a feedback voltage adjustment unit 720) according to the output current Iout flowing to a light-emitting element LED1 matches a first reference voltage Vref1; and a feedback voltage adjustment unit 720 for adjusting the feedback voltage Vfb1 to approach the first reference voltage Vref1, by an offset voltage Voffset according to the differential value of both voltages (=Vref2-Vout), until the output voltage Vout, appearing at one end of the light-emitting element LED1, reaches a second reference voltage Vref2, when power is turned on.SELECTED DRAWING: Figure 7
【課題】電源立ち上げ時におけるオーバーシュート電流の発生を防止する。【解決手段】発光素子駆動装置700は、発光素子LED1に流れる出力電流Ioutに応じた帰還電圧Vfb1(より正確には帰還電圧調整部720で調整済みの帰還電圧Vfb2)と第1基準電圧Vref1とが一致するように出力電流Ioutの定電流制御を行う出力電流駆動部710と;電源立ち上げ時において、発光素子LED1の一端に現れる出力電圧Voutが第2基準電圧Vref2に達するまでの間、両電圧の差分値(=Vref2−Vout)に応じたオフセット電圧Voffset分だけ、帰還電圧Vfb1を第1基準電圧Vref1に近付けるように調整する帰還電圧調整部720と;を有する。【選択図】図7
LIGHT-EMITTING ELEMENT DRIVE DEVICE
発光素子駆動装置
2019-10-03
Patent
Elektronische Ressource
Japanisch
IPC: | H01L Halbleiterbauelemente , SEMICONDUCTOR DEVICES / B60Q ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL , Anordnung von Signal- oder Beleuchtungsvorrichtungen, deren Einbau oder Halterung oder deren Schaltkreise bei Fahrzeugen allgemein / H05B ELECTRIC HEATING , Elektrische Heizung |
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