| 摘要 |
PROBLEM TO BE SOLVED: To realize a light emitting device drive circuit which is simple in constitution and capable of ensuring a light emitting device of a constant output at all times, even if the light emitting device changes in characteristics with a temperature change. SOLUTION: A light emitting device drive circuit is equipped with a drive transistor 21 which feeds a bias current and a pulse current to a light emitting device 1 whose cathode is grounded, a control resistor 22 which controls the bias current and the pulse current supplied to the light emitting device 1, and a resistance voltage divider composed of split resistors which are connected in series so as to separately set the pulse current and the bias current, wherein the split resistors which are connected in series are formed of a temperature- dependent resistor 55.
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