| 摘要 |
An LED driving circuit can improve characteristics. A first current increasing circuit 10i 4 is constituted of a first slow regulating unit 10i 41 and a post-stage first supplying circuit 10i 43 and, from a point in time of output switching of a first comparator 10i 2 , that is, when a set temperature exceeding a reference potential Va is attained, gradually increases a temperature compensated current I T1 (”I1) and thereby suppresses the lowering of emission output. Here, by gradually increasing the temperature compensated current I T1 by making use of charging/discharging functions of a capacitor, etc., that is, by increasing the temperature compensated current I T1 over a longer time than a pulse width that a photodetecting element, onto which light from an LED 11 is made incident, can respond within, pulse width distortion and jitter can be suppressed. |
