REAL-TIME, FINE ADJUSTMENT OF DRIVER CURRENT OF A LIGHT EMITTING DEVICE OF AN OPTICAL RAIN SENSOR

The present invention relates to a real-time, fine adjustment of light emitting device current in an optical rain sensor using an external regulated current source. The regulated current source comprises: a variable current source to supply an output current (lout) with a constant intensity that is adjustable based on an external regulation signal; a controlled switch to be connected between a terminal of the light emitting device and said output terminal of the variable current source. The controlled switch is adapted to switch between an on state and an off state in synchronization with the driver current pulse supplied to the light emitting element for connecting and disconnecting said variable current source, thereby generating a compensation current signal (Ic) based on said regulation voltage (Vreg) and that is superimposed on the driver current pulse across the light emitting device for reducing an imbalance between the first and second light pulses.