CIRCUIT ARRANGEMENTS AND METHODS FOR A REMOTE CONTROL RECEIVER HAVING A PHOTODIODE

摘要

A control unit ( 2 ) of a remote control receiver sets the forward or reverse direction operating mode of the photodiode ( 1 ) as a function of the useful signal level of its output signal, and to be precise, during standby, the photovoltaic operating mode (forward mode), since in this mode no external bias current is required. If the useful signal level of the photodiode ( 1 ) exceeds a predefined threshold, the reverse mode is set, and this brings with it a higher sensitivity. A series circuit (A) of a number of identical photodiodes DA 1 DAn the forward mode allows the realization of a controlled current source ( 6 ) having a transistor (T), since the permissible diode voltage (Ud) of the overall arrangement may have n times the value of the operating voltage of an individual photodiode. Thus at the same time the voltage across the individual diodes can be set to a very low value and a favorable operating range for the current source can be set. The possible sensitivity of the receiver module having diodes in this operating mode can thereby be considerably increased.