OSRAM OPTOTRONIC Constant current LED power supplies with 3DIM - Manual (Page 18)

18
3.2.2. Light sensor application
3.2.2.1. Using OSRAM DIM MICO/PICO
Daylight compensation can be easily obtained with the
LEDset interface by connecting existing commercial light
sensors (only plug-and-play sensors as described in the
DIM MICO/PICO is a light sensor from OSRAM which is
compatible with 1…10 V interfaces. The sensor works once
it is connected directly between Vset and GNDset.
This sensor is used to monitor, measure and maintain the
brightness level of its detection area to a preset value, which
is adjustable by a setpoint potentiometer screw. Once the
daylight decreases and the brightness of the area reaches or
falls below the preset value, the sensor starts to increase its
impedance between Vset and GNDset, thus increasing the
Vset voltage level. The higher current demand to the LEDset
ECG results in an artifi cial light compensation by the light of
the LED module.
Note: The 274 µA of Iset are enough to supply the sensor.
Particular attention should be paid to presetting the bright-
ness setpoint of the sensor, referring to the setup procedures
described in the DIM MICO/PICO datasheet. In any case,
Vset should be in the range of 10 to 11 V at the desired
maximum current output (no daylight present) to avoid
reaching the turn-off range of the LEDset interface charac-
teristic (see fi gure 4).
This warning does not apply if a LEDset ECG is used in
combination with a current set (CS) confi guration. For more
details, please see chapter 3.2.2.3. General notes on local
dimming: LEDset and “current set” combination.
For more detailed information about DIM MICO/PICO,
please refer to www.osram.com/lms-sensors
following chapter). Light sensing can be approached by
using standard 1…10 V-compatible light sensors or by devel-
oping light sensors from IC chips and converting their output
signal to the Vset range of the LEDset interface.
LEDset APPLICATIONS
Figure 9: Local dimming – light sensor application with DIM MICO/PICO.