Planar LC1200R - Manual (Page 20)

LC1200R User’s Guide 021-0183-00 Rev A 20 of 29
6.3 Dimming
6.3.1 Photodiode Board and Automatic Dimming Connector
The photodiode board must be mounted in the user’s system so that the photodiode is
exposed to the ambient light. In bright conditions, the LC1200R will adjust to maximum
brightness. In dark conditions, the LC1200R will adjust to approximately 25% of the
maximum luminance. Connector Pin Assignments are in Table 8
Table Table Table Table 8 8 8 8
Pin Pin Pin Pin Description Description Description Description
1 Output from photodiode anode
2 5V input from the LC12F for
photodiode cathode
3 No connection
6.3.2 Dimming Control Connector Pin Assignment and Performance
A separate connector will allow dimming via an analog input and will allow the inverter to be
inhibited. A 5V reference and ground are provided for cases where an external potentiometer is used
to generate the DIM input. If used, a 50k potentiometer is recommended.
Any connection made to the DIM input will override the Automatic dimming function, thus leave the
DIM input open if using the photodiode for automatic dimming.
Connector mates with Molex 5264 and 42219 series.
Connector Pin Assignments:
Table Table Table Table 9 9 9 9
Pin Pin Pin Pin Name Name Name Name Description Description Description Description
1 5V REF 5V source for upper leg of potentiometer, if use; current
limited with 2.2k series resistance
2 DIM 0-5V input to facilitate manual dimming; leave open if not
used. Connect to wiper of pot if used.
3 GND Ground for lower leg of potentiometer, if used
4 NC No connection
5 DISABLE Low (<0.5V) will turn off the backlight, High (>2V) will have no
effect on Monitor brightness
6.3.3 Automatic Brightness Mode
For Automatic Brightness Mode, install the photodiode board so that the ambient light conditions
are monitored and leave the DIM pin on the Dimming Control connector open.