Planar LC1200R Photodiode Board and Automatic Dimming Connector, Automatic Brightness Mode

6.3Dimming

6.3.1Photodiode 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 8

Pin Description

1Output from photodiode anode

2 5V input from the LC12F for photodiode cathode

3 No connection

6.3.2Dimming 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 9

Pin	Name	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.

LC1200R User’s Guide 021-0183-00 Rev A 20 of 29