EL640.200-SK Operations Manual (020-0348-00B)
12
Dimming
There are two standard methods for dimming the EL640.200-SK display. To
perform analog dimming in either buffered or non-buffered mode, connect a
100 K
:
variable resistor between LUMA and GND. Alternatively, an external
voltage or current mode D/A converter may be used to facilitate dimming by
sinking a maximum of 250 µA nominal (for maximum dimming) from LUMA to
GND on the input connector. Open circuit voltage is 5 V nominal.
To perform digital dimming in buffered mode, the internal scan frequency is
controlled via the LUM1 and LUM0 inputs. When these inputs are left open,
the display is scanned at 240 Hz—the maximum scan rate. With the
combination of the two inputs, LUM1 and LUM0, the following scan
frequencies are obtained:
Table 6. Digital Luminance Control.
Approx. Relative Luminance
Max
75%
50%
25%
LUM1
1
1
0
0
LUM0
1
0
1
0
Frame rate (Hz) *
240
180
120
60
Analog Luminance Control
Luminance control circuitry is provided to allow the user to adjust the
luminance from 5 to 100 percent of the maximum. Connecting a 100 K
:
variable resistor between LUMA and GND will give a brightness range from
approximately 5 to 100 percent of the full luminance value. Alternatively, an
external voltage or current mode D/A converter may be used to facilitate
dimming by sinking a maximum of 250 µA (for maximum dimming) from
LUMA to GND on the input connector.
Table 7. Analog Luminance Control.
Approx. Relative Luminance
Dimming
Maximum (No resistor connected)
100 % (Default)
Maximum (100 K
:
resistor connected)
100 %
Minimum (O
:
resistor connected)
5% maximum, 0% minimum
Open Circuit voltage
5V nominal
Sink Current
250
P
A nominal, Vin = 0V
Brightness values are measured as a percentage of full On Luminance with the
external resistor disconnected.
