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Epson Research and Development
Vancouver Design Center
S1D13504
S5U13504B00C Rev. 2.0 PCI Evaluation Board User Manual
X19A-G-014-01
Issue Date: 2002/12/02
4.3.2 Buffered LCD Connector
J1 provides the same LCD panel signals as those directly from S1D13504, but with voltage-
adapting buffers which can be set to 3.3V or 5V. Pin 32 on this connector provides power
for the LCD panel logic at the same voltage as the buffer power supply.
4.3.3 Adjustable LCD Panel Positive Power Supply (VDDH)
Most passive LCD color and passive single monochrome LCD panels require a positive
bias voltage b24V and +40V. The S5U13504B00C uses a Maxim MAX754 LCD
Contrast Controller to provide this voltage range. VDDH can be adjusted using RV1 (200
Ω
potentiometer) to provide an output voltage from +24V to +40V.
To enable the VDDH power supply, the evaluation board uses the LCDPWR# output from
the S1D13504, inverted by U6, to control the MAX754 as shown in the following table..
Note
When manually adjusting the voltage, set the potentiometer according to the panel’s
specific power requirements before connecting the panel.
4.3.4 Manual/Software Adjustable LCD Panel Negative Power Supply (VLCD)
Most passive monochrome LCD panels require a negative bias voltage between -14V and
-24V. The S5U13504B00C uses a Maxim MAX749 Digitally Adjustable LCD Bias Supply
to provide this voltage range. VLCD can be adjusted using RV2 (500K potentiometer) to
provide an output voltage from -16V to -23V.
To enable the VLCD power supply, the evaluation board uses the LCDPWR# output from
the S1D13504, inverted by U6, to control the MAX749 as shown in the following table..
Note
When using manual adjust, set the potentiometer according to the panel’s specific power
requirements before connecting the panel.
Table 4-5: Controlling the MAX754
S1D13504 Output Signal
Turn MAX754 On
Turn MAX754 Off
LCDPWR#
low
high
Table 4-6: Controlling the MAX749
S1D13504 Output Signal
Turn MAX749 On
Turn MAX749 Off
LCDPWR#
low
high