
Page 12
Epson Research and Development
Vancouver Design Center
S1D13706
Connecting to the Epson D-TFD Panels
X31B-G-012-03
Issue Date: 01/02/23
2.4 Swing Power Supply for the Vertical Drive (V0Y) and Logic (VCCY / V5Y)
Voltages
The vertical drive voltage (V0Y) and vertical logic voltages (VCCY and V5Y) require a
swing power supply. To obtain the required voltage range, VEEY is used to swing the
vertical system voltages through the recommended -32V to 32V range. The swing circuit
is shown in Figure 2-5: “Swing Power Supply for Vertical System Voltages” .
Figure 2-5: Swing Power Supply for Vertical System Voltages
The swing power supply is controlled by the S1D13706 output signal GPIO3 (FRS). When
GPIO3 is low, transistor Q1B turns on and Q1A turns off. V5Y (vertical logic low
potential) goes to GND. Transistor U1 also turns on and VCCY (vertical logic high
potential) = VCC = 3.3V. V0Y (vertical liquid crystal drive supply) swings to | VEEY | +
4.5 when GPIO3 goes low since the reference changes to VEEY from GND for this signal.
When GPIO3 is high, transistor Q1A turns on and Q1b turns off. V5Y goes to the level of
VEEY. VCCY is now referenced to VEEY and its level goes to VEEY + VCC. Diode D8
forward biases and sets V0Y = VDDH = 4.5V.
The following table shows the values of V5Y, V0Y, and VCCY for the high and low values
of the control signal GPIO3 (FRS).
Table 2-1: Swing Power Supply Values
FRS
GPIO3 (FRS)
Low (GND)
GPIO3 (FRS)
High (3.3V)
Power Supply Potential V0Y
|VEEY| + VDDH
VDDH
Power Supply Potential VCCY
VCC
VEEY + VCC
Power Supply Potential V5Y
GND
VEEY
VCC
VDDH
VCCY
V0Y
V5Y
VEEY
FRS
C7
1u 50V
R1
220
R7
220
R9
1M
Q1A
XP4601
2
6
1
C5
220p 50V
U1
2SB709A
1
2
3
Q1B
XP4601
5
4
3
R8
4.7K
R5
4.7K
D3
1SS388
C1
0.047u 50V
C6
4.7u 16V
R3
220
R2
220
C2
0.047u 50V
C4
220p 50V
D4
1SS388
D2
1SS355
R6
4.7K
C3
220p 50V
C8
0.1u 16V
D1
1SS355
R4
220