SSD1805TR1 ETC2 [List of Unclassifed Manufacturers], SSD1805TR1 Datasheet - Page 19

• Manufacturer Part Number: SSD1805TR1
• Description: 132 x 68 STN LCD Segment / Common Monochrome Driver with Controller
• Manufacturer: ETC2 [List of Unclassifed Manufacturers]

7.5
This module generates the LCD voltage required for display driving output. It takes a single supply input and
generates necessary bias voltage. It consists of:
1) 2X, 3X, 4X and 5X regulated DC-DC voltage converter
2) Bias Divider
3) Bias Ratio Selection circuitry
SSD1805 Series
The built-in DC-DC regulated voltage converter is used to generate the large positive voltage supply.
SSD1805 can produce 2X, 3X, 4X or 5X boosting from the potential different between V
external boosting capacitors are required for configuration. Please refer to the command table for detail
description. The feedback gain control for LCD driving contrast curves can be selected by IRS pin to
either internal (IRS pin = H) or external (IRS pin = L). If internal resistor network is enabled, eight settings
can be selected through software command. If external control is selected, external resistors are required
to connect between V
detail connections.
If the output op-amp buffer option in Set Power Control Register command is enabled, this circuit block
will divide the regulator output (V
capacitors to reduce the external hardware and pin counts.
The software control circuit of 1/4 to 1/9 bias ratio in order to match the characteristic of LCD panel.
LCD Driving Voltage Generator and Regulator
+
+
C
C
2
2
+
+
Rev 1.1
C
C
1
1
ss
P 19/52
and V
Figure 4 - SSD1805 Hardware configuration
F
V
V
V
V
V
V
V
V
V
V
V
V
(R1), and between V
Jun 2004
OUT
HREF
DD
CI
LREF
SS
OUT
HREF
DD
CI
LREF
SS
OUT
) to give the LCD driving levels. The divider does not require external
SSD1805
SSD1805
F
and V
Normal Power Mode
Recommended capacitance value:
C
C
Low Power Mode
In Low Power Mode, TEST4 must > 4V
Recommended capacitance value:
C
C
1
2
1
2
OUT
: 1uF ~ 2.2uF
: 2.2uF ~ 4.7uF
: 1uF ~ 2.2uF
: 2.2uF ~ 4.7uF
(R2). See application circuit diagrams for
Solomon Systech
SS1
- V
CI
. No