SSD1815 datasheet(11/35 Pages) ETC

11 / 35 page

SOLOMON

SSD1815

REV 1.5

03/2000

LCD Driving Voltage Generator and Regulator

This module generates the LCD voltage required for display driv-

ing output. It takes a single supply input and generate necessary volt-

age levels. This block consists of:

1. 2X, 3X and 4X DC-DC voltage converter

The built-in DC-DC voltage converter is use to generate large neg-

ative LCD driving voltage with reference to VDD from the voltage

input (VSS1). For SSD1815, it is possible to produce 2X, 3X or 4X

boosting from the protential different between VSS1 - VDD.

Detail configurations of the DC-DC converter for different boosting

multiples are given in Figure 6 at the right.

2. Voltage Regulator (Voltages referenced to VDD)

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).

For internal resistor network is enabled, there are eight setting can

be set by software.

If external control is selected, external resistors are required to be

connected between VDD and VF (R1), and between VF and VL6

(R2).

3. Contrast Control (Voltages referenced to VDD)

Software control of the 64 contrast voltage levels at each voltage

regulator feedback gain. The equation of calculating the LCD driv-

ing voltage is given as:

where

and

4. Bias Divider

Divide the regulator output to give the LCD driving voltages (VL2 -

VL5). A low power consumption circuit design in this bias divider

saves most of the display current comparing to traditional design.

5. Bias Ratio Selection circuitry

Software control of 1/7 and 1/9 bias ratio to match the characteris-

tic of LCD panel. In addition, 1/4, 1/5, 1/6 and 1/8 bias ratios are

also software selectable using the extended command for any

mux application.

6. Self adjust temperature compensation circuitry

This block provides 4 different compensation settings to satisfy

various liquid crystal temperature gradings by software control.

Default temperature coefficient (TC) setting is TC0.

)

(

)

(

Contrast

Gain

ref

−

∗

−

Int. Reg.Resistor

Ratio Setting

Ext.

Resistor

Gain

-3.29

-3.76

-4.29

-4.82

-5.39

-5.76

-6.40

-6.95 -(1+R2/R1)

92.59 91.86 91.12 90.40 89.67 89.18 88.29 87.49

96.68

(-0.01%/

°C)

(-0.10%/

°C)

(-0.18%/

°C)

(-0.25%/

°C)

VBE

0.025

0.523

0.520

0.517

0.72

0.423

0.272

0.121

SSD1815

C3N

C1P C1N

C2P C2N

VEE

Remarks:

1. C1 = 0.47 - 1.0uF

2. Boosting input from VSS1.

3. VSS1 should be lower potential than or equal to VSS

4. All voltages are referenced to VDD

VSS1

SSD1815

C3N

C1P C1N

C2P C2N

VEE

VSS1

SSD1815

C3N

C1P C1N

C2P C2N

VEE

VSS1

2X Boosting Configuration

3X Boosting Configuration

4X Boosting Configuration

Figure 6 - Configurations for DC-DC Converter

SSD1815 датащи(PDF) 11 Page - List of Unclassifed Manufacturers

SSD1815 датащи(HTML) 11 Page - List of Unclassifed Manufacturers

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

датащи скачать

ссылки URL