5

FN6189.2

August 29, 2006

Application Information

This device provides the ability to reduce the flicker of an LCD

test and alignment. A 128-step resolution is provided under

digital control, which adjusts the sink current of the output.

The output is connected to an external voltage divider, so that

the device will have the capability to reduce the voltage on the

output by increasing the output sink current.

serial interface.

Expected Output Voltage

The ISL45041 provides an output sink current, which lowers

the voltage on the external voltage divider (VCOM output

voltage). Equation 1 and Equation 2 can be used to calculate

NOTE: Where setting is an integer between 1 and 128.

will keep the output MOS transistor in the saturation region.

Expected current settings and 7-Bit accuracy occurs when the

output MOS transistor is operating in the saturation region.

Figure 2 shows the internal connection for the output MOS

source of the output transistor. This voltage is equal to

(Equation 2) should be determined (setting equal to 128) so the

Ramp-Up of the VDD Power Supply

It is required that the ramp-up from 10% VDD to 90% VDD

level be achieved in less than or equal to 10ms to assure

that the EEPROM and Power-on-reset circuits are

synchronized and the correct value is read from the

EEPROM Memory.

TABLE 1.

SETTING VALUE

VOUT

1

5.468

10

5.313

20

5.141

30

4.969

40

4.797

50

4.625

60

4.453

70

4.281

80

4.109

90

3.936

100

3.764

110

3.592

128

3.282

FIGURE 1. OUTPUT CONNECTION CIRCUIT EXAMPLE

-

+

ISL45041

SET

OUT

AVDD

AVDD

I

OUT

Setting

128

--------------------- x

AV

DD

20 R

SET

()

---------------------------

=

V

OUT

R

2

R

1

R

2

+

---------------------

⎝⎠

⎜⎟

⎛⎞

AV

Setting

128

--------------------- x

R

1

20 R

SET

()

---------------------------

–

⎝⎠

⎜⎟

⎛⎞

=

(EQ. 1)

(EQ. 2)

FIGURE 2. OUTPUT CONNECTION CIRCUIT EXAMPLE

RSET

VOUT PIN

R1

R2

AVDD

VSAT

0.5V

ISET PIN

SETTING

128

---------------------------- x

AV

DD

20

------------------

ISL45041