R

(k

)=

W

IREF

V

(V)

IREF

I

(mA)

OLC

TLC59282

www.ti.com

SBVS152A – DECEMBER 2010 – REVISED DECEMBER 2010

DETAILED DESCRIPTION

SETTING FOR THE CONSTANT SINK CURRENT VALUE

Where:

(1)

resistor value is shown in Figure 10. Table 1 describes the constant-current output versus external resistor value.

Table 1. Constant-Current Output versus External Resistor Value

1.12

1.26

35

1.44

30

1.68

25

2.02

20

2.52

15

3.37

10

5.05

5

10.1

2

25.2

CONSTANT-CURRENT DRIVER ON/OFF CONTROL

When BLANK is low, the corresponding output is turned on if the data in the on/off control data latch are '1' and

remains off if the data are '0'. When BLANK is high, all outputs are forced off. This control is shown in Table 2.

Table 2. On/Off Control Data Truth Table

CONSTANT-CURRENT OUTPUT

OUTPUT ON/OFF DATA

STATUS

0

Off

1

On

When the IC is initially powered on, the data in the 16-bit shift register and output on/off data latch are not set to

the respective default value. Therefore, the output on/off data must be written to the data latch before turning the

constant-current output on. BLANK should be at a high level when powered on because the constant-current

may be turned on as a result of random data in the output on/off data latch.

The output on/off data corresponding to any unconnected OUTn outputs should be set to '0' before turning on the

Copyright © 2010, Texas Instruments Incorporated

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