點晶科技股份有限公司

SILICON TOUCH TECHNOLOGY INC

.

新竹市科學園區展業一路9號7樓之1

9-7F-1, Prosperity RoadⅠ, Hsin-Chu, Taiwan, R.O.C.

Tel：886-3-5645656

Fax：886-3-5645626

16-channel 16-bit PWM Constant Current LED Driver

Version : A.003

Page 9

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DM634

Constant-Current Output

Constant-current value (Iout

between the REXT pin and GND. The current scale ranging can be adjusted from 5mA to 70mA by

varying the resistor value. User can input GBC value to increase Iout to 90mA. The reference

voltage of REXT terminal (Vrext) is approximately 1.23V. The output current value is calculated by

the following equation:

Iout(mA)

5

10

20

30

40

50

60

70

M

41.13

39.35

36.78

35.09

33.75

32.53

31.35

30.09

Output Current as a Functiono Rext value

0

10

20

30

40

50

60

70

80

0

1

23

4

5

678

9

10

Rext(KΩ)

Output Current as a Function of Output Voltage

0

10

20

30

40

50

60

70

80

0

0.5

1

1.5

2

2.5

3

Vout (V)

In order to obtain a good performance of constant-current output, a suitable output voltage is

necessary. Users can get related information about the minimum output voltage above.

× M