TLC5903

LED DRIVER

SLLS383 – DECEMBER 1999

17

POST OFFICE BOX 655303

PRINCIPLES OF OPERATION

0

10

20

30

40

50

60

70

80

90

0.1

1

10

R(IREF) – kΩ

Conditions : V

I

V

R

38

R

47

I

NOTE: The output current is at 16 bit output.

When at 8-bit output, it will be the sum current of two

outputs. This sum current should be set up with the range

of 10 mA to 120 mA. The resistor, R(IRF), should be located

as close as possible to IREF terminal to eliminate the noise

influence.

Figure 4. Current on Constant Current Output vs External Resistor

RIREF = 4.70 k

0

1.0

0.2

0

0.4

0.6

0.8

100

10

VO – Output Voltage –V

0.1

0.3

0.5

0.7

0.9

20

30

40

50

60

70

80

90

RIREF = 2.35 k

RIREF = 1.57 k

RIREF = 1.18 k

RIREF = 940

RIREF = 780

RIREF = 670

RIREF = 590

minimum voltage applied

Ω

Ω

Ω

Ω

Ω

Ω

Ω

Ω

Ω

Ω

NOTE: VCCLOG = VCCANA = PVCC = 5 V, TA = 25°C.

Figure 5. Current on Constant Current Output vs Voltage Applied To Constant Current Output Terminal