RT4539A

Copyright © 2022 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation

DS4539A-01

December 2022

www.richtek.com

19

LED Current Setting

The LED current of each channel can be set by I2C interface and more details are shown in Table 6.

Set Maximum LED current as shown below. This maximum current is scaled as described in the 0x02h Register.

Address

Bit

Name

Default Value

Description

Resolution

R/W

02h

[7: 0] ILED Current

Setting

20mA

(0x82h)

Control the max current

0x00h: 0mA

0x01h to 0x2Fh: 10.04mA

0x82h: 20mA

0xFFh: 35mA

~0.12mA

(0x2Fh to 0xFFh)

R/W

When the LED current setting command is below 0x82h, the LED current will be kept at 20mA. When the command is

0x00h, the LED current will be set to 0mA. The maximum LED current setting is 35mA. The one step of LED current

is approximately 0.12mA.

Table 6. LED Current Setting

ILED

(mA)

0x02h

<7: 0>

ILED

(mA)

0x02h

<7: 0>

ILED

(mA)

0x02h

<7: 0>

ILED

(mA)

0x02h

<7: 0>

ILED

(mA)

0x02h

<7: 0>

35.00

FF

29.24

CF

23.48

9F

17.72

6F

11.96

3F

34.88

FE

29.12

CE

23.36

9E

17.60

6E

11.84

3E

34.76

FD

29.00

CD

23.24

9D

17.48

6D

11.72

3D

34.64

FC

28.88

CC

23.12

9C

17.36

6C

11.60

3C

34.52

FB

28.76

CB

23.00

9B

17.24

6B

11.48

3B

34.40

FA

28.64

CA

22.88

9A

17.12

6A

11.36

3A

34.28

F9

28.52

C9

22.76

99

17.00

69

11.24

39

34.16

F8

28.40

C8

22.64

98

16.88

68

11.12

38

34.04

F7

28.28

C7

22.52

97

16.76

67

11.00

37

33.92

F6

28.16

C6

22.40

96

16.64

66

10.88

36

33.80

F5

28.04

C5

22.28

95

16.52

65

10.76

35

33.68

F4

27.92

C4

22.16

94

16.40

64

10.64

34

33.56

F3

27.80

C3

22.04

93

16.28

63

10.52

33

33.44

F2

27.68

C2

21.92

92

16.16

62

10.40

32

33.32

F1

27.56

C1

21.80

91

16.04

61

10.28

31

33.20

F0

27.44

C0

21.68

90

15.92

60

10.16

30

33.08

EF

27.32

BF

21.56

8F

15.80

5F

10.04

01~2F

32.96

EE

27.20

BE

21.44

8E

15.68

5E

10.04

32.84

ED

27.08

BD

21.32

8D

15.56

5D

10.04

32.72

EC

26.96

BC

21.20

8C

15.44

5C

10.04

32.60

EB

26.84

BB

21.08

8B

15.32

5B

0.00

0

32.48

EA

26.72

BA

20.96

8A

15.20

5A

32.36

E9

26.60

B9

20.84

89

15.08

59

32.24

E8

26.48

B8

20.72

88

14.96

58

32.12

E7

26.36

B7

20.60

87

14.84

57

32.00

E6

26.24

B6

20.48

86

14.72

56

31.88

E5

26.12

B5

20.36

85

14.60

55

31.76

E4

26.00

B4

20.24

84

14.48

54

31.64

E3

25.88

B3

20.12

83

14.36

53

31.52

E2

25.76

B2

20.00

82

14.24

52

31.40

E1

25.64

B1

19.88

81

14.12

51