Rev. 1.00

9

April 19, 2012

HT7938A

06 %'!&)

VI N

EN

SW

OV P

FB

10 m H/ 22 m H

GN D

1N 5819

10 k W

PW M Si gna l

150k W

0. 1 m F

10 k W

C1

1 m F

C2

4. 7 m F

15 W

10 S1 P

Fig.16 Application for Dimming Control Using a Filtered PWM Signal

Note:Astheaboveapplicationcircuitsareunabletoshowthefulldrivecapabilitiesandseries/paralleldrive

combinationsofthisdevicethefollowingsupplementalinformationisprovided.

Forthegeneralfullvoltagerangesituation:

1.VinVariableVoltageof2.6V~5.5V

2.LEDforwardvoltageof3.5Vmax.

Maximum LED Drive Capability

Series

Parallel

Total

3

3

9

4

2

8

5

2

10

6

1

6

7

1

7

8

1

8

9

1

9

10

1

10

Itisalsoimportanttonotethatforaninputvoltagesupplywhichcanbemaintainedat5.0Vorhigher,the

devicepossessesevenhigherdrivecapabilitieswhichcandriveahighernumberofparallelconnectedLEDs.

ThefollowingtabledepictsthemaximumLEDnumberspossibleforthishigherinputvoltagerange.

1.VinVariableVoltageof5.0V~5.5V

2.LEDforwardvoltageof3.5Vmax.

Maximum LED Drive Capability

Series

Parallel

Total

3

13

39

3

10

40

3

9

27

4

8

32

5

4

20

6

4

24

7

3

21

8

2

16

9

2

18

10

2

20