SC5010H View Datasheet(PDF) - Semtech Corporation

Part Name

Description

MFG CO.

SC5010H

High Efficiency 8-Channel LED Driver with I2C Interface and Phase-Shifted PWM Dimming

Semtech Corporation 

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SC5010H

Applications Information (continued)

An example for calculating the fading time is shown in

this section. Assuming LED PWM dimming frequency is

10kHz, then 10 bits are assigned for 1024 duty cycle

settings.

TPWM = 100 µs (with 10kHz dimming frequency)

Cycle in Zone #1 = (511 - Starting Duty Cycle) x [(Zone #1

Step Interval) / (Zone #1 Step Increment)]

Duty

Cycle

Zone

1

2

3

Duty Cycle

Step

Step

Range Increment Interval

0 to 511

1

2

512 to 767

1

1

768 to 1024

2

1

Total Steps

within the

Range

512

256

256

Time required to go from 10% (102/1024) to 90%

(922/1024) duty cycle can be calculated using the follow-

ing equation:

Cycle in Zone #2 = Total Stpes in Zone #2 x [(Zone #2 Step

Interval) / (Zone #2 Step Increment)]

Cycle in Zone #3 = (End Duty Cycle - 768) x [(Zone #3 Step

Interval) / (Zone #3 Step Increment)]

In this case, the total cycle will be:

Total cycle = 2 x (511-102) + 1 x 256 + 0.5 x (922 - 768)

= 1151

Total Fading Time = Total Cycle x TPWM

= 1151 x 100 µs = 115.1ms

Vin

(6.5-27V)

PGND

Vcc (5V)

AGND

C1

4.7µF X 2

R2

3 7 .4 K Ω

Q2

C7

10nF

L1

4.7µH

D1

Q1

R9

0.1Ω

C2

2 .2 µF

R1

10KΩ

U1 28 27 26 25 24 23 22

R11

309KΩ

C6

4.7µF X 3

R10

10KΩ

Vout

10 WLEDs per channel

R3

10KΩ

R4, 10kΩ

R5, 10KΩ

C3

1 µF

R6

100kΩ

1 VCC

2 EN

3 UVLO

4

SCP

5 BG

6

FSET

7

AGND

S C 5010H

IO2 21

IO3 20

IO4 19

18

IO5

IO6 17

IO7 16

15

IO8

R15

20KΩ

8

R7, 110KΩ

C4

100pF

C5

2.7pF

THP

9 10 11 12 13 14 PAD

R8

25.5kΩ

SYNC SCL SDA

FLT PWMI

Figure 2 — Detailed Application Circuit

21

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