MP3302 –40V, 1.3A, SINGLE-CELL STEP-UP WHITE LED DRIVER WITH SINGLE WIRE DIMMING CONTROL

MP3302 Rev. 0.98

www.MonolithicPower.com

9

5/5/2010

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TYPICAL APPLICATION CIRCUITS

MP3302

SW

IN

FB

GND

EN

LED+

LED-

C4

330nF

50V

D2

5.6V

ZENER

D1

B0540

L1

4.7uH/1A

Optional

Bias Circuit

GND

EN

VIN

3.3V -18V

C1

4.7uF

16V

C3

0.1uF

50V

1

28

6

4

Figure 5 — Driving 27 WLEDs (9 WLEDs in Series and 3 Strings Paralleled) with 3.3V―18V Input Voltage

In order to improve the MOSFET on-resistance at low input voltage and make the chip compatible for

high input voltage, the additional bias circuit should be used.

MP3302

SW

IN

FB

GND

EN

GND

EN

LED+

LED-

VIN

4.5V-16V

C1

4.7uF

16V

C4

0.47uF

25V

L2

4.7uH/1A

C3

0.1uF

25V

Q2

2N3904

D2

5.6V

ZENER

Required Bias Circuit

for High Input Voltage

L1

C5

D1

4.7uH/1A

2.2uF/25V

B0530

8

2

4

1

6

Figure 6 — Wide Input Voltage Sepic Converter for 27 WLEDs ( 3 WLEDs in Series and 9 Strings Paralleled )