MP4603 – WHITE LED DRIVER FOR LARGE SIZE BACKLIGHTING

MP4603 Rev1.0

www.MonolithicPower.com

16

4/27/2012

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© 2012 MPS. All Rights Reserved.MP4603

Select

R19=300kΩ as

the

compensation

resistor.

Selecting the Input and Output Capacitor

Estimate the input capacitor and output

capacitor using the following equations.

L_ AVG

OUT

IN

sIN

IN

OUT

IV

C

fV (V

V

)











LED

OUT

OUT

sOUT

IN

OUT

IV

C

fV

(V

V

)











output voltage. Select C2=2.2μF ceramic

capacitor as the input capacitor and C8=2.2μF

as the output capacitor

Setting the Over Voltage Protection

Set the OVP point is about 1.1x-to-1.2x of the

output voltage so that the OVP point is about

60V to 66V.

OVP

12

R

V1.2V (1

)

R

Select R12=20kΩ and R5=1MΩ; the OVP point

is 63V.