User manual

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=
:
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k9.49R3
k98.6R2
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V1.10
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ONTURN
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R3
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D
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444 mA
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830 mA
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2
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12
1
i
L-PP
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I
LED
I
RMST-
www.ti.com Design Procedure
(19)
(20)
The chosen component from step 6 is:
(21)
6.8 Re-Circulating Diode
Determine minimum D1 voltage rating and current rating:
(22)
(23)
A 60V, 5A diode is chosen with V
D
= 750mV. Determine P
D
:
(24)
The chosen component from step 7 is:
(25)
6.9 Input Under-Voltage Lockout (UVLO)
Solve for R3:
(26)
The closest 1% tolerance resistor is 49.9 kΩ therefore V
HYS
is:
(27)
Solve for R2:
(28)
The closest 1% tolerance resistor is 6.98 kΩ therefore V
TURN-ON
is:
(29)
The chosen components from step 8 are:
(30)
7
SNVA391D–May 2009–Revised May 2013 AN-1954 LM3409 Demonstration Board
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