LM3409HVEVAL National Semiconductor, LM3409HVEVAL Datasheet - Page 18
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LM3409HVEVAL
Manufacturer Part Number
LM3409HVEVAL
Description
BOARD EVALUATION FOR LM3409HV
Manufacturer
National Semiconductor
Series
PowerWise®r
Specifications of LM3409HVEVAL
Current - Output / Channel
1.5A
Outputs And Type
1, Non-Isolated
Voltage - Output
42V
Features
Dimmable
Voltage - Input
6 ~ 75 V
Utilized Ic / Part
LM3409HV
Kit Contents
Board, Datasheet
Svhc
No SVHC (15-Dec-2010)
Kit Features
Drives 12 LEDs At Maximum Average LED Current 1.5A From DC Input Voltage 48V
Mcu Supported Families
LM3409HV
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
www.national.com
Design Example #1
EN PIN PWM DIMMING APPLICATION FOR 10 LEDS
SPECIFICATIONS
f
V
V
I
Δi
Δv
V
η = 0.95
1. NOMINAL SWITCHING FREQUENCY
Assume C
The closest 1% tolerance resistor is 24.9 kΩ therefore the
actual t
SW
LED
IN
O
TURN-ON
LED-PP
IN-PP
= 35V
= 48V; V
= 525kHz
= 2A
OFF
= 1.44V
= Δi
= 10V; V
OFF
and target f
IN-MAX
L-PP
= 470pF and η = 0.95. Solve for R
= 1A
HYS
= 75V
= 1.1V
SW
are:
OFF
:
18
The chosen components from step 1 are:
2. INDUCTOR RIPPLE CURRENT
Solve for L1:
The closest standard inductor value is 15 µH therefore the
actual Δi
The chosen component from step 2 is:
L-PP
is:
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