LM3409MYX National Semiconductor Corporation, LM3409MYX Datasheet - Page 18
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LM3409MYX
Manufacturer Part Number
LM3409MYX
Description
Pfet Buck Controller For High Power Led Drives
Manufacturer
National Semiconductor Corporation
Datasheet
1.LM3409MYX.pdf
(30 pages)
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
LM3409MYX
Manufacturer:
NS/国半
Quantity:
20 000
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:
30085618