LM3429MHX National Semiconductor, LM3429MHX Datasheet - Page 22

• Manufacturer Part Number: LM3429MHX
• Description: LM3429 N-Channel Controller for Constant Current LED Drivers; Package: TSSOP EXP PAD; No of Pins: 14; Qty per Container: 2500/Reel
• Manufacturer: National Semiconductor

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Design Example #1
BUCK-BOOST APPLICATION - 6 LEDs at 1A
SPECIFICATIONS
N = 6
V
r
V
V
V
f
V
I
Δi
Δi
Δv
I
V
V
V
V
1. OPERATING POINT
Solve for V
SW
LED
LIM
LED
LED
IN
IN-MIN
IN-MAX
SNS
TURN-ON
HYS
TURN-OFF
HYSO
L-PP
LED-PP
IN-PP
= 24V
= 700 kHz
= 6A
= 1A
= 325 mΩ
= 3.5V
= 100 mV
= 3V
= 500 mA
= 10V
= 10V
= 1V
= 70V
= 50 mA
= 10V
= 40V
O
and r
D
:
22
Solve for D, D', D
2. SWITCHING FREQUENCY
Assume C
The closest standard resistor is actually 35.7 kΩ therefore the
f
The chosen components from step 2 are:
SW
is:
T
= 1 nF and solve for R
MAX
, and D
MIN
:
T
:
300944i1