LM3429BSTEVAL/NOPB National Semiconductor, LM3429BSTEVAL/NOPB Datasheet - Page 5

• Manufacturer Part Number: LM3429BSTEVAL/NOPB
• Description: BOARD EVAL FOR BOOST LM3429
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LM3429BSTEVAL/NOPB

• Current - Output / Channel: 1A
• Outputs And Type: 1, Non-Isolated
• Features: Dimmable
• Voltage - Input: 10 ~ 26 V
• Utilized Ic / Part: LM3429
• Core Chip: LM3429
• Topology: Buck-Boost
• No. Of Outputs: 1
• Dimming Control Type: PWM / Analog
• Development Tool Type: Hardware - Eval/Demo Board
• Mcu Supported Families: LM3429 Family
• Msl: MSL 1 - Unlimited
• Lead Free Status / RoHS Status: Lead free by exemption / RoHS compliant by exemption
• Voltage - Output: -
• Other names: *LM3429BSTEVAL; *LM3429BSTEVAL/NOPB; LM3429BSTEVAL

Design Procedure
Refer to LM3429 datasheet for design considerations.
SPECIFICATIONS
N = 9
V
r
V
V
f
V
I
Δi
Δi
Δv
I
V
V
1. OPERATING POINT
Solve for V
Solve for D, D', D
2. SWITCHING FREQUENCY
Assume C7 = 1 nF and solve for R10:
The closest standard resistor is actually 35.7 kΩ therefore the
f
The chosen components from step 2 are:
LED
SW
LED
LIM
SW
LED
IN
IN-MIN
SNS
TURN-ON
TURN-OFF
L-PP
LED-PP
IN-PP
= 24V
= 700 kHz
is:
= 6A
= 1A
= 325 mΩ
= 3.5V
= 100 mV
= 250 mA
= 10V; V
= 100 mV
= 17 mA
= 10V; V
= 60V; V
O
and r
IN-MAX
MAX
D
HYS
HYSO
:
, and D
= 27V
= 3V
= 15V
MIN
:
5
3. AVERAGE LED CURRENT
Solve for R9:
Assume R1 = 12.4 kΩ and solve for R8:
The closest standard resistor for R9 is 0.1Ω and the closest
for R8 (and R7) is actually 1 kΩ therefore I
The chosen components from step 3 are:
4. INDUCTOR RIPPLE CURRENT
Solve for L1:
The closest standard inductor is 33 µH therefore the actual
Δi
Determine minimum allowable RMS current rating:
The chosen component from step 4 is:
L-PP
is:
LED
is:
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