LM3409HVEVAL National Semiconductor, LM3409HVEVAL Datasheet - Page 4

• 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

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Design Procedure
SPECIFICATIONS
V
V
f
I
Δi
Δv
V
η = 0.97
1. NOMINAL SWITCHING FREQUENCY
Assume C7 = 470pF and η = 0.97. Solve for R6:
The closest 1% tolerance resistor is 16.5 kΩ therefore the
actual t
The chosen components from step 1 are:
2. INDUCTOR RIPPLE CURRENT
Solve for L1:
The closest standard inductor value is 33 µH therefore the
actual Δi
SW
LED
IN
O
TURN-ON
LED-PP
IN-PP
= 42V
= 48V; V
= 400kHz
= 1.5A
OFF
= 1.44V
= Δi
L-PP
= 10V; V
and target f
IN-MAX
L-PP
is:
= 300mA
HYS
= 75V
= 1.1V
SW
are:
4
The chosen component from step 2 is:
3. AVERAGE LED CURRENT
Determine I
Assume V
The closest 1% tolerance resistor is 0.15 Ω therefore the
I
The chosen component from step 3 is:
4. OUTPUT CAPACITANCE
No output capacitance is necessary.
5. INPUT CAPACITANCE
Determine t
Solve for C
Choose C
Determine I
The chosen components from step 5 are:
LED
is:
IN
ADJ
IN-MIN
L-MAX
ON
:
IN-RMS
= 1.24V and solve for R9:
:
:
:
: