LM3424BKBSTEVAL National Semiconductor, LM3424BKBSTEVAL Datasheet - Page 31

• Manufacturer Part Number: LM3424BKBSTEVAL
• Description: BOARD, EVALUATION, FOR LM3424BKBST
• Manufacturer: National Semiconductor

Specifications of LM3424BKBSTEVAL

• Kit Contents: Assembled LM3424 Buck-Boost Evaluation Board, Application Note, LM3424 Datasheet
• Svhc: No SVHC (15-Dec-2010)
• Kit Features: 1A Output, Thermal Foldback, Analogue Dimming, High Frequency
• Mcu Supported Families: LM3424

1. OPERATING POINT
Solve for V
Solve for D, D', D
2. SWITCHING FREQUENCY
Solve for R
The closest standard resistor is 14.3 kΩ therefore f
The chosen component from step 2 is:
3. AVERAGE LED CURRENT
Solve for R
Assume R
The closest standard resistor for R
R
HSP
is actually 1 kΩ therefore I
CSH
O
T
SNS
:
and r
:
= 12.4 kΩ and solve for R
MAX
D
:
, and D
MIN
:
LED
SNS
is:
is actually 0.1Ω and for
HSP
:
SW
is:
31
The chosen components from step 3 are:
4. THERMAL FOLDBACK
Find the resistances corresponding to T
BK
datasheet. Assuming R
R
Solve for R
The chosen components from step 4 are:
5. INDUCTOR RIPPLE CURRENT
Solve for L1:
The closest standard inductor is 33 µH therefore Δi
Determine minimum allowable RMS current rating:
The chosen component from step 5 is:
NTC-BK
= 24.3 kΩ and R
= 24.3 kΩ.
GAIN
:
NTC-END
REF1
= 7.15 kΩ) from the manufacturer's
= R
REF2
= 49.9 kΩ, then R
BK
and T
www.national.com
END
L-PP
(R
BIAS
is:
NTC-
=