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Design Calculations - 120V, 30W
f
SW-MIN
– 45kHz
V
IN
– 120V
AC
V
IN-MIN
– 90V
AC
V
IN-MAX
– 135V
AC
I
LED
– 700mA
Δ
v
OUT
= 2V
Δ
v
IN-PK
= 60V
I
P-PK-LIM
= 3A
V
T-DES-MAX
= 400V
P
OUT-MAX
= 30W
D
@IIN-MAX-PK
= 0.5
V
OUT
= 50V
η
=0.9
10.2 Preliminary Calculations
Maximum peak input voltage:
(34)
Minimum peak input voltage:
(35)
Maximum average input current:
(36)
Maximum peak input current:
(37)
Maximum peak primary current:
(38)
10.3 Main Switching MOSFET
Maximum drain-to-source voltage:
(39)
Maximum peak MosFET current:
(40)
Maximum RMS MosFET current:
(41)
Maximum power dissipation:
(42)
Resulting component choice:
25
SNVA485B – June 2011 – Revised May 2013
AN-2150 LM3450A Evaluation Board
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