EPR-21 Datasheet, PDF (15/32 Pages) Power Integrations, Inc. – Engineering Prototype Report (EP-21) - 30 W DC-DC Converter with DPA424

19-Nov-02
VDB
TRANSFORMER CORE SELECTION
Core Type
pr14x8
Core
Bobbin
AE
LE
AL
BW
PR14x8
PR14x8_Bo
LG MAX
0.005
D FACTOR
L
1.10
NMAIN
NS2
VOUT2 ACTUAL
TRANSFORMER DESIGN PARAMETERS
NP
BM
BP
LP MIN
IMAG
OD_P
AWG_P
DUTY CYCLE VALUES
DUVON MIN
DVMIN
DVMAX
DOVOFF MAX
CURRENT WAVESHAPE PARAMETERS
IP
IPRMS
COUPLED INDUCTOR OUTPUT PARAMETERS
LMAIN
8
WLMAIN
Page 15 of 32
EPR-21 – 5 V, 30 W DC-DC Converter
0.7 Volts
voltage drop
Bias diode forward voltage drop
P/N:
P/N:
0.253 cm^2
2.53 cm
2000 nH/T^2
4.4 mm
0.005 mm
1.00
4
0
0.0 Volts
B65755-J-R87
B65542-B-T1
Core Effective Cross Sectional Area
Core Effective Path Length
Ungapped Core Effective Inductance
Bobbin Physical Winding Width
Maximum actual gap when zero gap
specified
Duty cycle factor
Transformer primary layers (split
primary recommended)
Main rounded turns
Vout2 rounded secondary turns (AC
stacked winding)
Approximate Output2 voltage of with
NS2 = 0 turns (AC stacked secondary)
15
1449 Gauss
2794 Gauss
0.342 mHenries
0.151 Amps
0.38 mm
27 AWG
Primary rounded turns
Max operating flux density at minimum
switching frequency
Max transient flux density at minimum
switching frequency
Minimum primary magnetizing
inductance (assumes LG MAX-5um)
Peak magnetizing current at minimum
input voltage
Primary wire outer diameter
Primary Wire Gauge (rounded to
maximum AWG value)
0.68
Duty cycle at minimum undervoltage
threshold
0.61
Duty cycle at minimum DC input
voltage
0.29
Duty cycle at maximum DC input
voltage
0.22
Duty cycle at maximum DC overvoltage
threshold
1.835 Amps
1.246 Amps
Maximum peak primary current at
maximum DC input voltage
Maximum primary RMS current at
minimum DC input voltage
8.0 uHenries
144 uJoules
Main / Output2 coupled output
inductance (referred to Main winding)
Main / Output2 coupled inductor full-
load stored energy
Power Integrations, Inc.
Tel: [phone] Fax: [phone]
www.powerint.com