04-Oct-2005
EP-85 6 V, 330 mA Low Cost Charger
R2
3.00 k-ohms
1N400
Recommended Bias Diode
3
DC INPUT VOLTAGE PARAMETERS
VMIN
80 Volts
Minimum DC Input Voltage
VMAX
375 Volts
Maximum DC Input Voltage
CURRENT WAVEFORM SHAPE PARAMETERS
DMAX
IAVG
IP
IR
IRMS
0.48
Maximum Duty Cycle
0.04 Amps
0.12 Amps
0.12 Amps
0.05 Amps
Average Primary Current
Minimum Peak Primary Current
Primary Ripple Current
Primary RMS Current
TRANSFORMER PRIMARY DESIGN PARAMETERS
LP
2738 uHenries Typical Primary Inductance. +/- 5%
LP_TOLERANCE
NP
5.00
5 %
108
Primary inductance tolerance
Primary Winding Number of Turns
ALG
BM
233 nH/T^2
1922 Gauss
Gapped Core Effective Inductance
Info
!!! Info. Flux densities above ~ 1500 Gauss may produce
audible noise. Verify with dip varnished sample transformers.
Increase NS to greater than or equal to 11 turns or increase
VOR
BAC
ur
LG
801 Gauss
1654
0.08 mm
AC Flux Density for Core Loss Curves (0.5 X Peak to Peak)
Relative Permeability of Ungapped Core
!!! INCREASE GAP>>0.1 (increase NS, decrease VOR,bigger
Core
Warning
BWE
OD
INS
DIA
AWG
17.2 mm
0.16 mm
0.04 mm
0.12 mm
37 AWG
Effective Bobbin Width
Maximum Primary Wire Diameter including insulation
Estimated Total Insulation Thickness (= 2 * film thickness)
Bare conductor diameter
Primary Wire Gauge (Rounded to next smaller standard AWG
value)
CM
20 Cmils
Bare conductor effective area in circular mils
CMA
374 Cmils/Am Primary Winding Current Capacity (150 < CMA < 500)
p
TRANSFORMER SECONDARY DESIGN PARAMETERS
Lumped parameters
ISP
1.68 Amps
Peak Secondary Current
ISRMS
IRIPPLE
CMS
0.65 Amps
0.56 Amps
130 Cmils
28 AWG
Secondary RMS Current
Output Capacitor RMS Ripple Current
Secondary Bare Conductor minimum circular mils
Secondary Wire Gauge (Rounded up to next larger standard
AWG value)
AWGS
DIAS
ODS
0.32 mm
1.08 mm
Secondary Minimum Bare Conductor Diameter
Secondary Maximum Outside Diameter for Triple Insulated
Wire
INSS
0.38 mm
Maximum Secondary Insulation Wall Thickness
VOLTAGE STRESS PARAMETERS
VDRAIN
- Volts
Peak Drain Voltage is highly dependent on Transformer
capacitance and leakage inductance. Please verify this on the
bench and ensure that it is below 650 V to allow 50 V margin for
transformer variation.
PIVS
34 Volts
Output Rectifier Maximum Peak Inverse Voltage
Note: Gap size was verified with transformer vendor as being acceptable. Higher flux
density resulted in peak audible noise of <35 dBA without enclosure, also acceptable as
a further 10 dB reduction is typical once inside sealed enclosure.
Power Integrations
Tel: +1 408 414 9200 Fax: +1 408 414 9201
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