DER-75
2.4W Power Supply using LNK520P
September 12, 2005
7 Transformer Spreadsheets
LinkSwitch (LNK52X) 030404 Rev.1.7; Copyright Power
Integrations 2004
LinkSwitch (LNK52X) 030404; Rev.1.7;
Copyright Power Integrations 2004
INPUT INFO
OUTPUT UNIT
DI-75 - 042304A
ENTER APPLICATION VARIABLES
VACMIN
VACMAX
fL
VO
IO
85
265
50
5
0.48
Volts
Volts
Hertz
Volts
Amps
Minimum AC Input Voltage
Maximum AC Input Voltage
AC Mains Frequency
Output Voltage
Continuous Nominal Output current
VBIAS
tC
20
3
Bias voltage (recommended default 20V, minimum 16V)
Bridge Rectifier Conduction Time Estimate
msec
CIN
9.4
uFarads Input Filter Capacitor
ESTIMATED LOSSES
PCORE
146.3907 mW
Estimated Core Losses at peak Flux Density (BP)
Primary clamp resistor (recommended default clamp
resistor, RCLAMP)
RCLAMP
ESR
200 Kohm
0.15 Ohms
Output Capacitor ESR
Estimated Resistance of transformer secondary
winding.
RSEC
0.2 Ohms
DC INPUT VOLTAGE PARAMETERS
VMIN
VMAX
Minimum DC Input Voltage
Maximum DC Input Voltage
97.50129 Volts
374.7666 Volts
ENTER OUTPUT CABLE PARAMETERS
Resistance of total length of cable from power supply
terminals to load and back.
Drop along cable connecting power supply to load
RCABLE
VCABLE
0.3 Ohms
0.144 Volts
ENTER LinkSwitch & OUTPUT DIODE VARIABLES
115 Doubled/230
Universal
LinkSwitch
LNK520
Power
5.5 3.5
I^2 f
2710 A^2 Hz
I^2 f (typical) co-efficient for LinkSwitch
VOR
54
54 Volts
Reflected Output Voltage (40<VOR<80 recommended)
Error in Feedback voltage as a result of leakage
inductance in primary circuit.
Output Winding Diode Forward Voltage Drop (0.5~0.7V
for schottky and 0.7~1.0V for PN diode)
VLEAK
VD
2 Volts
0.56
1.1
0.56 Volts
VR
ID
60 Volts
Amps
Rated Peak Rep Reverse Voltage of secondary diode
Rated Average Forward current for secondary diode
DISCONTINUOUS MODE CHECK
KDP
TON
TDON
1.531793
6.587284 us
11.24319 us
Ensure KDP > 1.15 for discontinuous mode operation.
Linkswitch conduction time
Secondary Diode conduction time
VOLTAGE STRESS ON LinkSWITCH AND OUTPUT DIODE
Maximum Drain Voltage Estimate (Includes Effect of
Leakage Inductance)
Output Rectifier Maximum Reverse Voltage
VDRAIN
PIVS
508.1666 Volts
44.58646 Volts
CURRENT WAVEFORM SHAPE PARAMETERS
Maximum Operating Duty Cycle
Average Primary Current
Primary RMS Current
DMAX
IAVG
IRMS
0.276666
0.035137 Amps
0.077135 Amps
Power Integrations
Tel: +1 408 414 9200 Fax: +1 408 414 9201
www.powerint.com
Page 11 of 23
CONFIDENTIAL
POWERINT [ Power Integrations ]
