INSTRUCTION MANUAL
PFE500F
Series
TDK-Lambda
<Page>
·
Selection Method of External Bulk Capacitor for Boost Voltage
Boost voltage bulk capacitor is selected by ripple voltage, ripple current and output hold-up time.
Select capacitor value such that boost voltage ripple voltage does not exceed 15Vp-p.
Note) When ambient temperature is -20 deg C or less,
ripple
voltage
of
the
boost
voltage
might increase due to ESR characteristics. Therefore, verify
above
characteristics
by
actual evaluation.
For output hold-up time, refer to separate document “PFE500F Series Evaluation Data” and use
appropriate
capacitor up to 1,200uF maximum. (It is recommended that
verification
should
be
done through actual
evaluation).
For allowable ripple current value, refer to Fig. 1-2 and select a capacitor with higher ripple current rating.
The recommended boost voltage bulk capacitance value range is 390uF-1,200uF.
When using with reduced the bulk capacitance value, it is necessary to reduce output power as shown in Fig1-3.
Note that reducing the bulk capacitance affects output hold-up time, dynamic line response and dynamic load
response characteristics.It is recommended that verification should be done through actual evaluation.
TFR1 : 10 to 100 ohm
By connecting resistor across R and +BC terminals as shown in Fig. 1-1, in-rush current during line throw-in
can be suppressed. Failures due to in-rush current such as melting of external fuse, welding of relay or switch
connecting joints or shutdown of No-Fuse Breakers (NFB) might occur. Therefore, select TFR1 in consideration
of the surge current capability of the external components. (TFR1 is recommended to use the Thermal Fuse
Resistor.)
Note) 1. Do not connect resistors that is out of range from the values shown above as this might result in power
module damage.
2. Note that this module will not operate without this external resistor.
10/21
Fig. 1-2 Ripple current value (A value per one of Fig. 1-1 connection)
0
20
40
60
80
100
120
0
200
400
600
800
1000
1200
Bulk Cap.
(uF)
O
ut
pu
t P
ow
er
(%
)
390uF
1200uF
Tbp:25degC
0
400
800
1200
1600
2000
0
20
40
60
80
100
Load Current (%)
R
ip
pl
e
C
ur
re
nt
(
m
A
r
m
s)
100VAC
200VAC
Fig. 1-3 Output Power v.s. Boost Voltage Bulk Capacitance For PFE500F Series
