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1.9 Input smoothing electrolytic capacitor（C102)
The input smoothing electrolytic capacitor has a large effect on the characteristics and life of the product.
Select the capacitor by paying attention to the following:
①Install the capacitor very close to the module (M101) and use a wide pattern to connect M101.
A triangle wave high frequency current
flows. Make the wiring wide and short.
②Select an electrolytic capacitor such that the ripple voltage is 25Vp-p or less.
In addition, make sure that the peak voltage of the ripple voltage does not exceed the input voltage range.
Take the variation in capacitance and the capacitance reduction due to aging into consideration when selecting the
capacitance.
The capacitance required to reduce the ripple voltage to 25Vp-p or less can be estimated from the following
expression. As the calculation result is only a reference, conduct a thorough check using actual equipment.
≥
⋅
C
102
4
K
Rev.3.1 May, 2013
⋅
⋅
⋅
Io
(max)
5 (
f
(
50
2
Vin(rms)：Effective input voltage(Vrms)
ｆ：Commercial power frequency（Hz）
Io(max)：Maximum output current in use(A)
K：Coefficient (varies depending on model. Refer to the following.)
・EPM0310SJ
： 4.71
・EPM0510SJ
： 7.14
・EPM1205SJ
： 16.0
・EPM1210SJ
： 15.0
・EPM1505SJ
： 18.8
・EPM1510SJ
： 18.8
・EPM2405SJ
： 30.0
TAMURA CORPORATION
EPM Series Application Notes
Ripple
voltage
25Vp-p or
Time (t)
⋅
−
Vin
(
rms
)
625
))
Input voltage range
110VDC to 450VDC
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