40IMX7-05-8 Datasheet, PDF (6/14 Pages) Power-One – IMX7, IMS7 Series Data Sheet 7-Watt DC-DC Converters

IMX7, IMS7 Series Data Sheet
®
7-Watt DC-DC Converters
Input Transient Voltage Protection
In many applications transient voltages on the input of the
converter may occur and are possibly caused by short circuits
between Vi+ and Vi–, where the network inductance may
cause high energy pulses.
In order to protect the converters, transient suppressors are
fitted to the input; see table below:
Table 3: Built-in transient voltage suppressor
Model
20IMX7 ¹
24IMS7 ²
40IMX7 ²
48IMS7 ²
70IMX7 ²
110IMX7 ²
Breakdown
Voltage
V_{BR nom}
Peak Power
at 1 ms
P_P
Peak Pulse
Current
I _PP
overvoltage lockout at approx. 38 V
53 V
600 W
7.7 A
100 V
1500 W
11 A
100 V
600 W
4.1 A
144 V
600 W
2.9 A
167 V
600 W
2.5 A
1 _{The built-in overvoltage trigger shuts down the converter at}
approx. 38 V protecting the input up to 50 V. For higher transient
voltages an external suppressor or voltage limiting circuit as,
e.g., for IEC/EN 61000-4-5, level 2 compliance should be
provided.
2 _{If transients generating currents above the peak pulse current}
are possible, an external limiting network such as the circuit
recommended for IEC/EN 61000-4-5, level 2 compliance, is
necessary.
To achieve IEC/EN 61000-4-5, level 2 compliance, an
additional inductor and capacitor should be provided
externally as shown in the figure below. The components
should have similar characteristics as listed in table 4.
07064
L
Vi+
+
i
C
D
Note: Suppressor diode D is only necessary for 20IMX7 models.
To withstand 150 V transients according to 19 Pfl 1, applicable for
40 IMX7 models, the same external circuitry with similar
components as for IEC/EN 61000-4-5, level 2 compliance can be
used.
Input Fuse and Reverse Polarity Protection
The suppressor diode on the input also provides for reverse
polarity protection by conducting current in the reverse
direction, thus protecting the converter. An external fuse is
required to limit this current. We recommend for:
– 20IMX7 and 24IMS7 a fast 2 A (F2A) fuse
– 40IMX7 and 48IMS7 a fast 1 A (F1A) fuse
– 70IMX7 a fast 0.63 A (F.63A) fuse
– 110IMX7 a fast 0.63 A (F.63A) fuse.
Inrush Current
The inrush current has been kept as low as possible by
choosing a very small input capacitance. A series resistor
may be inserted in the input line to limit this current further.
A
04030a
4
3
2
1
0
0
20
40
60
80 µs
Fig. 5
Typical inrush current at V_{i nom} , P_{o nom} measured according to
ETS 300132-2 (40IMX7).
Vi–
Fig. 4
Example for external circuitry to comply with IEC/EN
61000-4-5, level 2 (transzorb D only for 20IMX7).
Table 4: Components for external circuitry to comply with
IEC/EN 61000-4-5
Model
20IMX7
24IMS7
40IMX7
48IMS7
70IMX7
110IMX7
L
330 µ H, 1 A, 0.115 Ω
330 µ H, 0.6 A, 0.42 Ω
330 µ H, 0.6 A, 0.42 Ω
330 µ H, 0.6 A, 0.42 Ω
1000 µ H, 0.6 A, 0.42 Ω
330 µ H, 0.2 A
C
D
68 µF, 63 V 1.5KE39A
68 µF, 63 V
n.a.
68 µF, 100 V
n.a.
68 µF, 100 V
n.a.
68 µF, 100 V
n.a.
200 µF, 200 V n.a.
BCD20007-G Rev AE, 14-May-2012
Page 6 of 14
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