20IMX4-12-8 Datasheet, PDF (5/12 Pages) Power-One – IMX4 Series Data Sheet 4 Watt DC-DC Converters

IMX4 Series Data Sheet
®
4 Watt DC-DC Converters
Input Transient Voltage Protection
In many applications transient voltages on the converter input
are always possible. These may be caused for example by
short circuits between Vi+ and Vi–, where the network
inductance may generate high energy pulses.
In order to protect the converter, a transient voltage
suppressor diode is fitted to the input; see table below.
Table 4: Built-in transient voltage suppressor
Model
5 IMX4
20IMX4
40IMX4
70IMX4
Breakdown
voltage
V_{BR nom}
--
40 V
100 V
150 V
Peak power
at 1 ms
P_P
--
600 W
600 W
600 W
Peak pulse
current
I _PP
--
10.3 A
4.1 A
2.9 A
Fuse and Reverse Polarity Protection
The suppressor diode on the input also protects against
reverse polarity input voltage. An external fast fuse is required
to limit this reverse current; see table below.
Table 6: External input fuse
Model
5IMX4
20IMX4
40IMX4
70IMX4
Fuse type
Fast 1.6 A
Fast 1 A
Fast 0.5 A
Fast 0.315 A
If transients generating currents above the peak pulse current
I _PP are possible, an external limiting network such as the circuit
shown in figure 8 is recommended. It provides compliance with
transients according to IEC/EN 61000-4-5, level 2. The comp-
onents are specified in table 5.
If 40IMX4 converters should withstand 150 V transients
according to 19Pfl1, the same external circuitry with similar
components as shown in figure 8 can be used.
L_i
+
C_i
Vi+
D
Vi–
04036b
Fig. 8
External circuitry to comply with
IEC/EN 61000-4-5, level 2.
Table 5: Components for the circuitry fig. 8
Model
L_i
C_i
D
20IMX4
330 µH, 0.42 W
1A
68 µF, 50 V
ON 1.5KE 39 A
40IMX4
330 µH, 0.42 W
0.6 A
68 µF, 100 V
ON 1.5KE 82 A
70IMX4
330 µH, 0.65 W
0.3 A
100 µF, 200 V
–
BCD20006-G Rev AC, 06-Jul-2012
Page 5 of 12
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