Datasheet

RUW15 Series
Isolated Ultra-Wide Input DC/DC Converters
KDC_RUW15.B02 Page 6 of 13
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SURGE SUPPRESSION (continued)
Figure 2 – Suggested surge limiting circuit
Figure 3 – Response to 3.5 x Vnom surge with circuit of Figure 2
Table 3 - NF F 01-510 SURGES AND TRANSIENTS
Nominal
Input
Input range
Brown-out
100ms
(0.5xVin)
Transient
100ms
Solution
24 V 18 - 34 V 12V 40V RUW15H
72 V 50 - 90 V 36V 115V RUW15
110 V 77 - 137 V 55V 176V
RUW15 +
limiter
EN 50155 also defines low energy surges and transient burst immunity requirements according to EN 50121-3-2. These are handled by a transorb, D4 in Figure 2. D6 is
for reverse polarity protection and may be omitted if this function is not required.
Vin
0V
R12
R11
R6
R9
R5
R3
R10
R1
R2
R8
R4
R7
D2
D6
D4
D1 D3
D5
U1
C2
Q3
Q1 Q2
C1
Vo
This circuit has been evaluated successfully over temperature for nominal 110 VDC input worst case 3.5 Vnom surge as specified in RIA12. Waveforms obtained are
shown in Figures 3. Suggested component values for 110V input are given in Table 4.