VIPer20/SP/DIP - VIPer20A/ASP/ADIP
Figure 22: Input Voltage Surges Protection
D1
R1
(Optional)
R2
39R
Auxilliary winding
DRAIN
VDD
C2
22nF
-
+
C1
OSC
Bulk capacitor
13V
COMP SOURCE
VIPerXX0
ELECTRICAL OVER STRESS RUGGEDNESS
The VIPer may be submitted to electrical over
stress caused by violent input voltage surges or
lightning. Following the enclosed Layout
Considerations chapter rules is the most of the
time sufficient to prevent catastrophic damages,
however in some cases the voltage surges
coupled through the transformer auxiliary winding
can overpass the VDD pin absolute maximum
rating voltage value. Such events may trigger the
VDD internal protection circuitry which could be
damaged by the strong discharge current of the
VDD bulk capacitor. The simple RC filter shown in
figure 22 can be implemented to improve the
application immunity to such surges.
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STMICROELECTRONICS [ ST ]
