VIPER100A Datasheet, PDF (21/31 Pages) STMicroelectronics – SMPS PRIMARY I.C.

VIPer100A-E/ASP-E
6 Electrical Over Stress
6 Electrical Over Stress
6.1 Electrical Over Stress Ruggedness
The VIPer may be submitted to electrical over-stress, caused by violent input voltage surges or
lightning. Following the Layout Considerations is sufficient to prevent catastrophic damages
most of the time. However in some cases, the voltage surges coupled through the transformer
auxiliary winding can exceed the V_DD pin absolute maximum rating voltage value. Such events
may trigger the V_DD internal protection circuitry which could be damaged by the strong
discharge current of the V_DD bulk capacitor. The simple RC filter shown in Figure 23 can be
implemented to improve the application immunity to such surges.
Figure 23. Input Voltage Surges Protection
R1
D1
(Optional)
R2
39R
C1
Bulk capacitor
C2
22nF
VDD
-
OSC
13V +
VIPerXX0
DRAIN
COMP SOURCE
Auxilliary winding
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