VIPER115LSTR datasheet(24/37 Pages) STMICROELECTRONICS

24 / 37 page

General description

VIPer11

24/37

DS11873 Rev 5

5.14

Disable function

When the voltage across the DIS pin exceeds the internal threshold VDIS_th (1.2 V typ.), a

time filter tDIS (1 msec, typ.) is activated.

If, at the end of tDIS, the condition is no more met, the occurrence of a temporary

disturbance is assumed and the IC continues to work normally; otherwise, a fault condition

is recognized and the IC is disabled in auto-restart for tDIS_RESTART (500 msec, typ.).

When VDIS falls below VDIS_th, the IC completes the current tDIS_RESTART, then resumes

normal operation.

During the fault, the VCC voltage is maintained between VCCSON and VCCoN through the HV

current source periodical activation.

A simple input overvoltage protection can be realized by connecting a voltage divider

between the DIS pin and the rectified mains, as shown in Figure 31.

Figure 31. Connection for input overvoltage protection (isolated or non-isolated

topologies)

In case of non-isolated topologies, with the same principle an output overvoltage protection

can be implemented, as shown in Figure 32.

If the Disable function is not required, DIS pin must be soldered to GND, which excludes the

function.

VIPER115LSTR Datasheet(PDF) 24 Page - STMicroelectronics