VIPER319XDTR datasheet(22/39 Pages) STMICROELECTRONICS

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Figure 34. OVP timing

VOVP

OVP count

OVP triggered

and IC disabled

VOVP_th

VDD

OVP check and

IC re-enabled

ovp_eoc

OVP check and

IC disabled

< tOVP_DEB

tOVP_DEB

tOVP_REST

tOVP_DEB

VCCon

VCSon

An input overvoltage protection can be easily realized connecting the rectified mains to OVP pin through a voltage

divider, as shown in Figure 35. Connection for input overvoltage protection (iso/non-iso topologies).

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

as shown in Figure 36. Connection for output overvoltage protection (non-iso topologies).

If the OVP feature is not required, OVP pin must be connected to GND, which excludes the function.

If the OVP feature is required, RH value can be set arbitrarily, but some Mohms at least are recommended in

order to minimize the power consumption of the OVP network. Then, if Vin/out_OVP is the desired input/output

overvoltage threshold, the value of RL can be calculated from the following formula:

Equation 4

(4)

RL= RH

Vin/out_OVP

VOVP_tℎ −1

The power consumption of the OVP network at given Vin is expressed as:

Equation 5

(5)

POVPVin = Vin2RH+RL

in case of connection for input overvoltage protection and

Equation 6

(6)

POVPVOUT = VOUT2

RH+RL

in case of connection for output overvoltage protection.

VIPER31

General description

DS13285 - Rev 6

page 22/39

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