DocID026993 Rev 1

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AN4599

Circuit description

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Figure 4. Current sensing lossless capacitive current divider

2.6

Thermal protection

To render the application unbreakable, it was necessary to apply thermal protection near the

output diodes, the warmest area on the power (PWR) supply.

A thermal resistor NTC2 in partition with the R2 resistance is processed by a TSM103W,

used as comparator with high hysteresis.

When the output diodes reach 120 °C, the output of TSM103W drives Q3 to drain the

current from the optocoupler. The PWR supply shuts off and stays off as long as TSM103W

is supplied.