DIO70040

Version 1.3, Aug 2025

www.dioo.com

© 2025 Dioo Microcircuits Co., Ltd. Jiangsu

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9.5. Thermal protection

Thermal protection prevents damage to the IC when heavy overload or short circuit conditions are present for

extended periods of time. The conditions force the DIO70040 into constant current mode, and under short circuit

conditions, the voltage across the switch is equal to the input voltage. The increased dissipation causes the

junction temperature to rise to high levels. The protection circuit senses the junction temperature of the switch

and shuts it off. Hysteresis is built into the thermal sense circuit, and after the device has cooled approximately

20 degrees, the switch turns back on. The switch continues to cycle in this way until the overload or input power

is removed.

9.6. Reverse-voltage protection

The reverse-voltage protection feature turns off the P-channel MOSFET whenever the output voltage exceeds

the input voltage by 175 mV (typ). A reverse current of (VOUT - VIN) / RDS(ON) will be present when this occurs. This

prevents damage to devices on the input side of the DIO70040 by preventing significant current from sinking into

the input capacitance. The DIO70040 devices allow the P-channel MOSFET to turn on once the output voltage

goes bellow the input voltage.

9.7. FLG output

Error flag is an open-drain output of a N-channel MOSFET. If current limiting or short circuit occurs, FLG is

pulled low after a delay of 8 ms (typ), and if no current limiting or short circuit occurs, FLG is pulled high after a

delay of 8 ms (typ). If reverse-voltage protection occurs, FLG is pulled low after a delay of 4 ms (typ), and if no

reverse-voltage protection occurs, FLG is pulled high after a delay of 4 ms (typ). If overtemperature protection

occurs, FLG is pulled low immediately, and if no overtemperature protection occurs, FLG is pulled high after

a delay of 8 ms (typ).