AN2620 datasheet(8/20 Pages) STMICROELECTRONICS

8 / 20 page

Short-circuit protection

AN2620

8/20

Doc ID 13883 Rev 3

Short-circuit protection

In short condition, the ST1S10 has two short protection functions to avoid a damaged

device.

●

Overcurrent protection (OCP). The ST1S10 DC-DC converter is provided with a switch

overcurrent protection. If the switch current limit is reached, in order to protect the

application and the internal power switches and bonding wires, the device is

immediately shut down and kept in this condition for a Toff period time (Toff = 135 µs typ)

and turns on again for a Ton period (Ton = 22 µs typ with typical application conditions).

This operation is repeated cycle by cycle. Normal operation is resumed when no

overcurrent is detected.

●

Overvoltage protection (OVP). In order to protect the whole application and reduce the

total power dissipation during an overload or an output short-circuit condition, the

device is provided with a dynamic short-circuit protection which works by internally

monitoring the VFB (feedback voltage). In case of overload or output short-circuit, if the

VOUT voltage is reduced causing the feedback voltage (VFB) to drop below 0.3 V typ,

the device goes in shutdown for Toff time (Toff = 288 µs typ) and turns on again for a Ton

period (Ton = 130 µs typ). This operation is repeated cycle by cycle. Normal operation is

resumed when no overload is detected (VFB > 0.3 V typ) for a full Ton period. This

dynamic operation can greatly reduce the power dissipation in overload condition, still

ensuring excellent power-on startup, in most conditions.

AN2620 Datasheet(PDF) 8 Page - STMicroelectronics