Power Electronic Fuse from STMicroelectronics Integrates Value-Added Features for safety.

Sustaining up to 4A continuous current over a wide operating input-voltage range of 8V to 48V, with low insertion loss thanks to its integrated low-RDS(ON) VIPower™ MOSFET, the STEF01 programmable electronic fuse from STMicroelectronics extends the benefits of fast-acting overload protection to applications at higher power ratings.

When connected in series to the main power rail, the STEF01 protects the load against over-current and over-voltage. The voltage is clamped to a user-defined maximum, preset with external resistors. Excessive current is restricted to the programmed safe limit by controlling the internal power MOSFET, and folds back to a lower limit if a strong over-current or short-circuit is detected.

The STEF01 leverages ST’s BCD8 high-voltage process to integrate value-added features, including dV/dt control to prevent excessive inrush current during startup or hot-swap insertion. This slows the output-voltage ramp-up time to at least 3ms, which can be increased if desired by connecting an external capacitor. Programmable Under-Voltage Lockout (UVLO), also set using external components, allows the user to fine-tune the desired voltage-rail minimum value to suit the load requirements.

Further features include thermal shutdown with latching or auto-retry, and maximum dissipated-power protection, which each prevent exceptionally high power from damaging the STEF01 when starting up into heavy capacitive loads, or during large load transients or short-circuits at high voltage. There is also a power-good indicator, and an enable/fault pin that can be used as either a status monitor or to control the device. A dedicated gate-driver output for controlling an external N-channel MOSFET simplifies implementation of reverse-current protection.

The STEF01 delivers flexible and convenient protection for a wide range of applications, including industrial hot-swap boards and control equipment, circuit breakers, power buses, security or lighting systems, telecom power modules, or distributed power systems.