Built with safety and simplicity in mind

To offer a safe and quick way to disconnect a faulty load from 12V bus, STMicroelectronics has designed its STPW12 programmable electronic power breaker.

Inserted between the power rail and the load, the STPW12 contains a low-resistance (50mΩ) power switch and precision circuitry for sensing the load power. If the user-programmed limit is exceeded, the switch is designed to turn off and a signal on the dedicated monitor/fault pin informs the host system. In normal operation, this output presents an analogue voltage proportional to the load power to permit continuous monitoring.

The STPW12 is built-in auto-restart after a user-adjustable delay and includes programmable PWM masking time to prevent protection triggering by inrush current. STMicroelectronics says this will simplify design for safety and ease certification to standards such as the UL 60730 specifications for abnormal operation.

This integrated solution replaces discrete circuitry or a combination of ICs such as a current-sense amplifier or a hot-swap controller plus MOSFET switches.

The power threshold and masking time are each programmed using a resistor. An external capacitor sets the auto-retry delay. With the addition of input and output capacitors, these are the only external components needed to complete the circuit, STMicroelectronics adds.

A direct PWM mode with programmable masking time to modulate the load energy allows flexibility to control the internal power switch with an external signal. A set of protection features is provided, including Under-Voltage Lockout (UVLO), thermal shutdown, and short-circuit current limit.

Bethan Grylls