The STMicroelectronics STPM801 is the market's first automotive-qualified ideal diode and hot-swap integrated controller on the market, introduced for functional safety applications.
The ideal diode controller drives an external MOSFET that replaces a conventionally used Schottky diode for reverse input protection and output voltage retention. The reduced voltage drop across the MOSFET reduces power dissipation during normal operation compared to the forward voltage of the Schottky diode.
When a reverse voltage event occurs, in case of faults such as power supply failure, power outage, or input short circuit, turning off the MOSFET blocks the associated reverse current transients.
The ideal diode controller circuit also provides power ORing, to switch between a main battery and a backup battery to ensure uninterrupted supply of safety-critical equipment such as autonomous driving and advanced driver assistance systems (ADAS).
The integrated hot-swap controller drives a second external N-channel MOSFET to protect loads during hot-swap events. A soft-start function controls the turn-on transient of this second MOSFET by charging a capacitor of known value connected to its gate at constant current to avoid high inrush currents. The overvoltage and undervoltage pins cut off the output voltage whenever the input voltage is not within specified limits.
The STPM801 also includes protection and monitoring features suitable for applications that meet functional safety requirements for systems up to Automotive Safety Integrity Level (ASIL) D in accordance with ISO 26262. The features are packaged in a VFQFN-32 area 5mm x 5mm, saving PCB space. and minimizing the demand for external components.
Operating with a supply voltage of 4V-65V and a quiescent current of 25µA, the STPM801 resists automotive electrical hazards and minimizes battery consumption when the vehicle is turned off. It is used in zonal/body ECUs, ADAS ECUs, high-performance computing ECUs, infotainment ECUs, redundant power supply systems, and dual battery systems.
