Italian Semiconductor ST Launches Thermal Switching Ideal Diode Controller

The STPM801 semiconductor STPM801 is the first ideal diode controller in the market that integrates Yin switching, suitable for vehicle functional safety applications.

This ideal bipolar controller drives an external controller MOSFET switch transistor instead of a Schottky diode, commonly used in input reverse protection and voltage maintenance circuits. The voltage drop on the MOSFET is lower than the positive voltage of the Schottky diode, so the dissipated power during normal operation is also lower than that of the diode. When a reverse voltage event is caused by a power failure, power outage, or input short circuit, turning off the MOSFET power transistor can prevent related reverse current transients.

The ideal diode control circuit also provides power switching between the main power supply and the backup battery. The ORing controller ensures uninterrupted power supply for the main safety equipment of unmanned driving and advanced driving assistance systems (ADAS).

The built-in Yin switching controller drives the second external N-channel MOSFET to maintain the load during the conversion period between the main power supply and backup battery. The soft start function is to charge a capacitor with a known capacity connected to the gate with a constant current, in order to operate the on/off transient of the second MOSFET transistor and prevent high surge currents. As long as the input voltage is not within a specific threshold, the overvoltage and undervoltage pins will cut off the voltage.

STPM801 also has protection and detection functions, and is applicable to the ISO safety regulation 26262 Automotive Safety Integrity Level (ASIL) D-level system. These functions are integrated into a 5mm x 5mm VFQFFN in a 32 pack, saving PCB board area and minimizing the number of external components.

The working voltage range of STPM801 is 4V-65V, which can withstand automotive electrical risks μ A static current can minimize battery leakage when the car is turned off. The target applications include area/body ECU, ADAS ECU, high-performance computing ECU, information entertainment ECU, redundant power supply system, and dual battery system.