Intelligent power devices for standalone protection

Unlike conventional fuses, IPD as semiconductor fuses can protect circuits without degrading or breaking down, making it possible to achieve maintenance-free systems.

In recent years, as electrification has progressed following technological innovations in the automotive field (i.e. electric vehicles, autonomous driving), the concept of functional safety that can minimise risk and severity of accidents in the event of emergencies is needed to achieve safer vehicle systems. 

Fuses are typically used as a countermeasure to protect systems from overcurrent in the event of ECU malfunctions, but issues related to maintenance and degradation caused by ageing can arise after the fuse melts, calling for increased adoption of IPDs.

The new BV2Hx045EFU-C are the industry’s first high-side IPDs capable of providing standalone protection against overcurrent by incorporating an original overcurrent protection function. Conventional IPDs only protect against inrush current at startup, so MCUs and overcurrent detection ICs are needed for protection of steady-state currents, and there is still the possibility of an out of control situation due to compatibility issues with subsequent circuits connected to the IPD output.

In contrast, this new series can protect the system against both inrush and steady state overcurrent, ensuring greater system safety by providing a high reliability solution with fewer parts compared to conventional products. In addition, the overcurrent protection range can be adjusted with external components to enable broad compatibility.

ROHM is committed to developing high reliability and high functionality devices and contributing to safety, security and ecology in the automotive field.

Standard high side IPDs only protect against inrush current at startup, while MCUs and overcurrent detection ICs are needed to provide overcurrent protection for steady-state currents. Once an overcurrent condition of the steady state current is detected, the IPD output is controlled (ON/OFF) by the MCU Enable signal. Therefore, depending on the capacitance value of the subsequent circuit connected to the IPD output, inrush current at startup can cause overcurrent protection to be repeatedly detected and reset, resulting in oscillation.

In contrast, the BV2Hx045EFU-C integrates a proprietary function that provides standalone protection from both inrush and steady state overcurrent, ensuring stable drive operation and greater system reliability. In addition, an error signal can be sent to the MCU when an abnormality (i.e. overcurrent) has been detected, providing functional safety for the entire system.

This new series enables adjustment of the inrush protection time and abnormal current threshold of the steady state current by simply changing the external capacitor and resistor constants, ensuring support for a wide range of systems.

The BV2Hx045EFU-C are equipped with an original protection function that delivers standalone overcurrent protection for the entire system. This makes it possible to eliminate up to seven external parts compared to conventional solutions, decreasing mounting area by as much as 70%.