SSCB (Solid-State Circuit Breaker) for Single-Phase AC

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An SSCB (Solid-State Circuit Breaker) is a current interruption device that replaces the mechanical contacts and moving parts of conventional circuit breakers with power semiconductors such as MOSFETs and SiC devices. In recent years, the emergence of wide-bandgap semiconductors has made it increasingly possible to support high-voltage, high-current applications. Adopting semiconductors is expected to deliver the following performance improvements, enabling current interruption devices with greater safety and reliability.
SSCBs are utilized in applications that require fast and safe power control, including renewable energy systems, industrial power distribution, and data centers.

High-speed interruption: SSCBs can interrupt circuits in microseconds - significantly faster than conventional mechanical circuit breakers that typically operate in up to 20ms, suppressing energy release during short-circuit events.
No moving parts (mechanical contacts): Minimizes the risk of wear and failure, ensuring longer service life and high reliability interruption.
No arc discharge: Without mechanical contacts, arc discharge does not occur during interruption, preventing damage to peripheral equipment and wiring.
Additional functions enabled by electronic circuits: Communication capabilities and sensing-based condition monitoring can be easily integrated, facilitating more reliable system design.
Easy recovery and maintenance: Unlike MCCBs (Molded Case Circuit Breakers) which require manual reset, SSCBs can be reset remotely via communication functions.

ROHM supports the development of fast, highly safe SSCB systems by offering a broad lineup that includes wide-bandgap semiconductors (SiC, GaN), reinforced-isolation gate driver ICs, shunt resistors capable of high-speed current monitoring, and high-efficiency power supply ICs. A key challenge in SSCB design is the heat generated by power dissipation in the semiconductor switching section and shunt resistors. ROHM addresses this by providing thermal design support that extends to the PCB and enclosure, providing a comprehensive solution.

Block Diagram
Topology Selection
Reference Design
Design Model
ROHM Solution Simulator
Video
Catalog

Block Diagram

*Click to enlarge image.

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Topology Selection

When designing circuits, especially power circuits, it's essential to choose a circuit configuration that aligns with the required specifications, as the input/output voltages, power levels, and isolation needs will vary by application. Optimal component selection also depends on the topology. Using inappropriate components can lead to performance shortfalls, potentially requiring a complete redesign of the circuit. ROHM’s topology selection page helps users identify the most suitable devices for various circuit designs.

Topology Selection

Reference Design

ROHM provides a system-level evaluation board (solution board) that combines ROHM's IC and discrete products. We have already solved not only the characteristics of individual products but also the problems that may occur when combining them to build a system, thus contributing significantly to the reduction of development time for our customers.

Reference Design

Design Model

ROHM offers simulation models, including thermal models, PLECS models, and Ray files, for circuit and thermal simulations of discretes and ICs, including power devices.
　
　
　

Design Model

ROHM Solution Simulator

ROHM Solution Simulator is a new web-based electronic circuit simulation tool that can carry out a variety of simulations, from initial development that involves component selection and individual device verification to the system-level verification stage.
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