Normally-on SiC Power Module with Balancing Unit

The power module stack is divided into multiple power modules, each containing parallel-connected semiconductor switches. This segmentation allows the system to achieve high blocking voltage capability through series connection of modules while maintaining manageable complexity at each module level through parallel switch configuration.

The patent transitions from a single-dimensional approach (single switch or simple series connection) to a multi-dimensional architecture by combining parallel switch connections within modules and series module connections, creating a two-dimensional configuration that simultaneously addresses blocking voltage capability and device complexity.

The patent implements beforehand cushioning by providing a metal pad directly connected to each SiC semiconductor switch, creating a controlled short-circuit failure mode. This preparatory structure ensures that upon chip failure, the melting process is contained and controlled, preventing catastrophic system failure and maintaining reliability while preserving the low switching loss benefits of SiC devices.

The patent converts the potentially harmful uncontrolled melting process into a beneficial controlled failure mode. By designing the metal pad connection to create a predictable short-circuit path, the harmful thermal runaway is transformed into a controlled event that isolates the failure to a single switch while maintaining overall system reliability.