Design and development of a current limited solid state hybrid switch

The design and development of the first of a family of hybrid, low power, current limited, solid state switches is presented. This switch has a unique and novel thermal protection technique which ensures the FET temperature never exceeds a predetermined threshold level both under steady state and transient power dissipation operating modes. The design concept of the switch is briefly described and a test method using an infrared thermal imaging technique and test results which validate the concept are included. The paper concludes with a summary of future solid state switch developments using this design concept.