Abstract: A temperature controller that combines a solid state relay with internal circuitry that generates temperature control output for heating element loads or cooling compressor loads ranging from 24VAC up to 530VAC and at 25A up to 90A. A logic supply and control connectors provides connectors for various inputs. Power switch terminals connect the temperature controller to the heating element or cooling motor to be temperature controlled. Thermocouple terminals receive the leads from a type J or type K thermocouple from the heating element or cooling motor. The temperature controller rapidly and accurately senses, controls, and maintains the temperature of any process associated with a load. The temperature control output signal leaving the power switch controls the load in order to maintain a constant temperature delivered to the process. The temperature controller requires only a single non-regulated low current isolated DC supply to work the logic circuitry.

Abstract: A lead frame for use in solid state relays has a teardrop shaped frame. The frame has a small rounded portion connected to a large rounded portion. A power semiconductor is mounted in the large rounded portion. The teardrop shape eliminates sharp corners found in rectangular frames and allows heat to dissipate radially in all directions. More metal in close proximity to the power semiconductor, maintaining a lower aspect ratio of length to width, allows the semiconductor to run cooler at any given load. Several vent holes are located in the small rounded portion, which act as exhaust ports for the fumes generated in the heating stage of the solder re-flow, increasing solder coverage and improving reliability. The life of solder junctions utilizing the teardrop shaped lead frame which are subjected to temperature cycling while under load is increased, thus extending the life of the solid state relay.