Monolithic epitaxial Darlington transistor and its traction applications

The development of a planar-monolithic-epitaxial Darlington transistor and CAD aspects relating to the simulation behavior of the device in actual load conditions are described. A computer-aided design optimization procedure, based on approximate emitter geometry, and its effectiveness in analyzing the influence of physical parameters on the electrical characteristics of the Darlington transistor are discussed. Computed results are presented in order to analyze the effects of epitaxial collector thickness, resistivity, diffusion profile, and physical dimensions of emitter geometry. The implementation of the monolithic Darlington transistors in inverters for AC drives is described. Requirements and precautions for transistorized inverters, and details of a base-drive circuit, switch mode power supply, power block, protection circuits, and current sensing device are discussed.<>