What are the basic concepts about thermal design of using semiconductor devices?
A1 The power consumed by semiconductor devices is converted into heat. This generated heat causes a rise in temperature of semiconductor devices. Semiconductor devices will operate normally as long as the temperature does not exceed an upper limit (specified as the ambient temperature and the temperature of the junctions inside the semiconductor). When this upper limit is exceeded, the semiconductor stops operating normally and becomes damaged. Therefore, it is necessary to successfully dissipate the generated heat so as to keep the temperature within specified level. Thermal design is indispensable when using the semiconductor for high power application or using it under the high operating temperature. The concept of thermal resistance is used when considering heat dissipation. This approach is based on the similarity of the conduction of heat and the conduction of electricity. While the fine details are omitted here, by substituting heat (=power) for current, temperature for voltage,
