Fast measurement of the peak junction temperature of power transistors using electrical method

An electrical technique is described which can perform a fast measurement of the peak junction temperature of power transistors. The fundamental principles of this technique are summarized as three modifications to the standard electrical technique for measuring the junction temperature. Personal-computer-controlled equipment has been developed based on these principles. In comparison with the infrared-measured peak junction temperature, the measuring error of the equipment is within 8%, whereas the error of the standard electrical method may be up to 50% under the same conditions. The equipment reported here can provide convenience for device manufacturers and users in evaluating device thermal behavior and conducting reliability screening