A Study of Switching Frequency Impact on Reliability of DC-DC PoL Converters With Discrete Transistors

Point-of-Load (PoL) DC-DC Converters are based on buck converter topology which is actuated at a switching frequency. The value of the switching frequency determines the performance of the power converter, including its reliability. This article quantifies the influence of switching frequency on reliability and lifetime, in addition to efficiency, thermal response, and ripple. The analysis is conducted for a wide range of switching frequency variation (50 kHz to 500 kHz) and a conventional synchronous converter with discrete Si MOSFETs. The failure rate and reliability calculation follow a modern prediction standard, herein was adopted IEC-TR-62380 due to the concept of mission profile that it uses. The reliability calculation is based on the temperature of the device when the converter is working on a common load. A thermal scanning of the power converter provides this temperature under two different loads (mild and strong) is herein achieved with infrared photography.