A Novel Auxiliary Power Supply based on Self-Excited Buck for Switching Power Converter

With the development of technology, many systems have a higher requirement in the power density of switching power converter, such as data centers and automotive electronics. Auxiliary power supply plays a key role in realizing the miniaturization and high transmission efficiency of switching power converter. Actually, most of traditional auxiliary power supplies are difficult to keep high power density and adaptive self-protection with wide-range input voltage. In this paper, a novel auxiliary power supply based on self-excited Buck is proposed which has the following characteristics: 1) adaptive over-current protection and over-voltage protection; 2) high transmission efficiency in light load; 3) wide-range input voltage; 4) adaptive soft-start function. The proposed auxiliary power supply circuit is beneficial for the miniaturization design and wide-range input application of switching power converters.