Abstract:

To address the limitations of conventional start-up power supply solutions (such as shunt-regulated circuits and linear-regulated circuits) in high-voltage switching power supply systems,which are plagued by low efficiency and sustained high-voltage stress on power devices,a novel high-voltage start-up power supply circuit is proposed by sorting out existing technical bottlenecks and comparing the advantages and disadvantages of mainstream solutions in the field.Enhanced efficiency and reliability are achieved by adopting three key improvements in the proposed circuit:a two-stage power supply mechanism combining a linear regulator and an auxiliary power supply,dynamic hysteresis control based on an operational amplifier and a voltage divider network,and an integrated overvoltage protection unit.A prototype circuit is fabricated based on SIMetrix simulation data.Experimental results indicate that the efficiency of the prototype circuit is increased from 30%~40% of the conventional scheme to 72%.The rationality and feasibility of the proposed scheme are verified by both simulation validation and prototype circuit tests.

Key words: high-voltage switching power supply system, efficiency, high-voltage stress, linear regulator, dynamic hysteresis, start-up power supply