Abstract: A low-power green-mode switching power supply design is presented. The power supply employs a two-stage converter to shape the input current waveform and rapidly adjust the output voltage. Advanced power control technologies such as transition mode active power factor correction, quasi-resonant variable frequency control for power isolation conversion, and synchronous rectification are utilized to minimize the overall power loss of the supply, enhance system efficiency, and reduce harmonic pollution. Test results indicate that the switching power supply successfully meets the objectives of green design and satisfies the demands of high-performance applications.
Keywords: green mode; power factor correction; switch-mode power consumption; system efficiency
0 Introduction: Medium and small power switching power supplies are extensively employed in various electronic products like measurement instruments, communication devices, educational tools, and entertainment systems due to their superior performance. With growing concerns about environmental impact and energy usage, there is increasing emphasis on designing electronic products that are environmentally friendly, consume minimal power, and operate efficiently. Developing a green-mode power supply with zero pollution, low power consumption, and high efficiency has become a focal point in the field of switching power supply research.
This paper investigates a medium and small power switching power supply, incorporating advanced power control technologies such as transition mode active power factor correction, quasi-resonant variable frequency power isolation conversion, and synchronous rectification to achieve the goal of green power supply design.
1 System Structure and Working Principle: The switching power supply under study, as depicted in Figure 1, adopts a two-stage PFC (Power Factor Correction) architecture. It comprises a DC/DC converter consisting of a PFC pre-converter, an isolated converter, and a synchronous rectification circuit, along with a detection and protection circuit. After the AC voltage is rectified, it is fed into the PFC pre-converter for power factor correction conversion. Subsequently, the power supply control circuit manages the isolated converter to transform the DC voltage into a high-frequency AC pulse voltage. The pulse voltage is then rectified using a synchronous rectifier and filtered through a filter circuit, ultimately yielding the desired DC output.
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