The Design Of A Single-terminal Forward High-frequency Switching Power Supply

Power equipment used to achieve the power conversion and power transmission,which is basic to the various electronic devices working normally, and the high frequency and high efficient small switching power supply is an inevitable development trend, which is used more and more in communications, military equipment, transport facilities, instrumentation, industrial equipment, household appliances and other areas.This paper is from a S3C2410 embedded development project for a comprehensive information platform from, whose goal is providing a reliable power supply guarantees for an integrated information platform.This paper designed a single-terminal forward high-frequency multi-output switching power supply under the In-depth research and analysis of various principles, and the requirements of the characteristics of switching power supply basing on the indicators of the project. The characteristics of this switching power supply is that: it achieved four stable output with the single-terminal as the main topology, with current-mode control chip UC3842 and high-frequency transformer as the core, using EMI filters, MOSFET, the output filter circuit, sampling feedback channel and other major components and circuit modules. Switching Power Supply is 220V AC as the main input, four output voltages are 24V,±12V and +5 V DC voltage, and the switching frequency is 250kHz.With an area product method (AP), we identify the choice of the original or assistant side of the high-frequency transformer, design the output circuit, the compensator system, the start circuit and EMI filtering circuits.This The design of a single-terminal forward high-frequency switching power supply circuit is simulated by Pspice9.2, and it turns out that: the switching power supply's output voltage regulation characteristics, load regulation, output ripples, dynamic responses, temperature changes and so on meet requirements of the project, and has good overload, short circuit protection characteristics and waveform characteristics, and all the technical indicators are good to meet the requirements of the information platform power.