The Research & Design Of A Low Power Supply SMPS

This paper described comprehensively the basic method in SMPS designing. For instance, to BUCK circuit, We analysed gradually the CCM mode and the DCM mode in power stage by State-Space Averaging moethod. The inductor Volt-Second Balance and the Capacitor Charge Balance were also be figure out theoretically. It was pointed out that the Volt-Second Balance in inductor determined the DC voltage element in all kinds of smps, the Capacitor Charge Balance determined the DC current element. In stable state, the average voltage across the inductance is zero, and the average current across the capacitor is zero. A suitable L and C value could be obtained by analyzing the power's ripple.There list several key components whitch are important in SMPS ,the paper described every key component's equivalent circuit individualy,and almost every topology of SMPS was consist of these components. This paper also pay a great attention to the transformer's work theoretics and design procedure. How to confirm the gap and how did the magnetic current work were discussed reasonedly here .To get a transformer easyly and make the very few mistakes in transformer designing, there discuss the effect of the same winding's difference position in the transformer.According to the method of the SMPS's designing mentioned in the paper,we design a 10W power supply convertor. The circuit scheme , the diagram of printed circuit board and the bill of materials were listed in the fourth chapter. Finally, all datas of the convertor faultlessly fit the user's requirement.