After we design a switching power supply, we only basically realize its functions and indicators, and we still need to do various optimizations. 1. Optimization of power stage parameters After selecting the power stage topology, we can use the previous knowledge and the choice of steady-state operating point to optimize the power parameters, so as to minimize the inductance loss of switching power devices-power transformers and filters. The volume of the filter capacitor is the smallest-the power density of the whole power supply is the highest-the power stage layout is the most reasonable, and so on. Among these optimizations, the most important one is the optimization of power transformer, whose transformation ratio and winding mode will directly affect the selection of other power components and the efficiency and power density of the whole power stage. The reasonable selection of power switching devices, their driving circuits and absorption circuits is also very important to the performance of power stage. Loop parameter optimization After the power stage topology and control strategy are selected, the loop parameters can be optimized on the basis of power stage parameter optimization, so as to:-minimize the closed-loop voltage and audio isolation, thereby reducing the capacitance of PFC filter-minimize the closed-loop output impedance, thereby reducing the capacitance of DC output filter. In loop optimization, the most important thing is the compensator parameters. Optimization of modulator parameters (such as external oblique wave compensation content) and optical coupler circuit parameters. Among them, the PCB layout of the whole power supply has a great influence on the loop. Only under a good PCB layout, by optimizing the parameters of each part of the loop, can the gain bandwidth of the power loop be as large as possible, so as to achieve better dynamic performance and higher power density. Optimization of auxiliary power supply parameters In switching power supply products with winding power supply, the quality of auxiliary power supply must be optimized, so that:-the auxiliary power supply has the least influence on the steady-state performance of switching power supply-the auxiliary power supply has the least influence on the dynamic performance of switching power supply-the auxiliary power supply will not affect the reliability of the whole switching power supply, and the quality of its output voltage will generally not be very good. Through the optimization of auxiliary power supply, it is necessary to ensure that the performance change of the whole power supply is minimal and the reliability is no problem. 4. Other optimization-optimization of various protection circuits in power supply-optimization of EMI filter circuit-optimization of thermal environment in power supply-optimization of other functional circuits of power supply (such as current sharing, synchronization, hot plug, remote compensation, etc.). ) PCB layout optimization.