Design Of Low Power PFC For Home Audio Switching Power Supply

The commonly used audio source products can be regarded as consisting of two levels of structure.The former stage system converts the input AC to DC,and the latter tends to stabilize the output after the DC decompression.For the former circuit,it is more important to improve the efficiency and reduce the impact on the power grid,however,the latter tends to focus on the higher stable performance.In order to comply with the requirements of export and European acoustics to restrict EN61000-3-2,the acoustic power supply products often have to add harmonic restraining devices(power factor correction)between the front and rear levels.However,after loading PFC,the efficiency of power supply is reduced,and it is difficult to be compatible with the double requirements of harmonic limitation and efficiency.Although some sound power supply has good harmonic suppression ability,but the stable performance is deficient.Based on the active type BOOST PFC topologies of improvement,the issue focus on solving the problem of reduction efficiency with PFC,simplify the structure,reduce the loss of the system,at the same time improve the two levels of power supply voltage level after circuit performance.For the purpose,the energy consumption characteristics of PFC are analyzed and discussed.Through analysis,it is found that PFC power consumption is mainly composed of switching loss and flow loss.In this paper,the switching loss can be reduced by the SiC power device,and the flow loss can be realized by reducing the control of the switching device.Based on this starting point,we adopt reasonable control strategy in the process of researching electric property simulation scheme of ordinary Boost.According to the problems reflected,we improve the ordinary Boost topology to the Boost topology for coupling inductance in series,and derive the function relation between the duty ratio characteristics.To improve the sound power level of voltage stability performance,combined with modern home audio power standard,from a half bridge and full bridge LLC topology characteristic of formula through theoretical derivation,we proved that the voltage regulation performance is more stable and the efficiency is higher in the half-bridge LLC.In the circuit design phase,the variation function of the gain property is established to establish the two-dimensional characteristic image,and the circuit parameters are optimized by the image.Finally,according to the electrical characteristic standard of the home audio source,the electrical parameter test is correspondingly.The test process is compared to the same type of audio power supply.Basic electrical characteristics test,the test efficiency through performance test and so on,is found that coupled inductor in series of the Boost topology has higher efficiency,lower power consumption,and then use a half-bridge LLC topology circuit,in addition to have high efficiency,it also has a higher voltage regulation performance.