反激式开关电源钳位保护电路设计仿真研究

摘要

As the core component of flyback switching power supply,transformer was applied to complete the function of energy transfer.Due to the existence of self leakage,it can make switch tube bear very high spike voltage during turn off moment.The switch tube can be broke down by this spike voltage.Focused on these problems above,a clamping protection circuit was designed to reduce spike voltage and make sure that the switch tube can work within the scope of the safety voltage.Determination of circuit parameters was the key difficulty in design of clamping protection circuit.Circuit parameters were usually designed by the experience in which design method has no theoretical basis.The principle of the clamp protection circuit was analyzed,a specific parameter design method was proposed and simulation was carried out with saber software.Finally,effectiveness in suppressing the leakage with peak of clamping protection circuit was verified.%变压器作为反激式开关电源的核心部件,完成能量传递的功能,但由于自身漏感的存在,会导致开关管在关断瞬间承受很高的尖峰电压,将击穿开关管.针对上述问题,设计了钳位保护电路,目的是降低尖峰电压峰值,使开关管工作在安全电压范围内.钳位保护电路的设计难点在于电路参数的确定,以往通常由经验设计电路的参数,设计方法没有理论依据.分析了钳位保护电路的原理,提出了具体的参数设计方法,利用saber软件对其进行仿真,验证了钳位保护电路具有有效抑制漏感尖峰的作用.