新型恒频PWM驱动电路设计

Design of a New Type Constant Frequency PWM Driver Circuit

以驱动Buck变换器为例,设计了一种新型恒频PWM发生电路。电路由比例放大器、积分器、比较器、触发器、窄脉冲发生器和复位开关等几部分构成,实现了输出电压跟随给定基准变化,抵抗了电源波动和负载变化对输出电压的影响,保证输出电压的恒定。仿真和试验结果表明新型恒频PWM发生电路的可行性和有效性。电路可应用驱动其他开关变换器拓扑,具有一定的适用性。

In switching converter,PWM generation is the most important guarantes to achieve the performance index. Taking driving Buck converter as an example, a new type constant frequency PWM circuit was designed. The circuit is composed of proportional amplifier, integrator, comparator, trigger, narrow pulse generator and a reset switch. The output voltage follows the given reference to change, resisting the impact of power fluctuation and load change on the output voltage, so the constant output voltage is guaranteed. The simulation and experiment results show the feasibility and effectiveness of the new type constant frequency PWM generation circuit. The circuit has certain applicability to drive other switching converter topology.