The Solution To Optimize The Load Dynamic （优化负载动态解决方案）.pdf

Application Report SNVA684A – January 2014 The Solution to Optimize the Load Dynamic Performance in UCC28019A LED Lighting Application Richard Yang China Power FAE ABSTRACT With the increasing application on the wide input range of 90Vac-305vac for the high power PWM dimming LED street lighting, UCC28019A suite very well for this application. However, the PFC inductor noise issue, introduced by the PWM dimming of output load, may be the major concern. In this paper, the root cause of this phenomenon is analyzed based on the small signal model and the solution is proposed. To verify the validation of the proposed solution, the UCC28019A average model, together with the experiment, is used to check the verification. It is proved that the experiment result agrees very well with the analysis result and simulation result. Contents 1 Introduction 3 2 The UCC28019A load dynamic audible noise description 3 3 Analysis of the root cause based on UCC28019A operation principle 5 3.1 The PFC inductor current noise analysis based on the Vcomp variation during UCC28019A load stepping up 5 3.2 The root cause analysis for the UCC28019A Vcomp variation during UCC28019A load stepping up 9 3.3 T he primary The PFC inductor current noise analysis during UCC28019A load stepping