（东南大学）PWM_PFM自动切换降压DC_DC转换器的分析与设计

cicixu · 发表于 2009-3-25 10:35:39

dingdingding

freeray · 发表于 2009-3-25 11:37:50

下来看看，先感谢

prof3 · 发表于 2009-3-26 07:59:29

原帖由 refugee 于 2008-1-2 18:21 发表

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如图所示，改成虚线所示的结果就正确了

Refugee's modification is completely wrong. He does not understand the operation of this cicruit.

Acutally, if 改成虚线所示, the current sensor no longer monitors or detects Ids of Mp power transistor and of course fails. Originally schematic is correct although it is quite simple and not that much accurate. However, for PWM/PFM transition, the threshold varition +/-20% is acceptable. If used in Current Mode DC-DC, this circuit is not good enough.