※ 引述《noko (爆肝吧...男孩)》之銘言： : 想請教一下,在一般的dcdc裡面 : 大部分都會用PWM Control : 而PWM普遍看到的都是Voltage mode跟Current mode control : 小弟不才有個問題想了很久 : 在電流模式裡面,DCDC外部可以看作單極點系統 : 電壓模式DCDC外部是雙極點系統 : 而在電流模式裡面,因為電感可以等效為一個電阻效應 : 那為何可以等效成電阻效應呢? : 請板上的大大能幫忙解惑,謝謝 http://www.powermanagementdesignline.com/howto/202802181 節錄一段出來.... Current-mode control is desirable because the CMC loop in effect forces the peak current to be the same for each switch cycle as long as Vc is constant. Thus, the inductor in combination with the CMC loop can be thought of as a current source. Unlike voltage-mode control, the inductor L and output filter capacitor, Co, do not contribute a complex pole pair to the overall system loop. The removal of a power pole due to L in the CMC system loop removes the need for a corresponding zero in the overall system compensation network. A single RC network is adequate for optimal CMC system compensation, a significant reduction in complexity for tuning system performance. 如果這樣還是覺得不明所以 最基本的方式 可以去推導電流模式的電流控制迴路的轉移函數 跟電壓模式的轉移函數做比較 兩者的control-to-output transfer function 前者少一個pole --

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