直流/直流電壓調(diào)節(jié)器：如何選擇之間的離散和模塊化設計

　　有許多令人信服的理由選擇一個模塊化的開關直流/直流電壓調(diào)節(jié)器的設計，而不是傳統(tǒng)的控制器與外部元件-一個離散的穩(wěn)壓器設計。這些措施包括改進了上市時間、降低了總體設計成本、降低了組件成本、更緊湊的設計、更好的可靠性和更低的噪音。然而，有時一個離散的設計是更好的選擇。

　　離散是如何離散的？

　　設計一個簡單的可能，非隔離開關DC/DC穩(wěn)壓器從無到有僅僅使用分立元件。要做到這一點，設計師需要脈沖寬度調(diào)制（PWM）控制，電流開關，電感儲能。

　　然而，在實踐中，很少有來自調(diào)節(jié)器的設計，因為廉價，緊湊和可靠的控制器芯片廣泛使用。

　　Contemporary discrete regulator designs typically comprise a controller chip. These can be found from companies such as National Semiconductor， Fairchild Semiconductor， and Maxim Integrated Products that allied to deliver discrete components with FETs for gate drivers， inductance and capacitance.

　　However， modern integration technologies allow semiconductor vendors to introduce modular regulators. These chips typically integrate everything except the energy storage capacitor， which is difficult to include on the die because its value is more than 1 μF.

　　The design time and effort required to construct a regulator using an integrated module is clearly lower than a discrete design. However， there are some situations when discrete design is advantageous， such as when high efficiency at a specific operating point is a prerequisite.