共振式電源轉換控制器之設計

Abstract

隨著超大型積體電路技術的日益精進，電子產品正迅速邁向輕、薄、短、 小之境界。而傳統的電源供應器由於體積大且笨重，已不能符合現代電子 產品之需求。基於這種趨勢，當一種適用於高頻率操作之共振式電源轉架 構被提出以後，立刻吸引了大家的注意，因為在高頻率操作下，電感、變 壓器等磁性元件及濾波器電容等都可以大大地縮小，而這些元件也正是傳 統電源供應器中最佔體積及重量的部份。在我們國內，電源供應器是我國 電子產品中佔有極大產值的一項產品，但是其中控制器卻一直是仰賴國外 進口，國內並沒有廠商從事設計生產。有鑑於此，我們嘗試著提出這樣一 個共振式電源轉換控制器，它具有多功能與容易操作的特性，可以經由簡 單的邏輯控制來決定零電壓或零電流切換，也可以選擇用於單端或橋式的 電源轉換架構。另外，它也提供了零點偵測的功能，可以很方便地偵測到 電壓零點或電流零點。 As the technology of VLSI progresses continuously, the traditional power supply implementation becomes bulky and heavy as compared to that of the modern electronic system. In striving to reduce the size and to increase the effi- ciency simultaneously, power supply designers find that the key to the solution is to operate the switching power supply with resonant mode in high frequency. The most attractive feature is to take use of the ZVS/ZCS techno- logy so that the switching loss becomes not a barrier in the high frequency operation. A resonant mode power supply tends to be smaller in size and weight with lower EMI and higher efficiency. However, the resonant mode controllers for switching power supply are still not available in many design varieties. This paper presents a designed new one. It features the capabilities of choosing ZVS/ZCS control mode. It can work in half bridge/ full bridge topology, single ended/double ended operation , forward/flyback ope- ration, etc. In the chip, it includes circuits as : a pre- cision voltage reference, two wideband error amplifiers, a voltage controlled oscillator, a one shot generator and an output stage with steering logic. Circuits for zero vol- tage and zero current detection are also contained to ease the user's design. Examples of applications are included here to demonstrate the different usages of this control chip. Finally, a comparison of PWM mode and resonant mode converters is discussed.