隨著CMOS技術的進步，高性能處理器被廣泛用於消費電子產品。高端的處理器必須提供比以往更大的電流以滿足負載端的需求。而多相式轉換器被視為提供高電流負載的最佳架構。由於功率級元件寄生電阻的影響，每相給定相同的責任週期，並不能保證每相平均分攤負載電流。電流分配不均可能使得某一相承載過多的負載電流，造成該相電感電流飽和，甚至超出電流額定值或因為過熱而損害功率級元件，影響電源系統的可靠度。由此可見電流分配是多相式架構最為重要的研究議題。而主流電流分配為電流平衡與熱平衡兩種控制方法，常見的作法是取得每相的電流或溫度資訊送給控制器內部進行調整，使得最終每相位電流或溫度達到均勻的分布。然而，藉由感測電路取得電流或溫度資訊對於相位數越多的應用，就需要使用更多的感測硬體，此外，控制晶片也需預留更多的腳位數作為感測器的輸入，造成晶片面積變大及成本變高。有鑑於此，本論文整理現有無感測式的電流及熱平衡技術，並提出具電流及熱平衡控制之無感測式的演算法，最後以FPGA並搭配自行設計之四相式降壓型功率級電路板來驗證本論文所提出演算法的可行性。

With the advancement of CMOS technology, high-performance processors are widely used in consumer electronics. Multiphase converters are considered to be the best architecture to provide these applications. In practical use, however, mismatches between phases due to parasitic resistances of the power-stage components, cause each phase with the same duty cycle not to distribute the load current evenly. This can cause uneven thermal hotspot, switching transistors damage, and possibility of inductor saturation. As a result, the reliability of power management unit is degraded. Current sharing among phases is the most important research topic in multiphase toplogies. The mainstream sharing control can be divided into two categories: current balance and thermal balance. A common approach is to sense every phase current or temperature and send them to the controller for feedback control. However, the higher number of phase counts, the more sensing circuitries are needed, and in turn increase extra costs. Besides, the sensed data are required additional current or thermal sharing loop which makes the design of PWM controller more complicated. In light of this, the sensorless equivalent resistance (Req) ratio estimation is used in this work to obtain the current and thermal information implicitly. Based on the estimative results, the duty offset is further calculated and compensated for each phase to carry out either equal current sharing or uniform thermal distribution. Finally, the FPGA equipped with a self-designed four-phase buck converter platform is used to verify the feasibility of the proposed algorithm. The current balance scheme improves the current sharing error from 33% to 9.74%, while the thermal balance technique narrows down the peak temperature difference from 6.3 to 1.9 degree Celsius.

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