具光伏電能擷取與電池輔助之單電感雙輸入雙輸出升降壓轉換器

Abstract

近年來，隨著物聯網產品如穿戴式裝置的高度商品化，能源的需求大幅度的上升。為了確保產品操作的穩定性，必須由電池來提供穩定電力；然而，替數以萬計的裝置更換電池需要耗費大量的金錢與人力。因此，可永續利用且低汙染的獵能技術成為延長電池壽命的重要發展，其中，太陽能發電的單位面積發電量較大，已成為目前研究與商品化的主流，其相關應用包含無線智慧感測器、生醫電子元件等。若能結合電池和太陽能發電，可使系統在光照充足的情況下使用太陽能供給電源，反之則由電池供電，進而有效延長電池壽命。 本論文實現一個應用於物聯網產品的單電感雙輸入雙輸出升降壓器，輸入能源結合了鋅-空氣電池與太陽能發電，延長電池使用週期。除此之外，為了提高功率轉換效率，在使用電池當作輸入源時，會使用降壓模式來做切換，使用太陽能電池時，則是使用生降壓模式；在輸出方面，升降壓器會產生兩個輸出電壓，其電壓值為0.4-0.6伏與1-1.2伏，分別提供給低功率的數位電路與低電壓的高頻發射器使用。本論文提出的連續脈波省略調變可以在輸出兩個電壓的同時，降低兩個電壓間彼此的互穩壓效應，並在輕載時有較好的轉換效率。而對於低電壓系統而言，電壓漣波會嚴重影響系統效能，因此本論文提出一個二維自適應導通時間控制電路，能夠在輸入電壓0.55-1.4伏與輸出電壓0.4-0.6伏的範圍下達到平均2.1%的輸出電壓漣波比例。量測結果顯示最高效率可達92.5%，非常適合應用於電池與太陽能電池的混合能源系統。

In this paper, we presented a single-inductor dual-input dual-output (SIDIDO) power converter with two-dimensional adaptive on-time (2-D AOT) control for IoT applications. The proposed system combines energy from a 0.55-V to 0.7-V photovoltaic (PV) module with 1.4-V zinc-air battery to extend the battery life. The proposed converter respectively employs buck-boost mode and buck mode for PV module and the battery to produce two different output voltages. For low power digital circuits, a 0.4-0.6 V is supplied from the first output, and the other output with 1-1.2 V is designed to support RF circuits. The sequential pulse-skip-modulation (SPSM) is proposed to manage power flow of two outputs and minimize cross regulation with high light load efficiency. For low voltage systems, the output voltage ripple of the converter is important and should be well-controlled under different input and output conditions. Therefore, a 2-D AOT control is proposed to achieve an average of 2.1% voltage ripple under a 0.55-1.4 V input voltage range and a 0.4-0.6 V output voltage range. Moreover, the response time of self-tracking zero current detection (ST-ZCD) can be reduced, and dual-source efficiency are improved with the proposed 2-D AOT technique. A test chip is fabricated in TSMC 0.18 μm technology with 1.9x2.2 mm2 area. The measurement results demonstrate a 92.5% peak efficiency under an input voltage of 0.55-1.4 V with a 4.7 μH inductor.