獵能系統之升壓型電荷泵轉換電路設計與實現

Abstract

本文針對獵能系統研製出以電荷泵式直流對直流轉換器為主架構的儲能電路。首先介紹獵能系統，包含獵能源、交流對直流轉換器、直流對直流轉換器及儲能元件，回顧現有的文獻，了解應用產品的電壓和功率使用的範圍，以數個mW到數十個mW等級的能量規格，按照此目標進行設計。 電荷泵是一種不含電感元件的升壓型電路，又稱為無電感交換式直流對直流轉換器，在可攜式電源的設計中占有很重要的地位，本文中先敘述電荷泵的原理與設計方法，再以電路模擬軟體模擬後，依此理論與規格實現一個輸出電壓為輸入電壓兩倍的獵能系統，以硬體電路的方式來完成，其實體的長寬尺寸為32mm×32mm。 實驗過程分為閘極驅動量測、電壓轉換量測和獵能系統量測。由閘極驅動量測可知電晶體驅動IC能夠得到正確的驅動波形和避免導通狀態重疊；由電壓轉換量測可知電荷泵式直流對直流轉換器的電路充電動作；獵能系統量測首先使用直流電源來驗證，分為一般輸入電壓和低輸入電壓的情況，再利用手搖式發電機當作輸入獵能源，經過轉換電路後在儲能元件中儲存，在本實驗中藉由電路的分析和電晶體開關導通的穩定控制中，得到良好的儲能效果：當輸入電壓大於4V時，獵能系統的效率超過67%，而當輸入電壓為低電壓時，電荷泵式直流對直流轉換器的效率約有98%。

The paper presents an Energy Harvesting System based on Charge Pump DC/DC converter. At the beginning, introduce to the Energy Harvesting System, including an Energy Source, an AC/DC converter, a DC/DC converter and an Energy Storage. Review technical literatures, and realize the voltage and the power range of application products. It is designed from several mW to tens of mW. Charge Pump is a boost circuit without inductance, also called non-inductance switching DC/DC converter. It is important for portable power supply design. The paper firstly states the Charge Pump theorem and the design method. Then use the power simulation software to simulate the circuit. Implement the output voltage is twice of the input voltage in the Energy Harvesting System by hardware circuit. The dimension is 32mm×32mm. The experiment divides into three parts: the gate driver measurement, the voltage transfer measurement, and the Energy Harvesting System measurement. We know MOSFET driver IC exports correct waveforms and avoids cross-conduction in the gate driver measurement. We know the charge process of Charge Pump DC/DC converter in the voltage transfer measurement. The Energy Harvesting System measurement divides into normal input voltages and low input voltages by DC power supply. Then use a hand generator as an Energy Source and Energy is stored in the storage device through the converting circuit. By the circuit analysis and the stable control of MOSFET switches, we can obtain the good storage efficiency: When input voltages are greater than 4V, the efficiency of Energy Harvesting System exceeds 67%. When input is low voltages, the efficiency of Charge Pump DC/DC converter is about 98%.