本研究目的,主要為解決高功率二極體元件現行驅動方法,因接面溫度(Tj)上升,造成順向偏壓(VF)電壓下降後,產生驅動電路輸出功率下降問題。本研究使用外部儀表模擬建立二極體元件的 VF順向偏壓 (Forward Voltage) 之相對應電流對照表,並紀錄於非揮發性記憶體中,使被動元件(電阻、電容)、運算放大器增益(OPA)、類比/數位轉換器(ADC)、數位/類比轉換器(DAC)等誤差降到最小,並利用類比/數位(ADC)轉換電路,偵測功率二極體之順向偏壓,作為非揮發性記憶體的位址索引,將事先透過外部儀表校正後,存入非揮發性記憶體對應之電流紀錄資訊讀出,再經由該數位/類比(DAC)轉換控制電路,將該數位電流控制訊號轉換輸出一類比電流控制訊號,並回饋至功率極體負載中之電流驅動電路,以調整該功率二極體負載之輸出功率接近於恆定功率狀態,由於直接使用類比/數位(ADC)輸入信號當作位址索引,無須額外索引時間,大幅提高驅動電路輸出功率校準效率。
This work proposes to develop an automatic compensation device for power diode output. This device uses an analog-to-digital converter to detect the forward voltage (VF) as the index address for the non-volatile memory, which stores the pre-calibrated digital current data of the power diode, to get the corresponding digital current. The read digital current is then converted to an analog current by the digital-to-analog converter to feed to the current control circuit of the power diode. This mechanism can control the output of the power diode to an almost constant level. The use of the output of the analog-to-digital converter as the index address of the non-volatile memory does not need an extra time for indexing, and it can increase the efficiency of the calibration significantly.