- 學位論文
新型自適應斜坡漣波調變定導通時間控制之降壓型轉換器
A novel adaptive-ramp ripple-based constant on-time controlled buck converter
摘要
近年來，漣波調變定導通時間控制架構應用於許多行動裝置之直流轉換器中。此類轉換器，通常採用外加固定斜坡補償的方式，以克服其穩定度及步階負載暫態響應問題。為了保障轉換器可以正常工作，外加斜坡的斜率需要基於特定的工作條件，比如輸入電壓，輸出電壓和電路切換頻率以進行正確設計。 但是，在日漸重要的智慧電源管理晶片應用中，傳統固定斜率外加斜坡漣波調變定導通時間控制架構並無法滿足其要求。對該應用而言，轉換器之輸出電壓及頻率會隨著動態電壓範圍變動而變動以期提高系統總體最佳效率。為使轉換器穩定且步階暫態響應令人滿意，外加斜坡的斜率必須基於操作條件自動調節。本論文則提出一種新型自適應斜坡補償電路以解決上述問題。 所提出之自適應斜坡電路以類比方式實現。它可以集成於傳統控制電路中，且不會增加晶片的腳位。模擬和實驗結果都驗證了上述理論。該控制方式適用於許多行動裝置之直流轉換器，尤其是電源管理晶片應用中。
並列摘要
Ripple-based constant on-time (RBCOT) scheme has recently been adopted in the DC converters for many mobile applications. In this class of converters, an external ramp of fixed slope is often used to overcome system stability and step-load transient problems. To ensure converter proper operation, the slope of the external ramp must be properly designed according to the converter component values, and the specified operating conditions such as input voltage, output voltage, and switching frequency. However, for the up-and-coming smart power management integrated circuit (PMIC) applications, the conventional RBCOT scheme with a fixed-slope ramp simply cannot meet the requirements. For such an application, the converter output voltage and switching frequency can change due to the dynamic voltage scaling used in PMIC to improve the overall efficiency. To cope with the varying operating conditions, which keeping the converter stable with acceptable step-load response, the ramp slope must be adaptive in nature. In this thesis, a novel adaptive ramp scheme is proposed to deal with such a problem. The proposed adaptive ramp circuit is implemented in an analog circuit. It can be integrated with a conventional converter controller without additional pins. Simulations were conducted and a hardware experimental circuit was built to verify the proposed concept. This control scheme is suitable for DC converters for many mobile device applications, especially for PMIC.