This paper presents an AOT-controlled(adaptive-on-time,AOT)valley-current-mode buck converter for portable application.The buck converter with synchronous rectifier not only uses valley-current-mode control but also p...This paper presents an AOT-controlled(adaptive-on-time,AOT)valley-current-mode buck converter for portable application.The buck converter with synchronous rectifier not only uses valley-current-mode control but also possesses hybridmode control functions at the same time.Due to the presence of the zero-current detection circuit,the converter can switch freely between the two operating modes without the need for an external mode selection circuit,which further reduces the design difficulty and chip area.The converter for the application of high power efficiency and wide current range is used to generate the voltage of 0.6–3.0 V with a battery source of 3.3–5.0 V,while the load current range is 0.05–2 A.The circuit can work in continuous conduction mode with constant frequency in high load current range.In addition,a stable output voltage can be obtained with small voltage ripple.In pace with the load current decreases to a critical value,the converter transforms into the discontinuous conduction mode smoothly.As the switching period increases,the switching loss decreases,which can significantly improve the conversion efficiency.The proposed AOT controlled valley current mode buck converter is integrated with standard 0.18μm process and the simulation results show that the converter provides well-loaded regulations with power efficiency over 95%.When the circuit switches between the two conduction modes drastically,the response time can be controlled within 30μs.The undershoot voltage is controlled within 25 mV under a large current hopping range.展开更多
当输出电容等效串联电阻(equivalent series resistance,ESR)较小时,传统的固定导通时间(constant on-time,COT)控制的Buck变换器可能工作在不稳定的混沌状态。因此,文章提出COT控制的Buck变换器的仿ESR电压纹波(simulated voltage ripp...当输出电容等效串联电阻(equivalent series resistance,ESR)较小时,传统的固定导通时间(constant on-time,COT)控制的Buck变换器可能工作在不稳定的混沌状态。因此,文章提出COT控制的Buck变换器的仿ESR电压纹波(simulated voltage ripple,SVR)技术,通过构造与ESR电压纹波同步变化的纹波电压,并将此电压叠加到控制环路,实现了低ESR输出电容COT控制Buck变换器的稳定工作。仿真和实验结果验证了理论分析的正确性。展开更多
对动态电压调节(Dynamic Voltage Scaling,DVS)开关变换器的定频导通时间(Constant Frequency Turn-On Time,CFOT)控制技术进行了研究,在恒定导通时间(Constant On-Time,COT)基础上,通过引入输入电压前馈和输出参考电压反馈环路,实现不...对动态电压调节(Dynamic Voltage Scaling,DVS)开关变换器的定频导通时间(Constant Frequency Turn-On Time,CFOT)控制技术进行了研究,在恒定导通时间(Constant On-Time,COT)基础上,通过引入输入电压前馈和输出参考电压反馈环路,实现不同输入、输出电压条件下DVS开关变换器保持开关频率恒定。研究结果表明,CFOT控制不仅继承了传统COT控制环路设计简单、无需误差放大器及其相应的补偿网路、瞬态响应快的优点,而且消除了输入、输出电压变动对开关频率的影响。展开更多
基金supported by the National Natural Science Foundation of China(No.61974116)。
文摘This paper presents an AOT-controlled(adaptive-on-time,AOT)valley-current-mode buck converter for portable application.The buck converter with synchronous rectifier not only uses valley-current-mode control but also possesses hybridmode control functions at the same time.Due to the presence of the zero-current detection circuit,the converter can switch freely between the two operating modes without the need for an external mode selection circuit,which further reduces the design difficulty and chip area.The converter for the application of high power efficiency and wide current range is used to generate the voltage of 0.6–3.0 V with a battery source of 3.3–5.0 V,while the load current range is 0.05–2 A.The circuit can work in continuous conduction mode with constant frequency in high load current range.In addition,a stable output voltage can be obtained with small voltage ripple.In pace with the load current decreases to a critical value,the converter transforms into the discontinuous conduction mode smoothly.As the switching period increases,the switching loss decreases,which can significantly improve the conversion efficiency.The proposed AOT controlled valley current mode buck converter is integrated with standard 0.18μm process and the simulation results show that the converter provides well-loaded regulations with power efficiency over 95%.When the circuit switches between the two conduction modes drastically,the response time can be controlled within 30μs.The undershoot voltage is controlled within 25 mV under a large current hopping range.
文摘当输出电容等效串联电阻(equivalent series resistance,ESR)较小时,传统的固定导通时间(constant on-time,COT)控制的Buck变换器可能工作在不稳定的混沌状态。因此,文章提出COT控制的Buck变换器的仿ESR电压纹波(simulated voltage ripple,SVR)技术,通过构造与ESR电压纹波同步变化的纹波电压,并将此电压叠加到控制环路,实现了低ESR输出电容COT控制Buck变换器的稳定工作。仿真和实验结果验证了理论分析的正确性。
文摘对动态电压调节(Dynamic Voltage Scaling,DVS)开关变换器的定频导通时间(Constant Frequency Turn-On Time,CFOT)控制技术进行了研究,在恒定导通时间(Constant On-Time,COT)基础上,通过引入输入电压前馈和输出参考电压反馈环路,实现不同输入、输出电压条件下DVS开关变换器保持开关频率恒定。研究结果表明,CFOT控制不仅继承了传统COT控制环路设计简单、无需误差放大器及其相应的补偿网路、瞬态响应快的优点,而且消除了输入、输出电压变动对开关频率的影响。
文摘通过分析扰动后电感电流变化和输出电容电荷变化,导出V^2恒定导通时间(Constant On-Time,COT)控制Buck变换器发生次谐波振荡的临界条件,进一步建立了V^2-COT控制Buck变换器的分段线性模型,通过随输出电容等效串联电阻(Equivalent Series Resistance,ESR)变化的分岔图分析了变换器的稳定机理。最后,制作实验样机,验证了理论分析的结果。
