为解决目前电子产品降压型开关电源工作模式无法实现实时动态转换,导致功率消耗较大问题,在传统降压型开关电源的基础上,引入脉冲宽度调制/脉冲频率调制(Pulse Width Modulation/Pulse Frequency Modulation,PWM/PFM)技术设计了降压型...为解决目前电子产品降压型开关电源工作模式无法实现实时动态转换,导致功率消耗较大问题,在传统降压型开关电源的基础上,引入脉冲宽度调制/脉冲频率调制(Pulse Width Modulation/Pulse Frequency Modulation,PWM/PFM)技术设计了降压型开关电源。通过对开关电源芯片内部模块进行分析,设计开关电源电压稳压器结构,减小电源环路中的噪声信号;采用PWM/PFM调制技术,设计降压型开关电源的切换电路。通过实验分析可知,新的降压型开关电源优于传统开关电源。展开更多
This paper presents a novel dual-mode step-up （boost） DC/DC converter. Pulse-frequency modulation （PFM） is used to improve the efficiency at light load. This converter can operate between pulse-width modulation （...This paper presents a novel dual-mode step-up （boost） DC/DC converter. Pulse-frequency modulation （PFM） is used to improve the efficiency at light load. This converter can operate between pulse-width modulation （PWM） and pulse-frequency modulation. The converter will operate in PFM mode at light load and in PWM mode at heavy load. The maximum conversion efficiency of this converter is 96%. The conversion efficiency is greatly improved when load current is below 100 mA. Additionally, a soft-start circuit and a variable-sawtooth frequency circuit are proposed in this paper. The former is used to avoid the large switching current at the start up of the converter and the latter is utilized to reduce the EMI of the converter.展开更多
提出了一种针对便携式电子产品的高效单片开关DC/DC转换器.采用固定关断时间PWM控制方式代替传统的固定频率PWM控制方式,转换器的开关频率和开关电流损耗随输入电压减小而降低,弱化了转换效率随电池电压下降而降低的趋势;除一般PWM/PFM...提出了一种针对便携式电子产品的高效单片开关DC/DC转换器.采用固定关断时间PWM控制方式代替传统的固定频率PWM控制方式,转换器的开关频率和开关电流损耗随输入电压减小而降低,弱化了转换效率随电池电压下降而降低的趋势;除一般PWM/PFM供电模式外,该转换器增设了LDO供电模式以降低转换器的最小输入电压,提高了电池使用效率;另外,该转换器采用既能消除开关管与同步整流管瞬通电流损耗、又能消除其驱动缓冲级瞬通电流损耗的"嵌套"死区缓冲器.仿真结果表明,该转换器转换效率高达95%.转换芯片以0.5μm2P3M Mixed Signal CMOS工艺流片,实测效率达91%.展开更多
文摘为解决目前电子产品降压型开关电源工作模式无法实现实时动态转换,导致功率消耗较大问题,在传统降压型开关电源的基础上,引入脉冲宽度调制/脉冲频率调制(Pulse Width Modulation/Pulse Frequency Modulation,PWM/PFM)技术设计了降压型开关电源。通过对开关电源芯片内部模块进行分析,设计开关电源电压稳压器结构,减小电源环路中的噪声信号;采用PWM/PFM调制技术,设计降压型开关电源的切换电路。通过实验分析可知,新的降压型开关电源优于传统开关电源。
基金the National Science Council of Taiwan, China, under Grant No. NSC 95-2221-E-305010.
文摘This paper presents a novel dual-mode step-up （boost） DC/DC converter. Pulse-frequency modulation （PFM） is used to improve the efficiency at light load. This converter can operate between pulse-width modulation （PWM） and pulse-frequency modulation. The converter will operate in PFM mode at light load and in PWM mode at heavy load. The maximum conversion efficiency of this converter is 96%. The conversion efficiency is greatly improved when load current is below 100 mA. Additionally, a soft-start circuit and a variable-sawtooth frequency circuit are proposed in this paper. The former is used to avoid the large switching current at the start up of the converter and the latter is utilized to reduce the EMI of the converter.
文摘提出了一种针对便携式电子产品的高效单片开关DC/DC转换器.采用固定关断时间PWM控制方式代替传统的固定频率PWM控制方式,转换器的开关频率和开关电流损耗随输入电压减小而降低,弱化了转换效率随电池电压下降而降低的趋势;除一般PWM/PFM供电模式外,该转换器增设了LDO供电模式以降低转换器的最小输入电压,提高了电池使用效率;另外,该转换器采用既能消除开关管与同步整流管瞬通电流损耗、又能消除其驱动缓冲级瞬通电流损耗的"嵌套"死区缓冲器.仿真结果表明,该转换器转换效率高达95%.转换芯片以0.5μm2P3M Mixed Signal CMOS工艺流片,实测效率达91%.
