提出一种可根据负载变化在脉冲宽度调制(pulse width modulation,PWM)和脉冲频率调制(pulse frequency modulation,PFM)两种工作模式间自动切换的降压DC-DC芯片的设计法,推导出临界切换状态下的负载电流值表达式,在此基础上设计了一种PW...提出一种可根据负载变化在脉冲宽度调制(pulse width modulation,PWM)和脉冲频率调制(pulse frequency modulation,PFM)两种工作模式间自动切换的降压DC-DC芯片的设计法,推导出临界切换状态下的负载电流值表达式,在此基础上设计了一种PWM/PFM自动切换的DC-DC芯片.该系统在较大的负载变化范围内均具有较高效率.展开更多
This technical paper takes a study into efficiency comparison between PWM and PFM control modes in DC-DC buck converters. Matlab Simulink Models are built to facilitate the analysis of various effects on power loss an...This technical paper takes a study into efficiency comparison between PWM and PFM control modes in DC-DC buck converters. Matlab Simulink Models are built to facilitate the analysis of various effects on power loss and converting efficiency, including different load conditions, gate switching frequency, setting of voltage and current thresholds, etc. From efficiency vs. load graph, a best switching frequency is found to achieve a good efficiency throughout the wide load range. This simulation point is then compared to theoretical predictions, justifying the effectiveness of computer based simulation. Efficiencies at two different control modes are compared to verify the improvement of PFM scheme.展开更多
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
输入电压和负载宽范围变化时,变频控制LCC谐振变换器的开关频率变化范围宽,而移相控制LCC谐振变换器难以实现宽范围零电压关断(zero voltage switching,ZVS)。为了在较窄开关频率范围内实现LCC谐振变换器的宽范围软开关,该文提出一种...输入电压和负载宽范围变化时,变频控制LCC谐振变换器的开关频率变化范围宽,而移相控制LCC谐振变换器难以实现宽范围零电压关断(zero voltage switching,ZVS)。为了在较窄开关频率范围内实现LCC谐振变换器的宽范围软开关,该文提出一种脉宽-脉频调制(pulse width modulation-pulse frequency modulation,PWM-PFM)混合控制LCC变换器。通过同时调整LCC变换器原边开关管的导通角与开关频率,在宽输入电压和宽负载变化范围内,提出的PWM-PFM混合控制LCC变换器能在稳压输出的同时保持变换器ZVS软开关工作。此外,PWM-PFM混合控制LCC谐振变换器的开关频率范围较窄,简化了变换器磁性元件的设计。以工作在电容电压连续模式(continuous capacitor voltage mode,CCVM)的LCC谐振变换器为例,利用基波近似法,分析PWM-PFM混合控制LCC谐振变换器的工作原理和控制特性,对谐振元件和控制参数进行设计。最后,通过一台100-200V输入、48V/500W输出的实验样机验证了理论分析的正确性。展开更多
文摘提出一种可根据负载变化在脉冲宽度调制(pulse width modulation,PWM)和脉冲频率调制(pulse frequency modulation,PFM)两种工作模式间自动切换的降压DC-DC芯片的设计法,推导出临界切换状态下的负载电流值表达式,在此基础上设计了一种PWM/PFM自动切换的DC-DC芯片.该系统在较大的负载变化范围内均具有较高效率.
文摘This technical paper takes a study into efficiency comparison between PWM and PFM control modes in DC-DC buck converters. Matlab Simulink Models are built to facilitate the analysis of various effects on power loss and converting efficiency, including different load conditions, gate switching frequency, setting of voltage and current thresholds, etc. From efficiency vs. load graph, a best switching frequency is found to achieve a good efficiency throughout the wide load range. This simulation point is then compared to theoretical predictions, justifying the effectiveness of computer based simulation. Efficiencies at two different control modes are compared to verify the improvement of PFM scheme.
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。
文摘输入电压和负载宽范围变化时,变频控制LCC谐振变换器的开关频率变化范围宽,而移相控制LCC谐振变换器难以实现宽范围零电压关断(zero voltage switching,ZVS)。为了在较窄开关频率范围内实现LCC谐振变换器的宽范围软开关,该文提出一种脉宽-脉频调制(pulse width modulation-pulse frequency modulation,PWM-PFM)混合控制LCC变换器。通过同时调整LCC变换器原边开关管的导通角与开关频率,在宽输入电压和宽负载变化范围内,提出的PWM-PFM混合控制LCC变换器能在稳压输出的同时保持变换器ZVS软开关工作。此外,PWM-PFM混合控制LCC谐振变换器的开关频率范围较窄,简化了变换器磁性元件的设计。以工作在电容电压连续模式(continuous capacitor voltage mode,CCVM)的LCC谐振变换器为例,利用基波近似法,分析PWM-PFM混合控制LCC谐振变换器的工作原理和控制特性,对谐振元件和控制参数进行设计。最后,通过一台100-200V输入、48V/500W输出的实验样机验证了理论分析的正确性。