基于四管同步升降压变换器汽车适配器设计

Automotive Adaptor based on Four Switchers Synchro Buck-Boost Converter

讨论了四管同步Buck-Boost升降压变换器的工作原理。这种变换器有同步降压Buck、降升压Buck-Boost、同步升压Boost三种工作模式。详细分析了输入和输出接近相等时,四管同步降压及升压Buck-Boost模式的工作原理。降压Buck-Boost模式中电感先深去磁,再短时间的深激磁,然后长时间的浅激磁;升压Buck-Boost模式中电感先深激磁,再短时间的深去磁,然后长时间的浅去磁,从而维持低纹波的输出电压调节。还介绍了具有12V/24V通用电池电压输入范围的汽车电池适配器的设计过程,讨论了电感的计算和选取方法,以及PCB的设计原则。

The principle of a new type of four switchers synchronous Buck-Boost converter is discussed,which could operated at three modes of synchronous Buck mode, step down or step up Buck-Boost mode and synchronous Boost mode. The four-transistors switching operation of step down and step up Buck-Boost mode is analyzed in detail.The inductor was demagnetized strongly first and then magnetized strongly for a short time, and finally magnetized weakly for a long time in step down Buck-Boost mode, which could regulate output voltage when input voltage was lightly higher than output voltage. The inductor was magnetized strongly first and then demagnetized strongly for a short time and finally demagnetized weakly for a long time in step up Buck-Boost mode,which could regulate output voltage when input voltage was lightly lower than output voltage.The practical application of automotive adaptor with 12V/24V battery universal input voltage is given. The tips of calculating the inductor and layouting PCB are also presented.