开关电源模块并联供电系统的设计

本设计由两个电源并联构成,其中一个做主电源,另一个作为从电源。主从两个电源都基于DPA245R芯片,采用电感反激励式DC/DC变换器,使输出电压恒定为8.0V。电路工作时保持主电源的输出电流恒定,不同工作状态设置不同输出电流恒定值,从电源电流根据总输出电流的大小自动跟随。从而达到不同输出电流时,主从电源模块自动调节电流比的目的。电路具有负载短路过流保护和自动恢复功能。     

Pressure-induced phase transitions in the ZrXY (X= Si,Ge, Sn;Y= S,Se, Te) family compounds

Pressure is an effective and clean way to modify the electronic structures of materials, cause structural phase transitions and even induce the emergence of superconductivity. Here, we predicted several new phases of the ZrXY family at high pressures using the crystal structures search method together with first-principle calculations. In particular, the ZrGeS compound undergoes an isosymmetric phase transition from P4/nmm-I to P4/nmm-II at approximately 82 GPa. Electronic band structures show that all the high-pressure phases are metallic. Among these new structures, P4/nmm-II ZrGeS and P4/mmm ZrGeSe can be quenched to ambient pressure with superconducting critical temperatures of approximately 8.1 K and 8.0 K, respectively. Our study provides a way to tune the structure, electronic properties, and superconducting behavior of topological materials through pressure.