[Hardware Engineer] Why do DC-DC isolated switching power modules use transformers?

        DC-DC Of disconnector power module DC/DC DC → Direct , We know that DC current is generally stable in amplitude 、 Unchangeable ; The transformer belongs to [ Electric to magnetic ]→[ Magnetic conversion ] Change components , There is power frequency High frequency , This component can be used wherever conversion is required .

         If we directly input the DC power supply to the primary side of the transformer , The secondary side cannot sense energy , Only alternating electricity can produce a magnetic field . therefore ,DC/DC The front stage of switching power supply chip should be matched with switching devices PWM Generate opening according to a certain frequency / Turn off waveform , This makes DC become “ communication ”, Thus, the primary side generates a magnetic field and senses the secondary side , Then put the secondary side “ communication ” Rectification and filtering become DC , So it's done DC/DC Transformation of .

        AC/DC、DC/DC The high power in the power module is generally in the mode of switching power supply , The volume is smaller than the transformer , More efficient , But the ripple will be larger , Therefore, it is necessary to pass through the transformer to a certain extent AC/DC、DC/DC The ripple of the DC output voltage of the power module decreases , improve performance .