Hello,
Thanks a lot firstly. I have searched some websites to find some switching mode power supply schematic diagrams to tell the different protections to my student, and I also check in some datasheets to get the acurate comentary to let my student well understand the protection of DC switching power supply.
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Hi,
The specific stuff is the switch tube is controlled by high frequency PWM (Pulse width Modulation) signal, the DC is added to the primary level of the switch transformer, the switch transformer induces the high frequency voltage, and the load is supplied by rectifying and filtering. The output part feedback to the control circuit through a certain circuit to control the duty cycle of PWM to achieve the purpose of stable output. When AC power is input, it usually goes through EUB to filter out the interference on the power grid, meanwhile, it also filters out the interference of the power supply to the power grid.
When the power is the same, the higher the switching frequency, the smaller the volume of the switch transformer. But the higher the demand on the switch tube, the secondary of the switch transformer can contain more windings or windings have more than one tap to get the desired output. Protection circuits such as no-load, short circuit protection should also be added, otherwise the switching power supply may be destroyed.
I haven't arranged all the specific thing that I collect yet...