Every Component of a Switch Mode Power Supply Explained

see also

• How A Switch Mode Power Supply Really Works? Inside an SMPS

• inductor (bobine)
  • act as a spring (load a certain amount of current (like a spring tension))
  • this load is released when cutting input current
  • the energy is store in the iron core
  • the primary coil (bobine) => store energy from input current
  • the secondary coil retrieve the energy from iron core (at a different peace) - the smaller the inductor (core) the less energy stored
    • higher switching frequency in the charging/decharging process
• isolation
  • ?
• bridge of diod
  • pour redresser le courant alternatif
• capacitor
  • pour lisser le resultat du redressage
  • must be discharged before check
• MOSFET
  • control how much energy is put into the inductor
• Diod
  • to avoid output current comming back to the input
• Output capacitor
  • smooth again the resulting DC

Other details

• LED + resistor (to not blow the LED)
  • show that output current is flowing
  • does not means that there is no input current.
• resistor in // to outptu capacitor
  • to empty the output capacitor when powering down and avoid them being kept charged
• capacitor on the returning current (neutral side)
  • to avoid having frequeny noise commming back to the main
• fuse / input protection
  • to protect both main and psu
• NTC Thermistor
  • to limit the input current coming in
• MOX
  • voltage resistant thermistant / suppress high peak current

And other

• to make sure the Electro Magnetic compatibility (EMC) regulation is assured
  • in order to don’t mess with other equipment