The suppressing harmonic currents, MS (magnetic-switch) power supply

A new power supply which suppresses harmonic currents is proposed. The circuit is made up by inserting a choke coil and a transformer winding between the bridge rectifier and the input capacitor of an ordinary capacitor input-type power supply. The characteristics of the circuit use the transformer winding like a switch (a magnetic switch), and has a function to improve the power factor and to suppress harmonic currents. As this MS power supply has only one switch (MOSFET) and one control circuit, the whole circuit is simple, inexpensive, and meets IEC 1000-3-2 Class D standards concerning the harmonic currents of switching power supplies.