Power supply system

A power supply system, comprising:

• a primary side circuit comprising a primary side winding;
• a secondary side circuit comprising a secondary side winding, wherein the primary side winding and the secondary side winding are magnetically coupled to each other, and the secondary side winding outputs an output voltage;
• an auxiliary winding magnetically coupled to the secondary side winding, wherein the auxiliary winding comprises a first sub winding and a second sub winding which are connected to each other in series, and the auxiliary winding has a first tap, a second tap, and a ground tap:
• the first tap is provided at a dotted end of the first sub winding, the second tap is provided at a dotted end of the second sub winding, and the ground tap electrically couples a non-dotted end of the second sub winding to a ground electric potential:
• the secondary side winding maps the output voltage to the auxiliary winding so as to allow the first tap to generate a first auxiliary voltage and the second tap to generate a second auxiliary voltage;
• a blocking module electrically coupled to the first tap and the second tap, wherein the blocking module receives the first auxiliary voltage and the second auxiliary voltage, and the blocking module outputs one of the first auxiliary voltage and the second auxiliary voltage as a selected voltage;
• a control module electrically coupled to the second tap and the blocking module, wherein the control module receives the second auxiliary voltage, and the control module controls the blocking module to output the first auxiliary voltage or the second auxiliary voltage as the selected voltage according to an amplitude of the second auxiliary voltage;
• and
• a controller electrically coupled to the blocking module and the control module.