Power supply systems and control methods for generating operation power source

A method for generating an operation power source, comprising:

• providing a first winding and an auxiliary winding inductively coupled to each other, wherein the first winding has a first number of turns larger than the auxiliary winding does;
• and
• rectifying a first current from the first winding to generate an output power source;
• rectifying an auxiliary current from the auxiliary winding to generate an auxiliary power source;
• selecting one of the output power source and the auxiliary power source to be an input power source in response to one of the operation power source and the output power source;
• and
• supplying power from the input power source to generate and regulate the operation power source on a power line.

A power supply system for generating an operation power source, comprising:

• a first rectifier filter, connected to a first winding for providing an output power source;
• a second rectifier filter, connected to an auxiliary winding for providing an auxiliary power source, wherein the first winding and the auxiliary winding are inductively coupled with each other, and the first winding has a first number of turns larger than auxiliary winding does;
• and
• a power management module comprising:
• a first linear dropout connected between the output power source and the auxiliary power source for regulating the auxiliary power source at a first predetermined voltage;
• and
• a second linear dropout connected between the auxiliary power source and the operation power source for regulating the operation power source at a second predetermined voltage less than the first predetermined voltage.