Switching power supply circuit having independent loops

A switching power supply circuit, comprising:

• a power source;
• a pulse width modulation (PWM) circuit comprising a first output and a second output;
• a first switching circuit comprising a first transistor and a second transistor;
• a second switching circuit comprising a third transistor and a fourth transistor;
• a first transformer comprising a first primary winding and a second primary winding, the first primary winding and the second primary winding comprising a first common terminal, the first primary winding further comprising a first terminal, and the second primary winding further comprising a second terminal;
• and
• a second transformer comprising a third primary winding and a fourth primary winding, the third primary winding and the fourth primary winding comprising a second common terminal, the third primary winding further comprising a third terminal, and the fourth primary winding further comprising a fourth terminal;
• wherein the first output of the PWM circuit is connected to gate electrodes of the first and third transistors respectively, the second output of the PWM circuit is connected to gate electrodes of the second and fourth transistors respectively, the power source is connected to the first and second common terminals respectively, the first and second terminals are connected to drain electrodes of the first and second transistors respectively, and the third and fourth terminals are connected to drain electrodes of the third and the fourth transistors respectively.