Abstract: A switching power supply includes a secondary control circuit coupled to a secondary side of a transformer of the switching power supply, and a primary control circuit coupled to a primary side of the transformer. The secondary control circuit is configured to receive a power request signal of a load device, and encode the power request signal to generate encoded information. The primary control circuit is configured to receive, by use of the transformer, a feedback signal reflecting an output voltage of the switching power supply, decode the encoded information based on a change of the feedback signal, and based thereon, control the switching power supply to supply power to the load device.

Abstract: A system for controlling a skip mode of a switching power supply and a PWM controller are provided. The system includes a feedback signal detection circuit configured to detect an output voltage of the switching power supply and generate a feedback signal related to the output voltage; a primary winding sampling circuit coupled with a primary winding of the switching power supply and configured to sample a sampling voltage of the primary winding; a skip mode soft control circuit configured to receive the feedback signal and output an electrical signal; and a comparison circuit configured to determine a threshold for the sampling voltage, where the skip mode is activated when the feedback signal is greater than a soft activation voltage threshold, and the skip mode is pre-exited when the feedback signal is less than a predetermined voltage threshold and greater than a soft exit voltage threshold.

Abstract: A system for controlling a skip mode of a switching power supply and a PWM controller are provided. The system includes a feedback signal detection circuit configured to detect an output voltage of the switching power supply and generate a feedback signal related to the output voltage; a primary winding sampling circuit coupled with a primary winding of the switching power supply and configured to sample a sampling voltage of the primary winding; a skip mode soft control circuit configured to receive the feedback signal and output an electrical signal; and a comparison circuit configured to determine a threshold for the sampling voltage, where the skip mode is activated when the feedback signal is greater than a soft activation voltage threshold, and the skip mode is pre exited when the feedback signal is less than a predetermined voltage threshold and greater than a soft exit voltage threshold.