Non-synchronous switching regulator with improved output regulation at light or low loads

A non-synchronous switching regulator comprising:

• a highside power Field Effect Transistor (FET) coupled to an input voltage and a common node;
• a weak lowside FET coupled to a ground;
• a first diode with an anode coupled to the common node and a cathode coupled to the weak lowside FET;
• a second diode with an anode coupled to ground and a cathode coupled to the common node;
• an inductor coupled to the common node and an output capacitor;
• and
• a control circuit operative to control a duty cycle of an input signal provided to the highside power FET and the weak lowside FET resulting in the generation of a charge current through the inductor that charges the output capacitor to provide a regulated voltage at an output terminal, the lowside FET provides a path for a reverse current to prevent the regulator from entering a discontinuous mode that occurs at light loads on the output terminal.

A method of operating a non-synchronous switching regulator, the method comprising;

• switching a highside power switch coupled to an input voltage and a common node to an “ON” state;
• switching a lowside switch coupled to a ground and the common node to an “OFF” state;
• generating a charge current through an inductor coupled to the common node and an output capacitor;
• charging the output capacitor to a desired regulated output voltage;
• switching the highside power switch to an “OFF” state and the lowside switch to an “ON” state;
• providing an initial charging current to the inductor through a diode coupled to ground;
• and
• allowing a reverse current of the inductor to flow through the lowside switch to ground,
• wherein the lowside switch being substantially weaker than the highside power switch.