Patent ID: 9467045
Filing Date: 2016-10-11
CPC Classification: H02M

Claim Text:
1. A Switching Mode Power Supply (SMPS), comprising: a switching circuit having an input terminal and an output terminal, the switching circuit comprising a switch and an inductor, wherein the switching circuit regulates an output voltage at the output terminal based on an input voltage at the input terminal by controlling a switching action of the switch; and a controller configured to generate a switching control signal to control the switch, wherein the switching control signal transits from a first state to a second state when an output signal at the output terminal satisfies a predetermined condition, and the switching control signal transits from the second state to the first state after a period of time; wherein a switching frequency of the switch and an inductor ripple current of the inductor are both configured to vary with the input voltage; wherein the controller comprises: an output regulation circuit configured to generate an output regulation signal based on the output signal; an ON time control circuit configured to generate an ON time control signal, the ON time control circuit comprising: a ramp signal generating circuit configured to generate a ramp signal based on the input voltage and the output voltage; a reference signal generating circuit configured to generate a reference signal based on the output voltage; and a comparing circuit having a first input configured to receive the ramp signal, a second input configured to receive the reference signal, and an output configured to provide the ON time control signal based on the comparison between the ramp signal and the reference signal; and a logic circuit having a first input configured to receive the output regulation signal, a second input configured to receive the ON time control signal, and an output configured to provide the switching control signal; wherein the ramp signal generating circuit comprises: a current generating circuit configured to generate a current signal that is proportional to the voltage difference between the input voltage and the output voltage; and a capacitor charged by the current signal when the switch is in an ON state, and wherein the voltage across the capacitor forms the ramp signal.