Circuits and method for reducing light load power dissipation of a voltage converter

A voltage converter, comprising:

• a feedback circuit configured to receive an output voltage of the voltage converter, and to provide a feedback voltage based on the output voltage;
• and
• a control circuit, comprising:
• a feedback compensation signal generating circuit configured to receive the feedback voltage and to provide a feedback compensation signal based on the feedback voltage;
• a hysteresis comparator circuit configured to receive an output representation signal, a first threshold, and a second threshold, and to provide a selection signal based on a comparison of the output representation signal with the first and the second threshold;
• a selection circuit configured to receive the feedback compensation signal, an ultra-light load feedback value and the selection signal, and to select one of the feedback compensation signal and the ultra-light load feedback value as a selected feedback compensation signal based on the selection signal;
• and
• a switch control circuit configured to receive the selected feedback compensation signal and to provide a switch control signal based on the selected feedback compensation signal;
• wherein the second threshold is greater than the first threshold, and wherein, at the time the output representation signal is equal to the second threshold, the ultra-light load feedback value is greater than a value of the feedback compensation signal.

A method for controlling a voltage converter, comprising:

• generating a feedback compensation signal based on an output voltage of the voltage converter;
• comparing an output representation signal with a first threshold and a second threshold;
• adjusting a switch control signal to control the turn-on and turn-off of a power circuit of the voltage converter based on an ultra-light load feedback value when the output representation signal is less than the first threshold;
• adjusting the switch control signal based on the feedback compensation signal when the output representation signal is greater than the second threshold;
• wherein the second threshold is greater than the first threshold, and wherein, at the time the output representation signal is equal to the second threshold, the ultra-light load feedback value is greater than a value of the feedback compensation signal.