Voltage converter and control method thereof

A voltage converter for converting an input voltage into an output voltage, wherein the output voltage is output to a load, comprising:

• an input terminal, receiving the input voltage;
• an output terminal, outputting the output voltage to the load;
• an inductor coupled between the output terminal and a node;
• a first transistor coupled between the input terminal and the node;
• a pulse width modulation (PWM) controller, generating a first control signal according to the output voltage and a first reference voltage;
• an amplifier, generating a second control signal according to the output voltage and a second reference voltage;
• a detector coupled to the node, detecting a loading of the load according to a voltage of the node or a current of the inductor to generate a switching signal;
• and
• a switching circuit, selectively coupling one of the PWM controller and the amplifier to the first transistor according to the switching signal,
• wherein when the voltage converter operates in a light load condition, the detector controls the switching circuit to make the first transistor operating in a saturation region,
• wherein when the voltage converter does not operate in the light load condition, the detector controls the switching circuit to make the first transistor operating in a linear region or a cut-off region.