Control of operation of switching regulator to select PWM control or PFM control based on phase comparison

A control circuit of a switching regulator, the switching regulator converting a voltage input to an input terminal into a predetermined constant voltage and outputting the converted voltage from an output terminal, the switching regulator including a switching transistor performing switching in accordance with an input control signal;

• and an inductor charged with an input voltage by the switching of the switching transistor, wherein the switching of the switching transistor is controlled so that the output voltage output from the output terminal is the predetermined constant voltage, the control circuit comprising:
• a voltage comparator circuit part configured to compare a voltage at a connection of the switching transistor and the inductor and a predetermined voltage, and to generate and output a binary signal indicating a result of the comparison;
• a phase comparator circuit part configured to compare a phase of the control signal input to a control electrode of the switching transistor and aphase of the output signal of the voltage comparator circuit part, and to generate and output a signal indicating a result of the comparison;
• and
• a control circuit part configured to perform one of a first control and a second control on the switching transistor in accordance with the output signal of the phase comparator circuit part so that the output voltage output from the output terminal is the predetermined constant voltage, the first control being a PWM control and the second control being one of a PFM control and a VFM control,
• wherein the control circuit part is configured to perform the PWM control in response to the output signal of the phase comparator circuit part indicating that the control signal and the output signal of the voltage comparator circuit part are in phase, and to perform the one of the PFM control and the VFM control in response to the output signal of the phase comparator circuit part indicating that the control signal and the output signal of the voltage comparator circuit part are out of phase, and
• wherein the phase comparator circuit part is configured to determine that the control signal and the output signal of the voltage comparator circuit part are in phase in response to a difference between the phases thereof being less than a predetermined value.

A method of controlling an operation of a switching regulator, the switching regulator converting a voltage input to an input terminal into a predetermined constant voltage and outputting the converted voltage from an output terminal, the switching regulator including a switching transistor performing switching in accordance with an input control signal;

• and an inductor charged with an input voltage by the switching of the switching transistor, wherein the switching of the switching transistor is controlled so that the output voltage output from the output terminal is the predetermined constant voltage, the control method comprising steps of:
• (a) comparing a voltage at a connection of the switching transistor and the inductor and a predetermined voltage;
• (b) comparing a phase of the control signal input to a control electrode of the switching transistor and a phase of a binary signal indicating a result of said step (a);
• (bb) determining that a result of a comparison in (b) is that the control signal and the binary signal are in phase in response to a difference between the phases thereof being less than a predetermined value;
• and
• (c) performing a PWM control on the switching transistor in response to a determination in (bb) that the control signal and the binary signal are in phase, and performing one of a PFM control and a VFM control in response to the result of said step (b) indicating that the control signal and the binary signal are out of phase.