Control circuit for power supply including a detection circuit and a regulation circuit for regulating switching timing

1. A power supply comprising:

a converter including a first switch and a second switch coupled in series between a first potential and a second potential; and

a control circuit that controls activation and inactivation of the first switch and the second switch, wherein the control circuit includes:

a detection circuit that detects a magnitude relation of a voltage value at a node between the first and second switches and a reference value during a period in which the first switch and the second switch are inactivated, wherein the detection circuit generates a control signal corresponding to the magnitude relation;

a first timer circuit that generates a first pulse signal having a first given pulse width to activate the first switch;

a second timer circuit that generates a second pulse signal having a second given pulse width to activate the second switch; and

a regulation circuit that regulates a switching timing of the second switch in response to the control signal to decrease a difference between the voltage value at the node and the reference value and regulates the first given pulse width of the first pulse signal or the second given pulse width of the second pulse signal in accordance with the control signal.

2. A control circuit for controlling a power supply, the control circuit comprising:

a detection circuit that detects a voltage value at a node between a first switch and a second switch, which are coupled in series between a first potential and a second potential, during a period in which the first switch and the second switch are inactivated, wherein the detection circuit includes:

a first comparator that compares a voltage value at the node a first reference value, which is a first potential to generate a first signal, and

a second comparator that compares a voltage value at the node with a second reference value, which is a second potential, to generate a second signal,

wherein the detection circuit generates a control signal that corresponds to a magnitude relation of the voltage value at the node and the first and second reference values in accordance with the first and second signals; and

a regulation circuit that regulates a switching timing of the second switch in response to the control signal to decrease a difference between the voltage value at the node and the reference value.

3. The control circuit according to claim 2 , wherein the regulation circuit is configured to regulate the switching timing of the second switch in response to the control signal so that the voltage value at the node when the second switch is inactivated approaches the reference value.

4. The control circuit according to claim 3 , wherein the regulation circuit generates a regulation signal that advances an inactivation timing of the second switch when the voltage value at the node is higher than a first reference value and retards an inactivation timing of the second switch when the voltage value at the node is lower than a second reference value.

5. The control circuit according to claim 4 , further comprising:

a first timer circuit that controls activation and inactivation of the first switch; and

a second timer circuit that controls activation and inactivation of the second switch;

wherein the regulation circuit is coupled to the first timer circuit or the second timer circuit.

6. The control circuit according to claim 2 , wherein the regulation circuit includes:

a capacitor charged and discharged in accordance with the control signal from the detection circuit; and

an amplifier that generates a regulation signal for regulating the switching timing of the second switch based on the amount of charge accumulated in the capacitor.

7. The control circuit according to claim 6 , wherein the amplifier is a transconductance amplifier that controls the amount of current of the regulation signal in accordance with a difference of the amount of charge accumulated in the capacitor and the reference voltage.

8. The control circuit according to claim 6 , wherein the detection circuit includes:

a first pulse circuit that generates a one-shot pulse to start charging the capacitor when the voltage at the node is higher than a first reference value; and

a second pulse circuit that generates a one-shot pulse to start charging the capacitor when the voltage at the node is lower than a second reference value.

9. A control circuit for controlling a power supply, the control circuit comprising:

a detection circuit, that detects a magnitude relation of a reference value and a voltage value at a node between a first switch and a second switch, which are coupled in series between a first potential and a second potential, during a period in which the first switch and the second switch are inactivated, wherein the detection circuit generates a control signal corresponding to the magnitude relation;

a first timer circuit that generates a first pulse signal having a first given pulse width to activate the first switch;

a second timer circuit that generates a second pulse signal having a second given pulse width to activate the second switch; and

a regulation circuit that regulates, a switching timing of the second switch in response to the control signal to decrease a difference between the voltage value at the node and the reference value and regulates the second given pulse width of the second pulse signal in accordance with the control signal.

10. The control circuit according to claim 9 , wherein the regulation circuit includes an amplifier coupled between the detection circuit and the second tinier circuit, wherein the amplifier generates a regulation signal that finely regulates the second given pulse width of the second guise signal in accordance with the control signal from the detection circuit, and the amplifier provides the regulation signal to the second timer circuit.

11. A control circuit for controlling a power supply, the control circuit comprising:

a detection circuit that detects a magnitude relation of a reference value and a voltage value at a node between a first switch and a second, switch, which are coupled in series between a first potential and a second potential, during a period in which the first switch and the second switch are inactivated, wherein the detection circuit generates a control signal corresponding to the magnitude relation;

a first timer circuit that generates a first pulse signal having a first given pulse width to activate the first switch;

a second timer circuit that generates a second pulse signal having a second given pulse width to activate the second switch; and

a regulation circuit that regulates a switching timing of the second switch in response to the control signal to decrease a difference between the voltage value at the node and the reference value and regulates the first given pulse width of the first pulse signal in accordance with the control signal.

12. The control circuit according to claim 11 , wherein the regulation circuit includes an amplifier coupled between the detection circuit and the first timer circuit, wherein the amplifier generates a regulation signal that finely regulates the first given pulse width of the first pulse signal in accordance with the control signal from the detection circuit, and the amplifier provides the regulation signal to the first timer circuit.

13. A control circuit for controlling a power supply, the control circuit comprising:

a reverse flow detection circuit that detects coil current flowing reversely in a choke coil coupled to a node between a first switch and a second switch, which are coupled in series between a first potential and a second potential;

a detection circuit that detects a magnitude relation of a voltage value at the node and a reference value during a period in which the first switch and the second switch are inactivated, wherein the detection circuit generates a control signal corresponding to the magnitude relation; and

a correction circuit that corrects an operation speed of the reverse flow detection circuit in response to the control signal to decrease a difference between the voltage value at the node and the reference value.

14. The control circuit according to claim 13 , wherein the detection circuit includes:

a first comparator that compares the voltage value at the node with a first reference value and generates a first signal;

a second comparator that compares the voltage value at the node with a second reference value and generates a second signal;

wherein the detection circuit generates the control signal corresponding to a magnitude relation of the voltage value at the node and the first and second reference values in accordance with the first and second signals.

15. The control circuit according to claim 14 , wherein the detection circuit includes:

a first pulse circuit that generates a first one-shot pulse based on the first signal; and

a second pulse circuit that generates a second one-shot pulse based on the second signal;

wherein the correction circuit increases the operation speed of the reverse flow detection circuit in response to the first one-shot pulse and decreases the operation speed of the reverse flow detection circuit in response to the second one-shot pulse.

16. An electronic device comprising:

a power supply; and

an internal circuit supplied with voltage generated by the power supply, wherein the power supply includes:

a first switch and a second switch coupled in series between a first potential and a second potential;

a detection circuit that detects a voltage value at a node between the first and second switches during a period in which the first switch and the second switch are inactivated, wherein the detection circuit includes:

a first comparator that compares a voltage value at the node with a first reference value, which is a first potential to generate a first signal, and

a second comparator that compares a voltage value at the node with a second reference value, which is a second potential, to generate a second signal,

wherein the detection circuit generates a control signal that corresponds to a magnitude relation of the voltage value at the node and the first and second reference values in accordance with the first and second signals; and

a regulation circuit that regulates a switching timing of the second switch in response to the control signal to decrease a difference between the voltage value at the node and the reference value.

17. A method for controlling a power supply, the method comprising:

detecting a voltage value at a node between a first switch and a second switch, which are coupled in series between a first potential and a second potential, during a period in which the first switch and the second switch are inactivated;

comparing the voltage value at the node with a first reference value, which is a first potential, to generate a first signal;

comparing the voltage value at the node with a second reference value, which is a second potential, to generate a second signal;

generating a control signal corresponding to a magnitude relation of the voltage value at the node and the first and second reference values in accordance with the first and second signals; and

regulating a switching timing of the second switch in response to the control signal to decrease a difference between the voltage value at the node and the reference value.

18. The method according to claim 17 , further comprising:

advancing an inactivation timing of the second switch when the voltage value at the node is higher than the first reference value; and

retarding an inactivation timing of the second switch when the voltage value at the node is lower than the second reference value.