DC-DC converter, control circuit, and power supply control method
View Patent ↗A DC-DC converter includes a first amplifier that amplifies a first difference between a first reference voltage and a feedback voltage corresponding to an output voltage, a second amplifier that amplifies a second difference between the first reference voltage and an integrated value of the feedback voltage, and a controller that controls a switching circuit to change the output voltage when the first difference reaches the second different.
1. A DC-DC converter comprising:
a switching circuit comprising a first switch and a second switch coupled in series and configured to generate an output voltage;
a first amplifier configured to:
amplify a first difference between a first reference voltage and a feedback voltage corresponding to the output voltage, and
generate a first differential output voltage;
a second amplifier configured to:
amplify a second difference between a second reference voltage and an average value of the feedback voltage, the second reference voltage being equal to or different from the first reference voltage, and
generate a second differential output voltage; and
a controller configured to generate a control signal based on the first and second differential output voltages.
2. The DC-DC converter according to claim 1 , wherein the first reference voltage is a time-varying voltage.
3. The DC-DC converter according to claim 1 , wherein a time-varying voltage is added to the output voltage before the output voltage is input to the first amplifier.
4. The DC-DC converter according to claim 1 , wherein the controller is configured to:
generate a first voltage and a second voltage based on the first and second differential output voltages;
compare the first and second voltages; and
generate the control signal based on the comparison of the first and second voltages.
5. The DC-DC converter according to claim 1 , wherein a gain of the first amplifier is lower than a gain of the second amplifier.
6. The DC-DC converter according to claim 1 , comprising:
an inductor coupled between the switching circuit and an output terminal for generating the output voltage;
a current slope detector circuit configured to generate a slope voltage corresponding to a slope of an inductor current flowing through the inductor in an off-period of the switching circuit; and
an adder circuit configured to:
add the slope voltage to the second reference voltage; and
generate the first reference voltage.
7. The DC-DC converter according to claim 1 , wherein an output terminal of the first amplifier is coupled to an output terminal of the second amplifier.
8. The DC-DC converter according to claim 1 , wherein each of the first amplifier and the second amplifier comprises:
a transconductance amplifier; and
a resistor configured to convert a current output from the transconductance amplifier into a voltage.
9. A control circuit comprising:
a switching circuit comprising a first switch and a second switch coupled in series and configured to generate an output voltage;
a first amplifier configured to:
amplify a first difference between a first reference voltage and a feedback voltage corresponding to the output voltage, and
generate a first differential output voltage;
a second amplifier configured to:
amplify a second difference between a second reference voltage and an average value of the feedback voltage, the second reference voltage being equal to or different from the first reference voltage, and
generate a second differential output voltage; and
a controller configured to generate a control signal based on the first and second differential output voltages.
10. The control circuit according to claim 9 , wherein the first reference voltage is a time-varying.
11. The control circuit according to claim 9 , wherein a time-varying voltage is added to the output voltage before the output voltage is input to the first amplifier.
12. The control circuit according to claim 9 , wherein the controller is configured to:
generate a first voltage and a second voltage based on the first and second differential output voltages;
compare the first and second voltages; and
generate the control signal based on the comparison of the first and second voltages.
13. The control circuit according to claim 9 , wherein a gain of the first amplifier is lower than a gain of the second amplifier.
14. The control circuit according to claim 9 , wherein an output terminal of the first amplifier is coupled to an output terminal of the second amplifier.
15. The control circuit according to claim 9 , wherein each of the first amplifier and the second amplifier comprises:
a transconductance amplifier; and
a resistor configured to convert a current output from the transconductance amplifier into a voltage.
16. A method for controlling power supply, the method comprising:
generating an output voltage from a node at which a first switch and a second switch are coupled in series;
amplifying a first difference between a first reference voltage and a feedback voltage corresponding to the output voltage to generate a first differential output voltage;
amplifying a second difference between a second reference voltage and an average value of the feedback voltage to output a second differential output voltage, the second reference voltage being equal to or different from the first reference voltage; and
generating a control signal based on the first and second differential output voltages.
17. The method according to claim 16 , wherein the first reference voltage is a time-varying voltage.
18. The method according to claim 16 , wherein a time-varying voltage is added to the output voltage before the output voltage is input to the first amplifier.
19. The method according to claim 16 , wherein the generating of the control signal comprises:
generating a first voltage and a second voltage based on the first and second differential output voltages; and
comparing the first and second voltages.
20. The method according to claim 16 , wherein an amplification gain of the first difference is lower than an amplification gain of the second difference.