Device and method for controlling a switching power supply and corresponding switching power supply
View Patent ↗A control device is provided for a switching power supply having an output that supplies an output voltage. The switching power supply includes an inductor and two changeover switches for controlling coupling of the inductor. The control device includes a first capacitor for charging with continuous current from a 0V voltage level, a second capacitor for discharging of the continuous current from a predetermined voltage level that is greater than the voltage level of a DC power supply, and a comparison circuit. The comparison circuit compares the output voltage of the switching power supply with voltage levels of the first and second capacitors and generates control signals for controlling the two changeover switches of the switching power supply. Also provided are switching power supplies having such control devices and a method for controlling a switching power supply.
1. A control device for a switching power supply having an output that supplies an output voltage, the switching power supply including an inductor and two changeover switches for controlling coupling of the inductor, said control device comprising:
a first capacitor for charging with continuous current from a 0V voltage level;
a second capacitor for discharging of the continuous current from a predetermined voltage level that is greater than the voltage level of a DC power supply; and
a comparison circuit for comparing the output voltage of the switching power supply with voltage levels of the first and second capacitors and generating control signals for controlling the two changeover switches of the switching power supply.
2. The control device according to claim 1 , wherein the comparison circuit includes a first comparator having one terminal coupled to the output of the switching power supply and another terminal that receives the voltage level of the first capacitor.
3. The control device according to claim 2 , wherein the comparison circuit includes a second comparator having one terminal coupled to the output of the switching power supply and another terminal that receives the voltage level of the second capacitor.
4. The control device according to claim 1 , wherein the comparison circuit includes a second comparator having one terminal coupled to the output of the switching power supply and another terminal that receives the voltage level of the second capacitor.
5. A switching power supply having an output that supplies an output voltage, said switching power supply comprising:
first and second changeover switches;
an inductor coupled to a DC power supply by the first changeover switch and coupled to ground by the second changeover switch; and
a control circuit for controlling the first and second changeover switches, the control circuit including:
a first capacitor for charging with continuous current from a 0V voltage level;
a second capacitor for discharging of the continuous current from a predetermined voltage level that is greater than the voltage level of the DC power supply; and
a comparison circuit for comparing the output voltage of the switching power supply with voltage levels of the first and second capacitors and generating control signals for controlling the first and second changeover switches.
6. The switching power supply according to claim 5 , wherein the comparison circuit of the control circuit includes a first comparator having one terminal coupled to the output of the switching power supply and another terminal that receives the voltage level of the first capacitor.
7. The switching power supply according to claim 6 , wherein the comparison circuit of the control circuit includes a second comparator having one terminal coupled to the output of the switching power supply and another terminal that receives the voltage level of the second capacitor.
8. The switching power supply according to claim 5 , wherein the comparison circuit of the control circuit includes a second comparator having one terminal coupled to the output of the switching power supply and another terminal that receives the voltage level of the second capacitor.
9. A switching power supply having an output that supplies an output voltage, said switching power supply comprising:
first and second changeover switches;
an inductor having a first terminal coupled to a DC power supply and a second terminal coupled to the output of the switching power supply by the first changeover switch and coupled to ground by the second changeover switch; and
a control circuit for controlling the first and second changeover switches, the control circuit including:
a first capacitor for charging with continuous current from a 0V voltage level;
a second capacitor for discharging of the continuous current from a predetermined voltage level that is greater than the voltage level of the DC power supply; and
a comparison circuit for comparing the output voltage of the switching power supply with voltage levels of the first and second capacitors and generating control signals for controlling the first and second changeover switches.
10. The switching power supply according to claim 9 , wherein the comparison circuit of the control circuit includes a first comparator having one terminal coupled to the output of the switching power supply and another terminal that receives the voltage level of the first capacitor.
11. The switching power supply according to claim 10 , wherein the comparison circuit of the control circuit includes a second comparator having one terminal coupled to the output of the switching power supply and another terminal that receives the voltage level of the second capacitor.
12. The switching power supply according to claim 9 , wherein the comparison circuit of the control circuit includes a second comparator having one terminal coupled to the output of the switching power supply and another terminal that receives the voltage level of the second capacitor.
13. A method for controlling a switching power supply having an output that supplies an output voltage, the switching power supply including an inductor, two changeover switches for controlling coupling of the inductor, and a control circuit for controlling the changeover switches, said method comprising the steps of:
charging a first capacitor with continuous current from a 0V voltage level;
discharging a second capacitor of the continuous current from a predetermined voltage level that is greater than the voltage level of a DC power supply; and
comparing the output voltage of the switching power supply with voltage levels of the first and second capacitors and generating control signals for controlling the first and second changeover switches based on the comparison.
14. The method according to claim 13 , wherein the comparing step includes the sub-step of comparing the output of the switching power supply with the voltage level of the first capacitor.
15. The method according to claim 14 , wherein the comparing step further includes the sub-step of comparing the output of the switching power supply with the voltage level of the second capacitor.
16. The method according to claim 13 , wherein the comparing step includes the sub-step of comparing the output of the switching power supply with the voltage level of the second capacitor.