Controlling A Multi-Mode Switching Converter

• US 20110006743A1
• Filed: 07/09/2009
• Published: 01/13/2011
• Est. Priority Date: 07/09/2009
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Fabbro, Simone
• Granted Patent: US 9,467,053 B2
• Time in Patent Office: Days
• US Class Current: 323/282
• CPC Class Codes: H02M 1/0048 Circuits or arrangements for reducing losses using snubbers H02M1/34
• CPC Class Codes: H02M 3/1582 Buck-boost converters H02M3/1584 takes precedence
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

Systems and methods for controlling a switching converter using a duty cycle associated with either a buck mode or a boost mode of the switching converter. More particularly, a controller determines when to change between buck mode and boost mode based on the duty cycle associated with one of the buck mode or the boost mode.

Claims

1. A switching converter comprising:

a buck branch with an associated buck duty cycle;

a boost branch with an associated boost duty cycle; and

a controller in communication with the buck branch and the boost branch and being configured to

at least one of determine the buck duty cycle,

determine the boost duty cycle, and

responsive to either determined duty cycle reaching a threshold associated with that duty cycle, change between the buck mode and the boost mode.

2. The switching converter of claim 1 further comprising a feedback loop from an output of the switching converter whereby the output voltage is used to adjust the operation of the controller.

3. The switching converter of claim 1 further comprising a feed-forward path from an input of the switching converter whereby the input voltage is used to adjust the operation of the controller.

4. The switching converter of claim 1 wherein the switching converter is associated with an electronic device to be powered with a battery and further comprising a load, wherein an input of the switching converter is in electrical communication with the battery and an output of the switching converter is in electrical communication with the load.

5. The switching converter of claim 1 wherein the controller is an analog controller.

6. The switching converter of claim 5 further comprising a modulation carrier wave generator with a modulation carrier wave output selected from the group consisting of a periodic modulation carrier wave output and a quasi-periodic modulation carrier wave output, the controller using the modulation carrier wave output to determine when to change between the modes.

7. The switching converter of claim 1 further comprising an inverter configured to invert a control signal associated with the buck mode, the controller being further configured to drive the boost branch with the inverted control signal.

8. A switching converter comprising:

a buck branch with a time varying buck duty cycle;

a boost branch with a time varying boost duty cycle; and

a controller configured to;

control the switching converter in a buck mode when an input voltage of the switching converter is about equal to or greater than an output voltage of the switching converter,

control the switching converter in a boost mode when the input voltage is about equal to or less than the output voltage,

determine at least one of the buck duty cycle or the boost duty cycle, and

responsive to either determined duty cycle reaching a threshold associated with that duty cycle, change between controlling the switching converter in the buck mode and the boost mode to maintain the output voltage at a selected voltage.

9. The switching converter of claim 8 wherein the controller is an analog controller implemented with analog circuitry.

10. The switching converter of claim 8 wherein the controller is implemented on a processor.

11. The switching converter of claim 8 wherein the controller is further configured to randomize the threshold associated with the determined duty cycle.

12. The switching converter of claim 8 further comprising a signal generator, the controller being further configured to use a signal generated by the signal generator to change between controlling the switching converter in the buck mode and the boost mode.

13. The switching converter of claim 12 wherein the signal generated by the signal generator is selected from the group consisting of a periodic signal and a quasi-periodic signal, the signal generated by the signal generator being a carrier signal of the controller.

14. A method comprising:

controlling a converter in either a buck mode or a boost mode;

determining a duty cycle of at least a buck branch of the converter or a boost branch of the converter; and

responsive to the determined duty cycle reaching a threshold, changing between the buck mode and the boost mode.

15. The method of claim 14 further comprising controlling the converter in the buck mode, the changing between modes being to the boost mode.

16. The method of claim 14 further comprising delaying the changing between the modes by applying a time delay to the threshold associated with the determined duty cycle.

17. The method of claim 14 further comprising using noise shaping in conjunction with the threshold to suppress oscillations in an output voltage of the converter.

18. The method of claim 14 further comprising delaying the changing between the modes by applying a hysteresis to the threshold associated with the determined duty cycle.

19. The method of claim 14 further comprising randomizing the threshold.

20. The method of claim 19 the randomizing of the threshold further comprising using a noise shaping technique.