Digital controller for switched capacitor DC-DC converter

Patent metadata

Field	Value
Publication number	US-9800150-B2
Application number	US-201113283558-A
Country	US
Kind code	B2
Filing date	Oct 27, 2011
Priority date	Oct 27, 2011
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

Abstract

Representative implementations of techniques and/or devices provide control of switching characteristics in a switched capacitor dc-dc converter. In various implementations, the switching characteristics are modified based on load characteristics (e.g., magnitude of the load current). The switching characteristics may be modified to reduce, minimize, or eliminate switching losses in the dc-dc converter.

First claim

What is claimed is:

1. A system comprising:
a direct current to direct current converter (dc-dc converter), including:
an energy storage element;
a first plurality of switches coupled to a first terminal of the energy storage element;
a second plurality of switches coupled to a second terminal of the energy storage element, wherein a conductance of each one of the first and second plurality of switches is adjustable; and
a digital controller arranged to independently control the conductance of each one of the first and second plurality of switches to switch an electrical connection between the energy storage element and an output load of the dc-dc converter between a parallel electrical connection and a series electrical connection by modulation of a switch timing of each one of the first and second plurality of switches, wherein the modulation of the switch timing is determined by adjustment of a gate-source voltage of each one of the first and second plurality of switches, and wherein the digital controller is arranged to program a first sub-set of the first and second plurality of switches to rest in a fixed state while a second sub-set of the first and second plurality of switches toggles states during a preset number of switching cycles.

2. The system of claim 1 , wherein the dc-dc converter includes a second energy storage element and a plurality of other switches coupled to the second energy storage element, and
wherein the second energy storage element is in series with the energy storage element during a first switching configuration of the first and second plurality of switches and plurality of other switches, and the second energy storage element is in parallel with the energy storage element during a second switching configuration of the first and second plurality of switches and plurality of other switches.

3. The system of claim 2 , further comprising an output energy storage element coupled to an output node of the dc-dc converter, and wherein the output energy storage element is in series with the energy storage element and the second energy storage element during a third switching configuration of the first and second plurality of switches and plurality of other switches, and the output energy storage element is in parallel with the energy storage element and the second energy storage element during a fourth switching configuration of the first and second plurality of switches and plurality of other switches.

4. The system of claim 1 , wherein the digital controller is arranged to independently control the conductance of each one of the first and second plurality of switches based on the output load coupled to an output node of the dc-dc converter.

5. The system of claim 4 , wherein the digital controller is arranged to independently control the conductance of one or more of a plurality of other switches based on the load coupled to the output node of the dc-dc converter.

6. The system of claim 1 , further comprising a feedback loop, wherein an output voltage of the dc-dc converter is fed back into the digital controller via an analog to digital converter (adc).

7. The system of claim 6 , wherein the digital controller is arranged to maintain an open loop transfer function of the system in a constant state with load current changes, based on information received from the feedback loop.

8. The system of claim 1 , further comprising a feedback loop, wherein an output voltage of the dc-dc converter is fed back into the digital controller via a comparator.

9. The system of claim 1 , further comprising a digital signal generator arranged to receive conductance information from the digital controller and output a switch configuration to one or more of the first and second plurality of switches and plurality of other switches.

10. The system of claim 9 , wherein the digital signal generator generates the switch configuration based on at least one of charge information and discharge information of the energy storage element.

11. The system of claim 1 , further comprising the output load, wherein the electrical connection between the energy storage element and the output load is the parallel electrical connection during a first switching configuration of the first and second plurality of transistors, and wherein the electrical connection between the energy storage element and the output load is the series electrical connection during a second switching configuration of the first and second plurality of transistors.

12. An apparatus comprising: an energy storage capacitor; a first plurality of transistors coupled to a first terminal of the energy storage capacitor; a second plurality of transistors coupled to a second terminal of the energy storage capacitor; and a digital controller arranged to independently control a conductance of each one of the first and second plurality of transistors based on an output load coupled to an output node of the apparatus, wherein the digital controller is arranged to independently control the conductance of a particular one of the first and second plurality of transistors by control of rate of change of at least a rising edge of a conductance adjustment signal provided to the particular one of the first and second plurality of transistors, and wherein the digital controller is arranged to program a first sub-set of the first and second plurality of transistors to rest in a fixed state while a second sub-set of the first and second plurality of transistors toggles states during a preset number of switching cycles.

13. The apparatus of claim 12 , wherein the digital controller is arranged to determine a switching frequency of the apparatus based on at least one of a charging time and a discharging time of the energy storage capacitor.

14. The apparatus of claim 12 , wherein one or more transistors of the first and second plurality of transistors comprises a metal-oxide-semiconductor (mos) transistor, and wherein the digital controller is arranged to adjust a gate-source voltage of at least one of the mos transistors.

15. The apparatus of claim 12 , further comprising a feedback loop, wherein an output voltage of the apparatus is fed back into the digital controller.

16. The apparatus of claim 12 , wherein the digital controller includes a proportional-integral-derivative controller (PID controller) arranged to program the conductance of each one of the first and second plurality of transistors.

Assignees

• Marsili Stefano
• Hoellinger Werner
• Maderbacher Gerhard
• Infineon Technologies Ag

Inventors

• Marsili Stefano
• Hoellinger Werner
• Maderbacher Gerhard

Classifications

• H02M3/158 Primary

  including plural semiconductor devices as final control devices for a single load · CPC title

• H02M3/07 Primary

  using capacitors charged and discharged alternately by semiconductor devices with control electrode {, e.g. charge pumps} · CPC title

• H02M3/157

  with digital control · CPC title