Power switch reliability in switched capacitor DC-DC converter

Patent metadata

Field	Value
Publication number	US-9520774-B2
Application number	US-201113230772-A
Country	US
Kind code	B2
Filing date	Sep 12, 2011
Priority date	Sep 12, 2011
Publication date	Dec 13, 2016
Grant date	Dec 13, 2016

Abstract

Representative implementations of devices and techniques minimize hot carrier stress in a switched capacitor dc-dc converter. Multi-switch arrangements may be used in conjunction with a timing scheme to stage power switch operation.

First claim

What is claimed is:

1. An apparatus, comprising:
an energy storage element;
a first switch coupled to a first terminal of the energy storage element; and
a second switch coupled to the first terminal of the energy storage element, the second switch arranged to toggle offset from the first switch, and the second switch to toggle once a voltage across the second switch reaches approximately a minimum voltage and wherein the first and second switches are arranged to toggle in an order based on a relative impedance of the first and second switches.

2. The apparatus of claim 1 , wherein the first switch is arranged to toggle when a voltage across the first switch is approximately a maximum voltage.

3. The apparatus of claim 1 , wherein the first switch has a greater impedance than the second switch, and wherein the first switch is arranged to toggle prior to the second switch.

4. The apparatus of claim 1 , wherein the first switch has an impedance that is at least a decade order of magnitude greater than the second switch, and wherein the second switch is arranged to toggle a preset duration after the first switch has toggled.

5. The apparatus of claim 1 , wherein the second switch is arranged to close after a preset delay, the preset delay commencing at a closing of the first switch.

6. The apparatus of claim 1 , wherein the first and second switches are arranged to open concurrently.

7. A direct current to direct current (dc-dc) converter, comprising:
an energy storage element; and
a plurality of switches coupled to a first terminal of the energy storage element, at least one of the plurality of switches arranged to receive a switching signal, the switching signal arranged to delay a switching of one or more of the plurality of switches by a preset time duration when another of the plurality of switches has toggled, and wherein the switching signal is arranged to switch the plurality of switches in an order based on a relative impedance of the plurality of switches.

8. The dc-dc converter of claim 7 , wherein one or more of the plurality of switches has a lower impedance than others of the plurality of switches, and wherein the switching signal is arranged to switch the one or more of the plurality of switches a preset duration after switching the others of the plurality of switches.

9. The dc-dc converter of claim 7 , wherein the one or more of the plurality of switches has an impedance that is at least a decade order of magnitude lower than the others of the plurality of switches, and wherein the switching signal is arranged to toggle the one or more of the plurality of switches a preset duration after at least one of the others of the plurality of switches have toggled.

10. The dc-dc converter of claim 7 , wherein the switching signal is arranged to close one or more of the plurality of switches after a preset delay, the preset delay commencing at a closing of one or more others of the plurality of switches.

11. The dc-dc converter of claim 7 , wherein at least two of the plurality of switches are arranged in parallel to each other.

12. A method comprising: toggling a first switch of a plurality of switches based on a relative impedance of the first switch and a second switch of the plurality of switches, wherein: the first switch has a higher impedance than the first switch, and one or more of the first switch and the second switch couple an energy storage device of a direct current to direct current (dc-dc) converter to a voltage source; commencing a preset time delay concurrent to toggling the first switch; and toggling the second switch at the conclusion of the preset time delay.

13. The method of claim 12 , further comprising toggling the second switch while a voltage across the second switch is at a minimum voltage.

14. The method of claim 12 , wherein at least one of the first switch and the second switch comprises a metal-oxide-semiconductor device.

15. The method of claim 12 , wherein the preset delay represents a time for a voltage across the second switch to change from a maximum voltage to a minimum voltage.

16. The method of claim 12 , wherein the first switch is arranged in parallel with the second switch.

17. The method of claim 12 , further comprising charging the energy storage device to a first voltage when the first switch is closed.

18. The method of claim 12 , further comprising charging the energy storage device to a second voltage when the second switch is closed.

19. The method of claim 12 , further comprising opening the first and second switches concurrently, and discharging the energy storage device.

20. The method of claim 12 , further comprising toggling the first switch while a voltage across the first switch is at a maximum voltage.

Assignees

• Hoellinger Werner
• Marsili Stefano
• Ankele Benno
• Infineon Technologies Ag

Inventors

• Hoellinger Werner
• Marsili Stefano
• Ankele Benno

Classifications

• H02M3/06

  using resistors or capacitors, e.g. potential divider · CPC title

• H02M3/07 Primary

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