High efficiency backup-power circuits for switch-mode power supplies

• US 8,754,545 B2
• Filed: 04/22/2010
• Issued: 06/17/2014
• Est. Priority Date: 04/22/2010
• Status: Active Grant

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Wai, Peter, Puckette, Robert
• Primary Examiner(s): CAVALLARI, DANIEL J
• Application Number:
  US12/765,792
• Publication Number:
  US 20110260539A1
• Time in Patent Office: 1,517 Days
• Field of Search: 307/46, 307/66
• US Class Current: 307/66
• CPC Class Codes: H02J 7/34 Parallel operation in networks using both storage and other dc sources, e.g. providing buffering H02J7/14 takes precedence
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: H02J 9/061 for DC powered loads
• CPC Class Codes: H02M 1/0096 Means for increasing hold-up time, i.e. the duration of time that a converter's output will remain within regulated limits following a loss of input power

Abstract

Disclosed are novel interconnections of a coupling circuit and an energy storage device which enables the storage device to provide back-up power for a switching power supply without requiring the device to store or output high voltage, and which enables full utilization of the energy stored in the device. In exemplary embodiments, the combination of the coupling circuit and the energy storage device may be coupled between the input and output of the switching power supply (e.g., between the non-ground terminals of the input and output ports of the switching power supply). The coupling circuit is configured to couple power from the energy storage device to the input of the switching power supply when the input power source is not provided to the switching power supply, and optionally to couple power from the input power source to the energy storage device when the input power source is provided.

Claims

1. A power supply comprising:

an input port to receive a source of input power, the input port having a first terminal and a second terminal;

an output port to provide output power, the output port having a first terminal and a second terminal;

a switching power supply having an input coupled to the input port to receive input power and an output coupled to the output port to provide output power;

a selected circuit node having a potential, wherein, when input power is provided to the input port, the potential difference between the first terminal of the input port and the selected circuit node has the same polarity as the potential difference between the first and second terminals of the input port, but is less in magnitude; and

a circuit combination of a coupling circuit and an energy storage device, a first terminal of the circuit combination being coupled to the first terminal of the input port, and a second terminal of the circuit combination being coupled to the selected circuit node, the circuit combination being configured to couple energy from the energy storage device to the input of the switching power supply when input power is not provided at the input port.

2. The power supply of claim 1, wherein the circuit combination is further configured to couple energy from the input port to the energy storage device when input power is provided at the input port.

3. The power supply of claim 1, wherein the energy storage device comprises a capacitor.

4. The power supply of claim 1, wherein the energy storage device comprises a battery.

5. The power supply of claim 1, wherein the selected circuit node is the output of the switching power supply.

6. The power supply of claim 1, wherein the coupling circuit comprises a first electrical connection between a first terminal of the energy storage device and the selected circuit node and a second electrical connection between a second terminal of the energy storage device and the first terminal of the input port.

7. The power supply of claim 1, wherein the coupling circuit comprises one or more resistors.

8. The power supply of claim 1, wherein the coupling circuit comprises one or more electrical components that allow the energy storage device to store energy from the input port when input power is provided and to release energy back to the input port when input power is not provided.

9. The power supply of claim 1, wherein the coupling circuit comprises one or more inductors.

10. The power supply of claim 1, wherein the switching power supply further comprises at least one switch and at least one energy storage element, and wherein the switching power supply repeatedly switches the at least one switch between a conducting state and non-conducting state when power is provided to its input, causing energy from the input port to be repeatedly stored into the energy storage element, and energy from the energy storage element to be repeatedly coupled to the output port.

11. The power supply of claim 10, wherein the energy storage element comprises an inductor or a capacitor.

12. The power supply of claim 1, wherein the switching power supply comprises a buck converter.

24. The power supply of claim 1, wherein the coupling circuit comprises one or more diodes.

25. The power supply of claim 1, wherein the coupling circuit comprises a linear regulator.

26. The power supply of claim 25, wherein the linear regulator compares the voltage across the energy storage device to a reference voltage, and regulates the current flow from the input port to the energy storage device to maintain the voltage across energy storage device to a value set by the reference voltage.

27. The power supply of claim 1, wherein the coupling circuit comprises one or more semiconductor devices.

28. The power supply of claim 1, wherein the coupling circuit further comprises a semiconductor device coupled between the first terminal of the input port and a terminal of the energy storage device and configured to provide a discharge path when the input power source is removed.

13. A power supply comprising:

an input port to receive a source of input power, the input port having a first terminal and a second terminal;

an output port to provide output power, the output port having a first terminal and a second terminal;

a switching power supply having an input coupled to the input port to receive input power, an output coupled to the output port to provide output power, and at least one switch, the switching power supply providing a common connection between the second terminal of the input port and the second terminal of the output port, the switching power supply repeatedly switching the at least one switch between a conducting state and non-conducting state when power is provided to its input; and

a circuit combination of a coupling circuit and an energy storage device, a first terminal of the circuit combination being coupled to the first terminal of the input port, and a second terminal of the circuit combination being coupled to the first terminal of the output port, the circuit combination being configured to couple energy from the energy storage device to the input of the switching power supply when input power is not provided at the input port.

14. The power supply of claim 13, wherein the circuit combination is further configured to couple energy from the input port to the energy storage device when input power is provided at the input port.

15. The power supply of claim 13, wherein the energy storage device comprises a capacitor.

16. The power supply of claim 13, wherein the energy storage device comprises a battery.

17. The power supply of claim 13, wherein the coupling circuit comprises a first electrical connection between a first terminal of the energy storage device and the first terminal of the output port and a second electrical connection between a second terminal of the energy storage device and the first terminal of the input port.

18. The power supply of claim 13, wherein the coupling circuit comprises one or more resistors.

19. The power supply of claim 13, wherein the coupling circuit comprises one or more electrical components that allow the energy storage device to store energy from the input port when input power is provided and to release energy back to the input port when input power is not provided.

20. The power supply of claim 13, wherein the coupling circuit comprises one or more inductors.

21. The power supply of claim 13, wherein the switching power supply further comprises at least one energy storage element, and wherein the switching of the at least one switch between a conducting state and non-conducting state causes energy from the input port to be repeatedly stored into the energy storage element, and energy from the energy storage element to be repeatedly coupled to the output port.

22. The power supply of claim 21, wherein the energy storage element comprises an inductor or a capacitor.

23. The power supply of claim 13, wherein the switching power supply comprises a buck converter.

29. The power supply of claim 13, wherein the coupling circuit comprises one or more diodes.

30. The power supply of claim 13, wherein the coupling circuit comprises a linear regulator.

31. The power supply of claim 30, wherein the linear regulator compares the voltage across the energy storage device to a reference voltage, and regulates the current flow from the input port to the energy storage device to maintain the voltage across the energy storage device to a value set by the reference voltage.

32. The power supply of claim 13, wherein the coupling circuit comprises one or more semiconductor devices.

33. The power supply of claim 13, wherein the coupling circuit further comprises a semiconductor device coupled between the first terminal of the input port and a terminal of the energy storage device and configured to provide a discharge path when the input power source is removed.