DC-DC Conversion for Multi-Cell Batteries

• US 20170302093A1
• Filed: 04/12/2017
• Published: 10/19/2017
• Est. Priority Date: 04/13/2016
• Status: Active Grant

• Current Assignee: Dialog Semiconductors (UK) Limited
• Original Assignee: Dialog Semiconductors (UK) Limited
• Inventors: Petersen, Holger
• Granted Patent: US 10,454,291 B2
• Time in Patent Office: Days
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0025 Sequential battery discharge in systems with a plurality of batteries
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/0063 with circuits adapted for supplying loads from the battery
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: H02M 7/4837 Flying capacitor converters

Abstract

A power supply has a multi-level DC-DC converter and a battery pack with two or more cells provided in series. The switching DC-DC converter provides a regulated voltage at an output. The converter has an energy storage element. The switching regulator is designed to selectively operate in two or more different modes. It switches between a first mode where one cell is connected (between battery and inductor of the converter), and the converter functions like a single cell buck converter and a second mode where two cells are connected in series and the converter functions like a two series cell buck converter. In general, any number of cells and modes can be provided, with successive cells being connected in series in each mode.

Claims

1. A power supply comprising:

a battery comprising a plurality of cells coupled in series; and

a switching DC-DC converter for providing a regulated voltage at an output and comprising an energy storage element;

said switching DC-DC converter being arranged to selectively operate in two or more different modes, wherein for each mode the energy storage element is coupled between a different number of cells and the output.

2. The power supply of claim 1, wherein the energy storage element comprises an inductor.

3. The power supply of claim 1, being arranged to switch from a first mode wherein the energy storage element is coupled between a first number of cells and the output and a second mode wherein the energy storage element is coupled between a second number of cells and the output, said second number of cells being greater than said first number of cells, when an input battery voltage provided by the coupled cell or cells falls below or reaches a predetermined threshold value.

4. The power supply of claim 1, further comprising a switched capacitor converter arranged to transfer charge between cells.

5. The power supply of claim 1, wherein, in each mode, a single switch is in series between the coupled cells and the energy storage element.

6. The power supply of claim 1, wherein the battery comprises one or more terminals between cells for the connection of a DC-DC converter input.

7. The power supply of claim 1, comprising a battery protection device at each intermediate positive node of the cell stack.

8. The power supply of claim 1, comprising a battery protection device at a negative node of the battery.

9. A switching DC-DC converter for providing a regulated voltage at an output, comprising an energy storage element and a plurality of selectable inputs;

and being arranged to selectively operate in two or more different modes, wherein for each mode the energy storage element is coupled between a different input and the output.

10. A battery comprising a plurality of cells coupled in series and wherein one or more intermediate terminals are provided between cells for the connection of a DC-DC converter input.

11. The battery of claim 10, comprising a battery protection device at one or more of each intermediate positive node of the cell stack.

12. The battery of claim 10, comprising a battery protection device at a negative node of the battery.

13. A method of supplying power comprising the steps of:

providing a power supply with a battery comprising a plurality of cells coupled in series; and

providing a switching DC-DC converter for providing a regulated voltage at an output and comprising an energy storage element;

said switching DC-DC converter being arranged to selectively operate in two or more different modes, wherein for each mode the energy storage element is coupled between a different number of cells and the output.

14. The method of claim 13, wherein the energy storage element comprises an inductor.

15. The method claim 13, wherein the power supply is arranged to switch from a first mode wherein the energy storage element is coupled between a first number of cells and the output and a second mode wherein the energy storage element is coupled between a second number of cells and the output, said second number of cells being greater than said first number of cells, when an input battery voltage provided by the coupled cell or cells falls below or reaches a predetermined threshold value.

16. The method of claim 13, further comprising the step of arranging a switched capacitor converter to transfer charge between cells.

17. The method of claim 13, wherein, in each mode, a single switch is in series between the coupled cells and the energy storage element.

18. The method of claim 13, wherein the battery comprises one or more terminals between cells for the connection of a DC-DC converter input.

19. The method of claim 13, further comprising the step of providing a battery protection device at each intermediate positive node of the cell stack.

20. The method of claim 13, further comprising the step of providing a battery protection device at a negative node of the battery.

21. A method of using a switching DC-DC converter to provide a regulated voltage at an output, comprising the steps of:

providing an energy storage element and a plurality of selectable inputs; and

arranging said selectable inputs to selectively operate in two or more different modes, wherein for each mode the energy storage element is coupled between a different input and the output.