Switched capacitor DC-DC voltage converter

• US 8,089,787 B2
• Filed: 07/03/2008
• Issued: 01/03/2012
• Est. Priority Date: 06/27/2008
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Melse, Abraham Lodewijk
• Primary Examiner(s): NGUYEN, MATTHEW VAN
• Application Number:
  US12/167,365
• Publication Number:
  US 20090323378A1
• Time in Patent Office: 1,279 Days
• Field of Search: 363/59, 363/60, 363/62, 323/268, 323/271, 327/535, 327/536
• US Class Current: 363/62
• CPC Class Codes: H02M 3/07 using capacitors charged and discharged alternately by semiconductor devices with control electrode , e.g. charge pumps

Abstract

The disclosure describes techniques for converting an input voltage level to two or more output voltage levels using only two pump capacitors and three switching phases. The disclosure also describes techniques for selectively controlling a dc-dc converter to operate in different conversion modes. One mode may use only two pump capacitors and three switching phases to produce output voltage levels with a first set of conversion ratios. Another mode may use two pump capacitors and two switching phases to produce output voltage levels with a second set of conversion ratios. The first mode may use three different subcircuit arrangements of the pump capacitors. The second mode may use two different subcircuit arrangements of the pump capacitors. A converter may include switches and pump capacitors that can be selectively configured to transition between two or three different subcircuits, thereby producing output voltages according to different conversion ratios on a selective basis.

Claims

1. A dc-dc voltage conversion device comprising:

an input node to receive a dc input voltage at an input level;

an output node to output a dc output voltage at an output level different from the input level;

a first pump capacitor and a second pump capacitor;

switches configured to selectively arrange only the first and second pump capacitors in at least three different subcircuits relative to the input node and the output node, wherein at least one of the subcircuits comprising a subcircuit in which the first and second pump capacitors are not coupled to the input node; and

a controller configured to control the switches to transition between at least three phases comprising the three different subcircuits to convert the dc input voltage at the input level at the input node to the dc output voltage at the output level at the output node, wherein the output level comprises at least one of 83%, 80%, 60%, 40%, 20%, or 17% of the input level.

2. The device of claim 1, further comprising a third capacitor coupled between the output node and a reference, wherein the output voltage is generated across the third capacitor, wherein each of the subcircuit configurations comprises a set of capacitors consisting essentially of the first pump capacitor, the second pump capacitor, and the third capacitor.

3. The device of claim 1, wherein:

the output node comprises a first output node to output a first dc output voltage at a first output level different from the input level, and a second output node to output a second dc output voltage at a second output level different from the input level,

the second output level is different from the first output level,

wherein the subcircuits are configured to convert the dc input voltage at the input level at the input node to the first dc output voltage at the first output level at the first output node and to the second dc output voltage at the second output level at the second output node.

4. The device of claim 3, wherein the controller is configured to control the switches such that a ratio x of the first output level to the input level and a ratio y of the second output level to the input level, represented as a percentage value, is one of x/y equal to approximately 80%/60%, 83%/50%, 80%40%, 60%/40%, 60%/20%, or 40%/20%.

5. The device of claim 3, wherein the controller is configured to control the switches such that a ratio x of the first output level to the input level and a ratio y of the second output level to the input level, represented as a percentage value, is x/y approximately equal to 80%/60%.

6. The device of claim 3, further comprising:

a third capacitor coupled between the first output node and a reference, wherein the first output voltage is generated across the third capacitor; and

a fourth capacitor coupled between the first output node and the reference, wherein the second output voltage is generated across the fourth capacitor,

wherein each of the subcircuits comprises a set of capacitors consisting essentially of the first pump capacitor, the second pump capacitor, and the third and fourth capacitors.

7. The device of claim 3, wherein:

a first one of the subcircuits comprises the input node connected to a first side of the first pump capacitor and to a first side of the second pump capacitor, a second side of the first pump capacitor connected to a first side of the third capacitor which is the first output node, a second side of the second pump capacitor connected to a first side of the fourth capacitor which is the second output node, and a second side of the third capacitor and a second side of the fourth capacitor connected to the reference;

a second one of the subcircuits comprises the input node connected to the first side of the second pump capacitor, the second side of the second pump capacitor connected to the second side of the first pump capacitor and the first side of the fourth capacitor which is the second output node, the first side of the first pump capacitor connected to the first side of the third capacitor which is the first output node, and the second side of the third capacitor and the second side of the fourth capacitor connected to the reference; and

a third one of the subcircuits comprises the second side of the second pump capacitor connected to the reference, the first side of the second pump capacitor connected to the second side of the first pump capacitor, the first side of the first pump capacitor connected to the first side of the fourth capacitor which is the second output node, the second side of the fourth capacitor connected to the reference, the second side of the third capacitor connected to the reference, where the first side of the third capacitor is the first output node,

wherein the controller controls the switches to continuously transition from the first subcircuit to the second subcircuit, then to the third subcircuit and back to the first subcircuit, and the dc output voltage at the first output node is 80% of the dc voltage at the input node, and the dc output voltage at the second output node is 60% of the dc voltage at the input node.

8. The device of claim 1, wherein the controller is configured to control the switches to transition between the at least three phases in response to a clock signal.

9. The device of claim 1, further comprising a mode selection module that selects one of a plurality of different operating modes, wherein the controller is configured to control the switches to form different sets of the subcircuits based on the selected operating mode.

10. A dc-dc voltage conversion method comprising:

receiving, at an input node, a dc input voltage at an input level;

outputting, at an output node, a dc output voltage at an output level different from the input level;

selectively arranging only first and second pump capacitors in at least three different subcircuits relative to the input node and the output node in at least three different phases to convert the dc input voltage at the input level at the input node to the dc output voltage at the output level at the output node, wherein at least one of the subcircuits comprises a subcircuit in which the first and second pump capacitors are not coupled to the input node, and wherein the output level comprises at least one of 83%, 80%, 60%, 40%, 20%, or 17% of the input level.

11. The method of claim 10, further comprising generating the output voltage across a third capacitor coupled between the output node and a reference, wherein each of the subcircuit configurations comprises a set of capacitors consisting essentially of the first pump capacitor, the second pump capacitor, and the third capacitor capacitors.

12. The method of claim 10, wherein the output node comprises first and second output nodes, and wherein outputting the dc output voltage comprises:

outputting, at the first output node, a first dc output voltage at a first output level different from the input level; and

outputting, at the second output node, a second dc output voltage at a second output level different from the input level,

wherein the second output level is different from the first output level, and

wherein the subcircuits are configured to convert the dc input voltage at the input level at the input node to the first dc output voltage at the first output level at the first output node and to the second dc output voltage at the second output level at the second output node.

13. The method of claim 12, further comprising arranging the first and second pump capacitors in the subcircuits such that a ratio x of the first output level to the input level and a ratio y of the second output level to the input level, represented as a percentage value, is one of x/y equal to approximately 80%/60%, 83%/50%, 80%40%, 60%/40%, 60%/20%, or 40%/20%.

14. The method of claim 12, further comprising arranging the first and second pump capacitors in the subcircuits such that a ratio x of the first output level to the input level and a ratio y of the second output level to the input level, represented as a percentage value, is x/y approximately equal to 80%/60%.

15. The method of claim 12, further comprising:

generating the first output voltage across a third capacitor coupled between the first output node and a reference; and

generating the second output voltage across a fourth capacitor coupled between the first output node and the reference, wherein each of the subcircuits comprises a set of capacitors consisting essentially of the first pump capacitor, the second pump capacitor, and the third and fourth capacitors.

16. The method of claim 12, wherein:

a first one of the subcircuits comprises the input node connected to a first side of the first pump capacitor and to a first side of the second pump capacitor, a second side of the first pump capacitor connected to a first side of the third capacitor which is the first output node, a second side of the second pump capacitor connected to a first side of the fourth capacitor which is the second output node, and a second side of the third capacitor and a second side of the fourth capacitor connected to the reference;

a second one of the subcircuits comprises the input node connected to the first side of the second pump capacitor, the second side of the second pump capacitor connected to the second side of the first pump capacitor and the first side of the fourth capacitor which is the second output node, the first side of the first pump capacitor connected to the first side of the third capacitor which is the first output node, and the second side of the third capacitor and the second side of the fourth capacitor connected to the reference; and

a third one of the subcircuits comprises the second side of the second pump capacitor connected to the reference, the first side of the second pump capacitor connected to the second side of the first pump capacitor, the first side of the first pump capacitor connected to the first side of the fourth capacitor which is the second output node, the second side of the fourth capacitor connected to the reference, the second side of the third capacitor connected to the reference, where the first side of the third capacitor is the first output node,

wherein the capacitors are selectively arranged to continuously transition from the first subcircuit to the second subcircuit, then to the third subcircuit and back to the first subcircuit, and the dc output voltage at the first output node is 80% of the dc voltage at the input node, and the dc output voltage at the second output node is 60% of the dc voltage at the input node.

17. The method of claim 10, wherein arranging the first and second pump capacitors comprises arranging the capacitors via switches, the method further comprising controlling the switches to transition between the at least three phases in response to a clock signal.

18. The method of claim 10, further comprising selecting one of a plurality of different operating modes, and controlling the switches to form different sets of the subcircuits based on the selected operating mode.

19. A dc-dc voltage conversion device comprising:

means for receiving, at an input node, a dc input voltage at an input level;

means for outputting, at an output node, a dc output voltage at an output level different from the input level;

means for selectively arranging only first and second pump capacitors in at least three different subcircuits relative to the input node and the output node in at least three different phases to convert the dc input voltage at the input level at the input node to the dc output voltage at the output level at the output node, wherein at least one of the subcircuits comprises a subcircuit in which the first and second pump capacitors are not coupled to the input node, and wherein the output level comprises at least one of 83%, 80%, 60%, 40%, 20%, or 17% of the input level.

20. The device of claim 19, further comprising means for generating the output voltage across a third capacitor coupled between the output node and a reference, wherein each of the subcircuit configurations comprises a set of capacitors consisting essentially of the first pump capacitor, the second pump capacitor, and the third capacitor.

21. The device of claim 19, wherein the output node comprises first and second output nodes, and wherein the means for outputting the dc output voltage comprises:

means for outputting, at the first output node, a first dc output voltage at a first output level different from the input level; and

means for outputting, at the second output node, a second dc output voltage at a second output level different from the input level,

wherein the second output level is different from the first output level, and

wherein the subcircuits are configured to convert the dc input voltage at the input level at the input node to the first dc output voltage at the first output level at the first output node and to the second dc output voltage at the second output level at the second output node.

22. The device of claim 21, further comprising means for arranging the first and second pump capacitors in the subcircuits such that a ratio x of the first output level to the input level and a ratio y of the second output level to the input level, represented as a percentage value, is one of x/y equal to approximately 80%/60%, 83%/50%, 80%40%, 60%/40%, 60%/20%, or 40%/20%.

23. The device of claim 21, further comprising means for arranging the first and second pump capacitors in the subcircuits such that a ratio x of the first output level to the input level and a ratio y of the second output level to the input level, represented as a percentage value, is x/y approximately equal to 80%/60%.

24. The device of claim 21, further comprising:

means for generating the first output voltage across a third capacitor coupled between the first output node and a reference; and

means for generating the second output voltage across a fourth capacitor coupled between the first output node and the reference,

wherein each of the subcircuits comprises a set of capacitors consisting essentially of the first pump capacitor, the second pump capacitor, and the third and fourth capacitors.

25. The device of claim 21, wherein:

a first one of the subcircuits comprises the input node connected to a first side of the first pump capacitor and to a first side of the second pump capacitor, a second side of the first pump capacitor connected to a first side of the third capacitor which is the first output node, a second side of the second pump capacitor connected to a first side of the fourth capacitor which is the second output node, and a second side of the third capacitor and a second side of the fourth capacitor connected to the reference;

a second one of the subcircuits comprises the input node connected to the first side of the second pump capacitor, the second side of the second pump capacitor connected to the second side of the first pump capacitor and the first side of the fourth capacitor which is the second output node, the first side of the first pump capacitor connected to the first side of the third capacitor which is the first output node, and the second side of the third capacitor and the second side of the fourth capacitor connected to the reference; and

a third one of the subcircuits comprises the second side of the second pump capacitor connected to the reference, the first side of the second pump capacitor connected to the second side of the first pump capacitor, the first side of the first pump capacitor connected to the first side of the fourth capacitor which is the second output node, the second side of the fourth capacitor connected to the reference, the second side of the third capacitor connected to the reference, where the first side of the third capacitor is the first output node,

wherein the capacitors are selectively arranged to continuously transition from the first subcircuit to the second subcircuit, then to the third subcircuit and back to the first subcircuit, and the dc output voltage at the first output node is 80% of the dc voltage at the input node, and the dc output voltage at the second output node is 60% of the dc voltage at the input node.

26. The device of claim 21, wherein the means for arranging the first and second pump capacitors comprises means for arranging the capacitors via switches, the device further comprising means for controlling the switches to transition between the at least three phases in response to a clock signal.

27. The device of claim 21, further comprising means for selecting one of a plurality of different operating modes, and means for controlling the switches to form different sets of the subcircuits based on the selected operating mode.

31. The device of claim 20, further comprising:

a third capacitor coupled between the first output node and a reference, wherein the first output voltage is generated across the third capacitor; and

a fourth capacitor coupled between the first output node and the reference, wherein the second output voltage is generated across the fourth capacitor,

wherein each of the subcircuits comprises a set of capacitors consisting essentially of the first pump capacitor, the second pump capacitor, and the third and fourth capacitors.

28. An implantable medical device comprising:

an implantable medical device housing;

medical device circuitry within the housing;

a battery, within the housing, that generates a dc input voltage; and

a dc-dc voltage conversion device, within the housing, comprising;

an input node to receive the dc input voltage at an input level;

an output node to output a dc output voltage at an output level different from the input level, wherein the dc output voltage provides operating power for at least some of the medical device circuitry,

a first pump capacitor and a second pump capacitor,

switches configured to selectively arrange only the first and second pump capacitors in at least three different subcircuits relative to the input node and the output node, wherein at least one of the subcircuits comprising a subcircuit in which the first and second pump capacitors are not coupled to the input node, and

a controller configured to control the switches to transition between at least three phases comprising the three different subcircuits to convert the dc input voltage at the input level at the input node to the dc output voltage at the output level at the output node, wherein the output level comprises at least one of 83%, 80%, 60%, 40%, 20%, or 17% of the input level.

29. The device of claim 28, further comprising a third capacitor coupled between the output node and a reference, wherein the output voltage is generated across the third capacitor, wherein each of the subcircuit configurations comprises a set of capacitors consisting essentially of the first pump capacitor, the second pump capacitor, and the third capacitor.

30. The device of claim 28, wherein:

the output node comprises a first output node to output a first dc output voltage at a first output level different from the input level, and a second output node to output a second dc output voltage at a second output level different from the input level,

the second output level is different from the first output level,

wherein the subcircuits are configured to convert the dc input voltage at the input level at the input node to the first dc output voltage at the first output level at the first output node and to the second dc output voltage at the second output level at the second output node, and

wherein the controller is configured to control the switches such that a ratio x of the first output level to the input level and a ratio y of the second output level to the input level, represented as a percentage value, is one of x/y equal to approximately 80%/60%, 83%/50%, 80%40%, 60%/40%, 60%/20%, or 40%/20%.

32. The device of claim 28, further comprising a mode selection module that selects one of a plurality of different operating modes, wherein the controller is configured to control the switches to form different sets of the subcircuits based on the selected operating mode.

33. A dc-dc voltage conversion device comprising:

an input node to receive a dc input voltage at an input level;

a first output node to output a first dc output voltage at a first output level different from the input level;

a second output node to output a second dc output voltage at a second output level different from the input level;

a set of capacitors consisting only of a first pump capacitor, a second pump capacitor, and a third pump capacitor;

switches configured to selectively arrange the set of capacitors in at least two different subcircuits relative to the input node and the output nodes, at least one of the subcircuits comprising a subcircuit in which the first, second, and third pump capacitors are not coupled to the input node; and

a controller configured to control the switches to transition between two phases comprising the two different subcircuits to convert the dc input voltage at the input level at the input node to the first output voltage at the first output level at the first output node and to the second output voltage at the second output level at the second output node, wherein the first output level comprises 80% of the input level and the second output level comprises 60% of the input level.

34. The device of claim 33, further comprising a fourth capacitor coupled between the first output node and a reference, wherein the first output voltage is generated across the fourth capacitor, and a fifth capacitor coupled between the second output node and a reference, wherein the second output voltage is generated across the fifth capacitor.

35. A dc-dc voltage conversion method comprising:

receiving, at an input node, a dc input voltage at an input level;

outputting, at a first output node, a first dc output voltage at a first output level;

outputting, at a second output node, a second dc output voltage at a second output level; and

selectively arranging a set of capacitors consisting only of a first pump capacitor, a second pump capacitor, and a third pump capacitor in at least two different subcircuits relative to the input node and the output nodes in two phases comprising the two different subcircuits to convert the dc input voltage at the input level at the input node to the first output voltage at the first output level at the first output node and to the second output voltage at the second output level at the second output node, wherein at least one of the subcircuits comprises a subcircuit in which the first, second, and third pump capacitors are not coupled to the input node, and wherein the first output level comprises 80% of the input level and the second output level comprises 60% of the input level.

36. The method of claim 35, further comprising:

generating the first output voltage across a fourth capacitor coupled between the first output node and a reference; and

generating the second output voltage across a fifth capacitor coupled between the second output node and a reference.

38. The device of claim 35, further comprising:

means for generating the first output voltage across a fourth capacitor coupled between the first output node and a reference; and

means for generating the second output voltage across a fifth capacitor coupled between the second output node and a reference.

37. A dc-dc voltage conversion device comprising:

means for receiving, at an input node, a dc input voltage at an input level;

means for outputting, at a first output node, a first dc output voltage at a first output level;

means for outputting, at a second output node, a second dc output voltage at a second output level; and

means for selectively arranging a set of capacitors consisting only of a first pump capacitor, a second pump capacitor, and a third pump capacitor in at least two different subcircuits relative to the input node and the output nodes in two phases comprising the two different subcircuits to convert the dc input voltage at the input level at the input node to the first output voltage at the first output level at the first output node and to the second output voltage at the second output level at the second output node, wherein at least one of the subcircuits comprises a subcircuit in which the first, second, and third pump capacitors are not coupled to the input node, and wherein the first output level comprises 80% of the input level and the second output level comprises 60% of the input level.

39. A dc-dc voltage conversion device comprising:

an input node to receive a dc input voltage at an input level;

a first output node to output a first dc output voltage at a first output level different from the input level;

a second output node to output a second dc output voltage at a second output level different from the input level and the first output level;

a first pump capacitor and a second pump capacitor;

switches configured to selectively arrange only the first and second pump capacitors in at least three different subcircuits relative to the input node and the first and second output nodes, wherein at least one of the subcircuits comprises a subcircuit in which the first and second pump capacitors are not coupled to the input node; and

a controller configured to control the switches to transition between at least three different phases to convert the dc input voltage at the input level at the input node to the first dc output voltage at the first output level at the first output node and to convert the dc input voltage at the input level at the input node to the second dc output voltage at the second output level at the second output node, wherein a ratio x of the first output level to the input level and a ratio y of the second output level to the input level, represented as a percentage value, is one of x/y equal to approximately 80%/60%, 83%/50%, 67%/50%, 80%40%, 75%/25%, 60%/40%, 60%/20%, 50%/33%, 50%/17%, or 40%/20%.