Switched-capacitor converters with low-voltage gate drivers

• US 9,502,968 B2
• Filed: 05/13/2014
• Issued: 11/22/2016
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: pSemi Corporation (Murata Manufacturing Co Limited)
• Original Assignee: Arctic Sand Technologies, Inc. (Murata Manufacturing Co Limited)
• Inventors: Giuliano, David, Szczeszynski, Gregory, Barrett, Raymond Jr.
• Primary Examiner(s): Jackson, LaKaisha
• Application Number:
  US14/276,426
• Publication Number:
  US 20140327479A1
• Time in Patent Office: 924 Days
• Field of Search: 363/59, 363/60, 327/536, 257/299
• US Class Current: 1/1
• CPC Class Codes: H02M 1/088 for the simultaneous control of series or parallel connected semiconductor devices
• CPC Class Codes: H02M 3/07 using capacitors charged and discharged alternately by semiconductor devices with control electrode , e.g. charge pumps
• CPC Class Codes: H02M 3/073 Charge pumps of the Schenkel-type

Abstract

An apparatus for converting voltage includes terminals coupled to external circuits at corresponding voltages and a switching network having driving circuits and semiconductor switches that interconnect capacitors in successive states to one another and to the terminals. The switches interconnect some capacitors to one another through a series of switches when an activation pattern causes them to be activated. Each driving circuit has power connections, a control input, and a drive output coupled to and controlling at least one switch. A drive output of one of them couples to and drives each switch. Some of the driving circuits are powered via corresponding power connections from at least one of the capacitors such that a voltage across the corresponding power connections is less than a highest of the corresponding voltages. The terminals and the switching network are constituents of a switched capacitor converter.

Claims

1. A switched capacitor power converter comprising a first terminal for coupling to a first external circuit at substantially a high voltage, a second terminal for coupling to a second external circuit at substantially a low voltage that is less than said high voltage in magnitude, a first plurality of active semiconductor switch elements configured to transition between first and second states that result in corresponding first and second electrical interconnections between capacitors and at least one of said first and second terminals, wherein, in said first state, first and second switch elements from said plurality of switch elements, when closed, define a DC current path between said first and second switch elements and connect at least some of said capacitors to one another, a plurality of switch-driving circuits, each switch element coupled to and for control by a drive output of one of said switch-driving circuits each switch-driving circuit having a control input, power connections, and a drive output coupled to and for control of one or more of said switch elements, wherein at least some switch-driving circuits are configured to be powered via said power connections of said switch-driving circuits from one or more of said capacitors such that a voltage across said power connections of said switch-driving circuit is substantially less than said high voltage.

2. The switched capacitor power converter of claim 1, further comprising a plurality of capacitors coupled to said first plurality of switch elements controllably coupled via said switch elements.

3. The switched capacitor power converter of claim 1, further comprising a plurality of terminals coupled to said first plurality of switch elements for connecting to said capacitors.

4. The switched capacitor power converter of claim 1, wherein said converter is configured to provide time varying voltages relative to said low voltage to at least some of said switch-driving circuits.

5. The switched capacitor power converter of claim 1, wherein each switch element has a maximum voltage rating that is less than said high voltage.

6. The switched capacitor power converter of claim 5, wherein said voltage across said power connections of said switch-driving circuit is configured to be driven from said capacitors with less than or substantially equal to two times said low voltage.

7. The switched capacitor power converter of claim 1, wherein each switch element in said series of multiple ones of said switch elements is driven by a corresponding switch-driving circuit, each of said switch-driving circuits being configured to be powered via said power connections of said switch-driving circuits from different capacitors of said plurality of capacitors that in operation have different voltages.

8. The apparatus of claim 1, wherein said switch elements are configured to permit conduction current to flow between said capacitors to one another through a series of multiple ones of said switch elements.

9. The apparatus of claim 1, wherein each capacitor in said at least some capacitors comprises a first terminal and a second terminal, wherein said first terminal is at a higher voltage than said second terminal, wherein said at least some capacitors comprise a first capacitor and a second capacitor, and wherein said multiple ones of said switch elements connect a first terminal of said first capacitor to a first terminal of said second capacitor.

10. The apparatus of claim 9, wherein said second terminal of said first capacitor is connected to a first phase voltage, wherein said second terminal of said second capacitor is connected to a second phase voltage, and wherein said first phase voltage is different from said second phase voltage.

11. The apparatus of claim 1, wherein said multiple ones of said switch elements connect higher voltage terminals of capacitors to each other.

12. The apparatus of claim 1, further comprising a pre-charge circuit connected to at least some of said capacitors.

13. An apparatus for converting voltage, said apparatus comprising first and second terminals and a switching network, said switching network comprising switch-driving circuits, and switch elements, wherein said first and second terminals are configured for coupling to corresponding first and second external circuits at corresponding first and second voltages, wherein said switch elements electrically interconnect capacitors to form a switched-capacitor network, wherein said switch elements electrically interconnect said capacitors in successive states to one another and to said terminals, wherein a first successive state is associated with a first switch-activation pattern and a second successive state is associated with a second switch-activation pattern, wherein in said first switch-activation pattern, all switches in a first subset of said switch elements are closed and all switches in a second subset of said switch elements are open, wherein in said second switch-activation pattern, all switches in said second subset of said switch elements are closed and all switches in said first subset of said switch elements are open, wherein said switch elements comprise first and second switch elements that are in series and in said first subset, wherein each switch-driving circuit comprises power connections, a control input, and a drive output coupled to and for control of one of said switch elements, wherein said switch-driving circuits comprise a first switch-driving circuit that is configured to be powered via corresponding first and second power connections, wherein said first power connection is coupled to one of said capacitors such that a voltage difference between said first and second power connections is less than a highest of said first and second voltages, and wherein said first and second terminals and said switching network are constituents of a switched-capacitor converter.

14. The apparatus of claim 13, wherein, when said switch elements are configured according to said first switch-activation pattern, said first and second switch elements interconnect some of said capacitors to one another.

15. The apparatus of claim 13, wherein said switched-capacitor converter is configured to provide, to said switch-driving circuits, time-varying voltages relative to a lowest of said corresponding voltages.

16. The apparatus of claim 13, wherein each switch element has a maximum voltage rating that is less than a particular voltage, wherein said particular voltage is a highest of said first and second voltages.

17. The apparatus of claim 13, wherein a voltage across said first and second power connections of said switch-driving circuit is less than or equal to a particular voltage, wherein said particular voltage is twice the lowest of said first and second voltages.

18. An apparatus for converting voltage, said apparatus comprising terminals and a switching network, said switching network comprising switch-driving circuits and switch elements, wherein said terminals are configured for coupling to corresponding external circuits at corresponding voltages, wherein said switch elements comprise active semiconducting-elements that electrically interconnect capacitors to form a switched-capacitor network that is configured to transition between successive states, wherein said switch elements electrically interconnect said capacitors in said successive states to one another and to said terminals, thereby defining a plurality of charge-transfer paths, each of which extends between said terminals, for facilitating charge transfer therebetween, wherein each switch-driving circuit comprises a drive output, power connections, and a control input, wherein each drive output is coupled to and controls one of said switch elements, wherein said plurality of charge transfer paths comprises a first charge transfer path and a second charge transfer path, wherein said switch-driving circuits comprise a first switch-driving circuit that controls a switch element that is a constituent element of said first charge-transfer path, wherein said first switch-driving circuit is powered via said power connections thereof by charge stored on a capacitor that is a constituent element of said second charge-transfer path, and wherein said terminals and said switching network are constituents of a switched-capacitor converter.

19. The apparatus of claim 18, wherein said switch-driving circuits comprise a first switch-driving circuit, wherein said first switch-driving circuit is configured to be powered via power connections thereof from charge stored in a capacitor set such that a voltage across said power connections is substantially less than a particular voltage, wherein said particular voltage is a highest of said corresponding voltages.

20. The apparatus of claim 18, further comprising capacitors coupled to said switch elements, wherein connections between said capacitors are controlled by said switch elements.

21. The apparatus of claim 18, wherein said terminals comprise capacitor terminals coupled to corresponding ones of said switch elements for connecting to said capacitors.

22. The apparatus of claim 18, wherein said switched-capacitor converter is configured to provide, to at least some of said switch-driving circuits, time-varying voltages relative to a lowest of said corresponding voltages.

23. The apparatus of claim 18, wherein each switch element has a maximum voltage rating that is less than a highest of said corresponding voltages.

24. The apparatus of claim 23, wherein said switch-driving circuits comprise a first switch-driving circuit, wherein said first switch-driving circuit comprises first and second power connections, wherein, in operation, a voltage difference exists across said first and second power connections, wherein said voltage difference arises at least in part from a capacitor that is connected to said first power connection, wherein said voltage difference is less than or equal to a particular voltage, wherein said particular voltage is less than or substantially equal to twice a lowest of said corresponding voltages.

25. The apparatus of claim 18, wherein said switch-driving circuits comprise a first switch-driving circuit and a second switch-driving circuit, wherein said switch elements comprise a first switch-element and a second switch-element, wherein said first switch-element is driven by said first switch-driving circuit, wherein said first switch-driving circuit is configured to be powered by a first capacitor that has a first voltage, wherein said second switch-element is driven by said second switch-driving circuit, wherein said second switch-driving circuit is configured to be powered by a second capacitor that has a second voltage, and wherein said first voltage is different from said second voltage.

26. The apparatus of claim 18, further comprising a phase generator, wherein said phase generator comprises phase-generator switch elements, wherein said phase generator is configured to provide a time-varying voltage level to one terminal of each of said capacitors, wherein said phase generator is configured to generate a voltage level for a capacitor in said first charge-transfer path using a voltage from a capacitor in said second charge-transfer path.

27. The apparatus of claim 18, wherein said switch elements comprise a first switch element and a second switch element, wherein said second switch element is in series with said first switch element, wherein, in operation, said first and second switches transition into a state in which said first and second switch elements permit a steady flow of charge between capacitors.

28. The apparatus of claim 18, wherein each switch element has a maximum voltage rating that is less than a highest of said corresponding voltages.

29. The apparatus of claim 18, wherein said switched-capacitor converter comprises a cascade-multiplier network.

30. The apparatus of claim 18, wherein said switched-capacitor converter comprises a series-parallel switched-capacitor network.

31. The apparatus of claim 18, further comprising a pre-charge circuit connected to said switched-capacitor network.

32. The apparatus of claim 31, wherein said pre-charging circuit is configured to initialize voltages on capacitors in said switched-capacitor network prior to clocked operation of said switched-capacitor network.

33. A method for converting a first voltage into a second voltage, said method comprising connecting a first terminal of a switched-capacitor power converter to a first external circuit, said switched-capacitor power converter comprising a switched-capacitor network in which capacitors are selectively interconnected by active semiconductor-switches, connecting a second terminal of said switched-capacitor power converter to a second external circuit, providing first control-signals to control inputs of switch-driving circuitry of said power converter, wherein said first control-signals cause first drive-signals at corresponding drive-outputs of said switch-driving circuitry, wherein said first drive-signals cause said active semiconductor-switches to execute a first switch-activation pattern, providing second control-signals to control inputs of said switch-driving circuitry, wherein said second control-signals cause second drive-signals at corresponding drive-outputs of said switch-driving circuitry, wherein said second drive-signals cause said active semiconductor-switches to execute a second switch-activation pattern, and providing power to said switch-driving circuitry through power connections thereof, said power being provided by capacitors from said switched-capacitor network, wherein, in said first switch-activation pattern, a first series of active semiconductor-switches connect first and second capacitors in said switched-capacitor network of said power converter so as to permit conduction current to flow between high-voltage terminals of first and second capacitors, wherein providing said power comprises causing a voltage across said power connections to be less than a highest of said first and second voltages.