Charge pump circuit incorporating corresponding parallel charge pump stages and method therefor

• US 7,023,260 B2
• Filed: 06/30/2003
• Issued: 04/04/2006
• Est. Priority Date: 06/30/2003
• Status: Expired due to Term

• Current Assignee: Innovative Memory Systems, Inc. (Wi-LAN Inc.)
• Original Assignee: Matrix Semiconductor, Inc. (Western Digital Corporation)
• Inventors: Scheuerlein, Roy E., Thorp, Tyler J.
• Primary Examiner(s): Tra, Quan
• Application Number:
  US10/610,315
• Publication Number:
  US 20040263238A1
• Time in Patent Office: 1,009 Days
• Field of Search: 327/536, 327/589, 363 59- 60
• US Class Current: 327/536
• CPC Class Codes: H02M 3/073 Charge pumps of the Schenkel-type
• CPC Class Codes: H02M 3/077 with parallel connected charge pump stages

Abstract

An improved charge pump circuit efficiently utilizes multiple charge pump stages to produce output voltages much larger than the power supply voltage by incorporating, in some embodiments, two parallel strings of series-coupled charge pump stages. Each corresponding charge pump stage in one string is controlled at least by a node in the corresponding charge pump stage of the other string.

Claims

1. A charge pump circuit for generating a boosted voltage, said circuit comprising:

two charge pump stages coupled other than in series with each other, each stage respectively including

an input and an output;

a charge transfer switch (CTS) coupling the input to the output, and having a control terminal for controlling opening and closing the CTS;

a control circuit having an output coupled to the control terminal; and

a charge pump capacitor coupled to the output of the stage;

wherein the control circuit for each pump stage is respectively coupled to the output of the pump stage and to the output of the other pump stage.

2. The charge pump circuit, as recited in claim 1, wherein the control circuit for one charge pump stage is configured to couple the CTS control terminal for the one charge pump stage to:

the output of the other charge pump stage to turn on the CTS for the one charge pump stage; and

the input of the one charge pump stage to turn off the CTS for the one charge pump stage.

3. The charge pump circuit, as recited in claim 2, wherein the control circuit for the other charge pump stage is configured to couple the CTS control terminal for the other charge pump stage to:

the output of the one charge pump stage to turn on the CTS for the other charge pump stage; and

the input of the other charge pump stage to turn off the CTS for the other charge pump stage.

4. The charge pump circuit, as recited in claim 2, wherein the control circuit for said one charge pump stage comprises:

a first transistor, responsive to the output of said one charge pump stage, for coupling the CTS control terminal for the one charge pump stage to the output of the other charge pump stage; and

a second transistor, responsive to the output of said one charge pump stage, for coupling the CTS control terminal for the one charge pump stage to the input of said one charge pump stage.

5. The charge pump circuit, as recited in claim 1, wherein each of the pair of charge pump stages has a substantially equal average voltage coupled to its respective input.

9. The charge pump circuit, as recited in claim 1, further comprising an output circuit for combining a respective boosted voltage signal on the respective output of each of a pair of charge pump stages onto a single output node for the charge pump circuit.

10. The charge pump circuit, as recited in claim 9, wherein the output circuit comprises at least a pair of cross-coupled PMOS devices.

11. The charge pump circuit, as recited in claim 9, wherein the output circuit comprises at least a pair of cross-coupled NMOS devices.

12. The charge pump circuit, as recited in claim 1, comprising NMOS CTS devices.

13. The charge pump circuit, as recited in claim 1, comprising PMOS CTS devices.

14. The charge pump circuit, as recited in claim 1, further comprising a second pair of charge pump stages, each of said second pair connected in series with an associated one of the first-mentioned two charge pump stages, each stage of said second pair respectively including:

an input and an output;

a charge transfer switch (CTS) coupling the input to the output, and having a control terminal for controlling opening and closing the CTS;

a control circuit having an output coupled to the control terminal; and

a charge pump capacitor coupled to the output of the stage;

wherein the control circuit for each pump stage of the second pair of charge pump stages is respectively coupled to the output of the pump stage and to the output of the other pump stage of the second pair.

15. The charge pump circuit, as recited in claim 14, comprising charge pump stages having N-channel CTS devices, and wherein the input of at least one charge pump stage is coupled to receive a supply voltage more positive than at least another supply voltage for the charge pump circuit.

16. The charge pump circuit, as recited in claim 15, further comprising an output circuit for combining a respective boosted voltage signal on the respective output of each of a pair of charge pump stages onto a single output node for the charge pump circuit, said output circuit comprising at least a pair of cross-coupled PMOS devices.

17. The charge pump circuit, as recited in claim 14, comprising charge pump stages having P-channel CTS devices, and wherein the input of at least one charge pump stage is coupled to receive a supply voltage more negative than at least another supply voltage for the charge pump circuit.

18. The charge pump circuit, as recited in claim 17, further comprising an output circuit for combining a respective boosted voltage signal on the respective output of each of a pair of charge pump stages onto a single output node for the charge pump circuit, said output circuit comprising at least a pair of cross-coupled NMOS devices.

19. The charge pump circuit, as recited in claim 14, wherein:

corresponding pairs of charge pump stages are driven by substantially complementary pulse signals; and

adjacent series-connected charge pump stages are driven by substantially complementary pulse signals.

20. The charge pump circuit, as recited in claim 19, further comprising means for recycling charge between the substantially complementary pulse signals driving a corresponding pair of charge pump stages.

21. The charge pump circuit, as recited in claim 20, wherein the means for recycling charge comprises a charge recycling circuit for coupling at least a pair of complementary pulses together during at least a portion of a pulsing cycle.

22. The charge pump circuit of claim 1, embodied in an integrated circuit including a three-dimensional memory array.

23. The charge pump circuit of claim 1 embodied in computer readable descriptive form suitable for use in design, test or fabrication of an integrated circuit.

53. The charge pump circuit, as recited in claim 16, wherein, for each respective one of the first-mentioned two charge pump stages, the respective control circuit is configured to couple the respective CTS control terminal for one respective charge pump stage to:

the output of the other respective charge pump stage to turn on the CTS for the one respective charge pump stage; and

the input of the one respective charge pump stage to turn off the CTS for the one respective charge pump stage.

6. A charge pump circuit for generating a boosted voltage, said circuit comprising:

two charge pump stages coupled other than in series with each other, each stage respectively including

an input and an output;

a charge transfer switch (CTS) coupling the input to the output, and having a control terminal for controlling opening and closing the CTS;

a control circuit having an output coupled to the control terminal; and

a charge pump capacitor coupled to the output of the stage;

wherein the control circuit for each pump stage is respectively coupled to the output of the pump stage and to a node of the other pump stage;

wherein at least one pump stage further comprises a startup device connected in parallel with its CTS.

7. The charge pump circuit, as recited in claim 6, wherein at least one charge pump stage comprises a diode-connected transistor startup device.

8. The charge pump circuit, as recited in claim 6, wherein at least one charge pump stage comprises a diode startup device.

24. A charge pump circuit for generating a boosted voltage, said circuit comprising a pair of charge pump stages having a substantially equal average voltage on respective input nodes thereof, each charge pump stage of the pair including a respective charge transfer switch (CTS) having a control terminal for controlling opening and closing the CTS, which control terminal is responsive to an output of the charge pump stage and responsive to an output node of the other charge pump stage of the pair.

25. The charge pump circuit, as recited in claim 24, wherein the respective input nodes of each charge pump stage of the pair are not coupled together.

26. The charge pump circuit, as recited in claim 24, wherein each charge pump stage includes a control circuit for controlling the CTS of the stage, said control circuit including:

an output coupled to the CTS;

a timing input coupled to an output of the charge pump stage; and

a first voltage input coupled to an output of the other charge pump stage.

27. The charge pump circuit, as recited in claim 26, wherein said control circuit for each charge pump stage further comprises a second voltage input coupled to the input of the stage.

28. The charge pump circuit, as recited in claim 27, wherein said control circuit for each charge pump stage comprises an NMOS device and a PMOS device having respective gate terminals both coupled to the timing input for the control circuit.

29. The charge pump circuit of claim 24, embodied in an integrated circuit including a three-dimensional memory array.

30. The charge pump circuit of claim 24 embodied in computer readable descriptive form suitable for use in design, test or fabrication of an integrated circuit.

31. A circuit for generating a boosted voltage, said circuit comprising a pair of multi-stage series-connected charge pumps, each of said pair having substantially symmetrical inter-coupled corresponding charge pump stages, each charge pump stage including a respective charge transfer switch control circuit having a control terminal for controlling opening and closing the CTS, which control terminal is responsive to an output of the charge pump stage and responsive to a node of a corresponding charge pump stage;

wherein corresponding charge pump stages are cross-coupled whereby each charge pump stage comprises a first respective node which is coupled to a second respective node of a corresponding charge pump stage; and

wherein the respective first node of each stage is an output node of the stage.

32. The circuit, as recited in claim 31, wherein pulse signals associated with corresponding stages are substantially out of phase.

35. The circuit of claim 31, embodied in an integrated circuit including a three-dimensional memory array.

36. An integrated circuit comprising a plurality of memory sub-arrays, each sub-array associated with a respective circuit for generating a boosted voltage as recited in claim 31.

37. The integrated circuit, as recited in claim 36, wherein the plurality of memory sub-arrays comprises a three-dimensional memory array having at least two memory planes disposed above a substrate.

38. The integrated circuit, as recited in claim 37, wherein each respective circuit for generating a boosted voltage is disposed beneath its associated sub-array.

39. The circuit of claim 31 embodied in computer readable descriptive form suitable for use in design, test or fabrication of an integrated circuit.

51. The circuit, as recited in claim 31, wherein corresponding charge pump stages are other than cross-coupled whereby each charge pump stage comprises a first respective node which is coupled to a second respective node of a corresponding charge pump stage.

52. The circuit, as recited in claim 51, wherein the respective first node of each charge pump stage is an output node of the charge pump stage.

33. A circuit for generating a boosted voltage, said circuit comprising:

a pair of multi-stage series-connected charge pumps, each of said pair having substantially symmetrical inter-coupled corresponding charge pump stages, each charge pump stage including a respective charge transfer switch control circuit which is responsive to an output of the charge pump stage and responsive to a node of a corresponding charge pump stage; and

at least one multi-stage series-connected charge pump having at least one stage closer to an output thereof which includes a smaller pump capacitor than that of a stage more distant from said output.

34. The circuit, as recited in claim 33, comprising a plurality of series-connected charge pump stages which are each sized proportionally smaller than its preceding stage.

40. A method for generating a boosted voltage, said method comprising the steps of:

providing at least two multi-stage series-connected charge pump circuits having substantially symmetrical inter-coupled corresponding charge pump stages, each charge pump stage including a charge transfer switch coupling an input thereof to an output thereof, and including a pump capacitor coupled to the output thereof; and

controlling opening and closing the charge transfer switch in each charge pump stage of one series-connected charge pump circuit responsive at least to its own output and to the output of the corresponding charge pump stage in the other series-connected charge pump circuit.

41. The method, as recited in claim 40, further comprising:

driving corresponding charge pump stages in both series-connected charge pump circuits with substantially complementary pulse signals; and

driving adjacent series-connected charge pump stages in each charge pump circuit with substantially complementary pulse signals.

42. The method, as recited in claim 40, further comprising coupling a control terminal for the charge transfer switch in at least one charge pump stage to:

the output of the corresponding charge pump stage in the other series-connected charge pump circuit to turn on the charge transfer switch; and

the input of said at least one charge pump stage to turn off the charge transfer switch.

43. The method, as recited in claim 40, further comprising combining the respective output signal from the respective last charge pump stage of both series-connected charge pump circuits to generate a single output conveying the boosted voltage.

44. An integrated circuit comprising:

at least two multi-stage series-connected charge pump circuits having substantially symmetrical inter-coupled corresponding charge pump stages, each charge pump stage including a charge transfer switch coupling an input thereof to an output thereof, and including a pump capacitor coupled to the output thereof; and

means for controlling opening and closing the charge transfer switch in each charge pump stage of one series-connected charge pump circuit responsive at least to its own output and to the output of the corresponding charge pump stage in the other series-connected charge pump circuit.

45. The integrated circuit, as recited in claim 44, further comprising:

means for driving corresponding charge pump stages in both series-connected charge pump circuits with substantially complementary pulse signals; and

means for driving adjacent series-connected charge pump stages in each charge pump circuit with substantially complementary pulse signals.

46. The integrated circuit, as recited in claim 44, wherein said means for controlling opening and closing the charge transfer switch in at least one charge pump stage comprises:

means for coupling a control terminal for the charge transfer switch to the output of the corresponding charge pump stage in the other series-connected charge pump circuit to turn on the charge transfer switch; and

means for coupling the control terminal for the charge transfer switch to the input of said at least one charge pump stage to turn off the charge transfer switch.

47. The integrated circuit, as recited in claim 44, further comprising means for combining the respective output signal from the respective last charge pump stage of both series-connected charge pump circuits to generate a single output conveying the boosted voltage.

48. The integrated circuit, as recited in claim 44, further comprising a three-dimensional memory array having at least two memory planes disposed above a substrate.

49. The integrated circuit of claim 44 embodied in computer readable descriptive form suitable for use in design, test or fabrication of the integrated circuit.

50. A circuit for generating a boosted voltage, said circuit comprising:

a first, second, third, and fourth multi-stage series-connected charge pumps, each having inter-coupled corresponding charge pump stages, each charge pump stage within a multi-stage series-connected charge pump including a respective charge transfer switch control circuit which is responsive to an output of the charge pump stage and responsive to a node of a corresponding charge pump stage within a different multi-stage series-connected charge pump; and

wherein each charge pump stage of the first multi-stage series-connected charge pump comprises a first respective node which is coupled to a second respective node of a corresponding charge pump stage within the second multi-stage series-connected charge pump; and

further comprises a second respective node which is coupled to a first respective node of a corresponding charge pump stage within the third multi-stage series-connected charge pump.