Method and apparatus for change pump circuit

• US 6,888,386 B2
• Filed: 04/23/2002
• Issued: 05/03/2005
• Est. Priority Date: 04/23/2002
• Status: Expired due to Fees

• Current Assignee: Winbond Electronics Corporation
• Original Assignee: Winbond Electronics Corporation
• Inventors: Peng, Yung-Chow
• Primary Examiner(s): Nguyen, Linh M.
• Application Number:
  US10/127,732
• Publication Number:
  US 20030197535A1
• Time in Patent Office: 1,106 Days
• Field of Search: 327/148, 327/150, 327/157, 327/159, 327/536, 327/537, 327/156, 331/17, 375/374
• US Class Current: 327/157
• CPC Class Codes: H03L 7/0895 Details of the current generators H03L7/0893 takes precedence
• CPC Class Codes: H03L 7/18 using a frequency divider or counter in the loop H03L7/20, H03L7/22 take precedence

Abstract

Charge-pumps consistent with this invention comprise a first transistor for sinking a current from an output node; a second transistor coupled between the first transistor and a ground node, wherein the second transistor interrupts the sinking current when the second transistor is turned off; and a current source to provide a turn-off current to a common node between the first transistor and the second transistor when the second transistor interrupts the sinking current. Charge-pump circuits consistent with this invention comprise a first transistor for sinking a current from an output node; a second transistor coupled between the first transistor and a ground node, wherein the second transistor interrupts the sinking current when the second transistor is turned off; and a clamping circuit to clamp a common node between the first transistor and the second transistor below a clamping voltage.

Claims

1. A charge-pump circuit comprising:

a first transistor for sinking a current from an output node;

a second transistor coupled in series with the first transistor and a power node, wherein the second transistor interrupts the sinking current when the second transistor is turned off;

a continuous current source to provide a turn-off current to a common node between the first transistor and the second transistor when the second transistor interrupts the sinking current; and

a clamping circuit to clamp the common node below a clamping voltage, wherein the clamping circuit comprises a metal-oxide-semiconductor (MOS) transistor with a source coupled to ground, a drain coupled to the common node, and a gate coupled to the common node.

2. The charge-pump circuit of claim 1, wherein the first transistor is a metal-oxide-semiconductor (MOS) transistor and the turn-off current is provided to a source node of the first transistor.

3. The charge-pump circuit of claim 1, wherein the first transistor is a metal-oxide-semiconductor (MOS) transistor and the turn-off current is provided to a source node of the first transistor.

27. The charge-pump circuit of claim 1, wherein the continuous current source provides a constant turn-off current.

4. A charge-pump circuit comprising:

a first transistor for sinking a current from an output node;

a second transistor coupled in series with the first transistor and a power node, wherein the second transistor interrupts the sinking current when the second transistor is turned off; and

a clamping circuit to clamp a common node between the first transistor and the second transistor below a clamping voltage when the second transistor interrupts the sinking current, wherein the clamping circuit comprises a metal-oxide-semiconductor (MOS) transistor with a source coupled to ground, a drain coupled to the common node, and a gate coupled to the common node.

5. A method for operating a charge-pump circuit, wherein the charge-pump circuit comprises a first transistor for sinking a current from an output node and a second transistor coupled in series with the first transistor and a power node, wherein the second transistor interrupts the sinking current when the second transistor is turned off, wherein the method comprises:

providing a continuous turn-off current to a common node between the first transistor and the second transistor for when the second transistor interrupts the sinking current; and

clamping the common node below a clamping voltage, wherein clamping uses a metal-oxide-semiconductor (MOS) transistor with a source coupled to ground, a drain coupled to the common node, and a gate coupled to the common node.

6. The method of claim 5, wherein the first transistor is a metal-oxide-semiconductor (MOS) transistor and the turn-off current is provided to a source node of the first transistor.

7. The method of claim 5, wherein the first transistor is a metal-oxide-semiconductor CMOS) transistor and the turn-off current is provided to a source node of the first transistor.

28. The method of claim 5, wherein the continuous turn-off current is constant.

8. A method for operating a charge-pump circuit having a first transistor for sinking a current from an output node and a second transistor coupled in series with the first transistor and a power node, wherein the second transistor interrupts the sinking current when the second transistor is turned off, wherein the method comprises:

clamping a common node between the first transistor and the second transistor below a clamping voltage when the second transistor interrupts the sinking current, wherein clamping uses a metal-oxide-semiconductor (MOS) transistor with a source coupled to ground, a drain coupled to the common node, and a gate coupled to the common node.

9. A charge-pump circuit comprising:

a first transistor to drive a current to an output node;

a second transistor coupled in series with the first transistor and a power supply, wherein the second transistor interrupts the driving current when the second transistor is turned off;

a continuous current source to provide a turn-off current to a common node between the first transistor and the second transistor when the second transistor interrupts the driving current; and

a clamping circuit to clamp the common node above a clamping voltage, wherein the clamping circuit comprises a metal-oxide-semiconductor (MOS) transistor with a source coupled to ground, a drain coupled to the common node, and a gate coupled to the common node.

10. The charge-pump circuit of claim 9, wherein the first transistor is a metal-oxide-semiconductor (MOS) transistor and the turn-off current is provided to a source of the MOS transistor.

11. The charge-pump circuit of claim 9, wherein the first transistor is a metal-oxide-semiconductor (MOS) transistor and the turn-off current is provided to a source of the MOS transistor.

29. The charge-pump circuit of claim 9, wherein the continuous current source provides a constant turn-off current.

12. A charge-pump circuit comprising:

a first transistor for driving a current to an output node;

a second transistor coupled in series with the first transistor and a power supply, wherein the second transistor interrupts the driving current when the second transistor is turned off; and

a clamping circuit to clamp a common node between the first transistor and the second transistor a clamping voltage when the second transistor interrupts the driving current, wherein the clamping circuit comprises a metal-oxide-semiconductor (MOS) transistor with a source coupled to ground, a drain coupled to the common node, and a gate coupled to the common node.

13. A method for operating a charge-pump circuit, wherein the charge-pump circuit comprises a first transistor for driving a current from an output node and a second transistor coupled in series with the first transistor and a power node, wherein the second transistor interrupts the driving current when the second transistor is turned off, wherein the method comprises:

providing a continuous turn-off current to a common node between the first transistor and the second transistor when the second transistor interrupts the driving current; and

clamping the common node to above a clamping voltage, wherein clamping uses a metal-oxide-semiconductor (MOS) transistor with a source coupled to ground, a drain coupled to the common node, and a gate coupled to the common node.

14. The method of claim 13, wherein the first transistor is a metal-oxide-semiconductor (MOS) transistor and the turn-off current is provided to a source node of the first transistor.

15. The method of claim 13, wherein the first transistor is a metal-oxide-semiconductor (MOS) transistor and the turn-off current is provided to a source node of the first transistor.

30. The method of claim 13, wherein the continuous turn-off current is constant.

16. A method for operating a charge-pump circuit having a first transistor for driving a current from an output node and a second transistor coupled in series with the first transistor and a power node, wherein the second transistor interrupts the driving current when the second transistor is turned off, wherein the method comprises:

clamping a common node between the first transistor and the second transistor above a clamping voltage when the second transistor interrupts the driving current, wherein clamping uses a metal-oxide-semiconductor (MOS) transistor with a source coupled to ground, a drain coupled to the common node, and a gate coupled to the common node.

17. An apparatus for operating a charge-pump circuit, wherein the charge-pump circuit comprises a first transistor for sinking a current from an output node and a second transistor coupled in series with the first transistor and a power node, wherein the second transistor interrupts the sinking current when the second transistor is turned off, wherein the apparatus comprises:

means for providing a continuous turn-off current to a common node between the first transistor and the second transistor when the second transistor interrupts the sinking current; and

means for clamping the common node below a clamping voltage, wherein the means for clamping uses a metal-oxide-semiconductor (MOS) transistor with a source coupled to ground, a drain coupled to the common node, and a gate coupled to the common node.

18. The apparatus of claim 17, wherein the first transistor is a metal-oxide-semiconductor (MOS) transistor and the turn-off current is provided to a source node of the first transistor.

19. The apparatus of claim 17, wherein the first transistor is a metal-oxide-semiconductor (MOS) transistor and the turn-off current is provided to a source node of the first transistor.

31. The apparatus of claim 17, wherein the continuous turn-off current is constant.

20. An apparatus for operating a charge-pump circuit having a first transistor for sinking a current from an output node and a second transistor coupled in series with the first transistor and a power node, wherein the second transistor interrupts the sinking current when the second transistor is turned off, wherein the apparatus comprises:

means for clamping a common node between the first transistor and the second transistor below a clamping voltage when the second transistor interrupts the sinking current, wherein the means for clamping uses a metal-oxide-semiconductor (MOS) transistor with a source coupled to ground, a drain coupled to the common node, and a gate coupled to the common node.

21. A phase-locked loop having a phase detector, a low pass filter, a voltage controlled oscillator, and a charge-pump circuit, wherein the charge pump circuit comprises:

a first transistor for sinking a current from an output node;

a second transistor coupled in series with the first transistor and a power node, wherein the second transistor interrupts the sinking current when the second transistor is turned off;

a continuous current source to provide a turn-off current to a common node between the first transistor and the second transistor when the second transistor interrupts the sinking current; and

a clamping circuit to clamp the common node below a clamping voltage, wherein the clamping circuit comprises a metal-oxide-semiconductor (MOS) transistor with a source coupled to ground, a drain coupled to the common node, and a gate coupled to the common node.

22. The phase-locked loop of claim 21, wherein the first transistor is a metal-oxide-semiconductor (MOS) transistor and the turn-off current is provided to a source node of the first transistor.

23. The phase-locked loop of claim 21, wherein the first transistor is a metal-oxide-semiconductor (MOS) transistor and the turn-off current is provided to a source node of the first transistor.

24. The phase-locked loop of claim 23, further including a divider circuit.

32. The phase-locked loop of claim 21, wherein the continuous current source provides a constant turn-off current.

25. A phase-locked loop having a phase detector, a low pass filter, a voltage controlled oscillator, and a charge-pump circuit, wherein the charge pump circuit comprises:

a first transistor for sinking a current from an output node;

a second transistor coupled in series with the first transistor and a power node, wherein the second transistor interrupts the sinking current when the second transistor is turned off; and

a clamping circuit to clamp a common node in series with the first transistor and the second transistor below a clamping voltage when the second transistor interrupts the sinking current, wherein the clamping circuit comprises a metal-oxide-semiconductor (MOS) transistor with a source coupled to ground, a drain coupled to the common node, and a gate coupled to the common node.

26. The phase-locked loop of claim 25, further including a divider circuit.