Method for reliably shutting off oscillator pulses to a charge-pump

• US 6,490,220 B1
• Filed: 08/13/2001
• Issued: 12/03/2002
• Est. Priority Date: 08/13/2001
• Status: Expired due to Term

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Batra, Shubneesh, Merritt, Todd A.
• Primary Examiner(s): Elms, Richard
• Assistant Examiner(s): LE, TOAN K
• Application Number:
  US09/927,373
• Time in Patent Office: 477 Days
• Field of Search: 365/226, 365/227, 365/189.09, 365/191, 365/194, 327/536, 327/390, 327/589, 307/110
• US Class Current: 365/226
• CPC Class Codes: G11C 5/145 Applications of charge pumps; Boosted voltage circuits; Clamp circuits therefor G11C5/141 takes precedence
• CPC Class Codes: H02M 1/0041 Control circuits in which a clock signal is selectively enabled or disabled
• 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

A multiple core charge pump includes a plurality of switches disposed between the taps of a delay chain and the individual charge pump cores. When the switches are closed, an oscillating clock signal is permitted to propagate through the delay chain and reach individual charge pump cores via the taps. A regulator senses the output voltage of the charge pump. When the output node reaches the desired voltage, the regulator simultaneously causes each of the switches to open, decoupling each of the charge pump cores from the taps of the delay chain, and preventing signals which are still propagating through the delay chain from triggering the charge pump cores. A transition detector may also be used to narrow the pulse width of the oscillating clock signal which is applied to each switch.

Claims

1. A charge pump comprising:

a plurality of charge pump cores, coupled to each other, for outputting a voltage signal having a boosted magnitude potential to an output node;

a plurality of switches, said plurality of switches receiving respectively delayed clock signals from an oscillator; and

a regulator for measuring the potential at the output node, said regulator controllably coupled to each of said plurality of switches and causing said each of said plurality of switches to open at the same time when the voltage at the output node has a magnitude which meets or exceeds a predetermined value.

2. The charge pump of claim 1, wherein the regulator causes each of said plurality of switches to close at the same time when the potential at the output node has a magnitude which is below the predetermined value.

3. The charge pump of claim 1, further comprising:

a plurality of latches, wherein the output of each of said plurality of switches is coupled a different one of the plurality of latches.

4. The charge pump of claim 3, wherein each of said plurality of latches is coupled a different one of said plurality of charge pump cores.

5. The charge pump of claim 1, further comprising:

a first plurality of delay elements, coupled to each other in series to form a delay chain and a second plurality of delay elements having a tap for supplying the delayed clock signals to said plurality of switches.

6. The charge pump of claim 1, further comprising:

a plurality of transition detectors, each of said plurality of transition detectors coupled to a different one of said plurality of switches, wherein each of said plurality of transition detectors reduces the pulse width of said delayed clock signals before said delayed clock signals are received by said plurality of switches.

7. The charge pump of claim 6, wherein said plurality of transition detectors are triggered by the trailing edges of the said delayed clock signals.

8. The charge pump of claim 6, wherein each of said plurality of transition detectors are triggered by the leading edges of said delayed clock signals.

9. A memory device comprising:

a memory array; and

a charge pump coupled to said memory array, said charge pump further comprising;

a plurality of charge pump cores, coupled to each other, for outputting a voltage signal having a boosted magnitude potential to an output node;

a plurality of switches, said plurality of switches receiving respectively delayed clock signals from an oscillator; and

a regulator for measuring the potential at the output node, said regulator controllably coupled to each of said plurality of switches and causing said each of said plurality of switches to open at the same time when the voltage at the output node has a magnitude which meets or exceeds a predetermined value.

10. The memory device of claim 9, wherein the regulator causes each of said plurality of switches to close at the same time when the potential at the output node has a magnitude which is below the predetermined value.

11. The memory device of claim 9, further comprising:

a plurality of latches, wherein the output of each of said plurality of switches is coupled a different one of the plurality of latches.

12. The memory device of claim 11, wherein each of said plurality of latches is coupled a different one of said plurality of charge pump cores.

13. The memory device of claim 9, further comprising:

a first plurality of delay elements, coupled to each other in series to form a delay chain and a second plurality of delay elements having a tap for supplying the delayed clock signals to said plurality of switches.

14. The memory device of claim 9, further comprising:

a plurality of transition detectors, each of said plurality of transition detectors coupled to a different one of said plurality of switches, wherein each of said plurality of transition detectors reduces the pulse width of said delayed clock signals before said delayed clock signals are received by said plurality of switches.

15. The memory device of claim 14, wherein said plurality of transition detectors are triggered by the trailing edges of the said delayed clock signals.

16. The memory device of claim 14, wherein each of said plurality of transition detectors are triggered by the leading edges of said delayed clock signals.

17. A processor system comprising:

a processor;

a memory coupled to said processor, said memory including a charge pump, said charge pump further comprising;

a plurality of charge pump cores, coupled to each other, for outputting a voltage signal having a boosted magnitude potential to an output node;

a plurality of switches, said plurality of switches receiving respectively delayed clock signals from an oscillator; and

a regulator for measuring the potential at the output node, said regulator controllably coupled to each of said plurality of switches and causing said each of said plurality of switches to open at the same time when the voltage at the output node has a magnitude which meets or exceeds a predetermined value.

18. The processor system of claim 17, wherein the regulator causes each of said plurality of switches to close at the same time when the potential at the output node has a magnitude which is below the predetermined value.

19. The processor system of claim 17, further comprising:

a plurality of latches, wherein the output of each of said plurality of switches is coupled a different one of the plurality of latches.

20. The processor system of claim 19, wherein each of said plurality of latches is coupled a different one of said plurality of charge pump cores.

21. The processor system of claim 17, further comprising:

a first plurality of delay elements, coupled to each other in series to form a delay chain and a second plurality of delay elements having a tap for supplying the delayed clock signals to said plurality of switches.

22. The processor system of claim 17, further comprising:

a plurality of transition detectors, each of said plurality of transition detectors coupled to a different one of said plurality of switches, wherein each of said plurality of transition detectors reduces the pulse width of said delayed clock signals before said delayed clock signals are received by said plurality of switches.

23. The processor system of claim 22, wherein said plurality of transition detectors are triggered by the trailing edges of the said delayed clock signals.

24. The processor system of claim 22, wherein each of said plurality of transition detectors are triggered by the leading edges of said delayed clock signals.

25. The processor system of claim 17, wherein said processor and said memory are integrated on a single semiconductor chip.

26. A method for operating a charge pump comprising the steps of:

supplying a plurality of delayed clock signals to respective cores of a charge pump via a plurality of switches; and

changing the state of each of said plurality of switches at the same time.

27. The method of claim 26, wherein said changing the state further comprising the steps of:

monitoring a voltage of an output signal of the charge pump; and

closing said plurality of switches at the same time when a magnitude of said voltage is below a predetermined value.

28. The method of claim 26, wherein said changing the state further comprises the steps of:

monitoring a voltage of an output of the charge pump; and

opening said plurality of switches at the same time when a magnitude of said voltage is equal to or above a predetermined value.

29. The method of claim 26, further comprising the step of:

reducing the pulse width of said plurality of delayed clock signals before the delayed clock signals arrive at the respective switches.

30. The method of claim 29, wherein said reducing is triggered at each trailing edge of a delayed clock signal.

31. The method of claim 30, wherein said reducing is triggered at each leading edge of a delayed clock signal.