Level shifters, memory systems, and level shifting methods

• US 10,014,861 B2
• Filed: 05/02/2016
• Issued: 07/03/2018
• Est. Priority Date: 01/08/2014
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Luthra, Yogesh
• Primary Examiner(s): Ho, Hoai V
• Application Number:
  US15/144,421
• Publication Number:
  US 20160248424A1
• Time in Patent Office: 792 Days
• Field of Search: 36518911
• CPC Class Codes: G11C 11/4074 Power supply or voltage generation circuits, e.g. bias voltage generators, substrate voltage generators, back-up power, power control circuits
• CPC Class Codes: G11C 11/4093 Input/output [I/O] data interface arrangements, e.g. data buffers
• CPC Class Codes: G11C 13/0011 comprising conductive bridging RAM [CBRAM] or programming metallization cells [PMCs]
• CPC Class Codes: G11C 13/0023 Address circuits or decoders
• CPC Class Codes: G11C 13/0038 Power supply circuits
• CPC Class Codes: G11C 13/0069 Writing or programming circuits or methods
• CPC Class Codes: G11C 5/145 Applications of charge pumps; Boosted voltage circuits; Clamp circuits therefor G11C5/141 takes precedence
• CPC Class Codes: G11C 5/147 Voltage reference generators, voltage or current regulators; Internally lowered supply levels; Compensation for voltage drops G11C5/141 takes precedence
• CPC Class Codes: G11C 7/1084 Data input buffers, e.g. comprising level conversion circuits, circuits for adapting load
• CPC Class Codes: G11C 7/12 Bit line control circuits, e.g. drivers, boosters, pull-up circuits, pull-down circuits, precharging circuits, equalising circuits, for bit lines
• CPC Class Codes: H03K 19/0013 in field effect transistor circuits
• CPC Class Codes: H03K 19/018571 of complementary type, e.g. CMOS

Abstract

Level shifters, memory systems, and level shifting methods are described. According to one arrangement, a level shifter includes an input configured to receive an input signal in a first voltage domain, an output configured to output an output signal from the level shifter in a second voltage domain different than the first voltage domain, a plurality of pull-down devices, and wherein one of the pull-down devices is coupled with the input and the output, a plurality of cross-coupled devices coupled with the pull-down devices and configured to provide transitions in the output signal as a result of transitions in the input signal, a plurality of current limiting devices coupled with the cross-coupled devices and configured to limit a flow of current from a source to the cross-coupled devices, and a plurality of dynamic devices configured to selectively provide charging current from the source to the cross-coupled devices.

Claims

1. A level shifter comprising:

an input configured to receive an input signal in a first voltage domain;

first cross-coupled circuitry coupled with a source of electrical energy;

second cross-coupled circuitry coupled between the first cross-coupled circuitry and an output node; and

an output coupled with the output node and configured to output an output signal from the level shifter in a second voltage domain different than the first voltage domain and the output signal having transitions corresponding to transitions within the input signal.

2. The level shifter of claim 1 further comprising current limiting circuitry coupled in parallel with the first cross-coupled circuitry, and wherein the first cross-coupled circuitry is configured to conduct electrical energy to the second cross-coupled circuitry during transitions in the output signal.

3. The level shifter of claim 1 further comprising pull-down circuitry coupled with the input and the output node and configured to selectively conduct electrical energy from the output node to ground.

29. The level shifter of claim 1 wherein the first cross-coupled circuitry and the second cross-coupled circuitry are configured to conduct electrical current from the source to the output node.

30. The level shifter of claim 1 wherein a switching device of the first cross-coupled circuitry and a switching device of the second cross-coupled circuitry are coupled in series with one another between the source and the output node.

4. A level shifter comprising:

an input configured to receive an input signal in a first voltage domain;

an output configured to output an output signal in a second voltage domain, wherein the first and second voltage domains are different;

level shifter circuitry coupled with the input and the output and configured to generate the output signal having a plurality of transitions which correspond to a plurality of transitions in the input signal;

wherein the level shifter circuitry comprises a plurality of charging devices which are configured to conduct electrical energy in parallel to one output node which is coupled with the output to provide the transitions in the output signal;

wherein the level shifter circuitry comprises a pull-up circuit coupled with the charging devices and which is configured to conduct the electrical energy from the charging devices to provide the transitions in the output signal from a first state to a second state;

wherein the pull-up circuit comprises a plurality of first cross-coupled devices, and wherein the charging devices are configured to conduct the electrical energy from a source to the first cross-coupled devices; and

wherein the charging devices and one of the first cross-coupled devices are within a first circuit branch of the level shifter circuitry, and wherein one of the charging devices is a second cross-coupled device which is coupled with a third cross-coupled device which is within a second circuit branch of the level shifter circuitry.

5. The level shifter of claim 4 wherein the level shifter circuitry comprises a pull-down circuit which is configured to selectively conduct electrical energy from the output node which is coupled with the output to ground to provide the transitions in the output signal from the second state to the first state.

6. The level shifter of claim 5 wherein the pull-down circuit comprises a pull-down device which is directly coupled with the input and the output node.

7. The level shifter of claim 4 wherein the charging devices conduct the electrical energy in parallel from a common source.

8. The level shifter of claim 4 wherein the second voltage domain includes voltages within a voltage range which is greater than a voltage range of the first voltage domain.

9. The level shifter of claim 4 further comprising bias circuitry configured to provide a bias signal to another of the charging devices.

10. The level shifter of claim 4 wherein the one of the charging devices is configured to only conduct the electrical energy as a result of the transitions in the input signal.

11. The level shifter of claim 10 wherein another of the charging devices is configured to limit the conduction of the electrical energy from a source.

12. A level shifter comprising:

an input configured to receive an input signal in a first voltage domain;

an output configured to output an output signal in a second voltage domain, wherein the first and second voltage domains are different;

first cross-coupled circuitry coupled with a source;

second cross-coupled circuitry coupled between the first cross-coupled circuitry and the output; and

wherein the first cross-coupled circuitry and the second cross-coupled circuitry are configured to conduct electrical energy from the source to the output to provide a plurality of transitions in the output signal.

13. The level shifter of claim 12 wherein the first cross-coupled circuitry and the second cross-coupled circuitry are each configured to conduct the electrical energy from the source as a result of a plurality of transitions in the input signal.

14. The level shifter of claim 12 wherein the first cross-coupled circuitry and the second cross-coupled circuitry are coupled in series with one another between the source and the output.

15. The level shifter of claim 12 wherein the first cross-coupled circuitry and the second cross-coupled circuitry each include a switching device which is configured to selectively conduct the electrical energy from the source to the output.

16. The level shifter of claim 15 wherein the switching devices of the first and second cross-coupled circuitry are coupled in series between the source and the output.

17. The level shifter of claim 15 further comprising an additional switching device which is coupled in parallel with the switching device of the first cross-coupled circuitry, and wherein the additional switching device is configured to selectively conduct electrical energy from the source to the second cross-coupled circuitry.

18. The level shifter of claim 17 wherein the additional switching device and the switching device of the first cross-coupled circuitry are each configured to conduct the electrical energy from the source to the second cross-coupled circuitry as a result of a transition in the input signal.

19. The level shifter of claim 17 wherein the switching devices of the first and second cross-coupled circuitry and the additional switching device are within a first circuit branch, and wherein gates of the switching devices of the first and second cross-coupled circuitry are coupled with nodes in a second circuit branch.

20. The level shifter of claim 17 further comprising bias circuitry configured to provide a bias signal to the additional switching device.

21. The level shifter of claim 17 wherein the additional switching device is configured to limit the conduction of the electrical energy to the second cross-coupled circuitry.

22. The level shifter of claim 21 wherein the switching device of the first cross-coupled circuitry is configured to only conduct the electrical energy from the source as a result of a transition in the input signal.

23. The level shifter of claim 12 wherein the output signal includes the electrical energy conducted via the first and second cross-coupled circuitry.

24. The level shifter of claim 12 wherein the second cross-coupled circuitry comprises a pull-up circuit coupled with the output and the pull-up circuit is configured to conduct the electrical energy from the source to the output to provide the transitions in the output signal from a first state to a second state.

25. The level shifter of claim 24 further comprising a pull-down circuit configured to selectively conduct electrical energy from an output node which is coupled with the output to ground to provide transitions in the output signal from the second state to the first state.

26. The level shifter of claim 12 wherein the second voltage domain includes voltages within a voltage range which is greater than a voltage range of the first voltage domain.

27. The level shifter of claim 12 wherein a switching device of the first cross-coupled circuitry is configured to only conduct the electrical energy from the source as a result of transitions in the input signal.

28. The level shifter of claim 12 wherein the second cross-coupled circuitry is configured to conduct the electrical energy from the source to an output node coupled with the output.

31. The level shifter of claim 12 wherein the first cross-coupled circuitry and the second cross-coupled circuitry are configured to conduct the electrical energy from the source to the output at the same moment in time.