Device and method for generating a low-voltage reference

• US 20070030053A1
• Filed: 08/04/2005
• Published: 02/08/2007
• Est. Priority Date: 08/04/2005
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Pan, Dong, Blodgett, Grey
• Granted Patent: US 7,256,643 B2
• Time in Patent Office: Days
• US Class Current: 327/539
• CPC Class Codes: G05F 3/30 Regulators using the difference between the base-emitter voltages of two bipolar transistors operating at different current densities G05F3/26 takes precedence

Abstract

A voltage reference generating method, source, memory device and substrate containing the same include a voltage reference generator comprised of a bandgap voltage reference circuit including a first complementary-to-absolute-temperature (CTAT) signal and a second complementary-to-absolute-temperature (CTAT) signal. The voltage reference generator further includes a differential sensing device for generating a reference signal substantially insensitive to temperature variations over an operating temperature range by differentially sensing the first and second CTAT signals. The method includes generating first and second complementary-to-absolute-temperature (CTAT) signals and generating a reference signal that is substantially insensitive to temperature variations over an operating temperature range.

Claims

1. A voltage reference generator, comprising:

a bandgap voltage reference circuit including a first complementary-to-absolute-temperature (CTAT) signal and a second complementary-to-absolute-temperature (CTAT) signal; and

a differential sensing device for generating a reference signal substantially insensitive to temperature variations over an operating temperature range from sensing the first and second CTAT signals.

2. The voltage reference generator of claim 1, wherein at least one of the first and second CTAT signals are configured to be sensitive to temperature variations over the operating temperature range.

3. The voltage reference generator of claim 1, wherein the differential sensing device is further configured to scale at least one of the first and second CTAT signals so both the first and second CTAT signals exhibit substantially equivalent variations over the operating temperature range.

4. The voltage reference generator of claim 1, further comprising a buffer configured to condition at least one of the first and second CTAT signals for coupling with the differential sensing device

5. The voltage reference generator of claim 1, wherein at least one of the first and second CTAT signals includes a nonzero temperature coefficient.

6. The voltage reference generator of claim 1, wherein the reference signal is at a level below ground potential over the operating temperature range.

7. A memory device, comprising:

a memory array; and

a voltage reference generator configured to facilitate data retention with the memory array, including;

a bandgap voltage reference circuit including a first complementary-to-absolute-temperature (CTAT) signal and a second complementary-to-absolute-temperature (CTAT) signal; and

a differential sensing device for generating a reference signal substantially insensitive to temperature variations over an operating temperature range from sensing the first and second CTAT signals.

8. The memory device of claim 7, wherein at least one of the first and second CTAT signals are configured to be sensitive to temperature variations over the operating temperature range.

9. The memory device of claim 7, wherein the differential sensing device is further configured to scale at least one of the first and second CTAT signals so both the first and second CTAT signals exhibit substantially equivalent variations over the operating temperature range.

10. The memory device of claim 7, further comprising a buffer configured to condition at least one of the first and second CTAT signals for coupling with the differential sensing device.

11. The memory device of claim 7, wherein at least one of the first and second CTAT signals includes a nonzero temperature coefficient.

12. The memory device of claim 7, wherein the reference signal is at a level below ground potential over the operating temperature range.

13. The memory device of claim 7, wherein the reference signal couples to at least one inactive word line of the memory array.

14. An electronic system comprising an input device, an output device, a memory device, and a processor device coupled to the input, output, and memory devices, at least one of the input, output, memory, and processor devices including a memory cell including at least one word line coupled to a voltage reference generator, comprising:

a bandgap voltage reference circuit including a first complementary-to-absolute-temperature (CTAT) signal and a second complementary-to-absolute-temperature (CTAT) signal; and

a differential sensing device for generating a reference signal substantially insensitive to temperature variations over an operating temperature range from sensing the first and second CTAT signals.

15. The electronic system of claim 14, wherein at least one of the first and second CTAT signals are configured to be sensitive to temperature variations over the operating temperature range.

16. The electronic system of claim 14, wherein the differential sensing device is further configured to scale at least one of the first and second CTAT signals so both the first and second CTAT signals exhibit substantially equivalent variations over the operating temperature range.

17. The electronic system of claim 14, further comprising a buffer configured to condition at least one of the first and second CTAT signals for coupling with the differential sensing device.

18. The electronic system of claim 14, wherein at least one of the first and second CTAT signals includes a nonzero temperature coefficient.

19. The electronic system of claim 14, wherein the reference signal is at a level below ground potential over the operating temperature range.

20. A semiconductor substrate on which is fabricated a memory device, comprising:

an array of memory cells; and

a voltage reference generator configured to facilitate data retention with the memory array, including;

a bandgap voltage reference circuit including a first complementary-to-absolute-temperature (CTAT) signal and a second complementary-to-absolute-temperature (CTAT) signal; and

a differential sensing device for generating a reference signal substantially insensitive to temperature variations over an operating temperature range from sensing the first and second CTAT signals.

21. The semiconductor substrate of claim 20, wherein at least one of the first and second CTAT signals are configured to be sensitive to temperature variations over the operating temperature range.

22. The semiconductor substrate of claim 20, wherein the differential sensing device is further configured to scale at least one of the first and second CTAT signals so both the first and second CTAT signals exhibit substantially equivalent variations overt the operating temperature range.

23. The semiconductor substrate of claim 20, further comprising a buffer configured to condition at least one of the first and second CTAT signals for coupling with the differential sensing device.

24. The semiconductor substrate of claim 20, wherein at least one of the first and second CTAT signals includes a nonzero temperature coefficient.

25. The semiconductor substrate of claim 20, wherein the reference signal is at a level below ground potential over the operating temperature range.

26. The semiconductor substrate of claim 20, wherein the reference signal couples to at least one inactive word line of the array of memory cells.

27. A method for generating a reference signal, comprising:

generating a first complementary-to-absolute-temperature (CTAT) signal;

generating a second complementary-to-absolute-temperature (CTAT) signal; and

generating the reference signal substantially insensitive to temperature variations over an operating temperature range from differentially sensing the first and second CTAT signals.

28. The method of claim 27, wherein at least one of the first and second CTAT signals are configured to be sensitive to temperature variations over the operating temperature range.

29. The method of claim 27, further comprising scaling at least one of the first and second CTAT signal so both the first and second CTAT signals exhibit substantially equivalent variations over the operating temperature range.

30. The method of claim 27, further comprising buffering at least one of the first and second CTAT signals for coupling with the differential sensing device.

31. The method of claim 27, wherein at least one of the first and second CTAT signals includes a nonzero temperature coefficient.

32. The method of claim 27, wherein generating the reference signal includes generating the reference signal at a level below ground potential over the operating temperature range.