Device and method for generating a low-voltage reference

• US 20070159238A1
• Filed: 02/27/2007
• Published: 07/12/2007
• Est. Priority Date: 08/04/2005
• Status: Active Grant

• Current Assignee: Greg Blodgett, Pascal David
• Original Assignee: Greg Blodgett, Pascal David
• Inventors: Blodgett, Greg, Pan, Dong
• Granted Patent: US 7,489,184 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 configured to generate a first complementary-to-absolute-temperature (CTAT) signal varying with a first temperature coefficient and a second complementary-to-absolute-temperature (CTAT) signal varying with a different second temperature coefficient; and

a differential sensing device configured to scale the first and second CTAT signals to exhibit approximately equal temperature coefficients and to generate a reference signal therefrom.

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 an operating temperature range.

3. The voltage reference generator of claim 1, wherein the differential sensing device is configured to scale at least one of the first and second CTAT signals causing the reference signal to exhibit substantially a temperature coefficient of zero over an 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 method for generating a reference signal, comprising:

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

generating a second complementary-to-absolute-temperature (CTAT) signal varying with a different second temperature coefficient;

scaling at least one of the first and second CTAT signals to exhibit substantially equivalent temperature coefficients; and

generating the reference signal by differentially sensing the first and second CTAT signals having the substantially equivalent temperature coefficients.

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

9. The method of claim 7, wherein scaling further comprises scaling at least one of the first and second CTAT signals to exhibit substantially equivalent temperature coefficients over an operating temperature range.

10. The method of claim 7, further comprising buffering at least one of the first and second CTAT signals before differentially sensing the first and second CTAT signals.

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

12. The method of claim 7, wherein generating the reference signal includes generating the reference signal at a level below ground potential over an operating temperature range.

13. 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 configured to generate a first complementary-to-absolute-temperature (CTAT) signal varying with a first temperature coefficient and a second complementary-to-absolute-temperature (CTAT) signal varying with a different second temperature coefficient; and

a differential sensing device configured to scale the first and second CTAT signals to exhibit approximately equal temperature coefficients and to generate a reference signal therefrom.

14. The memory device of claim 13, wherein at least one of the first and second CTAT signals are configured to be sensitive to temperature variations over an operating temperature range.

15. The memory device of claim 13, wherein the differential sensing device is configured to scale at least one of the first and second CTAT signals causing the reference signal to exhibit substantially a temperature coefficient of zero over an operating temperature range.

16. The memory device of claim 13, further comprising a buffer configured to condition at least one of the first and second CTAT signals for coupling with the differential sensing device.

17. The memory device of claim 13, wherein at least one of the first and second CTAT signals includes a nonzero temperature coefficient.

18. The memory device of claim 13, wherein the reference signal is at a level below ground potential over the operating temperature range.