Calibrated low-noise current and voltage references and associated methods

• US 7,177,610 B2
• Filed: 02/22/2002
• Issued: 02/13/2007
• Est. Priority Date: 01/12/2001
• Status: Active Grant

• Current Assignee: Silicon Laboratories Incorporated
• Original Assignee: Silicon Laboratories Incorporated
• Inventors: Scott, Jeffrey W., Tuttle, G. Tyson, Behrens, Richard T., Vishakhadatta, G. Diwakar, Kerth, Donald A., Srinivasan, Vishnu S.
• Primary Examiner(s): Anderson; Matthew
• Assistant Examiner(s): TRAN, TUAN A
• Application Number:
  US10/081,121
• Publication Number:
  US 20020168942A1
• Time in Patent Office: 1,817 Days
• Field of Search: 4551971- 3, 455/194.2, 455/195.1, 4552451- 2, 4552511- 2, 455254-264, 455/323, 455/333, 455/198.1, 455/118, 4551271- 3, 455/232.1, 455/233.1, 4552341- 2, 455/246.1, 327538-543, 323315-316, 341120-121
• US Class Current: 455/259
• CPC Class Codes: H04B 1/0003 Software-defined radio [SDR] systems, i.e. systems wherein components typically implemented in hardware, e.g. filters or modulators/demodulators, are implented using software, e.g. by involving an AD or DA conversion stage such that at least part of the signal processing is performed in the digital domain digital baseband systems H04L25/00; digital modulation/demodulation H04L27/00; CDMA H04B1/707; TDMA H04B7/2643; image transmission H04N5/00
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04B 15/02 Reducing interference from electric apparatus by means located at or near the interfering apparatus
• CPC Class Codes: H04B 15/04 the interference being caused by substantially sinusoidal oscillations, e.g. in a receiver or in a tape-recorder
• CPC Class Codes: H04B 2215/064 Reduction of clock or synthesizer reference frequency harmonics

Abstract

A low-noise current reference circuitry includes a voltage source, a current source, and a controller. The voltage source generates a reference voltage. The current source provides a low-noise output current in response to a control signal. The controller provides the control signal based at least in part on the relative magnitudes of the reference voltage and a voltage derived from the output current. A low-noise voltage reference circuitry includes a reference voltage source, a voltage source, and a controller. The reference voltage source generates a reference voltage. The voltage source provides a low-noise output voltage in response to a control signal. The controller provides the control signal based at least in part on the relative magnitudes of the output voltage and the reference voltage.

Claims

1. A radio-frequency (RF) apparatus, comprising:

a first integrated circuit, including;

a reference current generator configured to generate a reference output current, the reference current generator comprising;

a reference voltage source configured to provide a reference voltage;

a controllable current source configured to provide the reference output current in response to a first plurality of signals; and

a first controller configured to provide the first plurality of signals, the first plurality of signals being derived from the reference voltage and the reference output current,

wherein a noise content of the reference output current is lower than a noise content of the reference voltage.

2. The radio-frequency apparatus according to claim 1, wherein the reference voltage source comprises a low-drift reference voltage source.

3. The radio-frequency apparatus according to claim 2, wherein the reference output current is calibrated by calibrating the first plurality of signals.

4. The radio-frequency apparatus according to claim 3, wherein the signals in the first plurality of signals are configured to be held constant after calibrating the first plurality of signals.

5. The radio-frequency apparatus according to claim 4, wherein the controllable current source comprises a first adjustable resistor.

6. The radio-frequency apparatus according to claim 5, wherein the first adjustable resistor comprises a first plurality of switchable resistors configured to adjust a resistance of the first adjustable resistor in response to the first plurality of signals.

7. The radio-frequency apparatus according to claim 6, wherein the first controller uses successive approximation to generate the first plurality of signals.

8. The radio-frequency apparatus according to claim 7, wherein the reference voltage source comprises a band-gap reference.

9. The radio-frequency apparatus according to claim 8, wherein the first integrated circuit further comprises radio-frequency receiver circuitry.

10. The radio-frequency apparatus according to claim 9, further comprising a second integrated circuit coupled to the first integrated circuit, the second integrated circuit comprising digital signal processing circuitry, the digital signal processing circuitry further configured to accept a digital output of the radio-frequency receiver circuitry.

11. The radio-frequency apparatus according to claim 10, wherein the reference current generator supplies the reference output current to the radio-frequency receiver circuitry.

12. The radio-frequency apparatus according to claim 11, wherein the radio-frequency receiver circuitry and the reference current generator are powered up before a reception of a burst by the radio-frequency receiver circuitry.

13. The radio-frequency apparatus according to claim 12, wherein the reference output current is calibrated at power up.

14. The radio-frequency apparatus according to claim 2, wherein the first integrated circuit further comprises:

a reference voltage generator configured to generate a reference output voltage, the reference voltage generator comprising;

a controllable voltage source configured to provide the reference output voltage in response to a second plurality of signals; and

a second controller configured to provide the second plurality of signals, the second plurality of signals being derived from the reference voltage and the reference output voltage,

wherein a noise content of the reference output voltage is lower than a noise content of the reference voltage.

15. The radio-frequency apparatus according to claim 14, wherein the reference output voltage is calibrated by calibrating the second plurality of signals.

16. The radio-frequency apparatus according to claim 15, wherein the signals in the second plurality of signals are configured to be held constant after calibrating the second plurality of signals.

17. The radio-frequency apparatus according to claim 16, wherein the controllable voltage source comprises a second adjustable resistor.

18. The radio-frequency apparatus according to claim 17, wherein the second adjustable resistor comprises a second plurality of switchable resistors configured to adjust a resistance of the second adjustable resistor in response to the second plurality of signals.

19. The radio-frequency apparatus according to claim 18, wherein the second controller uses successive approximation to generate the second plurality of signals.

20. The radio-frequency apparatus according to claim 19, wherein the controllable voltage source is further configured to provide the reference output voltage in response to a signal derived from the reference output current.

21. The radio-frequency apparatus according to claim 20, wherein the first integrated circuit further comprises radio-frequency receiver circuitry.

22. The radio-frequency apparatus according to claim 21, further comprising a second integrated circuit coupled to the first integrated circuit, the second integrated circuit comprising digital signal processing circuitry configured to accept a digital output of the radio-frequency receiver circuitry.

23. The radio-frequency apparatus according to claim 22, wherein the reference voltage generator supplies the reference output voltage to the radio-frequency receiver circuitry.

24. The radio-frequency apparatus according to claim 23, wherein the radio-frequency receiver circuitry and the reference voltage generator are powered up before a reception of a burst by the radio-frequency receiver circuitry.

25. The radio-frequency apparatus according to claim 24, wherein the reference output voltage is calibrated at power up.