Crystal oscillator emulator

• US 8,063,711 B2
• Filed: 09/07/2010
• Issued: 11/22/2011
• Est. Priority Date: 10/15/2002
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell World Trade Limited (Marvell Technology Group Limited)
• Inventors: Sutardja, Sehat
• Primary Examiner(s): Kinkead; Arnold
• Application Number:
  US12/876,739
• Publication Number:
  US 20110001571A1
• Time in Patent Office: 441 Days
• Field of Search: 331/176, 331/185, 331/183, 331/108.C, 331/175, 331/74, 331/116.R
• US Class Current: 331/176
• CPC Class Codes: H01L 2224/05553 being rectangular
• CPC Class Codes: H01L 2224/49175 Parallel arrangements
• CPC Class Codes: H01L 23/34 Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements thermal treatment apparatus H01L21/00
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/1461 MEMS
• CPC Class Codes: H01L 2924/16152 Cap comprising a cavity for hosting the device, e.g. U-shaped cap
• CPC Class Codes: H01L 2924/16235 Connecting to a semiconductor or solid-state bodies, i.e. cap-to-chip
• CPC Class Codes: H01L 2924/3011 Impedance
• CPC Class Codes: H03L 1/026 by using a memory for digitally storing correction values H03L1/025 takes precedence
• CPC Class Codes: H03L 1/027 by using frequency conversion means which is variable with temperature, e.g. mixer, frequency divider, pulse add/substract logic circuit H03L1/023, H03L1/026 take precedence
• CPC Class Codes: H03L 5/00 Automatic control of voltage, current, or power
• CPC Class Codes: H03L 7/07 using several loops, e.g. for redundant clock signal generation
• CPC Class Codes: H03L 7/1974 for fractional frequency division
• CPC Class Codes: H03L 7/1976 using a phase accumulator for controlling the counter or frequency divider

Abstract

A crystal oscillator emulator integrated circuit includes a first temperature sensor configured to sense a first temperature of the crystal oscillator emulator integrated circuit. The memory is configured to (i) store calibration parameters and (ii) select at least one of the calibration parameters based on the first temperature. A semiconductor oscillator is configured to generate an output signal, wherein (i) the output signal has a frequency and an amplitude and (ii) the frequency is based on the at least one of the calibration parameters. An amplitude adjustment module is configured to (i) compare the amplitude to a predetermined amplitude and (ii) generate a control signal to adjust the amplitude based on the comparison.

Claims

1. A crystal oscillator emulator integrated circuit, comprising:

a first temperature sensor configured to sense a first temperature of the crystal oscillator emulator integrated circuit;

memory configured to (i) store calibration parameters and (ii) select at least one of the calibration parameters based on the first temperature, wherein the calibration parameters include a function of at least one of temperature change and absolute temperature;

a semiconductor oscillator configured to generate an output signal, wherein (i) the output signal has a frequency and an amplitude and (ii) the frequency is based on the at least one of the calibration parameters; and

an amplitude adjustment module configured to (i) compare the amplitude to a predetermined amplitude and (ii) generate a control signal to adjust the amplitude based on the comparison.

2. The crystal oscillator emulator integrated circuit of claim 1, wherein the semiconductor oscillator includes a resonating circuit.

3. The crystal oscillator emulator integrated circuit of claim 2, wherein the semiconductor oscillator includes a bias adjusting circuit configured to (i) receive the control signal and (ii) generate a bias signal to bias the resonating circuit to adjust the amplitude based on the control signal.

4. The crystal oscillator emulator integrated circuit of claim 3, wherein the bias signal includes a voltage bias signal.

5. The crystal oscillator emulator integrated circuit of claim 3, wherein the bias signal includes a current bias signal.

6. The crystal oscillator emulator integrated circuit of claim 3, wherein the resonating circuit includes:

an inductive-capacitive (LC) circuit; and

cross-coupled transistors in communication with the LC circuit.

7. The crystal oscillator emulator integrated circuit of claim 1, further comprising a select input configured to select the frequency based on an external passive component.

8. The crystal oscillator emulator integrated circuit of claim 1, further comprising:

a heater configured to adjust the first temperature; and

a disabling circuit configured to disable the heater after the calibration parameters are stored.

9. The crystal oscillator emulator integrated circuit of claim 8, wherein the heater is configured to operate in response to the first temperature sensor.

10. The crystal oscillator emulator integrated circuit of claim 1, wherein the semiconductor oscillator is selected from a group consisting of inductive-capacitive (LC) oscillators, resistive capacitive (RC) oscillators and ring oscillators.

11. A method for operating a crystal oscillator emulator integrated circuit, the method comprising:

sensing a first temperature of the crystal oscillator emulator integrated circuit;

storing calibration parameters in memory;

selecting at least one of the calibration parameters based on the first temperature;

generating an output signal having a frequency and an amplitude using a semiconductor oscillator,

wherein the frequency is based on at least one of the calibration parameters;

comparing the amplitude to a predetermined amplitude; and

generating a control signal to adjust the amplitude based on the comparison.

12. The method of claim 11, wherein the semiconductor oscillator includes a resonating circuit.

13. The method of claim 12, further comprising generating a bias signal to bias the resonating circuit to adjust the amplitude based on the control signal.

14. The method of claim 13, wherein the bias signal includes a voltage bias signal.

15. The method of claim 13, wherein the bias signal includes a current bias signal.

16. The method of claim 11, further comprising configuring a select input to select the frequency based on an external passive component.

17. The method of claim 11, further comprising:

providing a heater to adjust the first temperature; and

disabling the heater after the calibration parameters are stored.