Crystal oscillator emulator

• US 7,791,424 B2
• Filed: 04/03/2007
• Issued: 09/07/2010
• 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 M
• Application Number:
  US11/732,304
• Publication Number:
  US 20070176705A1
• Time in Patent Office: 1,253 Days
• Field of Search: 331/158, 331/176, 331/66, 331/117.R, 331/117.FE
• US Class Current: 331/158
• 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 comprises a first temperature sensor that senses a first temperature of the integrated circuit. Memory stores calibration parameters and selects at least one of the calibration parameters based on the first temperature. A semiconductor oscillator generates an output signal having a frequency, which is based on the calibration parameters, and an amplitude. An amplitude adjustment module compares the amplitude to a predetermined amplitude and generates a control signal that adjusts the amplitude based on the comparison.

Claims

1. A crystal oscillator emulator integrated circuit, comprising:

a first temperature sensor that senses a first temperature of said integrated circuit;

memory that stores calibration parameters and that selects at least one of said calibration parameters based on said first temperature;

a semiconductor oscillator that generates an output signal having a frequency, which is based on said calibration parameters, and an amplitude; and

an amplitude adjustment module that compares said amplitude to a predetermined amplitude and that generates a control signal that adjusts said amplitude based on said comparison.

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

3. The crystal oscillator emulator integrated circuit of claim 2 wherein said semiconductor oscillator includes a bias adjusting circuit that receives said control signal and that generates a bias signal that biases said resonating circuit to adjust said amplitude based on said control signal.

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

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

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

an inductive-capacitive (LC) circuit; and

cross-coupled transistors that communicate with said LC circuit.

7. The crystal oscillator emulator integrated circuit of claim 1 further comprising a select input that selects said frequency as a function of an external passive component.

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

a heater that adjusts said first temperature; and

a disabling circuit that disables said heater after said calibration parameters are stored.

9. The crystal oscillator emulator integrated circuit of claim 8 wherein said heater operates in response to said first temperature sensor.

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

11. A crystal oscillator emulator integrated circuit, comprising:

first temperature sensing means for sensing a first temperature of said integrated circuit;

storing means for storing calibration parameters and for selecting at least one of said calibration parameters based on said first temperature;

semiconductor oscillating means for generating an output signal having a frequency, which is based on said calibration parameters, and an amplitude; and

amplitude adjustment means for comparing said amplitude to a predetermined amplitude and for generating a control signal that adjusts said amplitude based on said comparison.

12. The crystal oscillator emulator integrated circuit of claim 11 wherein said semiconductor oscillating means includes resonating means for resonating.

13. The crystal oscillator emulator integrated circuit of claim 12 wherein said semiconductor oscillating means includes bias adjusting means for receiving said control signal and for generating a bias signal that biases said resonating means to adjust said amplitude based on said control signal.

14. The crystal oscillator emulator integrated circuit of claim 13 wherein said bias signal includes a voltage bias signal.

15. The crystal oscillator emulator integrated circuit of claim 13 wherein said bias signal includes a current bias signal.

16. The crystal oscillator emulator integrated circuit of claim 13 wherein said resonating means includes:

inductive-capacitive (LC) resonating means for resonating; and

cross-coupled transistors that communicate with said LC resonating means.

17. The crystal oscillator emulator integrated circuit of claim 11 further comprising selecting means for selecting said frequency as a function of an external passive component.

18. The crystal oscillator emulator integrated circuit of claim 11 further comprising:

heating means for adjusting said first temperature; and

disabling means for disabling said heating means after said calibration parameters are stored.

19. The crystal oscillator emulator integrated circuit of claim 18 wherein said heating means operates in response to said first temperature sensing means.

20. The crystal oscillator emulator integrated circuit of claim 11 wherein said semiconductor oscillating means is selected from a group consisting of inductive-capacitive (LC) oscillating means, resistive capacitive (RC) oscillating means and ring oscillating means.