Temperature stabilized CMOS oscillator circuit

• US 6,377,130 B1
• Filed: 09/12/2000
• Issued: 04/23/2002
• Est. Priority Date: 09/12/2000
• Status: Expired due to Term

• Current Assignee: Rockwell Collins, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Rockwell Collins, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Haman, Leo J.
• Primary Examiner(s): KINKEAD, ARNOLD M
• Application Number:
  US09/660,014
• Time in Patent Office: 588 Days
• Field of Search: 331/186, 331/176, 331/117.R, 331/158, 331/116.R, 331/66, 331/116.FE
• US Class Current: 331/176
• CPC Class Codes: H03B 5/04 Modifications of generator to compensate for variations in physical values, e.g. power supply, load, temperature
• CPC Class Codes: H03B 5/06 Modifications of generator to ensure starting of oscillations
• CPC Class Codes: H03B 5/364 the amplifier comprising field effect transistors H03B5/366 takes precedence

Abstract

A temperature stabilized CMOS oscillator circuit modifies the gain of a CMOS oscillator transistor to cancel the gain variation over temperature using a bias circuit. The bias circuit utilizes a combination of two current mirrors to establish a temperature compensating supply current to a CMOS oscillator transistor. A primary current mirror and a temperature variable resistor establish a current in the current mirror output to the CMOS oscillator transistor. A secondary current mirror and a temperature variable resistor divert current from the primary current mirror over temperature to vary the current mirror output to the CMOS oscillator transistor to compensate for its gain variation.

Claims

1. A temperature stabilized CMOS oscillator circuit having stabilized gain over temperature comprising:

a crystal oscillator for providing an output signal said crystal oscillator further comprising a CMOS oscillator transistor; and

a bias circuit connected to the crystal oscillator as a current source to provide a supply current to the CMOS oscillator transistor and to vary the supply current over temperature to provide the stabilized gain, wherein the bias circuit further comprises;

a primary current mirror connected to the crystal oscillator to provide a supply current to the CMOS oscillator transistor; and

a secondary current mirror connected to the primary current mirror to divert current from the primary current mirror to vary the supply current over temperature.

2. The temperature stabilized CMOS oscillator of claim 1 wherein the crystal oscillator is from the group consisting of Pierce, Colpitts, Clapp, and Hartley.

3. The temperature stabilized CMOS oscillator of claim 1 wherein the primary current mirror comprises:

a primary pair of CMOS transistors connected as a current mirror current source; and

a resistor with a low positive temperature coefficient connected to the primary pair of CMOS transistors to set a primary current mirror current that sets the supply current.

4. The temperature stabilized CMOS oscillator of claim 3 wherein the secondary current mirror comprises:

a secondary pair of CMOS transistors connected as a secondary current mirror current source; and

a resistor with a high positive temperature coefficient connected to the secondary pair of CMOS transistors to set a secondary current mirror current that diverts current from the primary current mirror current.

5. A temperature stabilized CMOS oscillator circuit having stabilized gain over temperature comprising:

a crystal oscillator for providing an output signal said crystal oscillator further comprising a CMOS oscillator transistor;

a primary current mirror connected to the crystal oscillator to provide a supply current to the CMOS oscillator transistor; and

a secondary current mirror connected to the primary current mirror to ,divert current from the primary current mirror to vary the supply current over temperature to provide the stabilized gain.

6. The temperature stabilized CMOS oscillator of claim 5 wherein the primary current mirror comprises:

a primary pair of CMOS transistors connected as a current mirror current source; and

a resistor with a low positive temperature coefficient connected to the primary pair of CMOS transistors to set a primary current mirror current that sets the supply current.

7. The temperature stabilized CMOS oscillator of claim 6 wherein the secondary current mirror comprises:

a secondary pair of CMOS transistors connected as a secondary current mirror current source; and

a resistor with a high positive temperature coefficient connected to the secondary pair of CMOS transistors to set a secondary current mirror current that diverts current from the primary current mirror current.