Stage having controlled variable resistance load circuit for use in voltage controlled ring oscillator

• US 6,351,190 B1
• Filed: 05/09/2000
• Issued: 02/26/2002
• Est. Priority Date: 05/13/1996
• Status: Expired due to Term

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Ovard, David K., Tuttle, John R., Rotzoll, Robert R., Tuttle, Mark E., Lowrey, Tyler, Higgins, Brian P., Yu, Shu-Sun, Devereaux, Kevin M., Pax, George E., OʼToole, James E.
• Primary Examiner(s): Grimm, Siegfried H.
• Application Number:
  US09/568,085
• Time in Patent Office: 658 Days
• Field of Search: 331/57, 331/177.R
• US Class Current: 331/57
• CPC Class Codes: G06K 19/0707 the arrangement being capable of collecting energy from external energy sources, e.g. thermocouples, vibration, electromagnetic radiation G06K19/0702 takes precedence
• CPC Class Codes: G06K 19/0712 the arrangement being capable of triggering distinct operating modes or functions dependent on the strength of an energy or interrogation field in the proximity of the record carrier active means for hindering electromagnetic reading or writing G06K19/07336
• CPC Class Codes: G06K 19/0716 at least one of the integrated circuit chips comprising a sensor or an interface to a sensor
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 19/0726 the arrangement including a circuit for tuning the resonance frequency of an antenna on the record carrier
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/07758 arrangements for adhering the record carrier to further objects or living beings, functioning as an identification tag
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10059 transponder driven
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H03L 7/0995 the oscillator comprising a ring oscillator
• CPC Class Codes: H03L 7/148 said digital means comprising a counter or a divider

Abstract

A stage for a voltage controlled oscillator includes a first p-channel transistor having a gate defining a control node, having a source adapted to be coupled to a supply voltage, and having a drain; a second p-channel transistor having a gate coupled to the control node, having a source coupled to the supply voltage, and having a drain; a first n-channel transistor having a gate defining a first input, having a drain coupled to the drain of the first p-channel transistor and defining a first node, and having a source; a second n-channel transistor having a gate defining a second input, having a drain coupled to the drain of the second p-channel transistor and defining a second node, and having a source; a current draw; first and second loads; a first source follower having an input coupled to the first node; and a second source follower.

Claims

1. A stage for a voltage controlled oscillator, the stage comprising:

a first p-channel transistor having a gate defining a control node, having a source adapted to be coupled to a supply voltage, and having a drain;

a second p-channel transistor having a gate coupled to the control node, having a source coupled to the supply voltage, and having a drain;

a first n-channel transistor having a gate defining a first input, having a drain coupled to the drain of the first p-channel transistor and defining a first node, and having a source;

a second n-channel transistor having a gate defining a second input, having a drain coupled to the drain of the second p-channel transistor and defining a second node, and having a source;

a current draw coupled to the sources of the first and second n-channel transistors and configured to direct current away from the sources of the first and second n-channel transistors;

a first load coupled between the supply voltage and the drain of the first n-channel transistor;

a second load coupled between the supply voltage and drain of the second n-channel transistor;

a first source follower having an input coupled to the first node and having an output defining a first output of the stage; and

a second source follower having an input coupled to the second node and having an output defining a second output of the stage.

2. A transmitter including a ring oscillator having a chain of stages, each stage comprising:

a first p-channel transistor having a gate defining a control node, having a source adapted to be coupled to a supply voltage, and having a drain;

a second p-channel transistor having a gate coupled to the control node, having a source coupled to the supply voltage, and having a drain;

a first n-channel transistor having a gate defining a first input, having a drain coupled to the drain of the first p-channel transistor and defining a first node, and having a source;

a second n-channel transistor having a gate defining a second input, having a drain coupled to the drain of the second p-channel transistor and defining a second node, and having a source;

a current draw coupled to the sources of the first and second n-channel transistors directing current away from the sources of the first and second n-channel transistors;

a first load coupled between the supply voltage and the drain of the first n-channel transistor;

a second load coupled between the supply voltage and drain of the second n-channel transistor;

a first source follower having an input coupled to the first node and having an output defining a first output of the stage; and

a second source follower having an input coupled to the second node and having an output defining a second output of the stage.

3. A stage for a voltage controlled oscillator, the stage comprising:

a first p-channel transistor having a gate, having a source, and having a drain;

a second p-channel transistor having a gate coupled to the gate of the first p-channel transistor, having a source coupled to the supply voltage, and having a drain;

a first n-channel transistor having a gate defining a first input, having a drain coupled to the drain of the first p-channel transistor and defining a first node, and having a source;

a second n-channel transistor having a gate defining a second input, having a drain coupled to the drain of the second p-channel transistor and defining a second node, and having a source;

a current source coupled to the sources of the first and second n-channel transistors and configured to direct current from the sources of the first and second n-channel transistors;

a first load coupled between the source of the first p-channel transistor and the drain of the first n-channel transistor;

a second load configured to be coupled between a supply voltage and the drain of the second n-channel transistor;

a first source follower having an input coupled to the first node and having an output defining a first output of the stage; and

a second source follower having an input coupled to the second node and having an output defining a second output of the stage.

4. A stage for a voltage controlled oscillator in accordance with claim 3 wherein the first source follower comprises a transistor having a gate coupled to the first node, a drain, and a source;

and the source follower further comprises a current source configured to direct current from the source of the transistor of the source follower.

5. A stage for a voltage controlled oscillator in accordance with claim 3 wherein the second source follower comprises a transistor having a gate coupled to the second node, a drain, and a source;

and the source follower further comprises a current source configured to direct current from the source of the transistor of the second source follower.

6. A transmitter including a ring oscillator having a plurality of chained stages, at least one of the stages comprising:

a first p-channel transistor having a gate, having a source adapted to be coupled to a supply voltage, and having a drain;

a second p-channel transistor having a gate coupled to the gate of the first p-channel transistor, having a source coupled to the supply voltage, and having a drain;

a first n-channel transistor having a gate defining a first input, having a drain coupled to the drain of the first p-channel transistor and defining a first node, and having a source;

a second n-channel transistor having a gate defining a second input, having a drain coupled to the drain of the second p-channel transistor and defining a second node, and having a source;

a current source coupled to the sources of the first and second n-channel transistors and configured to direct current from the sources of the first and second n-channel transistors;

a first load coupled between the source of the first p-channel transistor and the drain of the first n-channel transistor;

a second load coupled between the supply voltage and drain of the second n-channel transistor;

a first source follower having an input coupled to the first node and having an output defining a first output of the stage; and

a second source follower having an input coupled to the second node and having an output defining a second output of the stage.

7. A transmitter in accordance with claim 6 wherein the first source follower comprises a transistor having a gate coupled to the first node, a drain, and a source;

and the source follower further comprises a current source configured to direct current from the source of the transistor of the source follower.

8. A transmitter in accordance with claim 7 wherein the second source follower comprises a transistor having a gate coupled to the second node, a drain, and a source;

and the source follower further comprises a current source configured to direct current from the source of the transistor of the second source follower.

9. A stage for a voltage controlled oscillator, the stage comprising:

a first p-channel transistor having a gate defining a control node, having a source, and having a drain;

a second p-channel transistor having a gate coupled to the control node, having a source coupled to the source of the first p-channel transistor, and having a drain;

a first n-channel transistor having a gate defining a first input, having a drain coupled to the drain of the first p-channel transistor and defining a first node, and having a source;

a second n-channel transistor having a gate defining a second input, having a drain coupled to the drain of the second p-channel transistor and defining a second node, and having a source;

a current source coupled to the sources of the first and second n-channel transistors and configured to direct current from the sources of the first and second n-channel transistors;

a first load coupled between the source of the first p-channel transistor, and the drain of the first n-channel transistor;

a second load coupled between the source of the first p-channel transistor, and drain of the second n-channel transistor;

a first output coupled to the first node; and

a second output coupled to the second node.

10. A stage for a voltage controlled oscillator in accordance with claim 9 and further comprising a first source follower defining the first output, the first source follower including a transistor having a gate coupled to the first node, a drain, and a source;

and the first source follower further including a current source configured to direct current from the source of the transistor of the source follower.

11. A stage for a voltage controlled oscillator in accordance with claim 10 and further comprising a second source follower defining the second output, the second source follower including a transistor having a gate coupled to the second node, a drain, and a source;

and the second source follower further including a current source configured to direct current from the source of the transistor of the second source follower.

12. A transmitter including a ring oscillator having a plurality of chained stages, at least one of the stages comprising:

a first p-channel transistor having a gate defining a control node, having a source, and having a drain;

a second p-channel transistor having a gate coupled to the control node, having a source coupled to the source of the first p-channel transistor, and having a drain;

a first n-channel transistor having a gate defining a first input, having a drain coupled to the drain of the first p-channel transistor and defining a first node, and having a source;

a second n-channel transistor having a gate defining a second input, having a drain coupled to the drain of the second p-channel transistor and defining a second node, and having a source;

a current source coupled to the sources of the first and second n-channel transistors to direct current from the sources of the first and second n-channel transistors;

a first load coupled between the source of the first p-channel transistor, and the drain of the first n-channel transistor;

a second load coupled between the source of the first p-channel transistor, and drain of the second n-channel transistor;

a first output coupled to the first node; and

a second output coupled to the second node.

13. A transmitter in accordance with claim 12 and further comprising a first source follower defining the first output, the first source follower including a transistor having a gate coupled to the first node, a drain, and a source;

and the first source follower further including a current source configured to direct current from the source of the transistor of the source follower.

14. A transmitter in accordance with claim 12 and further comprising a second source follower defining the second output, the second source follower including a transistor having a gate coupled to the second node, a drain, and a source;

and the second source follower further including a current source configured to direct current from the source of the transistor of the second source follower.

15. A voltage controlled oscillator including a plurality of stages, at least one of the stages comprising:

a first p-channel transistor having a gate defining a control node, having a source, and having a drain;

a second p-channel transistor having a gate coupled to the control node, having a source coupled to the source of the first p-channel transistor, and having a drain;

a first n-channel transistor having a gate defining a first input, having a drain coupled to the drain of the first p-channel transistor and defining a first node, and having a source;

a second n-channel transistor having a gate defining a second input, having a drain coupled to the drain of the second p-channel transistor and defining a second node, and having a source;

a current source coupled to the sources of the first and second n-channel transistors and configured to direct current from the sources of the first and second n-channel transistors;

a first load configured to be coupled between a supply voltage and the drain of the first n-channel transistor;

a second load coupled between the supply voltage and drain of the second n-channel transistor;

a first source follower having an input coupled to the first node and having an output defining a first output of the stage; and

a second source follower having an input coupled to the second node and having an output defining a second output of the stage.

16. A voltage controlled oscillator in accordance with claim 15 wherein the first source follower comprises a transistor having a gate coupled to the first node, a drain coupled to the supply voltage, and a source;

and the source follower further comprises a current source configured to direct current from the source of the transistor of the source follower.

17. A voltage controlled oscillator in accordance with claim 15 wherein the second source follower comprises a transistor having a gate coupled to the second node, a drain coupled to the supply voltage, and a source;

and the source follower further comprises a current source configured to direct current from the source of the transistor of the second source follower.