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US 6,384,654 B1Granted
High speed circuit of particular utility in delay and phase locked loops
OwnerGlenn Nouferinventor
Life of this patent
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Abstract
A delay stage for use in a voltage-controlled delay chain of a delay locked loop or in a voltage-controlled ring oscillator of a phase locked loop has pullup and pulldown transistors driven by a first input to the delay stage, at least one of which is in series with a delay control transistor, and a second pullup and pulldown transistor gated by a second input to the delay stage. When used in a delay chain, the first input is driven by a signal that leads the second input to the delay stage.
Claims16
A delay stage for use in a voltage-controlled delay chain of a delay locked loop or in a voltage-controlled ring oscillator of a phase locked loop comprising
- a first pullup transistor coupled to drive a stage output,
- a first pulldown transistor coupled to drive the stage output,
- a ratioed pullup transistor coupled to drive the stage output,
- a ratioed pulldown transistor coupled to drive the stage output, and
- a control transistor coupled in series with a transistor selected from the group of transistors consisting of the first pullup transistor and the first pulldown transistor;
- wherein the first pullup transistor and the first pulldown transistor each have a gate coupled to a first input to the delay stage and the ratioed pullup transistor and the ratioed pulldown transistor each have a gate coupled to a second input to the delay stage;
- and wherein the control transistor has a gate connected to a control voltage input of the delay stage.
4 more elements
A voltage-variable delay chain for use in a delay locked loop or in a ring oscillator of a phase locked loop comprising at least one delay stage further comprising
- a first pullup transistor coupled to drive a stage output,
- a first pulldown transistor coupled to drive the stage output,
- a ratioed pullup transistor coupled to drive the stage output,
- a ratioed pulldown transistor coupled to drive the stage output, and
- a control transistor coupled in series with a transistor selected from the group of transistors consisting of the first pullup transistor and the first pulldown transistor,
- wherein the first pullup transistor and the first pulldown transistor each have a gate coupled to a first input to the delay stage and the ratioed pullup transistor and the ratioed pulldown transistor each have a gate coupled to a second input to the delay stage;
- and wherein a transistor selected from the group consisting of the first pullup transistor and the first pulldown transistor is coupled to a drain of the control transistor, the control transistor having a gate connected to a control voltage input of the delay stage;
- and
- wherein the first input of the delay stage is connected to a signal of the delay stage that leads the signal of the delay chain connected to the second input of the delay stage.
6 more elements
A voltage-variable delay chain for use in a delay locked loop or in a ring oscillator of a phase locked loop comprising at least a first, a second, and a third delay stage, each delay stage comprising
- a first pullup transistor coupled to drive a stage output,
- a first control transistor coupled in series with the first pullup transistor and having a gate coupled to a first control signal,
- a first pulldown transistor coupled to drive the stage output,
- a second control transistor coupled in series with the first pulldown transistor and having a gate coupled to a second control signal,
- a second pullup transistor coupled to drive the stage output,
- a second pulldown transistor coupled to drive the stage output, and
- wherein the first pullup transistor and the first pulldown transistor each have a gate coupled to a first input to the delay stage and the second pullup transistor and the second pulldown transistor each have a gate coupled to a second input to the delay stage;
- and
- wherein the second input to the first delay stage is coupled to the first input of the third delay stage, the second input to the second delay stage is coupled to the output of the first delay stage, and the second input of the third delay stage is coupled to the output of the second delay stage.
6 more elements
A voltage-controlled ring oscillator having at least a first, a second, and a third delay stage, each delay stage comprising:
- a first pullup transistor coupled to drive a stage output,
- a first control transistor coupled in series with the first pullup transistor and having a gate coupled to a first control signal,
- a first pulldown transistor coupled to drive the stage output,
- a second control transistor coupled in series with the first pulldown transistor and having a gate coupled to a second control signal,
- a second pullup transistor coupled to drive the stage output,
- a second pulldown transistor coupled to drive the stage output, and
- wherein the first pullup transistor and the first pulldown transistor each have a gate coupled to a first input to the delay stage and the second pullup transistor and the second pulldown transistor each have a gate coupled to a second input to the delay stage;
- and
- wherein the second input to the first delay stage is coupled to the first input of the third delay stage, the second input to the second delay stage is coupled to the output of the first delay stage, and the second input of the third delay stage is coupled to the output of the second delay stage.
6 more elements
A voltage-controlled ring oscillator having at least a first, a second, and a third voltage-controlled delay stage, each delay stage comprising:
- a first pullup transistor coupled to drive a stage output,
- a first control transistor coupled in series with the first pullup transistor and having a gate coupled to a first analog control signal,
- a first pulldown transistor coupled to drive the stage output,
- a second control transistor coupled in series with the first pulldown transistor and having a gate coupled to a second analog control signal,
- a second pullup transistor coupled to drive the stage output,
- a second pulldown transistor coupled to drive the stage output, and
- wherein the first pullup transistor and the first pulldown transistor each have a gate coupled to a first input to the delay stage and the second pullup transistor and the second pulldown transistor each have a gate coupled to a second input to the delay stage;
- wherein the second input to the first delay stage is coupled to the first input of the third delay stage, the second input to the second delay stage is coupled to the output of the first delay stage, and the second input of the third delay stage is coupled to the output of the second delay stage;
- and
- wherein a delay of the first, second, and third delay stages is variable with the first analog control signal and the second analog control signal.
7 more elements
A voltage-variable delay chain for use in a delay locked loop or in a ring oscillator of a phase locked loop comprising
- at least a first, a second, third, and fourth delay stage, each delay stage comprising
- a first pullup transistor coupled to drive a stage output,
- a first control transistor coupled in series with the first pullup transistor and having a gate coupled to a first analog control signal,
- a first pulldown transistor coupled to drive the stage output,
- a second control transistor coupled in series with the first pulldown transistor and having a gate coupled to a second analog control signal,
- a second pullup transistor coupled to drive the stage output,
- a second pulldown transistor coupled to drive the stage output, and
- wherein the first pullup transistor and the first pulldown transistor each have a gate coupled to a first input to the delay stage and the second pullup transistor and the second pulldown transistor each have a gate coupled to a second input to the delay stage;
- wherein the second input to the first delay stage is coupled to the first input of the third delay stage, the second input to the second delay stage is coupled to the output of the first delay stage, and the second input of the third delay stage is coupled to the output of the second delay stage;
- and
- wherein the second input to the fourth delay stage is coupled to the output of the third delay stage, and the first input to the fourth delay stage is coupled to the output of the second delay stage.
8 more elements
A voltage-variable delay chain for use in a delay locked loop or in a ring oscillator of a phase locked loop comprising
- at least one delay stage further comprising
- a first pullup transistor coupled to drive a stage output,
- a first pulldown transistor coupled to drive the stage output,
- a ratioed pullup transistor coupled to drive the stage output,
- a ratioed pulldown transistor coupled to drive the stage output, and
- a control transistor coupled in series with a transistor selected from the group of transistors consisting of the first pullup transistor and the first pulldown transistor,
- wherein the first pullup transistor and the first pulldown transistor each have a gate coupled to a first input to the delay stage and the ratioed pullup transistor and the ratioed pulldown transistor each have a gate coupled to a second input to the delay stage;
- and wherein a transistor selected from the group consisting of the first pullup transistor and the first pulldown transistor is coupled to a drain of the control transistor, the control transistor having a gate connected to an analog control voltage input of the delay stage;
- wherein the first input of each delay stage is connected to a signal of the delay stage that leads the signal of the delay chain connected to the second input of the delay stage;
- and
- wherein a delay of the delay chain is a function of the analog control voltage of at least one delay stage of the delay chain.
8 more elements
A voltage-controlled variable delay stage for use in a voltage-controlled delay chain of a delay locked loop or in a voltage-controlled ring oscillator of a phase locked loop comprising
- a first pullup transistor coupled to drive a stage output,
- a first pulldown transistor coupled to drive the stage output,
- a ratioed pullup transistor coupled to drive the stage output,
- a ratioed pulldown transistor coupled to drive the stage output, and
- a control transistor coupled in series with a transistor selected from the group of transistors consisting of the first pullup transistor and the first pulldown transistor;
- wherein the first pullup transistor and the first pulldown transistor each have a gate coupled to a first input to the delay stage and the ratioed pullup transistor and the ratioed pulldown transistor each have a gate coupled to a second input to the delay stage;
- and wherein the control transistor has a gate connected to an analog control voltage input of the delay stage;
- and
- wherein a delay of the voltage-controlled variable delay stage is controlled by the analog control voltage input of the delay stage.
6 more elements
Dependencies are inferred from the claim text.