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US 6,587,065 B1Granted
Stable current-control reference systems
AssigneeAnalog Devices, Inc.
InventorsJoseph Michael Hensley, Michael R. Elliott
Life of this patent
Estimating the term…
Abstract
Current-control reference systems are provided in which stabliity is realized with sensors that shift clamp windows in response to a reference's current-control signal to thereby maintain feedback control in the reference under steady-state and transient operating conditions.
Claims26
A reference system that provides a current-control reference signal, comprising:
- a feedback-controlled amplifier that includes a feedback transistor and provides a current-control reference signal which maintains a substantially-constant control current in said feedback transistor;
- a clamp that limits signal excursions on a signal path of said feedback-controlled amplifier to a clamp window;
- and
- a sensor that shifts said clamp window in response to transient values of said current-control reference signal;
- feedback control thereby maintained about said amplifier.
2 more elements
A reference system that provides a current-control reference signal in response to an input voltage, comprising:
- a feedback-controlled amplifier that includes a feedback transistor and, in response to said input voltage, provides a current-control reference, signal which maintains a substantially-constant control current in said feedback transistor;
- a bias circuit that establishes a clamp voltage;
- a clamp that responds to said clamp voltage and limits signal excursions on a signal path of said feedback-controlled amplifier to a clamp window;
- and
- a sensor that responds to transient values of said current-control reference signal and modifies currents in said bias circuit to thereby shift said clamp window.
2 more elements
A pipelined analog-to-digital converter (ADC) system that converts an analog signal to a digital signal, the system comprising:
- a pipelined ADC that includes an initial converter stage and at least one subsequent converter stage that each convert a respective analog signal to a respective digital signal with a respective ADC, convert said respective digital signal to a corresponding analog signal with a respective digital-to-analog converter (DAC) and pass a respective residue signal that is the difference between said respective and corresponding analog signals to a subsequent converter stage;
- and
- a reference system that provides a current-control reference signal to at least one of said initial and subsequent converter stages wherein said reference system includes:
- a) a feedback-controlled amplifier that includes a feedback transistor and provides said current-control reference signal which maintains a substantially-constant control current in said feedback transistor;
- b) a clamp that limits signal excursions on a signal path of said feedback-controlled amplifier to a clamp window;
- and
- c) a sensor that shifts said clamp window in response to transient values of said current-control reference signal;
- feedback control thereby maintained about said amplifier.
5 more elements
Dependencies are inferred from the claim text.