Pipelined analog-to-digital converters with gain-matching structures
AssigneeAnalog Devices, Inc.
InventorCarl W. Moreland
Life of this patent
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Abstract
Pipelined ADC systems are provided with gain-matching structures that substantially eliminate gain errors between preceding and succeeding converter stages. These structures include reference signal-conditioning elements which mimic at least one of main signal-conditioning elements in the succeeding converter stages. The reference signal-conditioning elements control reference signals which maintain a match between the full-scale range of a digital-to-analog converter (DAC) in a succeeding stage and the “gained-up” step size of a DAC in a preceding stage. This match substantially eliminates the gain errors.
Claims27
A pipelined analog-to-digital converter system that converts an analog input signal to a corresponding digital output signal, the system comprising:
- successive converter stages that each provides respective bits of said digital output signal and provides a respective residue signal to a succeeding converter stage with the aid of a respective digital-to-analog converter (DAC) that converts said respective bits with a respective conversion gain that varies in accordance with a respective reference signal wherein at least one of said converter stages includes a main pipeline of main signal-conditioning elements that interact with a respective DAC to process a preceding residue signal into a succeeding residue signal;
- and
- a reference pipeline of reference signal-conditioning elements that mimic at least one of said main signal-conditioning elements wherein said reference pipeline processes a preceding reference signal into a succeeding reference signal.
A pipelined analog-to-digital converter system that converts an analog input signal to a corresponding digital output signal, the system comprising:
- a preceding converter stage that provides preceding bits of said digital output signal and provides a preceding residue signal with the aid of a preceding digital-to-analog converter (DAC) that converts said preceding bits with a preceding conversion gain that varies in accordance with a preceding reference signal;
- a succeeding converter stage that provides succeeding bits of said digital output signal and processes said preceding residue signal into a succeeding residue signal with a main pipeline of main signal-conditioning elements and a succeeding DAC that converts said succeeding bits with a succeeding conversion gain that varies in accordance with a succeeding reference signal;
- and
- in said succeeding converter stage, a reference pipeline of reference signal-conditioning elements that each mimic a corresponding one of said main signal-conditioning elements wherein said reference pipeline processes said preceding reference signal into said succeeding reference signal.
A pipelined analog-to-digital converter (ADC) that converts an analog input signal to a corresponding digital output signal, comprising:
- a preceding converter stage that includes:
- a) a preceding ADC that converts said analog input signal into preceding bits of said digital output signal;
- b) a preceding pipeline of preceding signal-conditioning elements that processes said analog input signal into a preceding pipelined signal;
- and
- c) a preceding digital-to-analog converter (DAC) that converts said preceding bits to a preceding analog signal with a conversion gain in accordance with a preceding reference signal and subtracts said preceding analog signal from said preceding pipelined signal to generate a preceding residue signal;
- and
- a succeeding converter stage that includes:
- a) a succeeding pipeline of succeeding signal-conditioning elements that processes said preceding residue signal into first and second succeeding pipelined signals;
- b) a succeeding ADC that converts said first succeeding pipelined signal into succeeding bits of said digital output signal;
- c) a reference pipeline of reference signal-conditioning elements that mimic at least one of said succeeding signal-conditioning elements wherein said reference pipeline processes said preceding reference signal into a succeeding reference signal;
- and
- c) a succeeding DAC that converts said succeeding bits to a succeeding analog signal with a conversion gain in accordance with said succeeding reference signal and subtracts said succeeding analog signal from said second succeeding pipelined signal to generate a succeeding residue signal.
Dependencies are inferred from the claim text.