Multi-stage analog to digital converter
AssigneeSemiconductor Components Industries, LLC
InventorSinisa Milicevic
Life of this patent
Estimating the term…
Abstract
A multi-stage analog-to-digital converter (ADC) suitable for low power applications, such as glucose monitoring, may be required to digitize a slow-moving signal. As such, a multi-stage ADC must be versatile. Accordingly, the multi-stage ADC can be configured to operate at different bandwidths and resolutions through the use of ADC stages that can be enabled or disabled in an exchange between resolution and speed. Each ADC stage digitizes an input signal (e.g., a voltage or a current) using an analog comparison to access a lookup table for a digital signal that represents the input signal at a particular accuracy. Unlike other multi-stage approaches, the digitization is asynchronous (i.e., requires no clock) and can provide simplicity, speed, and low-power operation to the multi-stage ADC.
Claims20
A multi-stage analog-to-digital converter (ADC) for generating a digital word representing an analog sample of a signal, the multi-stage ADC comprising:
- an ADC stage included in a sequence of ADC stages, the ADC stage configured to:
- access a lookup-table, based on an input signal received by the ADC stage and a reference level received by the ADC stage, and output a digital word segment corresponding to a level of the input signal relative to the reference level;
- and
- a synchronizing and recording circuit configured to:
- combine digital word segments from the sequence of ADC stages to generate the digital word representing the analog sample of the signal.
A multi-stage analog-to-digital converter (ADC), the multi-stage ADC comprising:
- a sequence of ADC stages, each ADC stage including:
- a front-end computing portion configured to:
- compare an input signal received by the ADC stage to reference ranges set by a reference level received by the ADC stage, and
- generate, based on the comparison, a plurality of signals, each of the plurality of signals representing the input signal compared to one of the reference ranges;
- an encoding portion configured to:
- retrieve a digital word segment stored in a lookup-table based on the plurality of signals, and
- output the digital word segment;
- and
- a quantum level computing portion configured to:
- generate a next reference level for a next ADC stage in the sequence of ADC stages,
- generate a next input signal for the next ADC stage in the sequence of ADC stages, and
- transmit the next reference level and the next input signal to the next ADC stage in the sequence of ADC stages.
A method for analog to digital conversion, the method comprising:
- determining a first level of an input signal relative to a reference level;
- accessing a lookup-table based on the first level to obtain a first digital word segment;
- adjusting the input signal and the reference level to obtain an adjusted input signal and an adjusted reference level;
- determining a second level of the adjusted input signal relative to the adjusted reference level;
- accessing a lookup-table based on the second level to obtain a second digital word segment;
- and
- combining the first digital word segment and the second digital word segment to obtain a digital representation of the input signal.
Dependencies are inferred from the claim text.