Round-Robin Nyquist ADC Sensing for Low-Latency Sensor Readout
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Solution Overview
Problem
Conventional sensor technologies using sigma-delta analog-to-digital converters (ADCs) face high latency and increased current consumption due to filtering and quantization noise, which hinder efficient digitization of sensor signals.
Innovation Solution
Implementing a group of continuous-time Nyquist rate ADCs in a round-robin manner, where a multiplexer selects sensor output signals and a sense amplifier converts them to analog signals, which are then converted to digital signals by continuous-time Nyquist rate ADCs, reducing latency, circuit size, and current draw.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sigma-delta ADCs are used for digitizing sensor signals, then measurement precision is improved, but latency increases and current consumption increases
Solution Approach 1:
The patent divides the sensor system into multiple independent sensing channels, each with its own continuous-time Nyquist rate ADC. This segmentation allows parallel processing of multiple sensor signals without the need for complex filtering operations, thereby reducing latency while maintaining digitization precision.
Solution Approach 2:
The patent employs periodic sampling at the Nyquist rate for each sensing channel. By sampling at regular intervals matching the signal frequency characteristics, the system achieves accurate digitization without requiring the continuous filtering operations of sigma-delta ADCs, thus reducing latency.
2Measurement precision
If sigma-delta ADCs are used for digitizing sensor signals, then measurement precision is improved, but current consumption increases
Solution Approach 1:
The patent segments the ADC functionality across multiple continuous-time Nyquist rate converters operating in parallel. Each converter handles a specific sensing channel with simplified conversion logic, reducing the overall computational burden and power consumption compared to a single sigma-delta ADC processing all channels sequentially with complex filtering.
Solution Approach 2:
The continuous-time Nyquist rate ADCs perform conversion continuously at the Nyquist rate without the need for lengthy filtering and decimation operations. This continuous action maintains measurement precision while significantly reducing the time and energy required for each conversion cycle.
3Ease of manufacture
If conventional sensor technologies are used, then ease of manufacture is maintained, but device complexity increases due to filtering and quantization noise handling
Solution Approach 1:
The patent extracts the filtering and quantization noise handling functions from the ADC circuitry itself. By using continuous-time Nyquist rate ADCs that sample at the Nyquist rate, the system eliminates the need for complex digital filtering and noise shaping circuits, thereby reducing device complexity while maintaining ease of manufacture.
Data Source
AI summary
Facilitating a reduction in sensor system latency, circuit size, and current draw utilizing a group of continuous-time Nyquist rate analog-to-digital converters (ADCs) in a round-robin manner is presented herein. A sensor system can comprise a group of sensors that generate respective sensor output signals based on an external excitation of the sensor system; a multiplexer that facilitates a selection, based on a sensor selection input, of a sensor output signal of the respective sensor output signals corresponding to a sensor of the group of sensors; a sense amplifier comprising a charge or voltage sensing circuit that converts the sensor output signal to an analog output signal; and a continuous-time Nyquist rate analog-to-digital converter of the group of continuous-time Nyquist rate ADCs that converts the analog output signal to a digital output signal representing at least a portion of the external excitation of the sensor system.