Current-Mode ADC With Single-Line Sensing for Picoamp Resolution
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Solution Overview
Problem
Prior art analog to digital converters (ADCs) are power consumptive, provide low resolution, and fail to meet performance requirements in various applications due to inadequate power budget and resolution accuracy.
Innovation Solution
The development of novel ADC designs and architectures that enable high-resolution digital format data conversion with simultaneous drive and sense capabilities, utilizing a single line for both driving and sensing analog signals, and incorporating non-linear N-bit digital to analog converters (DACs) for broad dynamic range sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If prior art ADC designs are used, then device complexity is reduced, but power consumption increases and resolution decreases
Solution Approach 1:
The patent combines drive and sense capabilities into a single line interface, merging multiple functions (driving the sensor and sensing the signal) into one communication path. This reduces the number of separate circuit components and interconnections, thereby reducing device complexity while maintaining high resolution through the integrated architecture.
Solution Approach 2:
The single line serves multiple functions: it acts as both a drive line for powering the sensor and a sense line for reading the sensor output. This multi-functional approach reduces the number of dedicated components needed, lowering device complexity while preserving measurement precision through the unified interface design.
2Measurement precision
If prior art ADC designs are used, then device complexity is reduced, but measurement precision decreases
Solution Approach 1:
The patent integrates drive and sense operations into a single line, combining multiple functional paths into one. This merging reduces the number of separate circuit blocks and interconnections required, simplifying the overall device architecture while enabling high-resolution measurements through the integrated signal path.
3Reliability
If conventional ADC architectures are used, then ease of manufacture is improved, but performance requirements are not met
Solution Approach 1:
The single line interface performs multiple functions (driving and sensing), reducing the number of separate components that need to be manufactured and assembled. This multi-functional design simplifies the manufacturing process while achieving high performance through the integrated architecture that reduces signal path complexity.
4Measurement precision
If prior art ADCs are used, then power budget is sufficient, but resolution accuracy is inadequate
Solution Approach 1:
The integrated single-line architecture combines drive and sense functions, reducing the number of separate amplifiers, multiplexers, and interconnections required in conventional ADCs. This consolidation reduces static and dynamic power consumption while maintaining high resolution accuracy through the streamlined signal path and reduced noise floor.
Data Source
AI summary
An analog to digital converter (ADC) senses an analog signal (e.g., a load current) to generate a digital signal. The ADC operates based on a load voltage produced based on charging of an element (e.g., a capacitor) by a load current and a digital to analog converter (DAC) output current (e.g., from a N-bit DAC). The ADC generates a digital output signal representative of a difference between the load voltage and a reference voltage. This digital output signal is used directly, or after digital signal processing, to operate an N-bit DAC to generate a DAC output current that tracks the load current. The digital output signal provided to the N-bit DAC is an inverse function of the load current. The ADC is operative to sense very low currents (e.g., currents as low as is of pico-amps) and consume very little power (e.g., less than 2 μW).