Auto-Ranging ADC Current Sensing Across Wide Dynamic Range
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Solution Overview
Problem
Conventional analog-to-digital converters (ADCs) require high resolution and large die area to accurately measure current over a wide range, from amperes to microamperes, leading to increased power consumption and die area requirements, which is inefficient for power management in electronic systems.
Innovation Solution
An auto-ranging analog-to-digital converter (ADC) system with a dynamically configurable transistor arrangement and replica device that scales inputs by generating a replicated load current and voltage, allowing the ADC to dynamically configure its transistor arrangement based on digital values to achieve high precision current measurement with reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a very high resolution ADC (16-bit and more) is used to measure current over a wide range, then measurement precision is improved, but die area requirements increase
Solution Approach 1:
The patent divides the current measurement range into multiple segments or ranges. Instead of using a single high-resolution ADC for the entire range, the system segments the measurement task into multiple lower-resolution ADCs, each optimized for specific current ranges. This segmentation allows accurate measurement across the full range while reducing the die area required compared to a single 16-bit ADC.
Solution Approach 2:
The patent employs dynamic ranging capability where the ADC can automatically adjust its measurement range based on the input signal magnitude. The system dynamically switches between different measurement ranges or configurations, allowing a lower-resolution ADC to achieve effective high-resolution measurement across a wide current range by adapting to the signal level, thereby reducing die area while maintaining precision.
2Measurement precision
If a very high resolution ADC (16-bit and more) is used to measure current over a wide range, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent segments the measurement function across multiple lower-resolution ADCs instead of using one high-resolution ADC. Each ADC operates at lower power levels, and by dividing the measurement task, the total power consumption is reduced while maintaining the required measurement precision through coordinated operation of the segmented ADCs.
Solution Approach 2:
The dynamic ranging mechanism allows the ADC to operate at optimal power levels by adjusting its measurement range based on signal magnitude. When high current is present, the ADC operates in a lower-resolution mode consuming less power; when low current requires higher precision, the system dynamically adjusts to maintain accuracy only when necessary, reducing overall power consumption compared to continuously operating at maximum resolution.
3Measurement precision
If multiple ADCs are used to perform current sensing, then measurement precision over wide range is improved, but die area requirements increase
Solution Approach 1:
The patent applies segmentation by dividing the current measurement range into multiple segments, with each ADC dedicated to measuring a specific segment. This segmentation strategy allows the use of multiple simpler, lower-resolution ADCs that collectively cover the full measurement range, reducing total die area compared to using fewer high-resolution ADCs while maintaining measurement precision across all ranges.
4Measurement precision
If multiple ADCs are used to perform current sensing, then measurement precision over wide range is improved, but power consumption increases
Solution Approach 1:
The patent segments the measurement function across multiple ADCs, but optimizes the configuration so that not all ADCs operate simultaneously at full power. By segmenting the measurement ranges and using switching mechanisms, the system activates only the necessary ADCs for the current measurement range, reducing total power consumption compared to running multiple ADCs continuously while maintaining measurement precision.
Data Source
AI summary
Embodiments of the present disclosure provide a method and system for an auto-ranging analog-to-digital converter (ADC) for dynamically scaling inputs to an ADC. The auto-ranging ADC includes a dynamically configurable transistor arrangement for delivering a load current and a replica device for replicating the load current. A current sense resistor generates a replicated load voltage based on the replicated current. The ADC generates a digital value based on the replicated load voltage. The auto-ranging ADC also includes an auto-ranging controller for dynamically configuring the transistor arrangement based on the digital value to scale the inputs to the ADC.