Multi-Sensor Signal Processing Circuit With Shared Voltage ADC
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Solution Overview
Problem
Existing signal processing systems require separate ADCs for processing current-based and voltage-based sensor signals, leading to inefficiencies and potential time delays in processing multiple sensor types.
Innovation Solution
A signal processing circuit that processes two current-based sensor signals in parallel using a single voltage-based ADC by converting one current signal to the voltage domain, with selection units to route signals to appropriate ADCs and a current-voltage converter, allowing flexible operation and simultaneous digital conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate ADCs are provided for current-based and voltage-based sensor signals, then each sensor type can be processed independently, but the device complexity and cost increase
Solution Approach 1:
The voltage-based ADC is designed to handle both voltage-based sensor signals directly and current-based sensor signals after current-to-voltage conversion. The selection unit routes current-based signals through the current-voltage converter before the voltage ADC, while voltage-based signals are routed directly to the voltage ADC, allowing one ADC to serve multiple signal types
Solution Approach 2:
A current-voltage converter is introduced as an intermediary component between the current-based sensor input and the voltage-based ADC. This converter transforms current signals into voltage signals that the voltage ADC can process, enabling current-based sensors to use the same ADC as voltage-based sensors
2Device complexity
If a single voltage-based ADC is shared for both current-based and voltage-based sensor signals, then device complexity is reduced, but time delays may occur in signal processing
Solution Approach 1:
The signal processing path is segmented into two parallel channels: one for current-based signals (through current-voltage converter) and one for voltage-based signals (direct path). The selection unit dynamically assigns signals to appropriate channels, allowing simultaneous processing without time delays
Solution Approach 2:
The selection unit provides dynamic routing capability, automatically selecting the appropriate processing path for each sensor signal based on its type. This dynamic assignment ensures that current-based and voltage-based signals are processed simultaneously through different paths, eliminating time delays
3Productivity
If dedicated ADCs are provided for each current-based sensor signal, then parallel processing is enabled, but the cost and device complexity increase
Solution Approach 1:
The voltage-based ADC is designed to universally process both voltage-based sensor signals and current-based sensor signals (after conversion). This multi-functionality allows multiple sensor signals to be processed in parallel through a single ADC, eliminating the need for multiple dedicated ADCs while maintaining parallel processing capability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables simultaneous processing of multiple sensor signals without time delay, improving efficiency and flexibility in handling current and voltage-based inputs, particularly for applications like photoplethysmography and electrocardiogram measurements.
Implementation Method 1
a current-voltage converter, coupled between the second current output of the first selection unit and the second voltage input of the second selection unit
Data Source
AI summary
A signal processing circuit includes a first current sensor input, a second current sensor input, a voltage sensor input for receiving a sensor voltage, a first selection unit, a second selection unit, a current analog-digital converter (ADC), a voltage ADC, digital processing block, and a current-voltage converter. The first selection unit includes a first current input coupled to the first current sensor input, and a second current input coupled to the second current sensor input. The second selection unit includes a first voltage input coupled to the voltage sensor input and a second voltage input. The current ADC is coupled to a first current output. The voltage ADC is coupled to a voltage output. The digital processing block is coupled to outputs of the current ADC and the voltage ADC. The current-voltage converter is coupled between a second current output and the second voltage input.