Reconfigurable Amplifier Circuit for Low-Noise Biosignal Switching
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Solution Overview
Problem
Instrumentation amplifiers face challenges in effectively measuring and amplifying both voltage and current biosignals, such as ECG and PPG, due to noise interference from voltage inputs during current measurement modes.
Innovation Solution
A reconfigurable amplifier system that selects between voltage and current inputs based on measurement modes, using a first amplifying circuit to block current flow in current measurement modes and a second amplifying circuit to mirror currents, thereby generating output voltages while minimizing noise from voltage inputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the amplifier uses a single configuration to measure both voltage and current biosignals, then it can handle multiple signal types, but noise interference occurs during current measurement due to voltage input connections
Solution Approach 1:
The amplifier dynamically reconfigures its circuit topology based on the measurement mode. During current measurement, the first switching element connects the first input terminal to ground, blocking voltage input. During voltage measurement, the switching element connects the first input terminal to the first amplifying circuit. This dynamic reconfiguration allows the same hardware to adapt to different measurement requirements without noise interference.
Solution Approach 2:
The amplifier is divided into separate functional paths: a first amplifying circuit for voltage signals and a second amplifying circuit for current signals. The first amplifying circuit includes a transimpedance amplifier for converting current to voltage, while the second amplifying circuit directly processes voltage inputs. This segmentation allows independent optimization of each signal path and prevents cross-interference between voltage and current measurement modes.
2Object-affected harmful factors
If the amplifier blocks current flow through the first load element during current measurement mode, then noise from voltage input is eliminated, but the circuit complexity increases due to additional switching elements
Solution Approach 1:
The first switching element serves multiple functions: it acts as a noise isolation switch during current measurement by grounding the first input terminal, and it serves as a signal routing switch during voltage measurement by connecting the first input terminal to the first amplifying circuit. This multi-functionality reduces the need for additional dedicated switching elements, thereby limiting the increase in circuit complexity while achieving effective noise suppression.
3Measurement precision
If the amplifier uses separate amplifying circuits for voltage and current inputs, then measurement precision is improved, but the device complexity increases
Solution Approach 1:
The amplifier merges the voltage and current measurement functions into a single integrated circuit architecture. The first amplifying circuit with transimpedance amplifier handles both voltage inputs directly and current inputs through impedance conversion. The second amplifying circuit provides additional voltage amplification capability. By merging these functions and using switching elements to route signals appropriately, the design achieves high measurement precision for both signal types without requiring completely separate amplifier modules, thus limiting the increase in device complexity.
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
The system effectively amplifies both voltage and current biosignals by reducing noise interference, improving measurement performance and compatibility with various biosignal types.
Implementation Method 1
a second amplifying circuit configured to mirror a current flowing through the first amplifying circuit in response to one of the voltage input and the current input and generate an output voltage based on the mirrored current
Data Source
AI summary
Disclosed is a reconfigurable amplifier and an amplification method thereof, the amplifier includes an input selector, a first amplifying circuit, and a second amplifying circuit. The input selector is configured to select one of a voltage input and a current input based on a voltage measurement mode and a current measurement mode. The first amplifying circuit includes a first load element, and is configured to apply a voltage corresponding to the voltage input to the first load element in the voltage measurement mode and receive the current input in the current measurement mode and block a current flowing through the first load element. The second amplifying circuit is configured to mirror a current flowing through the first amplifying circuit in response to one of the voltage input and the current input and generate an output voltage based on the mirrored current.