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Published on: May 15, 2021
The simulation of current generator design for multi-frequency electrical impedance tomograph
Cheng-Yu Chen1, Yi-Yu Lu, Wen-Lung Huang
1Inst. of Biomed. Eng., Nat. Cheng Kung Univ., Tainan, Taiwan, ROC.
Summary
A new steady current generator using an enhanced Howland circuit and a high-speed amplifier ensures stable output for Electrical Impedance Tomography (EIT) systems across a broad frequency range, improving system design.
Area of Science:
- Electrical Engineering
- Biomedical Engineering
- Instrumentation
Background:
- Developing next-generation Electrical Impedance Tomography (EIT) systems requires a stable current generator with a wide bandwidth.
- Existing current generators may not meet the performance demands for advanced EIT applications.
Purpose of the Study:
- To design and simulate a steady current generator suitable for new EIT systems.
- To evaluate the performance of an enhanced Howland circuit with a high-speed operational amplifier for current generation.
Main Methods:
- Constructed an enhanced Howland circuit using a high-speed operational amplifier.
- Simulated the electronic model of the current generator using Orcad PSpice 9.2 software.
- Analyzed output current stability across multiple frequencies and varying load impedances.
Main Results:
- The THS4021 operational amplifier model demonstrated stable output current from 10 kHz to 1 MHz.
- Stable performance was observed with load impedances ranging from 200 Ohms to 2 kOhms.
- The design achieved a high output impedance of 2.1 MOhms at 1 MHz.
Conclusions:
- The enhanced Howland circuit with the THS4021 provides a viable solution for stable, broad-bandwidth current generation in EIT systems.
- Simulation results offer valuable insights for designing current generators for EIT applications.
- This approach contributes to the advancement of EIT system capabilities.
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