# US 2021/0278450 A1 · Systems and methods to determine electrochemical impedance spectrogram rapidly in real time > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0278450 A1 - Document ID: US20210278450A1 - Status: Published application - Kind: A1 - Application number: 17/196,324 - Filed: 2021-03-09 - Published: 2021-09-09 - Earliest claimed: 2020-03-09 - Assignees: Arizona Board of Regents on behalf of Arizona State University - Inventors: Jitendran Muthuswamy - Web page: https://patentgrep.com/patent/US20210278450A1 ## CPC - G01R 27/08: Measuring resistance by measuring both voltage and current - G01R 31/389: Measuring internal impedance, internal conductance or related variables - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## Abstract Systems and methods to determine an electrochemical impedance spectrogram (EIS) rapidly in real time are provided. Embodiments described herein provide an approach to determine an EIS rapidly (e.g., much less than one second) over a wide band of frequencies. Since the EIS is a foundational diagnostic that is used in a wide variety of applications involving electrochemical events, the proposed approach will significantly impact a wide range of applications. Novel waveforms and systems analysis techniques are used to determine the electrochemical impedance over a wide range of frequencies simultaneously. Embodiments can be readily integrated into conventional electrochemical workstations and embedded devices. Other embodiments can be instantiated into custom-made hardware depending on the needs of a given application. The speed and resolution of the EIS obtained using this approach can be tailored to a wide variety of applications. ## Claims ### Claim 1 A method for measuring an electrochemical impedance spectrogram (EIS) in real time, the method comprising: applying a triangular excitation signal to a subject; obtaining electrical parameter measurements in response to the triangular excitation signal; and measuring an EIS of the subject based on the electrical parameter measurements. ### Claim 2 (depends on 1) The method of claim 1, wherein: the triangular excitation signal comprises a voltage signal; and the electrical parameter measurements comprise current measurements. ### Claim 3 (depends on 1) The method of claim 1, wherein: the triangular excitation signal comprises a current signal; and the electrical parameter measurements comprise voltage measurements. ### Claim 4 (depends on 1) The method of claim 1, wherein the triangular excitation signal comprises a sawtooth excitation signal. ### Claim 5 (depends on 1) The method of claim 1, wherein the triangular excitation signal comprises a ramp excitation signal. ### Claim 6 (depends on 1) The method of claim 1, wherein the triangular excitation signal has at least one of a non-uniform amplitude or a non-uniform period. ### Claim 7 (depends on 1) The method of claim 1, wherein measuring the EIS of the subject comprises determining a ratio of Fourier transforms of voltages of the triangular excitation signal and corresponding current measurements. ### Claim 8 (depends on 1) The method of claim 1, further comprising producing a sampling of the EIS at a plurality of frequencies. ### Claim 9 (depends on 8) The method of claim 8, further comprising determining an accuracy range of the sampling of the EIS. ### Claim 10 (depends on 9) The method of claim 9, wherein the accuracy range of the sampling of the EIS depends on at least one of: a mean square error between a profile of the subject and the measured samples; a material parameter of the subject; an amplitude of the triangular excitation signal; and a period of the triangular excitation signal. ### Claim 11 An electrochemical impedance spectrogram (EIS) measurement system, comprising: a working electrode configured to provide a triangular excitation signal to a subject; a counter electrode configured to measure an electrical parameter in response to the triangular excitation signal; and a processing device configured to obtain an EIS of the subject based on the triangular excitation signal and the measured electrical parameter. ### Claim 12 (depends on 11) The EIS measurement system of claim 11, wherein the counter electrode further provides a current return path from the working electrode. ### Claim 13 (depends on 11) The EIS measurement system of claim 11, further comprising a reference electrode configured to provide a reference voltage for the working electrode and the counter electrode. ### Claim 14 (depends on 11) The EIS measurement system of claim 11, wherein the counter electrode is further configured to provide a reference voltage. ### Claim 15 (depends on 11) The EIS measurement system of claim 11, further comprising measuring circuitry coupled to the counter electrode and configured to provide an indication of the electrical parameter to the processing device. ### Claim 16 (depends on 11) The EIS measurement system of claim 11, wherein the processing device is configured to obtain the EIS of the subject as a function of a fast Fourier transform (FFT) of the triangular excitation signal and a FFT of the measured electrical parameter. ### Claim 17 (depends on 16) The EIS measurement system of claim 16, further comprising a memory coupled to the processing device and storing the FFT of the triangular excitation signal. ### Claim 18 (depends on 17) The EIS measurement system of claim 17, wherein the memory further stores one or more measurement profiles, each measurement profile comprising excitation signal parameters. ### Claim 19 (depends on 18) The EIS measurement system of claim 18, wherein each of the one or more measurement profiles corresponds to a material of the subject. ### Claim 20 A non-transitory computer-readable medium which, when executed by a processing device, causes the processing device to: cause a triangular excitation signal to be applied to a subject; obtain electrical parameter measurements in response to the triangular excitation signal; and measure an electrochemical impedance spectrogram (EIS) of the subject based on the electrical parameter measurements.