Multi-channel portable electroencephalogram acquisition system and portable PCB
By designing a multi-channel portable EEG acquisition system, the ADS1299 acquisition chip with high input impedance and high common mode rejection ratio is adopted, combined with independent circuit layout, the problem of weak and susceptible interference of EEG signals is solved, and high-quality EEG signal acquisition and display is achieved.
Patent Information
- Application Number
- CN202510849831.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-24
- Publication Date
- 2025-08-12
AI Technical Summary
The existing EEG acquisition technology has the problem of weak and easy interference in EEG signals, especially the scalp signal is only about 50μV and is easily affected by electromagnetic interference, making it difficult to accurately extract high-quality EEG signals.
A multi-channel portable EEG acquisition system is designed, including a power management module, a signal processing module and an acquisition module. Through amplification, filtering and anti-interference processing, the ADS1299 acquisition chip with high input impedance and high common mode rejection ratio is adopted, and combined with independent analog and digital circuit layouts, high-quality signal acquisition is achieved.
It realizes high-quality EEG signal acquisition with strong anti-interference ability, low noise and low power consumption. It is suitable for portable applications, can clearly display the EEG waveform diagram, and has functional modular and efficient signal processing capabilities.
Smart Images
Figure CN120458599A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a multi-channel portable electroencephalogram (EEG) acquisition system and a portable PCB, belonging to the technical field of signal acquisition. Background Art
[0002] The acquisition of EEG signals is one of the important means to study brain activity. Currently, common EEG acquisition technologies mainly include electroencephalography (EEG), electrocorticography (ECoG), depth electrodes and functional magnetic resonance imaging (fMRI).
[0003] Electroencephalography (EEG) records the activity of neurons in the cerebral cortex by placing electrodes on the scalp. This relatively inexpensive and portable method is the most common neuroimaging method used in BCI (Brain-Computer Interface) research. The acquisition process involves placing electrodes on the surface of the scalp, typically secured with glue or a cap to ensure good contact between the electrodes and the scalp to reduce electromagnetic interference and signal contamination from muscle activity. Its advantage lies in its non-invasive nature, which can provide information on brain activity patterns in different states, such as sleep, wakefulness, and cognitive task execution, and can also be used to diagnose and monitor some brain diseases.
[0004] Electrocorticography (ECoG) involves surgically implanting electrodes onto the surface of the brain to record electrical activity. Compared to EEG, ECoG sensors have better spatial resolution and can accurately detect high-frequency brain activity that EEG cannot capture. The ECoG acquisition process requires neurosurgery to implant electrodes and is usually used before epilepsy surgery or for severely disabled patients.
[0005] Depth electrodes are also surgically implanted into the brain to record the electrical activity of neurons. This method is similar to ECoG, but records activity from a small group of neurons, providing a different picture of brain activity. Depth electrode acquisition also requires neurosurgery and is primarily used for epilepsy surgery or other medical needs.
[0006] While functional magnetic resonance imaging (fMRI) cannot directly measure electrical activity, it can be used to measure changes in cerebral blood flow associated with various mental activities. However, fMRI systems require strong magnetic fields, making them expensive and difficult to carry. It is primarily used to study brain function and structure, rather than to monitor brain activity in real time.
[0007] EEG is widely used because of its non-invasiveness and relatively low cost. The EEG signal is the sum of the postsynaptic potentials of the cerebral cortex neuron groups recorded from the cerebral cortex or scalp surface. It contains a large amount of physiological and pathological information and is a very typical bioelectric signal. The EEG signal can be divided into different brain waves according to the frequency and amplitude of the signal. Brain waves are easily affected by a person's physiological condition and mainly reflect the electrical activity characteristics of the brain. However, the EEG signal is a highly random and non-stationary signal with a very weak amplitude and a frequency range of 0.5~50HZ. Generally, the scalp signal is only about 50μV, and any signal exceeding ±100μV can be regarded as noise.
[0008] Due to the characteristics of weak EEG signals and susceptibility to interference, in order to accurately extract EEG signals, a multi-channel portable EEG acquisition system with high input impedance, high common mode rejection ratio, and high security is urgently needed. Summary of the Invention
[0009] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a multi-channel portable EEG acquisition system and a portable PCB.
[0010] In order to solve the above technical problems, the present invention is implemented by adopting the following technical solutions.
[0011] In a first aspect, the present invention discloses a multi-channel portable EEG acquisition system, comprising: a main control module, a power management module, an acquisition module, and a signal processing module; The power management module is used to supply power to the main control module, the acquisition module and the signal processing module; The signal processing module is used to amplify the multiple noisy brain signals so that they fall within the effective quantization interval of the acquisition module, and to perform bandpass filtering on the amplified noisy brain signals to obtain multiple noise-removed EEG signals; The acquisition module is used to collect the multi-channel EEG signals after noise removal and transmit them to the main control module; The main control module is used to control the signal processing module and the acquisition module to work, and transmit the EEG signal after noise removal to the host computer for EEG waveform display.
[0012] Furthermore, the power management module includes a linear regulator power supply circuit, a battery power supply circuit, and a USB power supply circuit; The voltage regulator power supply circuit is used to input voltage through the external interface J3 and output stable voltages of different magnitudes through multiple low-dropout linear regulators; The battery charging circuit is used to charge through the first USB interface, and a circuit protection is provided between the battery and the USB charging port so that the battery is charged at a constant current in the initial charging stage and switches to a constant voltage mode when the battery voltage approaches the full charge voltage; The USB power supply circuit is connected to the USB port of the computer through the second USB interface to supply power, and at the same time realizes a serial port connection with the USB port of the computer.
[0013] Furthermore, the signal processing module includes several groups of processing circuits; Each group of processing circuits is used to receive two noisy brain signals, amplify the two noisy brain signals through a preamplifier, and perform band-pass filtering on the amplified noisy brain signals through a multi-stage operational amplifier to obtain an EEG signal after noise removal.
[0014] Furthermore, the preamplifier is used to amplify the brain signal containing noise by at least 1000 times to reach the mV level.
[0015] Furthermore, the multi-stage operational amplifier is used to limit the bandwidth of the input signal, allowing only the target frequency band to pass through.
[0016] Furthermore, the acquisition module includes an electrostatic discharge protection circuit, a filter circuit, and an ADS1299 acquisition chip circuit; Each channel of the EEG signal after noise removal is processed by the electrostatic discharge protection circuit and then input into the filter circuit for filtering. After filtering, each channel of the EEG signal after noise removal is transmitted to the ADS1299 acquisition chip circuit.
[0017] Furthermore, the main control module adopts a single chip microcomputer STM32F103RCT6 with a reset circuit.
[0018] In a second aspect, the present invention further discloses a portable PCB, comprising the multi-channel portable EEG acquisition system described in the first aspect.
[0019] Furthermore, the layout of the PCB is as follows: the analog area including the electrode interface, amplifier, and ADC front end is separated from the digital area including the MCU and Bluetooth communication module, the power module is independently partitioned, and independent paths connecting the power module are configured for the analog and digital circuits. The trace width on the PCB board is not greater than 10 mm.
[0020] The beneficial effects achieved by the present invention are: The present invention amplifies and filters EEG signals through the design of a power management module, a signal processing module, an acquisition module and a main control module, and then performs a series of signal processing, and uploads the processed EEG data to a host computer for display. This system has strong anti-interference ability and low noise, as well as the advantages of low power consumption, modular functions and portability. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 It is a schematic diagram of the system modules of the present invention; Figure 2 is a schematic diagram of a power management module of the present invention; Figure 3 is a circuit diagram of a power management module of the present invention; Figure 4 is a schematic diagram of a signal processing module of the present invention; Figure 5 is a circuit diagram of a signal processing module of the present invention; Figure 6 It is a schematic diagram of the acquisition module of the present invention; Figure 7 It is a circuit diagram of the acquisition module of the present invention; Figure 8 It is a schematic diagram of the main control module of the present invention; Figure 9 This is a schematic diagram of the main control module circuit of the present invention; Figure 10 It is a schematic diagram of EEG waveform; Figure 11 This is the EEG data analysis result of channel 1 of the ADS1299 acquisition chip; Figure 12 This is the EEG data analysis result of channel 2 of the ADS1299 acquisition chip; Figure 13 This is the result of EEG data analysis of channel 3 of the ADS1299 acquisition chip; Figure 14 It is a portable PCB design drawing. DETAILED DESCRIPTION
[0022] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.
[0023] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.
[0024] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.
[0025] Example 1, as Figure 1 As shown, this embodiment introduces a multi-channel portable EEG acquisition system, including: a main control module, a power management module, an acquisition module and a signal processing module; The power management module is used to supply power to the main control module, the acquisition module and the signal processing module; The signal processing module is used to amplify the multiple noisy brain signals so that they fall within the effective quantization interval of the acquisition module, and to perform bandpass filtering on the amplified noisy brain signals to obtain multiple noise-removed EEG signals; The acquisition module is used to collect the multi-channel EEG signals after noise removal and transmit them to the main control module; The main control module is used to control the signal processing module and the acquisition module to work, and transmit the EEG signal after noise removal to the host computer for EEG waveform display.
[0026] like Figure 2 As shown, the power management module includes a linear regulator power supply circuit, a battery power supply circuit, and a USB power supply circuit; The voltage regulator power supply circuit is used to input voltage through the external interface J3 and output stable voltages of different magnitudes through multiple low-dropout linear regulators; The battery charging circuit is used to charge through the first USB interface, and a circuit protection is provided between the battery and the USB charging port so that the battery is charged at a constant current in the initial charging stage and switches to a constant voltage mode when the battery voltage approaches the full charge voltage; The USB power supply circuit is connected to the USB port of the computer through the second USB interface to supply power, and at the same time realizes a serial port connection with the USB port of the computer.
[0027] The signal processing module includes several groups of processing circuits; like Figure 4 As shown, each group of processing circuits is used to receive two noisy brain signals, amplify the two noisy brain signals through a preamplifier, and perform band-pass filtering on the amplified noisy brain signals through a multi-stage operational amplifier to obtain an EEG signal after noise removal.
[0028] The preamplifier is used to amplify the brain signal containing noise by at least 1000 times to reach the mV level.
[0029] The multi-stage operational amplifier is used to limit the bandwidth of the input signal and only allow the target frequency band to pass.
[0030] like Figure 6 As shown, the acquisition module includes an electrostatic discharge protection circuit, a filter circuit, and an ADS1299 acquisition chip circuit; Each channel of the EEG signal after noise removal is processed by the electrostatic discharge protection circuit and then input into the filter circuit for filtering. After filtering, each channel of the EEG signal after noise removal is transmitted to the ADS1299 acquisition chip circuit.
[0031] like Figure 8 As shown, the main control module adopts a single-chip microcomputer STM32F103RCT6 with a reset circuit.
[0032] Example 2, based on the same inventive concept as Example 1, this example introduces a multi-channel portable EEG acquisition system, such as Figure 1 As shown in the figure, it includes a power management module, a signal processing module, an acquisition module, and a main control module. This system amplifies and filters EEG signals, then performs a series of signal processing through acquisition and control circuits, and uploads the processed EEG data to a host computer for display. This system has strong anti-interference capabilities, low noise, low power consumption, modular functions, and portability.
[0033] like Figure 2 and Figure 3As shown, the power management module includes a linear regulator power supply circuit, a battery power supply circuit, and a USB power supply circuit. The regulator power supply circuit primarily utilizes components U1 (LP5907), U2 (TLV700), U3 (LM2664), and U4 (TPS72325). An external power supply connects to the entire system via interface J3. This power supply circuit also facilitates system debugging and prevents component failure from causing system failure. The battery power supply circuit includes a battery charging circuit and a battery protection circuit. The battery charging circuit is primarily implemented by USB1 and charges when the battery is low. To ensure stable charging, U13 (TP4056) is used for circuit protection. Initially, the battery is charged at a constant current. When the battery voltage approaches the full charge voltage, the circuit switches to a constant voltage mode, ensuring rapid charging without overcharging and damaging the battery, thereby effectively extending battery life. The USB power supply circuit allows the entire system to be powered directly from a computer's USB port when no external power supply or battery is available.
[0034] The signal processing module describes EEG signals as weak signals generated by brain neuronal activity, with amplitudes at only microvolts and susceptible to various interference sources. To extract authentic and effective EEG signals from complex noisy environments, a signal processing circuit is incorporated before acquisition. To prevent interference from increasing, the preamplifiers (INA826) U15, U20, U24, and U28 amplify the signals by more than 1000 times, bringing them to the mV level. This ensures they fall within the ADC's effective quantization range and avoids resolution loss due to excessively small signals. Due to the unique nature of EEG frequencies, a bandpass filter (OPA2277) is incorporated into the amplifier. This design limits the signal bandwidth, allowing only the target frequency band to pass through, reducing interference from irrelevant components on subsequent analysis.
[0035] The acquisition module uses the 24-bit acquisition chip ADS1299 with high precision, multi-channel synchronization, high anti-interference ability and low power consumption. In order to improve the reliability, stability and service life of the system, this design designs ESD circuit and capacitor filtering at the input front end of the acquisition circuit.
[0036] The main control module (MCU) is the STM32F103RCT6 microcontroller with high cost performance, rich peripherals and low power consumption. In order to ensure that the MCU and peripherals enter the initialization state when the system is powered on or when the program is abnormal, and to ensure stable operation of the system, a reset circuit is designed in the main control circuit.
[0037] The system designed in this paper collects data through the host computer and uses eeglab to analyze the collected data. The results of the analysis are as follows: Figure 10-13As shown. The EEG waveform diagram shows that the processed EEG waveform quality is acceptable. The EEG topography diagram shows that EEG activity in the specific area where the electrodes are placed is relatively strong, and the EEG signal is relatively stable and normal in spatial distribution. The baseline in the EEG time-domain waveform diagram is relatively stable, without significant fluctuations, and has a certain degree of periodicity, indicating that the signal retains EEG rhythm characteristics and is of good quality. The EEG time-domain diagram shows that the scalp discharge caused by the stimulation event during the paradigm is obvious, and the energy of different frequency bands can be clearly seen to change over time, indicating that the time domain resolution is acceptable and the signal can well support time domain analysis. The power spectrum density diagram does not show abnormally high power in areas such as the high-frequency band, and the energy peak is normal. In summary, the EEG signal collected by the system is of good quality, with low interference, and can well reflect the characteristics of normal electrical activity in the brain.
[0038] Example 3 is based on the same inventive concept as the other examples. Figure 14 As shown, this embodiment introduces a portable PCB, including the multi-channel portable EEG acquisition system described in the second aspect.
[0039] To achieve portability, small-package devices were selected for board manufacturing. Hardware PCB layout optimization mainly focused on separating the analog area (electrode interface, amplifier, ADC front end) from the digital area (MCU, Bluetooth communication module). The power module was partitioned independently, and independent paths for connecting the power module were configured for the analog and digital circuits. The trace width on the PCB board was no more than 10mm, and vias and right-angle turns were avoided. Impedance matching was ensured for the ADC input traces. Multi-layer PCB layered grounding was used, and a single-point connection between the analog ground and the digital ground was achieved through a 0Ω resistor. A protective ground was set for the electrode interface. In terms of component layout, the decoupling capacitor was placed close to the chip power pins, and a ground guard ring was drawn for high-impedance components.
[0040] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.
Claims
1. A multi-channel portable EEG acquisition system, characterized in that: include: Main control module, power management module, acquisition module and signal processing module; The power management module is used to supply power to the main control module, the acquisition module and the signal processing module; The signal processing module is used to amplify the multiple noisy brain signals so that they fall within the effective quantization interval of the acquisition module, and to perform bandpass filtering on the amplified noisy brain signals to obtain multiple noise-removed EEG signals; The acquisition module is used to collect the multi-channel EEG signals after noise removal and transmit them to the main control module; The main control module is used to control the signal processing module and the acquisition module to work, and transmit the EEG signal after noise removal to the host computer for EEG waveform display.
2. The multi-channel portable EEG acquisition system according to claim 1, characterized in that: The power management module includes a linear regulator power supply circuit, a battery power supply circuit, and a USB power supply circuit; The voltage regulator power supply circuit is used to input voltage through the external interface J3 and output stable voltages of different magnitudes through multiple low-dropout linear regulators; The battery charging circuit is used to charge through the first USB interface, and a circuit protection is provided between the battery and the USB charging port so that the battery is charged at a constant current in the initial charging stage and switches to a constant voltage mode when the battery voltage approaches the full charge voltage; The USB power supply circuit is connected to the USB port of the computer through the second USB interface to supply power, and at the same time realizes a serial port connection with the USB port of the computer.
3. The multi-channel portable EEG acquisition system according to claim 1, characterized in that: The signal processing module includes several groups of processing circuits; Each group of processing circuits is used to receive two noisy brain signals, amplify the two noisy EEG signals through a preamplifier, and perform band-pass filtering on the amplified noisy EEG signals through a multi-stage operational amplifier to obtain EEG signals after noise removal.
4. The multi-channel portable EEG acquisition system according to claim 3, characterized in that: The preamplifier is used to amplify the EEG signal containing noise by at least 1000 times to reach the mV level.
5. The multi-channel portable EEG acquisition system according to claim 3, characterized in that: The multi-stage operational amplifier is used to limit the bandwidth of the input signal and only allow the target frequency band to pass through.
6. The multi-channel portable EEG acquisition system according to claim 1, characterized in that: The acquisition module includes an electrostatic discharge protection circuit, a filter circuit, and an ADS1299 acquisition chip circuit; Each channel of the EEG signal after noise removal is processed by the electrostatic discharge protection circuit and then input into the filter circuit for filtering. After filtering, each channel of the EEG signal after noise removal is transmitted to the ADS1299 acquisition chip circuit.
7. The multi-channel portable EEG acquisition system according to claim 1, characterized in that: The main control module adopts a single chip microcomputer STM32F103RCT6 with a reset circuit.
8. A portable PCB, characterized in that: include: The multi-channel portable EEG acquisition system according to any one of claims 1 to 7.
9. The portable PCB according to claim 8, characterized in that: The layout of the PCB is as follows: the analog area including the electrode interface, amplifier, and ADC front end is separated from the digital area including the MCU and Bluetooth communication module, the power module is independently partitioned, and independent paths connecting the power module are configured for the analog and digital circuits. The trace width on the PCB board is not greater than 10 mm.