Passive bidirectional human body channel power supply and communication system

Abstract

The application discloses a passive bidirectional human body channel power supply and communication system, which comprises a chip device attached to or implanted in human tissue and an external electric control reading unit connected with the chip device through an electrode pair signal transmission, and the chip device and the external electric control reading unit are connected to form a power supply path, an uplink communication link and a downlink communication link; in the power supply path, the external electric control reading unit provides direct current power supply for the chip device; in the downlink communication link, the external electric control reading unit sends a pulse signal to the chip device, the chip device decodes the pulse signal and completes corresponding configuration; in the uplink communication link, the chip device sends a load signal on the human tissue side to the external electric control reading unit through a transistor current switch after pulse width modulation. The application can effectively reduce interference in the process of human body channel communication, realize passive uplink communication, eliminate a high-power transmitter in traditional human body channel communication and greatly reduce energy required for transmitting each bit of data.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of radio frequency signal transmission, and in particular to a passive bidirectional human body channel power supply and communication system. BACKGROUND

[0002] Wireless brain-machine interfaces (BMIs) transmit neural signals from the human / animal brain to external devices, providing an effective hardware tool for neurological disorder treatment and neuroscience research. Traditional wireless implant technology relies on bulky batteries, which can cause surgical pain and rejection reactions. In recent years, micro-BMI implants based on wireless power transmission (WPT) and wireless communication have adopted battery-free wireless technology. Currently, BMI implants require miniaturization, multi-channel, and deep brain access, and how to expand the data transmission rate and communication range of battery-free wireless chips is a challenge. There are several battery-free methods in the prior art: 1) Inductive coupling. Energy is transmitted from an external power source (TX) coil to an implanted power source (RX) coil, and communication between the implant and the external device can be active or passive. Miniature implant coils result in a short communication distance, and active / passive inductive coupling is limited by the wireless power range and power signal interference, respectively. For example, in "A 0.4mm3 Battery-Less Crystal-Less Neural-Recording SoC Achieving 1.6cm Backscattering Range with 2mm×2mm On-Chip Antenna", published in the top conference of integrated circuits VLSI in 2022, a 2mm 2 coil limits the communication distance to 1.6 centimeters. 2) Near-infrared (NIR) coupling. Due to the high loss of near-infrared in human tissue, a repeater coil is needed to expand the range, resulting in multiple implants, such as "A 0.19×0.17mm2 Wireless Neural Recording IC for Motor Prediction with Near-Infrared-Based Power and Data Telemetry", published in the top conference of integrated circuits ISSCC in 2020, which uses near-infrared to power the implant, but an additional repeater is needed to achieve effective power supply and communication. 3) Ultrasonic coupling. For example, in "A Sub-mm3 Ultrasonic Free-Floating Implant for Multi-Mote Neural Recording", published in the top journal of integrated circuits JSSC in November 2019, a 0.8mm 3Implants combined with ultrasonic devices, implant depth reaches 5 cm, but due to the large attenuation of ultrasonic waves in body tissue, the data transmission rate is limited to 35Kb / s.4) Active body channel communication (BCC). In August 2022, the top journal of integrated circuits JSSC published an article named "A Miniaturized Wireless Neural Implant With Body-Coupled Power Delivery and Data Transmission", through active body channel communication technology, the data transmission rate can be increased to 20.48Mbps, but it needs to consume 0.64mW of power consumption to drive the high-power transmitter (TX). In addition, the wireless power supply of all previous methods is through AC coupling, however, AC coupling as an interference signal of communication signal, has a strong blocking effect on external reception of wireless communication signal, reduces the quality of communication, and further shortens the effective range of wireless battery-free communication. SUMMARY

[0003] In order to solve the above technical problems existing in the prior art, the present application provides a passive bidirectional human body channel power supply and communication system based on direct current power supply and current switching, to increase the effective range of wireless battery-free communication and reduce the power consumption per bit required for communication, the specific technical scheme is as follows:

[0004] A passive bidirectional human body channel power supply and communication system, comprising: a chip device attached or implanted in human tissue and an external electrically controlled reading unit connected to it through an electrode pair signal transmission, the chip device and the external electrically controlled reading unit are connected to form a power supply path, an uplink communication link and a downlink communication link, in the power supply path, the external electrically controlled reading unit provides direct current power for the chip device; in the downlink communication link, the external electrically controlled reading unit sends pulse signals to the chip device, the chip device decodes the pulse signals and completes the corresponding configuration; in the uplink communication link, the chip device sends the load signal on the human tissue side to the external electrically controlled reading unit through the transistor current switch after pulse width modulation.

[0005] Further, the electrode pair includes an external electrode pair arranged and connected in the external electrically controlled reading unit and an internal electrode pair arranged and connected in the chip device, the external electrically controlled reading unit is provided with a direct current voltage source, the direct current voltage source is electrically connected to the external electrode pair and injects direct current, the current is conducted through the external electrode pair, the human tissue and the internal electrode pair and forms a current loop between the external electrode pair and the internal electrode pair.

[0006] Further, the chip device is provided with a power management module, the power management module receives the direct current voltage injected from the electrode pair, generates voltage signals and current signals required for the operation of the chip device.

[0007] Further, the chip device is internally provided with a pulse detection counter and a decoder, the external electric control reading unit is also provided with a pulse generating source, the pulse signal generated by the pulse generating source is transmitted to the pulse detection counter through the electrode pair, the pulse signal on the internal electrode pair is detected by the capacitor coupled amplifier in the pulse detection counter and amplified into a rail-to-rail digital signal, and then the pulse number is counted through the decoder, which corresponds to the writing of the specified register in the chip, so as to control the configuration of the internal register of the chip, that is, the downlink instruction signal is output through the decoder.

[0008] Further, the chip device is internally provided with a pulse detection counter and a decoder, the external electric control reading unit is also provided with a pulse generating source, the pulse signal generated by the pulse generating source is transmitted to the pulse detection counter through the electrode pair, the pulse signal on the internal electrode pair is detected by the capacitor coupled amplifier in the pulse detection counter and amplified into a rail-to-rail digital signal, and then the pulse number is counted through the decoder, which corresponds to the writing of the specified register in the chip, so as to control the configuration of the internal register of the chip, that is, the downlink instruction signal is output through the decoder.

[0009] Further, the external electric control reading unit is also provided with a reader, the reader is connected with the external electrode pair, and the reader detects the current change on the external electrode pair and restores it into a data signal of 0 and 1.

[0010] The beneficial effects of the present application are: the traditional wireless implant technology relies on heavy batteries, which can cause surgical pain and rejection, and the traditional wireless power communication technology is carried out through AC coupling, and the AC coupling acts as an interference signal of the communication signal, which has a strong blocking effect on the external reception of the wireless communication signal, reduces the communication quality, and further shortens the effective range of wireless battery-free communication. In the present application, DC power is used for power supply, and compared with the traditional AC transmission, the DC power transmission will not cause the blocking problem; a class-S current switching technology is proposed in the uplink communication link to carry out pulse width modulation; in the downlink communication link, a pulse detection counter and a decoder are used to process the pulse signal generated by the external pulse generating power source, the pulse number is recorded as the downlink communication link data to control the configuration of the internal register of the chip. The present application can effectively reduce the interference in the human body channel communication process under the efficient body tissue power supply, realize the passive uplink communication, eliminate the high-power transmitter in the traditional human body channel communication, greatly reduce the energy required for transmitting each bit of data; in addition, the pulse counting mode is used to realize the downlink communication, and the wireless power supply and bidirectional communication are completed on the basis of four electrodes. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1It is a passive bidirectional human body channel power supply and communication system principle diagram based on DC power supply and current switching of an embodiment of the present application;

[0012] Figure 2 It is a waveform diagram of the uplink communication link signal and the decoded PWM signal of an embodiment of the present application;

[0013] Figure 3 It is a test waveform diagram of the downlink communication link of an embodiment of the present application; DETAILED DESCRIPTION

[0014] In order to make the purpose, technical scheme and technical effect of the present application clearer, the present application is further described in detail below in combination with the drawings and embodiments of the present application.

[0015] An embodiment of the present application provides a passive bidirectional human body channel power supply and communication system based on DC power supply and current switching, which comprises a power supply path composed of two pairs of electrodes in contact with human tissues, an uplink communication link and a downlink communication link.

[0016] The power supply path adopts a DC power supply mode, comprising a DC voltage source and a power management module, and the implanted electrodes collect the DC voltage and send it to the power management module, which generates the voltage and current required for the chip to work, that is, the power management module supplies power for the chip. The DC power supply mode reduces interference in the communication process, the implanted electrodes collect DC, and the power management module converts the collected DC energy into corresponding voltage and current signals to wirelessly power the entire chip.

[0017] The uplink communication link uses PWM pulse width modulation technology, including a transistor current switch, through an amplitude-time converter (ATC) module, and uses a class-S current switching technology to switch pulses, instead of directly switching analog signals or switching methods through ADC to generate high-speed bit streams. The analog signal output by the front-end amplification circuit and the sawtooth wave signal output by the sawtooth wave generation circuit are converted into corresponding pulse width modulation signals PWM after ATC, and PWM switches the transistor current switch to achieve efficient outward transmission of data signals without interfering with wireless power supply. PWM technology is used to quantize analog signals, converting high-speed bit streams into pulse signals of different widths, thereby avoiding intersymbol interference caused by tissue resistance-capacitance effects. At the same time, since the switching of the current switch is a passive communication method, it does not require a high-power transmission unit, which can greatly reduce the power consumption of the overall system and reduce the energy required to transmit each bit of data.

[0018] The downlink communication link comprises a pulse detection counter and a decoder, which processes the pulse signal generated by the external pulse generator, and a capacitor-coupled amplifier in the pulse detection counter detects and amplifies the received pulse signal, and the number of pulses is recorded as the downlink communication link data. Specifically, the capacitor-coupled amplifier detects the pulse signal on the receiving electrode and amplifies it into a rail-to-rail digital signal, and then the decoder inside the chip counts the number of received pulses, and finally corresponds to the writing of a specified register, thereby completing the downlink instruction control of the chip by the external, that is, recording the number of pulses as the corresponding instruction to manipulate the register and complete the configuration of the chip.

[0019] The system of the embodiment of the application is used for communication of wearable or implantable devices, and the signal receiving device can be attached to the outside of human tissue or implanted in the human tissue.

[0020] The power supply path injects current into the external electrode pair through a direct current power supply, and the current is conducted through the two electrode pairs and the human tissue to form a current loop between the four electrodes, which can effectively reduce the blocking interference in the communication process relative to the alternating current power supply mode.

[0021] The external direct current voltage source acts on a pair of external electrodes to generate a current loop in the body tissue, and the passive body channel communication is realized through data switching. The external processing and decoding circuit, i.e., the external reader, can sense the change of the current and restore the data. In this way, the data can be transmitted from the implanted body to the external reader. At the same time, a class-S current switching technology is used for pulse width modulation to replace the direct switching mode of the analog signal or the switching method of generating a high-speed bit stream through an ADC, and the class-S current switching technology can convert the high-speed bit stream into a pulse signal with different widths, thereby avoiding the inter-symbol interference caused by the tissue resistance-capacitance effect.

[0022] Specifically, as shown in Figure 1 When there is a signal input on the external electrode pair, the signal passes through the body tissue medium and reaches the internal electrode pair located in the human tissue. The direct current power supply signal provides a power voltage for the chip through the power management module; the downlink pulse signal reaches the downlink decoding module based on pulse counting of the downlink communication link and is processed by the pulse detection counter and the decoder. Then, the capacitor-coupled amplifier of the pulse detection counter detects and amplifies the received pulse signal. At the same time, the analog signal and the sawtooth signal are converted into corresponding pulse width modulation signals PWM after passing through the ATC, the PWM switches the transistor current switch, and the data signal is transmitted outward. The PWM technology is used to quantize the analog signal, convert the high-speed bit stream into a pulse signal with different widths, and thereby avoid the inter-symbol interference caused by the tissue resistance-capacitance effect.

[0023] AsFigure 2 As shown, the external reader detects the current change and restores it as a data signal of '0' and '1'.

[0024] As shown, the internal electrode receives the down pulse signal and changes the front-end amplification gain accordingly. Figure 3

[0025] As can be seen from the above examples, the present application effectively avoids the problem of inter-symbol interference caused by the resistance-capacitance effect of human tissue and the problem of blocking of alternating current transmission, while eliminating the data transmission module with high power consumption, and has the characteristics of large effective communication range and low power consumption for transmitting single-bit data.

[0026] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Although the foregoing has described the implementation process of the present application in detail, those skilled in the art can still modify the technical solutions recorded in the foregoing examples or replace some of the technical features equivalently. Any modification, equivalent replacement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.​

Claims

1. A passive bidirectional human body channel power supply and communication system, comprising: The chip device attached or implanted in human tissue and the external electric control reading unit connected with the chip device through electrode pair signal transmission, the chip device and the external electric control reading unit form power supply path, uplink communication link and downlink communication link, characterized in that, in the power supply path, the external electric control reading unit provides direct current power for the chip device; in the downlink communication link, the external electric control reading unit sends pulse signal to the chip device, the chip device decodes the pulse signal and completes corresponding configuration; in the uplink communication link, the chip device sends the load signal on the human tissue side to the external electric control reading unit through pulse width modulation and transistor current switch. The electrode pair includes external electrode pair arranged in the external electric control reading unit and internal electrode pair arranged in the chip device, the external electric control reading unit is provided with direct current voltage source, the direct current voltage source is electrically connected with the external electrode pair and injects direct current, the current is conducted through the external electrode pair, human tissue and internal electrode pair and forms current loop between the external electrode pair and the internal electrode pair. The chip device is provided with pulse detection counter and decoder, the external electric control reading unit is also provided with pulse generation source, the pulse generation source sends the generated pulse signal to the pulse detection counter through the electrode pair, the capacitor coupled amplifier in the pulse detection counter detects the pulse signal on the internal electrode pair and amplifies it into rail-to-rail digital signal, then the pulse number is counted through the decoder, which corresponds to the writing of specified register in the chip, so as to control the configuration of internal register in the chip, that is, output downlink instruction signal through the decoder. The chip device is also provided with front-end amplification circuit, sawtooth wave generation circuit and amplitude-time converter, the front-end amplification circuit amplifies the load signal and outputs analog signal according to the downlink instruction signal, the sawtooth wave generation circuit generates sawtooth wave signal, the analog signal and the sawtooth wave signal are input into the amplitude-time converter and converted into corresponding pulse width modulation signal, the pulse width modulation signal switches the transistor current switch and then transmits to the external electric control reading unit through the electrode pair.

2. A passive bidirectional human body channel power supply and communication system as claimed in claim 1, characterized in that, The chip device is provided with power management module, the power management module receives the direct current voltage injected from the electrode pair and generates voltage signal and current signal required for the operation of the chip device.

3. A passive bidirectional human body channel power supply and communication system as claimed in claim 1, characterized in that, The external electric control reading unit is also provided with reader, the reader is connected with the external electrode pair, the reader detects the current change on the external electrode pair and restores it into data signal of 0 and 1.

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