Nerve stimulator chip for generating high-frequency current stimulation

Abstract

The invention provides and realizes a nerve stimulator chip for generating high-frequency current stimulation. Based on a CMOS (complementary metal oxide semiconductor) process, devices such as an MOS (metal oxide semiconductor) tube, a capacitor and a resistor are used for building a circuit, and the chip can generate high-frequency current stimulation through logic control of a switch. The circuit comprises a current generation module used for providing constant current output; the high-frequency square wave current generation module is used for converting constant current input into high-frequency square wave current output according to requirements; the output stage is used for controlling an overall output waveform mode and outputting high-frequency square wave current to the biological tissue; a logic control module; and waveform parameters such as a high-frequency square wave current parameter, a cathode stimulation stage pulse width and an anode stimulation stage pulse width of a control circuit output waveform. The circuit has the advantages that the structure is simple, the area is small, an inductor is not needed, stimulation parameters can be flexibly adjusted, the number of control ends is small, and operation is facilitated.

Description

Technical Field

[0001] The present invention specifically relates to a nerve stimulator chip for generating high-frequency current stimulation, and belongs to the technical field of integrated circuits. Background Art

[0002] In recent decades, mankind's understanding of the neural activities of organisms has become increasingly profound, and it has become possible to inject electric charges into organisms through neurostimulator chips to achieve various anticipated biological behavioral phenomena. With the discovery of research, researchers have realized that delivering high-frequency current stimulation to biological tissues can stop neurons from transmitting neural signals. Existing neurostimulator chips that can generate high-frequency current stimulation often require the use of DC-DC converters or dedicated digital control chips to achieve the output of high-frequency current stimulation; the use of DC-DC converters requires the use of inductors, which places greater demands on integrated circuit process support; the use of dedicated digital control chips is not conducive to the integration of neurostimulator chips. The present invention proposes a neurostimulator chip for generating high-frequency current stimulation, which uses basic MOS tubes, capacitors, and resistors to achieve the output of high-frequency square wave current, allowing the neurostimulator chip to use more integrated circuit processes and be more convenient to integrate. Summary of the Invention

[0003] The purpose of the present invention is to enable a neurostimulator chip to obtain a high-frequency square wave current output through components supported by basic integrated circuit technology.

[0004] The object of the present invention is achieved by the following measures:

[0005] Figure 1 This is a circuit diagram of a neurostimulator chip used to generate high-frequency current stimulation. The high-frequency square wave current generation module 125 and the output stage 126 are controlled by the logic control module 101 and the current generation module 105 to systematically deliver the high-frequency square wave current 115 to the biological tissue 120 as intended.

[0006] Current generation module 105 determines the current amplitude of constant current 106 output based on the control signal provided by external control signal 100. The on / off relationship between switch 111 and switch 2 112 allows the PMOS current mirror formed by PMOS 1 109 and PMOS 2 110 to have two output states: output and non-output. This allows high-frequency square wave current generation module 125 to convert the constant current provided by current generation module 105 into high-frequency square wave current 115.

[0007] The PMOS current mirror formed between PMOS 109 and PMOS 2 110 incorporates resistor 114 and capacitor 113 to ensure that the PMOS current mirror can keep pace with the switching states of switches 111 and 112, thereby indicating whether the PMOS current mirror output is controlled by switches 111 and 112. For MOS transistors, when used as switches, the speed at which the gate voltage reaches 0 or VDD is considered the switch turn-on speed. When used as current mirrors, the speed at which the gate voltage reaches a predetermined gate voltage is considered the current mirror speed. For NMOS transistors, turning on means charging the NMOS; the faster the charge, the faster it turns on. Turning off means discharging the charge; the faster the discharge, the faster it turns off. PMOS transistors operate in an inverse process. Capacitor 113 acts as an accelerator. When the voltage at one end of capacitor 113 changes, the voltage difference between its two terminals cannot change instantaneously. Capacitor 113 causes the voltage at the other end to change as well. Capacitor 113 generates a rapid positive or negative pulse on the gate of the MOS transistor. This causes a rapid change near the gate when the voltage far from the gate changes, causing the gate voltage of the MOS transistor to quickly reach or fall away from the predetermined voltage state. Resistor 114 reduces crosstalk, prevents gate oscillations between switch 1 111 and switch 2 112 during switching, and protects the MOS transistor gate.

[0008] Under the control of the output stage control signal 1 103 and the output stage control signal 2 (104), the output stage 126 composed of NMOS 1 116, NMOS 2 117, PMOS 3 118 and PMOS 4 119 has four working states: in the first working state, PMOS 3 118 and NMOS 2 103 are turned on under the control of the output stage control signal 1 103, and PMOS 4 119 and NMOS 1 116 are turned off under the control of the output stage control signal 2 104; in the second working state, PMOS 3 118 and NMOS 2 103 are turned on under the control of the output stage control signal 1 103. In the first operating state, PMOS 3 118 and NMOS 2 103 are turned on under the control of output stage control signal 1 103, while PMOS 4 119 and NMOS 1 116 are turned on under the control of output stage control signal 2 104. In the fourth operating state, PMOS 3 118 and NMOS 2 103 are turned off under the control of output stage control signal 1 103, while PMOS 4 119 and NMOS 1 116 are turned off under the control of output stage control signal 2 104. Depending on the operating state, output stage 126 outputs high-frequency square wave current 115 to biological tissue 120.

[0009] When PMOS 3 118 and NMOS 2 103 are turned on under the control of output stage control signal 1 103, and PMOS 4 119 and NMOS 1 116 are turned off under the control of output stage control signal 2 104, a voltage state approximately equal to the output stage power supply voltage 124 is reflected on electrode 1 122, and a voltage state approximately equal to ground 108 is reflected on electrode 2 123. A voltage drop is reflected on biological tissue 120 connected to electrode 1 122 and electrode 2 123, forming a conductive path 121, and high-frequency square wave current 115 flows in the reverse direction through the conductive path 121 on biological tissue 120. When PMOS 3 118 and NMOS 2 103 are turned off under the control of output stage control signal 1 103, and PMOS 4 119 and NMOS 1 116 are turned on under the control of output stage control signal 2 104, a voltage state approximately equal to ground 108 is reflected on electrode 1 122, and a voltage state approximately equal to ground 108 is reflected on electrode 2 123. The voltage state reflects a voltage drop on the biological tissue 120 connected to the electrode 1 122 and the electrode 2 123, forming a conductive path 121, and the high-frequency square wave current 115 flows in the forward direction through the conductive path 121 on the biological tissue 120. When the PMOS 3 118 and the NMOS 2 103 are turned on under the control of the output stage control signal 103, and the PMOS 4 119 and the NMOS 1 116 are turned on under the control of the output stage control signal 2 104, the conductive path 121 on the biological tissue 120 determines the direction of the high-frequency square wave current 115 flowing therethrough based on the voltage state remaining from the previous stimulation phase. When the PMOS 3 118 and the NMOS 2 103 are turned off under the control of the output stage control signal 103, and the PMOS 4 119 and the NMOS 1 116 are turned off under the control of the output stage control signal 2 104, the high-frequency square wave current provided by the high-frequency square wave current generating module 125 to the output stage 126 does not flow through the biological tissue 120.

[0010] Figure 2 The waveforms are the constant current 106 output by the current generation module 105 within the circuit, the high-frequency square wave current 115 output by the high-frequency square wave current generation module 125, and the current waveform flowing through the conductive path 121 on the biological tissue 120. The current generation module 105 regulates the amplitude of the constant current 106 based on the external control signal 100. The high-frequency square wave current generation module 125 generates the high-frequency square wave current 115 based on the waveform generation control signal 102. The output stage 126 determines the waveform parameters of the current flowing through the conductive path 121 on the biological tissue 120, such as the direction, pulse width, and interphase delay, based on the control of the output stage control signal 103 and the output stage control signal 2 104.

[0011] The present invention can use components supported by the most basic integrated circuit technology to build a circuit that can output high-frequency square wave current, and the high-frequency square wave current that can be output can reach the MHZ level. Compared with similar neural stimulator chips that can generate high-frequency square wave current, no inductor is required and no additional control chip is required. The high-frequency square wave current output by the present invention can stop the neural activity of the organism and stop the transmission of electrical signals between neurons. The present invention can be used as a medical device or auxiliary tool to output a relatively high-frequency high-frequency square wave current. At the same time, it has a simple structure, a small area, and the stimulation parameters can be flexibly adjusted, with fewer control terminals, which is conducive to operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Circuit diagram of a neurostimulator chip used to generate high-frequency current stimulation

[0013] Figure 2 The waveform diagram shows the internal and external output current of the neurostimulator chip used to generate high-frequency current stimulation.

[0014] Wherein: 100 is an external control signal; 101 is a logic control module; 102 is a waveform generation control signal; 103 is an output stage control signal 1; 104 is an output stage control signal 2; 105 is a current generation module; 106 is a constant current; 107 is a low voltage power supply voltage; 108 is ground; 109 is PMOS 1; 110 is PMOS 2; 111 is switch 1; 112 is switch 2; 113 is a capacitor; 114 is a resistor; 115 is a high-frequency square wave current; 116 is NMOS 1; 117 is NMOS 2; 118 is PMOS 3; 119 is PMOS 4; 120 is biological tissue; 121 is a conductive path; 122 is electrode 1;

[0015] 123 is electrode 2; 124 is the output stage power supply voltage; 125 is the high-frequency square wave current generating module; 126 is the output stage. DETAILED DESCRIPTION

[0016] According to the aforementioned invention, a circuit structure was constructed in simulation software by applying the 0.18 μm process provided by Semiconductor Manufacturing International Corporation (SMIC), and simulations verified that the design of the above structure had high feasibility.

[0017] To allow high-frequency square wave current 115 to flow through conductive path 121 on biological tissue 120, high-frequency square wave current generating module 125 converts constant current 106 provided by current generating module 105 into high-frequency square wave current 115. Current generating module 105 determines the amplitude of constant current 106 to be output based on a control signal provided by external control signal 100. The on / off relationship between switch 111 and switch 2 112 allows the PMOS current mirror formed by PMOS 1 109 and PMOS 2 110 to have two output states: output and non-output. This allows high-frequency square wave current generating module 125 to convert the constant current provided by current generating module 105 into high-frequency square wave current 115.

[0018] To ensure that the PMOS current mirror formed by PMOS 1 109 and PMOS 2 110 in the high-frequency square wave current generation module can keep pace with the changes in switches 111 and 112 controlled by waveform generation control signal 102, thereby reflecting the output of the PMOS current mirror controlled by switches 111 and 112, resistor 114 and capacitor 113 are added to the PMOS current mirror formed between PMOS 109 and PMOS 2 110. Capacitor 113 acts as an accelerator. When the voltage at one end of capacitor 113 changes, the voltage difference between its two terminals cannot change instantaneously. Capacitor 113 drives the voltage at the other end to change as well, causing a rapid positive or negative pulse to the gate of the MOS transistor. This causes a transient change far from the gate side to also change rapidly near the gate side, causing the gate voltage of the MOS transistor to quickly reach or move away from the predetermined voltage state. Resistor 114 reduces crosstalk, prevents gate oscillations between switches 111 and 112 during switching, and protects the MOS transistor gate.

[0019] In order to achieve various forms of current output on the biological tissue 120, under the control of the output stage control signal 103 and the output stage control signal 2 (104), the output stage 126 has four working states: the first working state, PMOS 3 118 and NMOS 2 103 are turned on, and PMOS 4 119 and NMOS 1 116 are turned off; the second working state, PMOS 3 118 and NMOS 2 103 are turned off, and PMOS 4 119 and NMOS 1 116 are turned on; the third working state, PMOS 3 118 and NMOS 2 103 are turned on, and PMOS 4 119 and NMOS 1 116 are turned on; the fourth working state, PMOS 3 118 and NMOS 2 103 are turned off, and PMOS 4 119 and NMOS 1 116 are turned off. According to different working states, the output stage 126 outputs a high-frequency square wave current 115 to the biological tissue 120 to meet different requirements.

[0020] In order to prevent the connection between neurons on the biological tissue 120, when PMOS 3 118 and NMOS 2 103 are turned on, and PMOS 4 119 and NMOS 1 116 are turned off, the voltage state of electrode 1 122 is approximately the output stage power supply voltage 124, and the voltage state of electrode 2 123 is approximately the ground 108. A voltage drop is reflected on the biological tissue 120 connected to electrode 1 122 and electrode 2 123, forming a conductive path 121. The high-frequency square wave current 115 flows in the reverse direction through the conductive path 121 on the biological tissue 120, and the neural activity on the biological tissue 120 is suppressed. When PMOS 3 118 and NMOS 2 103 are turned off, and PMOS 4 119 and NMOS 1 116 are turned on, the voltage state of electrode 1 122 is approximately the ground 108, and the voltage state of electrode 2 123 is approximately the output stage power supply voltage 124. The voltage state of the power supply voltage 124 reflects a voltage drop on the biological tissue 120 connected to the electrode 1 122 and the electrode 2 123, forming a conductive path 121. The high-frequency square wave current 115 flows in the forward direction through the conductive path 121 on the biological tissue 120, thereby suppressing the neural activity in the biological tissue 120. When the PMOS 3 118 and the NMOS 2 103 are turned on, and the PMOS 4 119 and the NMOS 1 116 are turned on, the conductive path 121 on the biological tissue 120 determines the direction of the high-frequency square wave current 115 based on the residual voltage state from the previous stimulation stage, which can be used for charge balance. When the PMOS 3 118 and the NMOS 2 103 are turned off, and the PMOS 4 119 and the NMOS 1 116 are turned off, the high-frequency square wave current provided by the high-frequency square wave current generating module 125 to the output stage 126 does not flow through the biological tissue 120.

[0021] Therefore, it can be found that the circuit constructed by the above structure can output a relatively high-frequency square wave current 115 to the biological tissue 120, and the required devices are relatively simple and the structure is clear.

Claims

1. A neurostimulator chip for generating high-frequency current stimulation, characterized in that: The invention comprises an external control signal (100) for providing a control signal to a logic control module (101) and a current generating module (105), a logic control module (101) for providing a waveform generating control signal (102), an output stage control signal 1 (103) and an output stage control signal 2 (104) to a high-frequency square wave current generating module (125) and an output stage (126), a current generating module (105) for providing a constant current (106) to the high-frequency square wave current generating module (125), a high-frequency square wave current generating module (125) for providing a high-frequency square wave current (115) and an output stage power supply (124) to the output stage (126), and a high-frequency square wave current generating module (125) for providing a high-frequency square wave current (115) and an output stage power supply (124) to the electrode 1 (122) and the electrode 2 (123). The invention relates to an output stage (126) for providing a conductive path (121), a high-frequency square wave current (115), an output stage power supply voltage (124) and a ground (108) for biological tissue (120), an electrode 1 (122) and an electrode 2 (123) for providing a conductive path (121), a high-frequency square wave current (115), an output stage power supply voltage (124) and a ground (108), and a waveform generating control signal (102), an output stage control signal 1 (103), an output stage control signal 2 (104), a constant current (106), a low-voltage power supply voltage (107), a ground (108), a PMOS 1 (109), a PMOS 2 (110), a switch 1 (111), a switch 2 (112), a capacitor (113), a resistor (114), a high-frequency square wave current (115), and a control signal. The high frequency square wave current generating module (125) is composed of the current (115), NMOS 1 (116), NMOS 2 (117), PMOS 3 (118), PMOS 4 (119), biological tissue (120), conductive path (121) and output stage power supply voltage (124); PMOS 1 (109), PMOS 2 (110), switch 1 (111), switch 2 (112), capacitor (113), resistor (114), waveform generation control signal (102) and output stage power supply voltage (124); NMOS 1 (116), NMOS 2 (117), PMOS 3 (118), PMOS 4 (119), output stage control signal 1 (103), The output stage control signal 2 (104) and the ground (108) constitute the output stage (126); the external control signal (100) is connected to the current generating module (105) and one end of the logic control module (101); the logic control module (101) is connected to one end of the external control signal (100), and also connects to one end of the switch 1 (111), the switch 2 (112), the PMOS 3 (118), the PMOS 4 (104), the NMOS 1 (116) and the NMOS 2 (117) by outputting the waveform control signal (102), the output stage control signal 1 (103) and the output stage control signal 2 (104), and is also connected to one end of the low voltage power supply voltage (107) and the ground (108);The current generating module (105) is connected to one end of the external control signal (100), one end of the high-frequency square wave current generating module (125), and one end of the low-voltage power supply voltage (107) and the ground (108); the high-frequency square wave current generating module (125) is connected to one end of the current generating module (105), one end of the output stage (126), and one end of the output stage power supply voltage (124); the output stage (126) is connected to one end of the high-frequency square wave current generating module (125), one end of the electrode 1 (122) and one end of the electrode 2 (123), and one end of the ground (108); the electrode 1 (122) and the electrode 2 (123) are connected to one end of the output stage (126) and one end of the biological tissue (120).

2. The stimulator according to claim 1, wherein: The external control signal (100) controls the current amplitude of the constant current (106) outputted by the current generating module (105); the high-frequency square wave current generating module (125) receives the constant current provided by the current generating module (105), and affects the output of the PMOS current mirror formed between the PMOS 1 (109) and the PMOS 2 (110) through the on-off relationship between the switch 1 (111) and the switch 2 (112), and finally converts the constant current (106) into the high-frequency square wave current (115); when the switch 1 (1 When switch 1 (111) is turned on and switch 2 (112) is turned off, the PMOS current mirror formed by PMOS 1 (109) and PMOS 2 (110) outputs; when switch 1 (111) is turned off and switch 2 (112) is turned on, the PMOS current mirror formed by PMOS 1 (109) and PMOS 2 (110) stops outputting; the PMOS current mirror formed by PMOS 1 (109) and PMOS 2 (110) is continuously switched between these two states, so that the final output is reflected as a high-frequency square wave current (115).

3. The stimulator according to claim 1, wherein: A PMOS current mirror is formed by adding a resistor (114) and a capacitor (113) between a PMOS 1 (109) and a PMOS 2 (110); the capacitor (113) plays an accelerating role. When the voltage at one end of the capacitor (113) changes, the capacitor (113) drives the voltage at the other end to change as well. The capacitor (113) brings a fast positive or negative pulse to the gate of the MOS tube, so that the gate of the MOS tube reaches a predetermined voltage state as soon as possible; the resistor (114) plays the role of reducing crosstalk, preventing gate oscillation of the switch 1 (111) and the switch 2 (112) during the switching process, and protecting the gate of the MOS tube; the combination of the capacitor (113) and the resistor (114) enables the PMOS current mirror formed by the PMOS 1 (109) and the PMOS 2 (110) to quickly keep up with the switching state of the switch 1 (111) and the switch 2 (112), thereby reflecting whether the PMOS current mirror controlled by the switch 1 (111) and the switch 2 (112) outputs or not.

4. The stimulator according to claim 1, wherein: The output stage (126) composed of NMOS 1 (116), NMOS 2 (117), PMOS 3 (118) and PMOS 4 (119) has four working states under the control of output stage control signal 1 (103) and output stage control signal 2 (104): in the first working state, the output stage control signal 1 (103) controls PMOS 3 (118) and NMOS 2 (103) to be turned on, and the output stage control signal 2 (104) controls PMOS 4 (119) and NMOS 1 (116) to be turned off; in the second working state, the output stage control signal 1 (103) controls PMOS 3 (118) and NMOS 2 (103) to be turned off, and the output stage control signal 2 (104) controls PMOS 4 (119) and NMOS 1 (116) to be turned off. 4) controls PMOS 4 (119) and NMOS 1 (116) to be turned on; in a third working state, the output stage control signal 1 (103) controls PMOS 3 (118) and NMOS 2 (103) to be turned on, and the output stage control signal 2 (104) controls PMOS 4 (119) and NMOS 1 (116) to be turned on; in a fourth working state, the output stage control signal 1 (103) controls PMOS 3 (118) and NMOS 2 (103) to be turned off, and the output stage control signal 2 (104) controls PMOS 4 (119) and NMOS 1 (116) to be turned off; according to different working states, the output stage (126) outputs a high-frequency square wave current (115) to the biological tissue (120).

5. The stimulator according to claim 1, wherein: When the output stage control signal 1 (103) of the output stage (126) controls the PMOS 3 (118) and the NMOS 2 (103) to be turned on, and the output stage control signal 2 (104) controls the PMOS 4 (119) and the NMOS 1 (116) to be turned off, the voltage state of the electrode 1 (122) is approximately the output stage power supply voltage (124), and the voltage state of the electrode 2 (123) is approximately the ground (108), and a voltage drop is reflected on the biological tissue (120) connected to the electrode 1 (122) and the electrode 2 (123). A conductive path (121) is formed, and a high-frequency square wave current (115) flows in the reverse direction through the conductive path (121) on the biological tissue (120); when the output stage control signal 1 (103) of the output stage (126) controls the PMOS 3 (118) and the NMOS 2 (103) to be disconnected, and the output stage control signal 2 (104) controls the PMOS 4 (119) and the NMOS 1 (116) to be turned on, the voltage state of the electrode 1 (122) is approximately the ground (108), and the voltage state of the electrode 2 (123) is approximately the output stage power supply voltage (124). ) voltage state, a voltage drop is reflected on the biological tissue (120) connected to the electrode 1 (122) and the electrode 2 (123), forming a conductive path (121), and the high-frequency square wave current (115) flows in the positive direction through the conductive path (121) on the biological tissue (120); when the output stage control signal 1 (103) of the output stage (126) controls the PMOS 3 (118) and the NMOS 2 (103) to be disconnected, and the output stage control signal 2 (104) controls the PMOS 4 (119) and the NMOS 1 (116) to be disconnected, the high-frequency square wave current (115) flows in the positive direction through the conductive path (121) on the biological tissue (120); The high-frequency square wave current provided by the square wave current generating module (125) to the output stage (126) does not flow through the biological tissue (120); when the output stage control signal 1 (103) of the output stage (126) controls the PMOS 3 (118) and the NMOS 2 (103) to be turned on, and the output stage control signal 2 (104) controls the PMOS 4 (119) and the NMOS 1 (116) to be turned on, the conductive path (121) on the biological tissue (120) determines the direction of the high-frequency square wave current (115) flowing through the biological tissue (120) according to the voltage state remaining in the previous stimulation stage.

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