Output current and output voltage amplification circuit capable of being externally connected to nerve electrical stimulator chip

Abstract

The invention provides an output current and output voltage amplification circuit which can be externally connected to a nerve electrical stimulator chip. The circuit can be realized by a PCB (Printed Circuit Board) or a chip with a BCD (Bipolar Compact Disc) high-voltage process, is connected with an output port of a nerve stimulator chip, and is used for increasing the electrical stimulation intensity and increasing the maximum voltage of an output stage, so that the output gets rid of the limitation of the parameters of the chip on the amplitude of the maximum output current and voltage. The circuit comprises a diode chain which is used for providing voltage for a nerve stimulator chip so as to enable the nerve stimulator chip to output double-phase current outwards and shunt the double-phase current at the same time; the multi-stage current proportion unit is used for providing a power supply voltage of a corresponding branch and randomly amplifying an input current according to requirements; and the reference voltage module is used for providing reference voltage for the biological tissue, so that a conductive path is formed. The circuit has the advantages that stimulation parameters can be flexibly adjusted, the circuit can be adjusted, and biphase current stimulation output can be achieved without a discrete switch.

Description

TECHNICAL FIELD

[0001] The present application relates to an output current and voltage amplification circuit externally connected to a nerve stimulator chip, and belongs to the technical field of integrated circuits and the field of electronic circuits. BACKGROUND

[0002] In recent decades, nerve stimulator chips have become a widely used medical device that can inject electric charges into biological tissues according to specific needs to achieve a variety of effects. However, due to the influence of integrated circuit technology, the voltage resistance of components of existing nerve stimulator chips is limited. At the same time, when designing a nerve stimulator chip, a voltage margin for MOS tubes is divided on a low power supply voltage that is already constrained. Various factors limit the maximum output current and voltage amplitude of the nerve stimulator chip. Although a board-level nerve stimulator can achieve a larger current output, the operability and flexibility of the output waveform are far inferior to those of a nerve stimulator chip. The present application proposes an output current and voltage amplification circuit externally connected to a nerve stimulator chip, which allows the final output of the circuit to break free from the limitation of the maximum output current and voltage amplitude specified by the parameters of the chip itself, thereby expanding the output range of the nerve stimulator chip. The present application maintains the advantages of the nerve stimulator chip, such as portable adjustment of the output waveform, diverse modes, and close proximity to actual nerve activity. At the same time, the present application has the advantage of a large output current and voltage amplitude of the circuit. Furthermore, by utilizing the characteristics of a triode, the voltage margin of the final output stage of the circuit is maximized. SUMMARY

[0003] The purpose of the present application is to allow a nerve stimulator chip to break free from the disadvantage of a small output current caused by various factors, and to obtain an output current waveform of the nerve stimulator chip with an amplified amplitude.

[0004] TECHNICAL SOLUTION

[0005] The purpose of the present application is achieved by the following measures:

[0006] Figure 1 The circuit structure diagram for amplifying the output stimulation current of a nerve stimulator chip is shown in FIG. 1. The nerve stimulator chip 100 adjusts the pulse width, current amplitude, and output mode of the output waveform parameters of the biphasic current 101 according to the desired output waveform pattern.

[0007] The diode chain 104, with the corresponding number of diodes 105 calculated according to the demand, the NPN 109 and PNP 111 conduction voltage drop, makes the diode chain center node voltage 106 between the output stage power supply voltage 102 and ground 103 of the stimulator chip. The high voltage output stage in the neurostimulator chip 100, according to its internal switch, makes the output node of the neurostimulator chip 100 embody the two voltage states of the output stage power supply voltage 102 and ground 103 of the stimulator chip, and is connected to the center node of the diode chain 104 of the diode chain center node voltage 106 between the output stage power supply voltage 102 and ground 103 of the stimulator chip. Finally, there are two opposite voltage drop states on the output end of the neurostimulator chip 100, so that the current direction of the neurostimulator chip 100 flowing to the center node of the diode chain 104 is opposite.

[0008] The diode chain 104, according to the forward conduction voltage of the diode 105, the conduction voltage drop of the NPN 109 and the PNP 111, provides the diode chain center node voltage 106 to the neurostimulator chip 100, and also according to the forward conduction characteristics of the diode 105, shunts the anode and cathode stage stimulation current of the biphasic current 101 output by the neurostimulator chip 100 to amplify the current amplitude of each of the anode and cathode stages according to the demand. When the high voltage output stage of the neurostimulator chip 100 connects the output stage power supply voltage 102 of the stimulator chip to the output node of the neurostimulator chip 100, the anode current output by the neurostimulator chip 100 will flow into the center node of the diode chain 104 along the voltage drop path from the output stage power supply voltage 102 of the stimulator chip to the diode chain center node voltage 106; at the same time, according to the forward conduction property of the diode 105, the diode 105 of the diode chain 104 center node is forward biased to the high voltage power supply voltage 114, and the diode 105 is reverse cut-off to the ground 103; the anode current of the neurostimulator chip 100 flowing into the center node of the diode chain 104 finally flows into the current proportional unit 107. When the high voltage output stage of the neurostimulator chip 100 connects the ground 103 to the output node of the neurostimulator chip 100, the cathode current output by the neurostimulator chip 100 will flow out of the center node of the diode chain 104 along the voltage drop path from the diode chain center node voltage 106 to the ground 103; at the same time, according to the forward conduction property of the diode 105, the diode 105 of the diode chain 104 center node is forward biased to the high voltage power supply voltage 114, and the diode 105 is reverse cut-off to the ground 103, the current of the neurostimulator chip 100 flowing out of the center node of the diode chain 104 finally flows out of the current proportional unit 113.

[0009] Since the anode and cathode currents are shunted by the forward conduction characteristics of the diodes 105 of the diode chain 104, only the shunted anode and cathode currents need to be amplified accordingly, and the amplified biphasic current 101 can be obtained at the last stage in the same way as the biphasic current. The current ratio unit 107, the current ratio unit 113, and the current ratio unit 116 are all composed of the output stage power supply voltage of the corresponding stimulator chip, transistors, N-stage transistor chains, and switches 108. The NPN 109 and the PNP 111 are transistors that can build a current replication structure similar to a MOS tube current mirror. Since the voltage drops of the PNP 111, the diode 105, and the NPN 109 are the foundation of the diode chain center node voltage 106, the number of various electronic devices on this branch needs to be calculated to obtain the required diode chain center node voltage 106. At the same time, in order to meet the requirements of a wide range of current ratio changes and the diode chain center node voltage 106, the current ratio unit cannot use a proportional resistor or other methods that affect the input and output currents of the transistor current mirror to achieve the amplification function of the current ratio unit, in order to avoid the disadvantage of being unable to calculate the number of diodes 105 due to the large range of resistance changes when using proportional resistors. Through the combination of the NPN 109 and the N-stage NPN chain 110 and the combination of the PNP 111 and the N-stage PNP chain 112, N-stage transistor mirror unit current mirrors are formed, respectively. By turning on and off the switch 108, the amplification factor of each stage of the current ratio unit is affected. Finally, the cathode and anode currents of the biphasic current 101 are amplified by a large range of the corresponding multi-stage current ratio unit. At the same time, the N-stage transistor mirror unit current mirror is used to amplify the input current, avoiding the limitation of the single transistor current flowing capacity when performing large current amplification ratio amplification.

[0010] The anode current waveform output by the neural stimulator chip 100 flows into the current ratio unit 107 through the diode chain 104, is amplified, flows into the current ratio unit 116, is amplified again, and reaches the output node of the overall circuit. The cathode current waveform output by the neural stimulator chip 100 flows out of the current ratio unit 113 through the diode chain 104, is amplified, flows out of the current ratio unit 107 below the current ratio unit 116, is amplified again, and reaches the output node of the overall circuit.

[0011] Since the anode and cathode stimulation in the biphasic current one 101 output by the neurostimulator chip 100 is separated in time, the anode and cathode currents in the biphasic current one 101 are also separated in time when reaching the output node, so that the output end of the overall circuit can automatically output according to the current direction without a switch. When the anode current of the neurostimulator chip 100 flows into the current proportional unit three 116, the cathode current does not flow into the current proportional unit one 107 below the current proportional unit three 116, at which time the output node of the overall circuit reflects the voltage state of the high-voltage power supply voltage two 115 and the current after two amplifications of the anode current stimulation in the biphasic current one 101 output by the neurostimulator chip 100. When the cathode current of the neurostimulator chip 100 flows into the current proportional unit one 107, the anode current does not flow into the current proportional unit three 116, at which time the output node of the overall circuit reflects the voltage state of the ground 103 and the current after two amplifications of the cathode current stimulation in the biphasic current one 101 output by the neurostimulator chip 100.

[0012] The two voltages and currents are connected to the biological tissue 120 through the electrode one 118. The reference voltage source module 122 is always connected to the electrode two 121 to provide the voltage state of the reference voltage 123 to the electrode two 121. When the output node of the overall circuit reflects the voltage state of the high-voltage power supply voltage two 115 and the current after two amplifications of the anode current stimulation in the biphasic current one 101 output by the neurostimulator chip 100, the anode current of the biphasic current two 117 flows through the conductive path 119 on the biological tissue 120 in the positive direction according to the voltage drop between the high-voltage power supply voltage two 115 and the reference voltage 123 between the electrode one 118 and the electrode two 121. When the output node of the overall circuit reflects the voltage state of the ground 103 and the current after two amplifications of the cathode current stimulation in the biphasic current one 101 output by the neurostimulator chip 100, the cathode current of the biphasic current two 117 flows through the conductive path 119 on the biological tissue 120 in the reverse direction according to the voltage drop between the ground 103 and the reference voltage 123 between the electrode one 118 and the electrode two 121. At this point, the current amplitude of the biphasic current one 101 output by the neurostimulator chip 100 is amplified to the biphasic current two 117 and flows into the biological tissue 120.

[0013] Figure TwoThe voltage waveform of the center node of the diode chain 104 output by the biphasic current one 101 of the neurostimulator chip 100 and the voltage waveform of the output node of the neurostimulator chip 100. It is also described that the waveform of the overall output circuit of the circuit and the voltage waveform caused by the stimulation current finally embodied on the biological tissue 120. The diode chain center node voltage 106 on the diode chain 104 needs to meet the original demand of the neurostimulator chip 100 for the reference voltage 123 to generate the biphasic current one 101. The output current of the neurostimulator chip 100 and the overall output current of the circuit: the biphasic current two 117 embody the subsequent circuit of the neurostimulator chip 100, only amplify the current amplitude of the anode and cathode stimulation, and do not make any modification to the remaining parameters of the biphasic current one 101, and retain the original required output parameters. And because there is resistance and capacitance on the biological tissue 120, the voltage waveform on the overall circuit output node will reflect the voltage rise brought by the resistance and the integration effect brought by the capacitance.

[0014] Advantages

[0015] The present application can make the neurostimulator chip free from the amplitude limitation of the maximum output current and voltage brought by the process, and can amplify the output current and voltage amplitude of the neurostimulator chip according to the needs. At the same time, it also does not destroy the advantage of the flexible output mode of the output current of the neurostimulator chip. It can also avoid the shortcomings that the board-level circuit has a large output current, but the output mode is relatively rigid and greatly different from the biological nerve activity mode. The present application can be used as an auxiliary circuit, which can ensure the advantages of adjustable output parameters, more output modes and close to biological nerve activity of the neurostimulator chip, and can also ensure the advantages of large output current of the board-level neurostimulator, while having the advantages of no need for additional control switch to realize the biphasic current, strong adjustability of the overall circuit, adjustable amplitude of the final output current of the circuit, and less influence of the triode on the voltage margin of the final output stage of the circuit. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The unit circuit diagram of the circuit for amplifying the output stimulation current of the neurostimulator chip.

[0017] Figure 2 The waveform diagram of the unit current and voltage of the circuit for amplifying the output stimulation current of the neurostimulator chip.

[0018] Wherein: 100 is a nerve stimulator chip; 101 is a biphasic current one; 102 is an output stage power voltage of the stimulator chip; 103 is a ground; 104 is a diode chain; 105 is a diode; 106 is a diode chain center node voltage; 107 is a current proportional unit one; 108 is a switch; 109 is an NPN; 110 is an N-stage NPN chain; 111 is a PNP; 112 is an N-stage PNP chain; 113 is a current proportional unit two; 114 is a high-voltage power voltage one; 115 is a high-voltage power voltage two; 116 is a current proportional unit three; 117 is a biphasic current two; 118 is an electrode one; 119 is a conductive path; 120 is a biological tissue; 121 is an electrode two; 122 is a reference voltage source module; and 123 is a reference voltage. DETAILED DESCRIPTION

[0019] According to the foregoing summary, by applying the 0.18μm process and the transistor device and the switch device provided by SMIC, the circuit structure is built in the simulation software, and it is verified by the simulation means that the design of the above structure has high feasibility.

[0020] In order to realize the corresponding changes on the biological tissue 120, the biphasic current two 117 needs to meet the current amplitude to cause the nerve potential change while meeting the corresponding output mode. For example, if the biological body is expected to produce different physiological phenomena, the corresponding nerve behavior has obvious difference, and the output mode of the output waveform composed of many biphasic current two 117 is completely different. The multiple current proportional units behind the nerve stimulator chip 100 amplify the anode and cathode current amplitude of the biphasic current one 101 output by the nerve stimulator chip 100. In addition to the current amplitude parameter, such as pulse width, output model and interphase delay, the parameters between the biphasic current one 101 and the biphasic current two 117 remain the same.

[0021] To meet the requirement of the reference voltage 123 for the neurostimulator chip 100 to generate the biphasic current 101, the diode chain 104, with the high voltage supply voltage 114, the ground 103 and the forward conduction voltage of the diodes 105, and the conduction voltage drop of the NPN 109 and the PNP 111, makes the diode chain center node voltage 106 to act as a similar reference voltage 123. When the high voltage output stage of the neurostimulator chip 100 provides the output stage supply voltage 102 of the stimulator chip outwardly, the diode chain node voltage between the output stage supply voltage 102 of the stimulator chip and the ground 103 makes the current of the neurostimulator chip 100 to flow into the center node of the diode chain 104 at this time, which is called the anodic current. When the high voltage output stage of the neurostimulator chip 100 provides the ground 103 outwardly, the diode chain node voltage between the output stage supply voltage 102 of the stimulator chip and the ground 103 makes the current of the neurostimulator chip 100 to flow out of the center node of the diode chain 104 at this time, which is called the cathodic current.

[0022] To amplify the anodic and cathodic current amplitudes of the neurostimulator chip 100 flowing into or out of the center node of the diode chain 104, the forward conduction voltage of the diodes 105 in the diode chain 104 can also provide a current shunt function. When the high voltage output stage of the neurostimulator chip 100 provides the output stage supply voltage 102 of the stimulator chip outwardly, the diode chain node voltage between the output stage supply voltage 102 of the stimulator chip and the ground 103 makes the current of the neurostimulator chip 100 to flow into the center node of the diode chain 104 at this time; while the diodes 105 in the center node of the diode chain 104 are forward biased to the ground 103, and the diodes 105 in the center node of the diode chain 104 are reverse cut-off to the high voltage supply voltage 114; the anodic current only flows into the current proportioning unit 107 and its associated branch. When the high voltage output stage of the neurostimulator chip 100 provides the ground 103 outwardly, the diode chain node voltage between the output stage supply voltage 102 of the stimulator chip and the ground 103 makes the current of the neurostimulator chip 100 to flow out of the center node of the diode chain 104 at this time; while the diodes 105 in the center node of the diode chain 104 are reverse cut-off to the ground 103, and the diodes 105 in the center node of the diode chain 104 are forward biased to the high voltage supply voltage 114; the cathodic current only flows into the current proportioning unit 113 and its associated branch.

[0023] To amplify the anode and cathode current amplitude of the bifurcated biphasic current one 101, the bipolar transistors NPN 109, PNP 111, N-stage NPN chain 110 and N-stage PNP chain 112 with switches 108 form multiple current scaling units. Both bipolar transistors NPN 109 and PNP 111 can be considered as a current source controlled by current, and can form a current mirror structure similar to MOS transistor current mirror. NPN 109 and N-stage NPN chain 110 form an N-stage bipolar transistor mirror unit current mirror, and PNP 111 and N-stage PNP chain 112 form an N-stage bipolar transistor mirror unit current mirror. Each stage of the bipolar transistor mirror unit current mirror mirrors and copies the input current to the output, and the N-stage bipolar transistor mirror unit current mirror can amplify the input current by N times. Through the switch 108 in each stage of the current scaling unit, the scaling factor of the final output current of each stage of the current scaling unit is determined. The anode and cathode currents of the bifurcated biphasic current one 101 are amplified by multiple stages according to the corresponding current scaling units.

[0024] To allow the bifurcated biphasic current one 101 to be amplified and stimulated to be normally output to the biological tissue 120, the reference voltage module 122 provides a constant reference voltage 123 to the electrode two 122, and the reference voltage 123 is between the high voltage power supply voltage two 115 and the ground 103. At the same time, because there is a time interval between the anode and cathode current stimulation of the biphasic current one 101 output by the neurostimulator chip 100, no additional switch is needed to generate the biphasic current two 117 on the overall circuit. When the anode stimulation flows from the center node of the diode chain 104 to the current scaling unit one 107, it is amplified once, and the amplified anode current continues to flow to the current scaling unit three 116, where it is amplified for the second time; At this time, the cathode stimulation does not flow into the current scaling unit one 107 below the current scaling unit three 116; only the anode current amplified twice and the high voltage power supply voltage two 115 are connected to the electrode one 118, and according to the voltage drop between the high voltage power supply voltage two 115 and the reference voltage 123, the anode current flows through the conductive path 119 on the biological tissue 120 in the forward direction. When the cathode stimulation flows from the center node of the diode chain 104 to the current scaling unit two 114, it is amplified once, and the amplified cathode current continues to flow to the current scaling unit one 107 below the current scaling unit three 116, where it is amplified for the second time; At this time, the anode stimulation does not flow into the current scaling unit three 116; only the cathode current amplified twice and the ground 103 are connected to the electrode one 118, and according to the voltage drop between the ground 103 and the reference voltage 123, the cathode current flows through the conductive path 119 on the biological tissue 120 in the reverse direction.

[0025] During the negative pulse phase, the high voltage output stage of the neurostimulator chip 100 provides ground 103 externally, the diode chain node voltage between the output stage supply voltage 102 of the stimulator chip and the ground 103, so that the current of the neurostimulator chip 100 at this time flows out of the center node of the diode chain 104, called the cathode current; at this time, the diode 105 of the center node of the diode chain 104 is reverse-biased to the ground 103, and the diode 105 is forward-biased to the high voltage supply voltage one 114; the cathode current only flows into the current proportional unit two 113 and its branch; the NPN 109 and the N-stage NPN chain 110 and the PNP 111 and the N-stage PNP chain 112 constitute an N-stage transistor mirror unit current mirror, which amplifies the cathode current flowing in according to the switch 108; the cathode current flows through the corresponding current proportional unit and is amplified in multiple stages, and finally reaches the output node; at this time, the anode stimulation does not flow into the current proportional unit three 116; only the cathode current amplified twice and the ground 103 are connected to the electrode one 118, and according to the voltage drop between the ground 103 and the reference voltage 123, the cathode current flows reversely through the conductive path 119 on the biological tissue 120.

[0026] During the negative pulse phase, the high voltage output stage of the neurostimulator chip 100 provides ground 103 externally, the diode chain node voltage between the output stage supply voltage 102 of the stimulator chip and the ground 103, so that the current of the neurostimulator chip 100 at this time flows out of the center node of the diode chain 104, called the cathode current; at this time, the diode 105 of the center node of the diode chain 104 is reverse-biased to the ground 103, and the diode 105 is forward-biased to the high voltage supply voltage one 114; the cathode current only flows into the current proportional unit two 113 and its branch; the NPN 109 and the N-stage NPN chain 110 and the PNP 111 and the N-stage PNP chain 112 constitute an N-stage transistor mirror unit current mirror, which amplifies the cathode current flowing in according to the switch 108; the cathode current flows through the corresponding current proportional unit and is amplified in multiple stages, and finally reaches the output node; at this time, the anode stimulation does not flow into the current proportional unit three 116; only the cathode current amplified twice and the ground 103 are connected to the electrode one 118, and according to the voltage drop between the ground 103 and the reference voltage 123, the cathode current flows reversely through the conductive path 119 on the biological tissue 120.

[0027] During the no pulse phase such as the phase-to-phase delay of the biphasic current stimulation one 101 and the delay between the stimulation waveforms, the neurostimulator chip 100 outputs zero current to the center node of the diode chain 104, and no current flows into the subsequent current proportional unit. The voltage state on the electrode one 118 is the reference voltage 123, and no current flows through the conductive path 119 on the biological tissue 120.

[0028] Therefore, it can be found that the circuit built by the above structure can amplify the amplitude of the biphasic current stimulation one 101 and output the biphasic current stimulation two 117 to the biological tissue 120 without changing the remaining waveform parameters. At the same time, the amplitude of the biphasic current stimulation one 101 can be amplified in a large range.

Claims

1. An output current and output voltage amplification circuit that can be externally connected to a neural electrical stimulator chip, characterized in that: The invention comprises a neurostimulator chip (100) for providing waveform information such as output pulse width, basic current amplitude and output mode for bi-phase current 2 (117) and bi-phase current 1 (101), a diode chain (104) for providing a diode chain center node voltage (106) for the neurostimulator chip (100) to enable it to output bi-phase current 1 (101), a current proportional unit 1 (107) for amplifying the bi-phase current 1 (101) output by the neurostimulator chip (100) and amplifying the input current of the previous stage, a high-voltage power supply voltage 1 (114) for the diode chain and a current proportional unit 2 (113) for amplifying the bi-phase current 1 (101) output by the neurostimulator chip (100), and the like. The last stage of the circuit provides a high-voltage power supply voltage 2 (115) and a current proportional unit 3 (116) for amplifying the input current of the previous stage, a reference voltage source module (122) for providing a reference voltage (123) for the electrode 2 (121), an electrode 1 (118) and an electrode 2 (121) for providing a biphasic current 2 (117) or a reference voltage (123), a high-voltage power supply voltage 2 (115) and a ground (103) for the biological tissue (120), and an output stage power supply voltage (102), a ground (103), a high-voltage power supply voltage 1 (114), a high-voltage power supply voltage 2 (115), a reference voltage (123), a diode (105), an NPN (109), an N-stage NPN chain (103) of the stimulator chip. 10), PNP (111), N-level PNP chain (112), switch (108) and biological tissue (120); NPN (109), switch (108), N-level NPN chain (110) and ground (103) constitute a current proportional unit 1 (107); PNP (111), switch (108), N-level PNP chain (112) and high-voltage power supply voltage 1 (114) constitute a current proportional unit 2 (113); PNP (111), switch (108), N-level PNP chain (112) and high-voltage power supply voltage 2 (115) constitute a current proportional unit 3 (116); the neurostimulator chip (100) is connected to the central node of the diode chain (104), also connected to the output stage power supply voltage (102) and ground (103) of the stimulator chip; the diode chain (104) is connected to one end of the current proportional unit 2 (113) and the current proportional unit 1 (107), and is also connected to one end of the neural stimulator chip (100); the current proportional unit 1 (107) is connected to one end of the current proportional unit 3 (116) and the electrode 1 (118), and is also connected to one end of the diode chain (104) and the current proportional unit 2 (113), and is also connected to ground (103); the current proportional unit 2 (113) is connected to one end of the current proportional unit 1 (107), is also connected to one end of the diode chain (104), and is also connected to the high voltage power supply voltage 1 (114);The current proportional unit 3 (116) is connected to one end of the electrode 1 (118), is also connected to one end of the current proportional unit 1 (107), and is also connected to the high voltage power supply voltage 2 (115); the reference voltage source module (122) is connected to one end of the electrode 2 (121), is also connected to the reference voltage (123) and the ground (103); the electrode 1 (118) is connected to one end of the biological tissue (120), is also connected to one end of the current proportional unit 3 (116) and the current proportional unit 1 (107); the electrode 2 (121) is connected to one end of the biological tissue (120), and is also connected to one end of the reference voltage source module (122).

2. The circuit according to claim 1, wherein: The neurostimulator chip (100) receives a control signal to control the current amplitude, pulse width and output mode of the bi-phase current (101) outputted to the outside. Since the neurostimulator chip (100) needs to output the bi-phase current (101) to the outside, the diode chain (104), NPN (109) and PNP (111) rely on the forward conduction voltage of the diode (105) and the conduction voltage drop of the NPN (109) and PNP (111) so that the central node voltage (106) of the diode chain is between the output stage power supply voltage (102) of the stimulator chip and the ground (103). The number of diodes (105) in the diode chain (104) needs to be based on the output stage power supply voltage (102) of the stimulator chip, the conduction voltage drop of the NPN (109) and PNP (111), and the neurostimulator chip. The requirement of the neurostimulator chip (100) for the reference voltage (123) is calculated; different output stage power supply voltages (102) of the stimulator chip have different numbers of diodes (105) of the matching diode chain (104), and the number of diodes (105) of the corresponding diode chain (104) is determined according to specific circumstances; when the high-voltage output stage of the neurostimulator chip (100) is in two voltage states, namely, the output stage power supply voltage (102) of the stimulator chip or the ground (103), there are two voltage drop states between the high-voltage output stage of the neurostimulator chip (100) and the central node of the diode chain (104), so that the current transmitted from the neurostimulator chip (100) to the central node of the diode chain (104) has two directions, flowing into and out of the central node of the diode chain (104), respectively.

3. The circuit according to claim 1, wherein: The forward conduction voltage characteristic of the diode (105) in the diode chain (104), coupled with the fact that the diode chain (104) is located between the high-voltage power supply voltage (114) and the ground (103), not only allows the diode chain center node voltage (106) to meet the demand of the neurostimulator chip (100) to output the biphasic current (101), but also serves to shunt the biphasic current (101); when the voltage state of the high-voltage output stage of the neurostimulator chip (100) is reflected as the voltage state of the output stage power supply voltage (102) of the stimulator chip, the voltage drop from the output stage power supply voltage (102) of the stimulator chip to the diode chain center node voltage (106) causes current to flow into the center node of the diode chain (104); at the same time, according to the forward conduction property of the diode (105), the diode (106) from the center node of the diode chain (104) to the ground (103) 5) forward conduction, the diode (105) to the high-voltage power supply voltage one (114) is reversely blocked, and the current flowing from the neurostimulator chip (100) into the central node of the diode chain (104) flows into the current proportional unit one (107); when the voltage state of the high-voltage output stage of the neurostimulator chip (100) is reflected as the voltage state of the ground (103), the voltage drop from the central node voltage (106) of the diode chain to the ground (103) causes the central node of the diode chain (104) to flow out of the current; at the same time, according to the forward conduction property of the diode (105), the diode (105) to the high-voltage power supply voltage one (114) of the central node of the diode chain (104) is forward conducted, and the diode (105) to the ground (103) is reversely blocked, and the current flowing out of the central node of the diode chain (104) of the neurostimulator chip (100) finally flows out of the current proportional unit two (113).

4. The circuit according to claim 1, wherein: The waveform of the biphasic current 1 (101) output by the neurostimulator chip (100) is considered to be a current with a certain state in the respective anode and cathode stages; by virtue of the shunting effect of the diode chain (104), the determined currents in the anode and cathode stages pass through the respective current proportional units and are amplified according to the required proportion; the current proportional unit 1 (107), the current proportional unit 2 (113) and the current proportional unit 3 (116) are respectively composed of an NPN (109), an N-level NPN chain (110), a PNP (111), an N-level PNP chain (112), a switch (108) and the output stage power supply voltage and ground (103) of the corresponding stimulator chip; Both NPN (109) and PNP (111) are devices that can withstand the output stage power supply voltage of the stimulator chip; an N-level transistor mirror unit current mirror composed of an N-level NPN chain (110) and an NPN (109) and an N-level transistor mirror unit current mirror composed of an N-level PNP chain (112) and a PNP (111) are controlled by a switch (108); current proportional unit one (107), current proportional unit two (113) and current proportional unit three (116) are based on the required number of corresponding N-level PNP chains (112), N-level NPN chains (110) and switches (108); the number of current proportional units through which the anode and cathode currents flow determines the amplification factor of the final anode and cathode current amplitudes.

5. The circuit according to claim 1, wherein: At the last stage of the circuit, a biphasic current 2 (117) is provided to the biological tissue (120) through the electrode 1 (118); in the anode stimulation stage, the current of the neurostimulator chip (100) flows into the central node of the diode chain (104), flows into the current proportional unit 1 (107), is amplified once, flows into the current proportional unit 3 (116), is amplified a second time, and is connected to the electrode 1 (118). By virtue of the high voltage power supply voltage 2 (115) of the current proportional unit 3 (116) reflected on the electrode 1 (118) and the reference voltage (123) reflected on the electrode 2 (121), the current flows in the forward direction through the conductive path (119) in the biological tissue (120); in the cathode stimulation stage, the current of the neurostimulator chip (100) flows out of the central node of the diode chain (104), flows out of the current proportional unit 2 (113), is amplified once, flows into the current proportional unit 1 (107) below the current proportional unit 3 (116), is amplified a second time, and is connected to the electrode 1 (118). ), with the ground (103) of the current proportional unit 1 (107) reflected on the electrode 1 (118) and the reference voltage (123) reflected on the electrode 2 (121), the current flows in the reverse direction through the conductive path (119) in the biological tissue (120); at the same time, since there is a time interval between the anode and cathode currents of the biphasic current 1 (101) output by the neurostimulator chip (100), when the overall circuit outputs the anode stimulation current of the biphasic current 2 (117) to the outside, the cathode stimulation current does not reach the current proportional unit 1 (107) below the current proportional unit 3 (116); and when the overall circuit outputs the cathode stimulation current of the biphasic current 2 (117) to the outside, the anode stimulation current does not reach the current proportional unit 3 (116); the overall circuit outputs the biphasic current 1 (101) to the outside according to the waveform parameters other than the current amplitude of the biphasic current 1 (101) output by the neurostimulator chip (100), and no additional control switch is required to realize the biphasic current output to output the biphasic current 2 (117).

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