CN110870945A - Gain adjustment module, control method and implantable neural stimulation system - Google Patents
Gain adjustment module, control method and implantable neural stimulation system Download PDFInfo
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- A61N1/00—Electrotherapy; Circuits therefor
- A61N1/18—Applying electric currents by contact electrodes
- A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
- A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
- A61N1/3605—Implantable neurostimulators for stimulating central or peripheral nerve system
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- A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
- A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
- A61N1/3605—Implantable neurostimulators for stimulating central or peripheral nerve system
- A61N1/36053—Implantable neurostimulators for stimulating central or peripheral nerve system adapted for vagal stimulation
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- A—HUMAN NECESSITIES
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- A61N1/00—Electrotherapy; Circuits therefor
- A61N1/18—Applying electric currents by contact electrodes
- A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
- A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
- A61N1/3605—Implantable neurostimulators for stimulating central or peripheral nerve system
- A61N1/3606—Implantable neurostimulators for stimulating central or peripheral nerve system adapted for a particular treatment
- A61N1/36062—Spinal stimulation
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- A61N1/18—Applying electric currents by contact electrodes
- A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
- A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
- A61N1/3605—Implantable neurostimulators for stimulating central or peripheral nerve system
- A61N1/36125—Details of circuitry or electric components
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- A—HUMAN NECESSITIES
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- A61N1/18—Applying electric currents by contact electrodes
- A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
- A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
- A61N1/3605—Implantable neurostimulators for stimulating central or peripheral nerve system
- A61N1/36128—Control systems
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- A—HUMAN NECESSITIES
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- A61N1/18—Applying electric currents by contact electrodes
- A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
- A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
- A61N1/3605—Implantable neurostimulators for stimulating central or peripheral nerve system
- A61N1/36128—Control systems
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- H—ELECTRICITY
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- H03K—PULSE TECHNIQUE
- H03K5/00—Manipulating of pulses not covered by one of the other main groups of this subclass
- H03K5/22—Circuits having more than one input and one output for comparing pulses or pulse trains with each other according to input signal characteristics, e.g. slope, integral
- H03K5/24—Circuits having more than one input and one output for comparing pulses or pulse trains with each other according to input signal characteristics, e.g. slope, integral the characteristic being amplitude
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Abstract
The invention discloses a gain adjustment module, a control method and an implanted nerve stimulation system, wherein the gain adjustment module comprises a gain control unit and an analog-to-digital conversion unit connected with the gain control unit, the gain control unit is used for acquiring an initial output signal according to a preset gain and a received initial input signal and adjusting the gain according to the value of the initial output signal to acquire a target gain, the gain control unit acquires a target output signal according to the target gain and the initial input signal, and the analog-to-digital conversion unit converts the target output signal into a digital signal. The gain adjusting unit can adjust the gain according to the value of the initial output signal, realize automatic control of the gain, and enable the finally obtained target gain to be suitable for the current electroencephalogram signal, so that the amplitude of the target output signal finally output to the analog-to-digital conversion unit is kept within a certain range, and the accuracy of analog-to-digital conversion is further improved.
Description
Technical Field
The invention relates to the field of implantable medical treatment, in particular to a gain adjusting module, a control method and an implantable neural stimulation system.
Background
Implantable medical systems, which are used in clinical medicine in recent years, generally include implantable neurostimulation systems (including deep brain stimulation system DBS, implantable cortical brain stimulation system CNS, implantable spinal cord electrical stimulation system SCS, implantable sacral nerve stimulation system SNS, implantable vagus nerve stimulation system VNS, etc.), implantable cardiac stimulation systems (commonly referred to as cardiac pacemaker), implantable drug infusion systems (IDDS), etc.
In an implantable medical system, a nerve stimulation system can effectively control the symptoms of functional neurological and psychiatric disorders by chronic electrical stimulation of target nerves.
The frequency and amplitude of the target nerve signal can reflect the condition of the nerve disease, the disease condition can be judged and an optimized treatment mode can be adopted by reading the target nerve signal, and the treatment effect of the nerve stimulation system can also be objectively judged.
The acquisition of target point nerve electroencephalogram signals requires that electroencephalogram signals are amplified through a gain operational amplifier unit, then converted into digital signals through an analog-digital conversion unit, and finally transmitted out through wireless communication.
In practical application, the difference of the amplitude of the electroencephalogram signals is large, and if the gain operational amplifier unit amplifies the electroencephalogram signals by a fixed gain factor, the amplified electroencephalogram signals received by the analog-to-digital conversion unit may have a phenomenon of large or small amplitude, so that the analog-to-digital conversion is inaccurate, and therefore, the gain factor of the gain operational amplifier unit needs to be adjusted to adapt to electroencephalogram signals with different amplitudes.
Disclosure of Invention
The invention aims to provide a gain adjusting module, a control method and an implanted nerve stimulation system.
In order to achieve one of the above objectives, an embodiment of the present invention provides a gain adjustment module, which includes a gain control unit and an analog-to-digital conversion unit connected to the gain control unit, wherein the gain control unit is configured to obtain an initial output signal according to a preset gain and a received initial input signal, and adjust a gain according to a value of the initial output signal to obtain a target gain, the gain control unit obtains a target output signal according to the target gain and the initial input signal, and the analog-to-digital conversion unit converts the target output signal into a digital signal.
As a further improvement of an embodiment of the present invention, the gain control unit includes a gain operational amplifier unit, a peak detection unit, a comparison unit, a coarse adjustment unit and a fine adjustment unit, where the gain operational amplifier unit and the peak detection unit are respectively configured to obtain an initial output signal and an initial peak voltage to complete a peak obtaining cycle, the comparison unit is configured to determine whether the initial peak voltage meets a preset condition, if so, a fine adjustment process is performed, the fine adjustment unit obtains a fine adjustment multiple and transmits the fine adjustment multiple to the gain operational amplifier unit, and the gain operational amplifier unit takes a product of the fine adjustment multiple and a preset gain as a target gain; if not, entering a coarse adjustment process, acquiring a coarse adjustment multiple provided by the coarse adjustment unit by the gain operation and amplification unit, replacing a preset gain with a product of the coarse adjustment multiple and the preset gain, acquiring an intermediate peak voltage by the gain operation and amplification unit and the peak detection unit according to a peak acquisition cycle, entering a fine adjustment process when the intermediate peak voltage meets a preset condition, and taking the product of the coarse adjustment multiple, the fine adjustment multiple and the preset gain as a target gain by the gain operation and amplification unit.
As a further improvement of an embodiment of the present invention, the comparing unit is configured to determine whether the initial peak voltage is within a preset range, if so, enter a fine tuning process, the fine tuning unit obtains a fine tuning multiple according to the current peak voltage and transmits the fine tuning multiple to the gain operational amplifier unit, where the fine tuning multiple is a multiple between the current peak voltage and a target value, and the gain operational amplifier unit takes a product of the fine tuning multiple and a preset gain as a target gain; if not, entering a coarse adjustment process.
As a further improvement of the embodiment of the present invention, the fine tuning unit includes a reference voltage unit and a comparator, the comparator includes a first input terminal, a second input terminal and a first output terminal, the first input terminal is connected to the peak detection unit, the second input terminal is connected to the reference voltage unit, wherein the peak detection unit is configured to output a current peak voltage, the reference voltage unit is configured to output a variable reference voltage, and when the output of the comparator is inverted, the fine tuning unit takes a current variable reference voltage value as the current peak voltage.
As a further improvement of the embodiment of the present invention, the reference voltage unit includes a first amplifier and a channel selection unit, the first amplifier includes a third input terminal, a fourth input terminal and a second output terminal, the third input terminal is connected to a first fixed reference voltage, the second output terminal is connected to the channel selection unit, the second output terminal is provided with a plurality of series resistors, the fourth input terminal is connected to different regions of the plurality of series resistors to realize that the first amplifier outputs a variable voltage, and the channel selection unit selects a variable voltage and outputs the variable voltage as the variable reference voltage.
As a further improvement of an embodiment of the present invention, the comparing unit is configured to determine whether the initial peak voltage is smaller than a preset value, if so, enter a fine tuning process, the comparing unit continues to determine whether a difference between the initial peak voltage and the preset value is smaller than a preset threshold, if not, the gain operational amplifier unit obtains a fine tuning multiple provided by the fine tuning unit and replaces a preset gain with a product of the fine tuning multiple and the preset gain, and the gain operational amplifier unit and the peak detection unit obtain a temporary peak voltage according to a peak obtaining cycle, repeat the peak obtaining cycle until a difference between the obtained temporary peak voltage and the preset value is smaller than the preset threshold, and if so, the fine tuning unit obtains a current fine tuning multiple and transmits the current fine tuning multiple to the gain operational amplifier unit, the gain operational amplifier unit takes the product of the current fine adjustment multiple and the preset gain as a target gain; if not, entering a coarse adjustment process.
As a further improvement of an embodiment of the present invention, the coarse adjustment multiple includes a plurality of selectable coarse adjustment multiples, the fine adjustment multiple includes a plurality of selectable fine adjustment multiples, and the plurality of selectable coarse adjustment multiples includes a first-stage coarse adjustment multiple, a second-stage coarse adjustment multiple and a third-stage coarse adjustment multiple which can be selected in sequence.
As a further improvement of the embodiment of the present invention, the fine adjustment multiple is implemented by a second amplifier, the second amplifier includes a fifth input terminal, a sixth input terminal, and a third output terminal, the fifth input terminal includes a fixed resistor and a variable resistor, one end of the variable resistor is connected between the fixed resistor and the fifth input terminal, the other end of the variable resistor is connected to the third output terminal, the sixth input terminal is connected to a second fixed reference voltage, and the third output terminal is connected to the gain operational amplifier unit, where the fine adjustment multiple is a ratio of the variable resistor to the fixed resistor.
As a further improvement of an embodiment of the present invention, the preset gain is a maximum gain of the gain adjusting module.
As a further improvement of an embodiment of the present invention, the peak detection unit includes a first switch, a diode, a first resistor, a first capacitor arranged in a grounded manner, and a second resistor and a second switch arranged in a grounded manner and connected in series, where the first switch is used to control input of the peak detection unit, the second switch is used to reset, the second resistor is used to limit discharge current, the diode is used to implement unidirectional storage of a plurality of input voltages in cooperation with the first resistor and the first capacitor, and then the peak voltage is obtained by the plurality of input voltages and is used as output of the peak detection unit.
As a further improvement of an embodiment of the present invention, the peak detecting unit includes a third amplifier, the third amplifier comprises a seventh input end, an eighth input end and a fourth output end, the seventh input end is provided with a third resistor and a second capacitor, the eighth input end is connected with the fourth output end and comprises a fourth resistor, a third switch and a third capacitor which are arranged on the ground and connected in series, the fourth output end is provided with a transistor, one end of the transistor is connected with a power supply voltage, the other end of the transistor is connected with the third capacitor, wherein the third resistor and the second capacitor are used for filtering, the third switch is used for resetting, the transistor is used for generating bias current, the peak voltage is obtained by a plurality of gradually increasing input voltages input by the seventh input terminal, and the fourth output terminal uses the obtained peak voltage as the output of the peak detection unit.
In order to achieve one of the above objects, an embodiment of the present invention provides an implantable neurostimulation system, which includes the gain adjustment module, the stimulation electrode and the terminal device according to any one of the above technical solutions, wherein the stimulation electrode is used for acquiring an electroencephalogram signal as an initial input signal of the gain adjustment module, and the gain adjustment module transmits the converted digital signal to the terminal device.
To achieve one of the above objects, an embodiment of the present invention provides a gain control method, including:
acquiring an initial input signal;
acquiring an initial output signal according to the initial input signal and a preset gain;
adjusting gain according to the value of the initial output signal to obtain a target gain;
acquiring a target output signal according to the initial input signal and the target gain;
converting the target output signal into a digital signal.
As a further improvement of an embodiment of the present invention, the step "adjusting a gain according to a value of the initial output signal to obtain a target gain" specifically includes:
acquiring an initial peak voltage of the initial output signal;
judging whether the initial peak voltage meets a preset condition or not;
if so, entering a fine tuning process, acquiring a fine tuning multiple, and taking the product of the fine tuning multiple and a preset gain as a target gain;
if not, entering a coarse adjustment process, obtaining a coarse adjustment multiple, replacing the product of the coarse adjustment multiple and the preset gain with the preset gain, obtaining a corresponding middle peak voltage, and entering a fine adjustment process when the middle peak voltage meets the preset condition.
As a further improvement of an embodiment of the present invention, the step "determining whether the initial peak voltage meets a preset condition; if yes, entering a fine tuning process, and taking the product of the fine tuning multiple and the preset gain as a target gain "specifically comprises:
judging whether the initial peak voltage is within a preset range;
and if so, entering a fine adjustment process, acquiring the current peak voltage, obtaining a fine adjustment multiple according to the current peak voltage, and taking the product of the fine adjustment multiple and the preset gain as a target gain, wherein the fine adjustment multiple is the multiple between the current peak voltage and the target value.
As a further improvement of an embodiment of the present invention, the step "determining whether the initial peak voltage meets a preset condition; if yes, entering a fine tuning process, and taking the product of the fine tuning multiple and the preset gain as a target gain "specifically comprises:
judging whether the initial peak voltage is smaller than a preset value;
if so, entering a fine tuning process, judging whether the difference value between the initial peak voltage and the preset value is smaller than a preset threshold value, if not, obtaining a fine tuning multiple, replacing the preset gain with the product of the fine tuning multiple and the preset gain, and obtaining a corresponding temporary peak voltage until the difference value between the temporary peak voltage and the preset value is smaller than the preset threshold value, and if so, taking the product of the current fine tuning multiple and the preset gain as a target gain.
Compared with the prior art, the invention has the beneficial effects that: the gain adjusting unit of an embodiment of the present invention can adjust the gain according to the value of the initial output signal, so as to realize automatic control of the gain, and enable the finally obtained target gain to be adapted to the current electroencephalogram signal, thereby enabling the amplitude of the target output signal finally output to the analog-to-digital conversion unit to be kept within a certain range, and further improving the accuracy of analog-to-digital conversion.
Drawings
FIG. 1 is a schematic diagram of an implantable neurostimulation system according to one embodiment of the present invention;
FIG. 2 is a schematic diagram of a gain adjustment module in conjunction with a stimulation electrode and a terminal device according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a gain control unit according to a first embodiment of the present invention;
FIG. 4 is a schematic diagram of a fine tuning unit according to a first embodiment of the present invention;
FIG. 5 is a circuit diagram of a reference voltage unit according to a first embodiment of the present invention;
FIG. 6 is a circuit diagram of an embodiment of a peak detection unit according to the first embodiment of the present invention;
FIG. 7 is a circuit diagram of another embodiment of a peak detection unit according to the first embodiment of the present invention;
FIG. 8 is a schematic diagram illustrating the operation steps of the gain adjustment module of the first embodiment of the present invention at different times;
FIG. 9 is a schematic diagram of a gain control unit according to a second embodiment of the present invention;
fig. 10 to 12 are schematic diagrams of a specific adjustment process of the gain control unit according to the second embodiment of the present invention;
FIG. 13 is a schematic diagram of fine tune multiple acquisition according to a second embodiment of the present invention;
FIG. 14 is a schematic diagram of the Rv circuit of FIG. 13;
fig. 15 is a flowchart illustrating a gain control method according to an embodiment of the present invention.
Detailed Description
The present invention will be described in detail below with reference to specific embodiments shown in the drawings. These embodiments are not intended to limit the present invention, and structural, methodological, or functional changes made by those skilled in the art according to these embodiments are included in the scope of the present invention.
Referring to fig. 1, an embodiment of the present invention provides an implantable neurostimulation system.
Implantable neurostimulation systems typically include several components: a plurality of stimulation electrodes 200 (here, left and right brain electrodes are taken as an example), an electrode lead 300, an extension lead 500, a pulse generator 400, and a terminal device 600.
Taking the deep brain stimulation system DBS as an example, the pulse generator 400 conducts an electrical pulse to the STN (Subthalamic Nucleus) Nucleus of the brain through the extension wire 500, the electrode wire 300 and the stimulation electrode 200 to achieve the purpose of treating diseases such as parkinson.
The terminal device 600 is exemplified by a program controller, which is used to adjust various stimulation parameters of the pulse generator 400, such as pulse amplitude, pulse width (i.e. pulse width), pulse frequency, etc., and it is understood that the terminal device 600 may also be other devices, such as a display device, etc., which may be determined according to the actual situation.
Referring to fig. 2, the implantable neurostimulation system further comprises a gain adjustment module 100.
The stimulation electrode 200 is used to acquire an electroencephalogram signal and transmit the electroencephalogram signal as an input signal to the gain adjustment module 100.
It should be noted that the electroencephalogram signal acquired by the stimulation electrode 200 may be an electroencephalogram signal in a stimulation state, or may be an electroencephalogram signal in a non-stimulation state.
The gain adjustment module 100 adjusts the gain according to the input signal and obtains the adjusted output signal, and the gain adjustment module 100 converts the output signal into a digital signal and transmits the digital signal to the terminal device 600.
Of course, it may also be transmitted not to the terminal device 600 but to other components.
The gain adjustment module 100 according to an embodiment of the present invention will be described in detail below.
With continued reference to fig. 2, the gain adjustment module 100 includes a gain control unit 10 and an analog-to-digital conversion unit 20.
The analog-to-digital conversion unit 20 is electrically connected to the gain control unit 10.
The gain control unit 10 is configured to obtain an initial output signal Vout according to a preset gain Ao and a received initial input signal Vin.
The initial output signal Vout is a signal obtained by amplifying the input signal Vin according to the preset gain Ao.
Then, the gain control unit 10 is configured to adjust the gain according to the value of the initial output signal Vout to obtain the target gain At, and the gain control unit 10 obtains the target output signal Vt according to the target gain At and the initial input signal Vin.
The analog-to-digital conversion unit 20 converts the target output signal Vt into a digital signal, and then transmits the digital signal to the terminal device 600 through wireless communication or limited communication, and the terminal device 600 can visually judge the state of an illness and adopt an optimized treatment mode through the digital signal, and can also objectively judge the treatment effect of the implanted nerve stimulation system.
The gain adjustment module 100 of this embodiment can adjust the gain according to the value of the initial output signal Vout, so as to achieve automatic control of the gain, and make the finally obtained target gain At be adapted to the current electroencephalogram signal, so that the amplitude of the target output signal Vt finally output to the analog-to-digital conversion unit 20 is kept within a certain range, and further, the accuracy of analog-to-digital conversion is improved.
Referring to fig. 3, a schematic diagram of a gain control unit 10 according to an embodiment of the invention is shown.
The gain control unit 10 includes a gain operational amplifier unit 11, a peak detection unit 12, a comparison unit 13, a coarse adjustment unit 14, and a fine adjustment unit 15.
The gain operational amplifier unit 11 is a low noise gain operational amplifier unit.
The gain operational amplifier unit 11 is configured to obtain an initial output signal Vout according to a preset gain Ao and a received initial input signal Vin.
The peak detection unit 12 is located between the gain operational amplifier unit 11 and the comparison unit 13.
The peak detection unit 12 is configured to obtain an initial peak voltage Vpeak0 of the initial output signal Vout.
Here, the gain operational amplifier unit 11 and the peak detection unit 12 are used to acquire the initial output signal Vout and the initial peak voltage Vpeak0, respectively, and complete one peak acquisition cycle.
The coarse tuning unit 14 and the fine tuning unit 15 are connected to the comparing unit 13 at one end and the gain operational amplifier unit 11 at the other end.
The comparing unit 13 is used for determining whether the initial peak voltage Vpeak0 meets a preset condition.
If yes, the fine tuning process is performed, the fine tuning unit 15 obtains the fine tuning multiple An and transmits the fine tuning multiple An to the gain operational amplifier unit 11, and the gain operational amplifier unit 11 takes the product of the fine tuning multiple An and the preset gain Ao as the target gain At (At ═ Ao × An).
If not, the process enters a coarse adjustment process, the gain operational amplifier unit 11 obtains a coarse adjustment multiple Am provided by the coarse adjustment unit 14 and replaces the preset gain Ao with a product of the coarse adjustment multiple Am and the preset gain Ao, the gain operational amplifier unit 11 and the peak detection unit 12 obtain An intermediate peak voltage Vpeak1 according to a peak value obtaining cycle, and enter a fine adjustment process when the intermediate peak voltage Vpeak1 meets a preset condition, and the gain operational amplifier unit 11 takes the product of the coarse adjustment multiple Am, the fine adjustment multiple An and the preset gain Ao as a target gain At (At ═ Ao An Am).
The gain control unit 10 of the present embodiment has various schemes, and fig. 3 and 4 illustrate two specific examples of the gain control unit 10, but not limited thereto.
Referring to fig. 3, a schematic diagram of the gain control unit 10 according to the first embodiment is shown.
The comparing unit 13 is used for determining whether the initial peak voltage Vpeak0 is within a preset range.
If yes, the fine tuning process is performed, the fine tuning unit 15 obtains a fine tuning multiple An according to the current peak voltage Vpeak, and transmits the fine tuning multiple An to the gain operational amplifier unit 11, where the fine tuning multiple An is a multiple between the current peak voltage Vpeak and the target value, and the gain operational amplifier unit 11 takes a product of the fine tuning multiple An and the preset gain Ao as the target gain At (At ═ Ao ═ An).
If not, the process enters a coarse adjustment process, the gain operational amplifier unit 11 obtains a coarse adjustment multiple Am provided by the coarse adjustment unit 14 and replaces the preset gain Ao with a product of the coarse adjustment multiple Am and the preset gain Ao, the gain operational amplifier unit 11 and the peak detection unit 12 obtain An intermediate peak voltage Vpeak1 according to a peak value obtaining cycle, and enter a fine adjustment process when the intermediate peak voltage Vpeak1 meets a preset condition, and the gain operational amplifier unit 11 takes the product of the coarse adjustment multiple Am, the fine adjustment multiple An and the preset gain Ao as a target gain At (At ═ Ao An Am).
Here, the target value may be a certain fixed value within a preset range.
The current peak voltage Vpeak is an actual peak voltage of an actually output electroencephalogram signal, the intermediate peak voltage Vpeak1 is a peak voltage correspondingly obtained according to a peak obtaining cycle, that is, when the initial peak voltage Vpeak0 is not within a preset range, the intermediate peak voltage Vpeak1 is repeatedly obtained according to the peak obtaining cycle, that is, the product of the coarse adjustment multiple Am and the preset gain Ao is repeatedly substituted for the preset gain Ao (i.e., the product of the coarse adjustment multiple Am and the preset gain Ao is used as a new gain), the intermediate output signal Vout1 is obtained according to the new gain (Am × Ao) and the initial input signal Vin, and the peak detecting unit 12 obtains the intermediate peak voltage Vpeak1 according to the intermediate output signal Vout 1.
It should be noted that "repeatedly replacing the coarse adjustment multiple Am in the preset gain Ao by the product of the coarse adjustment multiple Am and the preset gain Ao" is changed successively, for example, the coarse adjustment multiple Am in the second peak acquisition cycle is quadrupled, and the coarse adjustment multiple Am in the third peak acquisition cycle is also quadrupled, so that the new gain in the peak acquisition cycle at this time is the product of the coarse adjustment multiple Am in the second peak acquisition cycle, the coarse adjustment multiple Am in the third peak acquisition cycle, and the preset gain Ao.
Note that "the new gain is a product of the coarse adjustment multiple Am in the second peak acquisition cycle, the coarse adjustment multiple Am in the third peak acquisition cycle, and the preset gain Ao" actually means: when the coarse adjustment process is increasing the gain, the new gain is Ao 4 × 4, and when the coarse adjustment process is decreasing the gain, the new gain is Ao 1/4 × 1/4, that is, for convenience of description, the new gain is defined as the product of the coarse adjustment multiple and the preset gain Ao, but in actual operation, the product may be the product of the inverse of the coarse adjustment multiple and the preset gain Ao, and the coarse adjustment multiple and the fine adjustment multiple of other parts are also the same according to actual conditions.
Specifically, referring to fig. 4, the fine adjustment unit 15 includes a reference voltage unit 321 and a comparator 322.
The comparator 322 includes a first input end 3221, a second input end 3222 and a first output end 3223.
The first input terminal 3221 is connected to the peak detecting unit 12.
The second input terminal 3222 is connected to the reference voltage unit 321.
The peak detection unit 12 is configured to output a current peak voltage Vpeak, the reference voltage unit 321 is configured to output a variable reference voltage, and when the comparator 322 output is flipped, the fine adjustment unit 15 takes the current variable reference voltage as the current peak voltage Vpeak.
That is, the reference voltage unit 321 continuously generates variable reference voltages with various different magnitudes, compares the variable reference voltages with the current peak voltage Vpeak, and finally confirms the value of the current peak voltage Vpeak through the output result (0 or 1) of the first output terminal 3223, that is, when the first output terminal 3223 changes from output 0 to output 1, the current variable reference voltage approaches the actual current peak voltage Vpeak, and the current variable reference voltage may be regarded as the current peak voltage Vpeak.
Referring to fig. 5, a circuit diagram of the reference voltage unit 321 is shown.
The reference voltage unit 321 includes a first amplifier 3211 and a channel selection unit 3212.
The first amplifier 3211 includes a third input 32111, a fourth input 32112, and a second output 32113.
The third input terminal 32111 is connected to the first fixed reference voltage Vref1, the second output terminal 32113 is connected to the channel selection unit 3212, the second output terminal 32113 is provided with a plurality of series resistors Rx, the fourth input terminal 32112 is connected to different areas of the plurality of series resistors Rx to enable the first amplifier 3211 to output a variable voltage, the channel selection unit 3212 selects the variable voltage and outputs the variable voltage as a variable reference voltage, that is, the output terminal of the channel selection unit 3212 is connected to the second input terminal 3222 of the comparator 322.
Here, the first fixed reference voltage Vref1 is 1.2V, a variable voltage of 0 to 2V is generated by the operational amplifier action of the first amplifier 3211, the variation interval of the variable voltage is 20mV, and the variable voltage is selectively output to the second input terminal 3222 of the comparator 322 after being matched with a 6bit (64 channel) channel selection unit 3212.
In this embodiment, the gain adjustment process includes a coarse adjustment process (a wide range adjustment process with a larger multiple) and a fine adjustment process (a small range adjustment process with a smaller multiple), when the initial peak voltage Vpeak0 is not within a preset range and a condition is satisfied after a limited number of coarse adjustment processes, the fine adjustment process is entered, at this time, the final gain adjustment multiple is a product of the coarse adjustment multiple Am and the fine adjustment multiple An, and when the initial peak voltage Vpeak0 is within the preset range, the final gain adjustment multiple is the fine adjustment multiple An.
In addition, the coarse adjustment multiple Am of the embodiment may be a fixed multiple, and the fine adjustment multiple An may be obtained through a gradual approach process of the variable reference voltage, the obtaining process of the gain multiple is convenient and fast, the automatic control of the variable gain is realized, and the gain output efficiency is greatly improved.
It should be noted that, in this embodiment, the coarse tuning multiple Am includes several selectable coarse tuning multiples, and the several selectable coarse tuning multiples may be a fixed number and a fixed multiple, but are not limited thereto.
Taking the example that the coarse tuning multiple Am comprises three coarse tuning multiples, when the initial peak voltage Vpeak0 passes through the first coarse tuning multiple Am1Second-stage coarse adjustment multiple Am2And third-stage coarse tuning multiple Am3And when the intermediate peak voltage Vpeak1 acquired after the coarse adjustment is still not in the preset range, directly updating the preset gain Ao to the maximum adjustable gain multiple, and acquiring the target output signal Vt according to the maximum adjustable gain multiple and the initial input signal Vin.
In this embodiment, referring to fig. 6 and 7, two specific circuit diagrams of the peak detecting unit 12 are shown.
Referring to fig. 6, in an embodiment, the peak detecting unit 12a includes a first switch S1, a diode D1, a first resistor R1, a first capacitor C1 connected to ground, a second resistor R2 connected to ground and connected in series, and a second switch S2.
The first switch S1 is used to control the input of the peak detection unit 12a, the second switch S2 is used to reset, the second resistor R2 is used to limit the discharge current, the diode D1 cooperates with the first resistor R1 and the first resistor C1 to realize the unidirectional storage of a plurality of input voltages, and then the peak voltage is obtained through the plurality of input voltages and is used as the output of the peak detection unit 12 a.
Here, the output signal transmitted from the gain op-amp unit 11 to the peak detection unit 12a includes a plurality of voltage values, for example, the output signal is a sine wave, and at this time, since the diode D1 is in a unidirectional conducting structure, the peak voltage can be obtained by the filtering and storing actions of the first resistor R1 and the first capacitor C1.
The first resistor R1 is 40M Ω, the first capacitor C1 is 30pF, and the second resistor R2 is 20k Ω, and the peak detecting unit 12a of this embodiment has the advantage that all components are passive devices and there is substantially no power loss.
In another embodiment, in conjunction with fig. 7, the peak detection unit 12b includes a third amplifier 311 b.
The third amplifier 311b includes a seventh input terminal 3111b, an eighth input terminal 3112b and a fourth output terminal 3113 b.
The seventh input terminal 3111b is provided with a third resistor R3 and a second capacitor C2, the eighth input terminal 3112b is connected to the fourth output terminal 3113b and includes a fourth resistor R4, a third switch S3 and a third capacitor C3, the fourth resistor R4, the third switch S3 and the third capacitor C3 are connected in series and are connected to ground, the fourth output terminal 3113b is provided with a transistor T, one end of the transistor T is connected to the power supply voltage Vcc, and the other end of the transistor T is connected to the third capacitor C3.
The third resistor R3 and the second capacitor C2 are used for filtering, the third switch S3 is used for resetting, the transistor T is used for generating a bias current Ibias, which can control the voltage variation efficiency of the third capacitor C3, the peak voltage is obtained by a plurality of gradually increasing input voltages input by the seventh input terminal 3111b, and the obtained peak voltage is used as the output of the peak detection unit 12b by the fourth output terminal 3113 b.
Here, the output signal transmitted from the gain op-amp unit 11 to the peak detection unit 12b includes a plurality of voltage values, for example, the output signal is a sine wave, and at this time, because the circuit structure is only charged and not discharged, and then the peak voltage can be obtained by matching with filtering and storing.
The peak detection unit 12b of this embodiment has an advantage that the obtained peak voltage can accurately reflect the output of the gain op-amp unit 11, and is not affected by process variations.
In the present embodiment, with reference to fig. 8, the operation steps of the gain adjustment module 100 at different time instants are illustrated.
Because the amplitude of the electroencephalogram signal is uncertain, the peak detection unit 12 needs to continuously work for a period of time to obtain the peak voltage, here, the single working time of the peak detection unit 12 is taken as 1s as an example, that is, the time for the peak detection unit 12 to obtain one peak voltage is 1 s.
Since the current peak voltage Vpeak is obtained by successive approximation, the gain of the gain operational amplifier unit 11 needs to be adjusted step by step, and the peak value is sampled and approximated again after the gain of the gain operational amplifier unit 11 is adjusted each time.
Here, before each peak sampling, the reset processing of the peak voltage is required, and the time length of each reset is 2s as an example.
It can be seen that the shortest time length for obtaining the target gain At is 3s, that is, the peak detection unit 12 performs one processing to obtain the target gain At, and At this time, the time length for obtaining the target gain At is a sum of the reset time length 2s and the single working time length of the peak detection unit 12 which is 1 s.
The single gain adjustment time of the gain adjustment module 100 does not exceed 12 s.
That is, at this time, the approximation process is performed four times, and the peak detection unit 12 performs four times of processing (i.e., three times of coarse adjustment process plus one time of fine adjustment process).
The gain adjustment module 100 further comprises a clock unit, wherein the frequency of the clock unit is 1kHz, and the maximum time can be counted to 15s after frequency division.
In addition, it can be seen that when the peak voltage after the three coarse adjustment processes is still not within the preset range, if the peak voltage at this time is smaller than the minimum value of the preset range, the gain is directly set to the maximum value, and if the peak voltage at this time is larger than the maximum value of the preset range, the gain is directly set to the minimum value.
Fig. 9 is a schematic diagram of a gain control unit 10' according to a second embodiment.
The comparing unit 13 'is used for determining whether the initial peak voltage Vpeak 0' is smaller than a preset value.
If so, the fine tuning process is entered, and the comparing unit 13 'continues to determine whether the difference between the initial peak voltage Vpeak 0' and the preset value is smaller than the preset threshold, and if not, the gain op-amp unit 11 'obtains the fine tuning multiple An' provided by the fine tuning unit 15 'and replaces the preset gain Ao' with the product of the fine tuning multiple An 'and the preset gain Ao', and the gain op-amp unit 11 'and the peak detection unit 12' acquire the temporary peak voltage Vpeak2 'according to the peak acquisition cycle, repeat the peak acquisition cycle until the difference between the acquired temporary peak voltage Vpeak 2' and the preset value is less than the preset threshold, if less than the preset threshold, the fine tuning unit 15 'obtains the current fine tuning multiple An' and transmits the current fine tuning multiple An 'to the gain operational amplifier unit 11', and the gain operational amplifier unit 11 'takes the product of the current fine adjustment multiple An' and the preset gain Ao 'as the target gain At' (At ═ Ao '× An').
If not, entering a coarse tuning process, the gain operational amplifier unit 11 ' acquires a coarse tuning multiple Am ' provided by the coarse tuning unit 14 ' and replaces the product of the coarse tuning multiple Am ' and the preset gain Ao ' with the preset gain Ao ', and the gain operational amplifier unit 11 ' and the peak detection unit 12 ' acquire An intermediate peak voltage Vpeak1 ' according to a peak acquisition cycle, and enter a fine tuning process when the intermediate peak voltage Vpeak1 ' is smaller than a preset value, and the gain operational amplifier unit 11 ' takes the product of the coarse tuning multiple Am ', the fine tuning multiple An ' and the preset gain Ao ' as a target gain At ' (At ' ═ Ao ' An ' Am ').
Here, the intermediate peak voltage Vpeak1 'is a peak voltage correspondingly obtained according to a peak obtaining cycle, that is, when the initial peak voltage Vpeak0 is not less than the preset value, obtaining the intermediate peak voltage Vpeak 1' according to the peak obtaining cycle is repeated, that is, the product of the coarse adjustment multiple Am 'and the preset gain Ao' is repeated to replace the preset gain Ao ', and the intermediate output signal Vout 1' is obtained according to the new gain and the initial input signal Vin ', and the peak detecting unit 12' obtains the intermediate peak voltage Vpeak1 'according to the intermediate output signal Vout 1'.
Note that "repeatedly replacing the coarse adjustment multiple Am 'in the preset gain Ao'" with the product of the coarse adjustment multiple Am 'and the preset gain Ao' is changed successively, for example, the coarse adjustment multiple Am 'in the second peak acquisition cycle is quadrupled, and the coarse adjustment multiple Am' in the third peak acquisition cycle is doubled, so that the new gain in the third peak acquisition cycle is the quotient of the preset gain Ao 'and the coarse adjustment multiple Am' in the second peak acquisition cycle, and the coarse adjustment multiple Am 'in the third peak acquisition cycle (the new gain is Ao' × 1/4 ═ 1/4).
Likewise, the temporary peak voltage Vpeak2 ' is a peak voltage correspondingly obtained according to a peak obtaining cycle, that is, when the difference between the initial peak voltage Vpeak0 ' and the preset value is not less than the preset threshold, obtaining the temporary peak voltage Vpeak2 ' according to the peak obtaining cycle is repeated, that is, the product of the fine adjustment multiple An ' and the preset gain Ao ' is repeated to replace the preset gain Ao ', and the temporary output signal Vout2 ' is obtained according to the new gain and the initial input signal Vin ', and the peak detecting unit 12 ' obtains the temporary peak voltage Vpeak2 ' according to the temporary output signal Vout2 '.
It should be noted that, the "repeatedly replacing the fine adjustment multiple An ' by the product of the fine adjustment multiple An ' and the preset gain Ao ' for the fine adjustment multiple An ' in the preset gain Ao '" is individually changed, for example, the fine adjustment multiple An ' in the second peak obtaining cycle is 1.25, the fine adjustment multiple An ' in the third peak obtaining cycle is 1.5, then, the new gain in the second peak obtaining cycle is the product of the fine adjustment multiple An ' in the second peak obtaining cycle and the preset gain Ao ' (the new gain is Ao ' × 1.25), and the new gain in the third peak obtaining cycle is the product of the fine adjustment multiple An ' and the preset gain Ao ' in the third peak obtaining cycle (the new gain is Ao ' × 1.5).
Specifically, fig. 10 to 12 are combined to show a specific adjustment process of the gain control unit 10' of the present embodiment.
Here, it is assumed that the coarse adjustment multiple Am ' includes a first-stage coarse adjustment multiple Am1 ', a second-stage coarse adjustment multiple Am2 ', and a third-stage coarse adjustment multiple Am3 ', which are selectable in this order, the first-stage coarse adjustment multiple Am1 ' is quadrupled, and the second-stage coarse adjustment multiple Am2 ' and the third-stage coarse adjustment multiple Am3 ' are both doubled.
The largest selectable fine adjustment multiple of the fine adjustment multiples An' is not more than two times.
It can be understood that the final target gain At ' is the integration of the three-level adjustment results, and of course, according to the actual situation, the target gain At ' can be obtained only through the first-level adjustment, or the target gain At ' can be obtained through the first-level adjustment, the second-level adjustment and the three-level adjustment.
That is, the gain adjustment process includes a coarse adjustment process (a large-multiple wide-range adjustment process) and a fine adjustment process (a small-multiple small-range adjustment process), when the initial peak voltage Vpeak0 ' is greater than a preset value and a condition is satisfied after a limited number of coarse adjustment processes, the fine adjustment process is entered, at this time, the final gain adjustment multiple is a product of the coarse adjustment multiple Am ' and the fine adjustment multiple An ', and when the initial peak voltage Vpeak0 ' is not greater than the preset value, the final gain adjustment multiple is the fine adjustment multiple An '.
In addition, the coarse adjustment multiple Am ' of the present embodiment may be a fixed multiple, and the fine adjustment multiple An ' is obtained through a gradual approximation process between the temporary peak voltage Vpeak2 ' and the preset value, so that the finally obtained gain multiple is closer to the preset value.
It should be noted that, in this embodiment, the coarse tuning multiple Am 'includes a plurality of selectable coarse tuning multiples, and the plurality of selectable coarse tuning multiples are fixed and multiple fixed values, and when the initial peak voltage Vpeak 0' passes through the first-stage coarse tuning multiple Am in sequence1', second stage coarse adjustment multiple Am2' and third-stage coarse tuning multiple Am3When the intermediate peak voltage Vpeak1 ' obtained after the coarse adjustment is still greater than the preset value, the preset gain Ao ' is directly divided by the maximum adjustable gain multiple, and the target output signal Vt ' is obtained according to the preset gain Ao ' and the maximum adjustable gain multiple and the initial input signal Vin '.
In connection with fig. 13, several alternative fine-tuning multiples of the fine-tuning multiple An 'may be realized by the second amplifier 323, that is to say that the fine-tuning unit 15' also comprises the second amplifier 323.
Here, An adjustment circuit of the fine adjustment multiple An' of the third-stage adjustment is taken as An example.
The second amplifier 323 includes a fifth input port 3231, a sixth input port 3232, and a third output port 3233.
A fifth input 3231 receives the output of the second stage adjustment.
The fifth input terminal 3231 includes a fixed resistor Rc and a variable resistor Rv, one end of the variable resistor Rv is connected between the fixed resistor Rc and the fifth input terminal 3231, the other end of the variable resistor Rv is connected to the third output terminal 3233, the sixth input terminal 3232 is connected to the second fixed reference voltage Vref2, the third output terminal 3233 is connected to the gain op-amp unit 11, wherein the plurality of selectable fine-tuning multiples is a ratio of the variable resistor Rv to the fixed resistor Rc.
Here, the resistance value of the fixed resistor Rc is 2M Ω, the resistance value of the variable resistor Rv varies in a range of 2M Ω to 15.75M Ω, and the minimum variable step size of the variable resistor Rv is 0.25M Ω.
Specifically, referring to fig. 14, the variable resistor Rv includes a plurality of resistors with different resistances and a plurality of switches, and the output of each resistance can be realized through the cooperation of the plurality of resistors and the plurality of switches, that is, the resistance variation range of the variable resistor Rv is 2M Ω to 15.75M Ω, and the minimum variable step length of the variable resistor Rv is 0.25M Ω, where 6bit control bits are required.
For other descriptions (for example, the operation principle of the peak detecting unit 12') in this embodiment, reference may be made to the first embodiment, which is not described herein again.
The present invention further provides a gain control method, which is described with reference to fig. 15 and the foregoing gain adjustment module 100, and the control method includes the steps of:
acquiring an initial input signal Vin;
acquiring an initial output signal Vout according to an initial input signal Vin and a preset gain Ao;
adjusting the gain according to the value of the initial output signal Vin to obtain a target gain At;
acquiring a target output signal Vt according to the initial input signal Vin and the target gain At;
the target output signal Vt is converted into a digital signal.
According to the embodiment, the gain can be adjusted according to the value of the initial output signal Vout, automatic control of the gain is realized, and the finally obtained target gain At can adapt to the current electroencephalogram signal, so that the amplitude of the finally output target output signal Vt is kept within a certain range, and the accuracy of analog-to-digital conversion is further improved.
In this embodiment, the step of "adjusting the gain according to the value of the initial output signal Vout to obtain the target gain At" specifically includes:
acquiring an initial peak voltage Vpeak0 of the initial output signal Vout;
judging whether the initial peak voltage Vpeak0 meets a preset condition or not;
if so, entering a fine tuning process, acquiring a fine tuning multiple An, and taking the product of the fine tuning multiple An and the preset gain Ao as a target gain At;
if not, entering a coarse adjustment process, acquiring a coarse adjustment multiple Am, replacing the preset gain Ao with the product of the coarse adjustment multiple Am and the preset gain Ao, acquiring a corresponding intermediate peak voltage Vpeak1, and entering a fine adjustment process when the intermediate peak voltage Vpeak1 meets the preset condition.
Here, the fine tuning process and the coarse tuning process may have various schemes.
In the first embodiment, the step "determines whether the initial peak voltage Vpeak0 meets a preset condition; if yes, entering a fine tuning process, and taking the product of the fine tuning multiple An and the preset gain Ao as the target gain At "specifically including:
judging whether the initial peak voltage Vpeak0 is within a preset range;
if yes, entering a fine tuning process, acquiring the current peak voltage Vpeak, obtaining a fine tuning multiple An according to the current peak voltage Vpeak, taking the product of the fine tuning multiple An and the preset gain Ao as a target gain At, and taking the fine tuning multiple An as the multiple between the current peak voltage Vpeak and the target value.
In a second embodiment, the step "determines whether the initial peak voltage Vpeak' meets a preset condition; if yes, entering a fine tuning process, and taking the product of the fine tuning multiple An ' and the preset gain Ao ' as a target gain At ':
judging whether the initial peak voltage Vpeak' is smaller than a preset value;
if so, entering a fine tuning process, judging whether the difference between the initial peak voltage Vpeak 'and the preset value is smaller than a preset threshold value, if not, acquiring a fine tuning multiple An', replacing the preset gain Ao 'with the product of the fine tuning multiple An' and the preset gain Ao 'and acquiring a corresponding temporary peak voltage Vpeak 2' until the difference between the temporary peak voltage Vpeak2 'and the preset value is smaller than the preset threshold value, and if so, taking the product of the current fine tuning multiple An' and the preset gain Ao 'as a target gain At'.
For other descriptions of the gain control method of the present invention, reference may be made to the description of the gain adjustment module 100, which is not repeated herein.
It should be noted that the modules and units of the present invention may be independent or combined together.
In summary, because the amplitude of the electroencephalogram signal changes greatly, a certain time is needed for sampling to determine the peak voltage, and then the gain adjustment multiple is determined, the invention adopts a specific algorithm to gradually approximate the current peak voltage, thereby reducing the number of comparators, reducing the requirement on offset voltage of the comparators, realizing higher precision and rapid quantization, and rapidly determining the target gain At of the gain operational amplifier unit 11.
The gain control unit 10 of this embodiment can adjust the gain according to the value of the initial output signal Vout, and realize automatic control of the gain, so that the finally obtained target gain At can adapt to the current electroencephalogram signal, and thus the amplitude of the target output signal Vt finally output to the analog-to-digital conversion unit 20 is kept within a certain range, and the accuracy of analog-to-digital conversion is further improved.
It should be understood that although the present description refers to embodiments, not every embodiment contains only a single technical solution, and such description is for clarity only, and those skilled in the art should make the description as a whole, and the technical solutions in the embodiments can also be combined appropriately to form other embodiments understood by those skilled in the art.
The above-listed detailed description is only a specific description of a possible embodiment of the present invention, and they are not intended to limit the scope of the present invention, and equivalent embodiments or modifications made without departing from the technical spirit of the present invention should be included in the scope of the present invention.
Claims (16)
1. A gain adjustment module is characterized by comprising a gain control unit and an analog-to-digital conversion unit connected with the gain control unit, wherein the gain control unit is used for acquiring an initial output signal according to a preset gain and a received initial input signal and acquiring a target gain according to the value adjustment gain of the initial output signal, the gain control unit acquires a target output signal according to the target gain and the initial input signal, and the analog-to-digital conversion unit converts the target output signal into a digital signal.
2. The gain adjustment module of claim 1, wherein the gain control unit comprises a gain operational amplifier unit, a peak detection unit, a comparison unit, a coarse adjustment unit and a fine adjustment unit, the gain operational amplifier unit and the peak detection unit are respectively configured to obtain an initial output signal and an initial peak voltage to complete a peak obtaining cycle, the comparison unit is configured to determine whether the initial peak voltage meets a preset condition, if yes, a fine adjustment process is performed, the fine adjustment unit obtains a fine adjustment multiple and transmits the fine adjustment multiple to the gain operational amplifier unit, and the gain operational amplifier unit takes a product of a preset gain and the fine adjustment multiple as a target gain; if not, entering a coarse adjustment process, acquiring a coarse adjustment multiple provided by the coarse adjustment unit by the gain operation and amplification unit, replacing a preset gain with a product of the coarse adjustment multiple and the preset gain, acquiring an intermediate peak voltage by the gain operation and amplification unit and the peak detection unit according to a peak acquisition cycle, entering a fine adjustment process when the intermediate peak voltage meets a preset condition, and taking the product of the coarse adjustment multiple, the fine adjustment multiple and the preset gain as a target gain by the gain operation and amplification unit.
3. The gain adjustment module of claim 2, wherein the comparing unit is configured to determine whether the initial peak voltage is within a preset range, and if so, enter a fine tuning process, the fine tuning unit obtains a fine tuning multiple according to the current peak voltage and transmits the fine tuning multiple to the gain operational amplifier unit, the fine tuning multiple is a multiple between the current peak voltage and a target value, and the gain operational amplifier unit takes a product of the fine tuning multiple and a preset gain as a target gain; if not, entering a coarse adjustment process.
4. The gain adjustment module of claim 3, wherein the fine adjustment unit comprises a reference voltage unit and a comparator, the comparator comprises a first input terminal, a second input terminal and a first output terminal, the first input terminal is connected to the peak detection unit, the second input terminal is connected to the reference voltage unit, wherein the peak detection unit is configured to output a current peak voltage, the reference voltage unit is configured to output a variable reference voltage, and when the comparator output is flipped, the fine adjustment unit takes a current variable reference voltage value as the current peak voltage.
5. The gain adjustment module of claim 4, wherein the reference voltage unit comprises a first amplifier and a channel selection unit, the first amplifier comprises a third input terminal, a fourth input terminal and a second output terminal, the third input terminal is connected to a first fixed reference voltage, the second output terminal is connected to the channel selection unit, the second output terminal is provided with a plurality of series resistors, the fourth input terminal is connected to different regions of the plurality of series resistors to realize that the first amplifier outputs a variable voltage, and the channel selection unit selects a variable voltage and outputs the variable voltage as the variable reference voltage.
6. The gain adjustment module of claim 2, wherein the comparison unit is configured to determine whether the initial peak voltage is smaller than a preset value, if so, enter a fine tuning process, the comparison unit continues to determine whether a difference between the initial peak voltage and the preset value is smaller than a preset threshold, if not, the gain operational amplifier unit obtains a fine tuning multiple provided by the fine tuning unit and replaces a preset gain with a product of the fine tuning multiple and the preset gain, and the gain operational amplifier unit and the peak detection unit obtain a temporary peak voltage according to a peak obtaining cycle, repeat the peak obtaining cycle until a difference between the obtained temporary peak voltage and the preset value is smaller than the preset threshold, if so, the fine tuning unit obtains a current fine tuning multiple and transmits the current fine tuning multiple to the gain operational amplifier unit, the gain operational amplifier unit takes the product of the current fine adjustment multiple and the preset gain as a target gain; if not, entering a coarse adjustment process.
7. The gain adjustment module of claim 6, wherein the coarse adjustment multiple comprises a plurality of selectable coarse adjustment multiples, the fine adjustment multiple comprises a plurality of selectable fine adjustment multiples, and the plurality of selectable coarse adjustment multiples comprises a first stage coarse adjustment multiple, a second stage coarse adjustment multiple, and a third stage coarse adjustment multiple that can be selected in sequence.
8. The gain adjustment module of claim 6, wherein the fine adjustment multiple is implemented by a second amplifier, the second amplifier comprises a fifth input terminal, a sixth input terminal and a third output terminal, the fifth input terminal comprises a fixed resistor and a variable resistor, one end of the variable resistor is connected between the fixed resistor and the fifth input terminal, the other end of the variable resistor is connected to the third output terminal, the sixth input terminal is connected to a second fixed reference voltage, and the third output terminal is connected to the gain operational amplifier unit, wherein the fine adjustment multiple is a ratio of the variable resistor to the fixed resistor.
9. The gain adjustment module of claim 6, wherein the predetermined gain is a maximum gain of the gain adjustment module.
10. The gain adjustment module according to claim 2, wherein the peak detection unit includes a first switch, a diode, a first resistor, a first capacitor connected to ground, a second resistor connected to ground and in series, and a second switch, wherein the first switch is used to control an input of the peak detection unit, the second switch is used to reset, the second resistor is used to limit a discharge current, the diode is used to implement a unidirectional storage of a plurality of input voltages in cooperation with the first resistor and the first capacitor, and then the peak voltage is obtained by the plurality of input voltages and used as an output of the peak detection unit.
11. The gain adjustment module of claim 2, wherein the peak detection unit comprises a third amplifier, the third amplifier comprises a seventh input terminal, an eighth input terminal and a fourth output terminal, the seventh input terminal is provided with a third resistor and a second capacitor, the eighth input terminal is connected to the fourth output terminal and comprises a fourth resistor, a third switch and a third capacitor, the fourth resistor, the third switch and the third capacitor are connected in series and are connected to ground, the fourth output terminal is provided with a transistor, one end of the transistor is connected to a power voltage, the other end of the transistor is connected to the third capacitor, wherein the third resistor and the second capacitor are used for filtering, the third switch is used for resetting, the transistor is used for generating a bias current, and a peak voltage is obtained by a plurality of gradually increasing input voltages input to the seventh input terminal, the fourth output terminal uses the acquired peak voltage as the output of the peak detection unit.
12. An implantable neurostimulation system, characterized in that it comprises a gain adjustment module as claimed in any one of claims 1 to 11, a stimulation electrode and a terminal device, wherein said stimulation electrode is used to obtain an electroencephalogram signal as an initial input signal of said gain adjustment module, and said gain adjustment module transmits the converted digital signal to said terminal device.
13. A gain control method, comprising the steps of:
acquiring an initial input signal;
acquiring an initial output signal according to the initial input signal and a preset gain;
adjusting gain according to the value of the initial output signal to obtain a target gain;
acquiring a target output signal according to the initial input signal and the target gain;
converting the target output signal into a digital signal.
14. The gain control method according to claim 13, wherein the step of "adjusting the gain according to the value of the initial output signal to obtain the target gain" specifically comprises:
acquiring an initial peak voltage of the initial output signal;
judging whether the initial peak voltage meets a preset condition or not;
if so, entering a fine tuning process, acquiring a fine tuning multiple, and taking the product of the fine tuning multiple and a preset gain as a target gain;
if not, entering a coarse adjustment process, obtaining a coarse adjustment multiple, replacing the product of the coarse adjustment multiple and the preset gain with the preset gain, obtaining a corresponding middle peak voltage, and entering a fine adjustment process when the middle peak voltage meets the preset condition.
15. The gain control method according to claim 14, wherein the step of determining whether the initial peak voltage meets a predetermined condition; if yes, entering a fine tuning process, and taking the product of the fine tuning multiple and the preset gain as a target gain "specifically comprises:
judging whether the initial peak voltage is within a preset range;
and if so, entering a fine adjustment process, acquiring the current peak voltage, obtaining a fine adjustment multiple according to the current peak voltage, and taking the product of the fine adjustment multiple and the preset gain as a target gain, wherein the fine adjustment multiple is the multiple between the current peak voltage and the target value.
16. The gain control method according to claim 14, wherein the step of determining whether the initial peak voltage meets a predetermined condition; if yes, entering a fine tuning process, and taking the product of the fine tuning multiple and the preset gain as a target gain "specifically comprises:
judging whether the initial peak voltage is smaller than a preset value;
if so, entering a fine tuning process, judging whether the difference value between the initial peak voltage and the preset value is smaller than a preset threshold value, if not, obtaining a fine tuning multiple, replacing the preset gain with the product of the fine tuning multiple and the preset gain, and obtaining a corresponding temporary peak voltage until the difference value between the temporary peak voltage and the preset value is smaller than the preset threshold value, and if so, taking the product of the current fine tuning multiple and the preset gain as a target gain.
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| CN114209312A (en) * | 2021-12-02 | 2022-03-22 | 广州众诺电子技术有限公司 | Adaptive gain adjustment method, device, central processing unit and storage medium |
| WO2023035043A1 (en) * | 2021-09-10 | 2023-03-16 | Saluda Medical Pty Ltd | Improved programming of neuromodulation therapy |
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