CN114931702A

CN114931702A - Defibrillator

Info

Publication number: CN114931702A
Application number: CN202210721344.6A
Authority: CN
Inventors: 李萍; 单纯玉
Original assignee: Shanghai University of Medicine and Health Sciences
Current assignee: Shanghai University of Medicine and Health Sciences
Priority date: 2022-06-24
Filing date: 2022-06-24
Publication date: 2022-08-23

Abstract

The invention belongs to the technical field of medical instruments, and particularly relates to a defibrillator which comprises a direct-current power supply, a voltage converter, a rectifying circuit, a charging and discharging circuit and a pair of electrodes which are sequentially connected. The charge and discharge circuit includes: the first fixed end of the first charge-discharge switch is connected with the output end of the rectifying circuit; the first fixed end of the second charge-discharge switch is connected with the other output end of the rectifying circuit; one end of the first energy storage capacitor is connected with the movable end of the first charge-discharge switch, and the other end of the first energy storage capacitor is connected with the movable end of the second charge-discharge switch; the anode of the diode is connected with the second immovable end of the second charge-discharge switch, and the cathode of the diode is connected with the second immovable end of the first charge-discharge switch; and one end of the second energy storage capacitor is connected with the second immovable end of the first charge-discharge switch, the other end of the second energy storage capacitor is connected with the second immovable end of the second charge-discharge switch, and two ends of the second energy storage capacitor are respectively connected with two electrodes. The second energy storage capacitor is added, so that the defibrillation waveform is smooth, and the first charge-discharge switch is released as required, so that the defibrillation waveform is convenient to generate.

Description

Defibrillator

Technical Field

The invention belongs to the technical field of medical instruments, and particularly relates to a defibrillator.

Background

External defibrillators use electrodes to apply electrical pulses to the patient's skin (external electrodes) or to the exposed heart (internal electrodes) to achieve an apparatus for electrically defibrillating the heart. The first aid is used for emergency treatment of patients with ventricular fibrillation, ventricular tachycardia and suspected cardiac arrest. The external defibrillation electric pulse generally has the duration of 4-20 ms and the energy of 40-360J (joules). The pulse power is up to tens of kilowatts. The voltage amplitude is around 2000V. Defibrillation electric pulse has the characteristics of high voltage, high power and short time. External defibrillators are three types of medical devices, requiring stable, reliable, accurate, and safe defibrillation electrical pulses.

A defibrillator is an energy storage and discharge device, which generally consists of a low-voltage power supply, an energy storage capacitor, a high-voltage charging circuit, a discharging circuit, electrodes and the like. At present, defibrillation discharge control can be divided into two methods, namely a total amount control method and a process control method.

The total amount control means that the total amount of stored energy and released energy is controlled, and the release rate (discharge power) is not actively adjusted in the release process, so that the method is natural. The discharge waveform is generally an exponential wave. In defibrillation, first, the total amount of memory is determined according to some rule, called the preset energy. For example, CN202010941353 defibrillation discharging device and defibrillation method, CN202110778506 method and system for automatically adjusting external defibrillation current and defibrillation energy, and CN201810865883 a defibrillator bridge discharging circuit capable of accurately controlling conduction process. The control objective is to control the total released energy, which is indirectly controlled by controlling the stored energy, in such a way that the initial voltage of the storage capacitor is varied. The advantage of controlling the total energy method is good compliance. The main disadvantages are as follows:

the control variable is not consistent with the variable that has been used to effect defibrillation therapy. The control variable of the total control method is energy, only total energy is controlled, and the application mode is not controlled. Numerous literature studies have shown that the true variable for defibrillation is current, not energy. The defibrillation waveform is current on the ordinate and time on the abscissa. The energy is equal to the integral of the power over time. If a voltage of 5V is applied across a 50 ohm transthoracic resistor, a current of 0.1A is obtained. The pulse power is 0.5W for a duration of 720s, and 360J of energy can be applied. Although the human body obtains 360J of energy, defibrillation cannot be achieved with a 5V power supply. Since a current of 0.1A belongs to subthreshold stimulation. According to the principles of electrophysiology, in the case of subthreshold stimulation, tissue excitation is not caused even if the stimulation time is longer, and defibrillation cannot be realized.

The process control method continuously adjusts the release rate in the process of releasing the current to obtain the expected waveform. For example, patent CN201210556832 discloses an H-bridge circuit defibrillator output stage and a biphasic sawtooth square wave defibrillation high-voltage discharge method, which adopts a process control method. However, the existing process control process has slow regulation speed and insufficient regulation real-time performance, so that the output is sawtooth waves.

Disclosure of Invention

The invention aims to solve the technical problems of poor defibrillation effect and poor real-time defibrillation control and adjustment of the conventional defibrillator and provides the defibrillator.

A defibrillator comprises a direct current power supply, a voltage converter, a rectifying circuit and a pair of electrodes which are connected in sequence;

the defibrillator further comprises:

the charging and discharging circuit is positioned between the rectifying circuit and the electrode;

the charge and discharge circuit includes:

the first charging and discharging switch is provided with a first fixed end, a second fixed end and a movable end, the movable end can be switched between the first fixed end and the second fixed end, and the first fixed end is connected with the output end of the rectifying circuit;

the second charge and discharge switch is provided with a first fixed end, a second fixed end and a movable end, the movable end can be switched between the first fixed end and the second fixed end, and the first fixed end is connected with the other output end of the rectifying circuit;

one end of the first energy storage capacitor is connected with the movable end of the first charge-discharge switch, and the other end of the first energy storage capacitor is connected with the movable end of the second charge-discharge switch;

the anode of the diode is connected with the second immovable end of the second charge-discharge switch, and the cathode of the diode is connected with the second immovable end of the first charge-discharge switch;

and one end of the second energy storage capacitor is connected with the second immovable end of the first charge and discharge switch through an inductor, the other end of the second energy storage capacitor is connected with the second immovable end of the second charge and discharge switch, and the two ends of the second energy storage capacitor are respectively connected with the two electrodes.

Preferably, the defibrillator has a charging process, and the charging process is as follows:

when defibrillation is started, the movable end of the first charge-discharge switch is connected with the first immovable end of the first charge-discharge switch, the movable end of the second charge-discharge switch is connected with the first immovable end of the second charge-discharge switch, the direct-current low voltage provided by the direct-current power supply is increased to a preset high voltage through the voltage converter, and the direct-current low voltage is rectified by the rectifying circuit and then charges the first energy storage capacitor;

the defibrillator has a discharge process, which is:

after the defibrillator receives a discharge instruction, the movable end of the first charge-discharge switch is connected with the second immovable end of the first charge-discharge switch, the movable end of the second charge-discharge switch is connected with the second immovable end of the second charge-discharge switch, the energy of the first energy storage capacitor is transferred into the second energy storage capacitor through the first charge-discharge switch, the inductor and the diode, and the second energy storage capacitor forms voltage and releases the voltage to a human body through the pair of electrodes to generate defibrillation current.

Preferably, the charge and discharge circuit further includes:

a watt-second meter connected in series with a watt-second meter resistor and then connected in parallel with the second energy storage capacitor to detect a defibrillation voltage and a defibrillation current across a pair of the electrodes.

As a preferred scheme, after receiving a discharge instruction, the defibrillator drives the watt-hour meter to start metering or timing, when it is detected that the total metering energy reaches a preset target energy or reaches a preset time, the movable end of the first charge and discharge switch is disconnected from the second immovable end thereof, the movable end of the second charge and discharge switch is disconnected from the second immovable end thereof, and after the second energy storage capacitor releases all energy to the pair of electrodes, defibrillation discharge is finished.

As a preferred scheme, the first charge-discharge switch adopts a field effect transistor, a drain electrode of the first charge-discharge switch is used as a movable end of the first charge-discharge switch, a grid electrode of the first charge-discharge switch is used as a first immovable end of the first charge-discharge switch, and a source electrode of the first charge-discharge switch is used as a second immovable end of the first charge-discharge switch;

the defibrillator also includes a feedback control circuit, the feedback control circuit including:

the current sampling resistor is connected with a load resistor in series, and the load resistor is the equivalent resistance of a human body;

the non-inverting input end of the error amplifier is connected with the reference voltage end, and the inverting input end of the error amplifier is connected with the common end of the current sampling resistor and the load resistor;

the inverting input end of the comparator is connected with the output end of the error amplifier, and the non-inverting input end of the comparator is connected with a sawtooth generator;

and one end of the driver is connected with the output end of the comparator, and the other end of the driver is connected with the grid electrode of the first charge-discharge switch.

Preferably, the first charge and discharge switch is an N-channel field effect transistor, preferably a silicon carbide field effect transistor.

Preferably, the driver is an isolation driver.

Preferably, the feedback control circuit further includes:

one end of the first resistor is connected with the common end of the current sampling resistor and the load resistor, and the other end of the first resistor is connected with the inverting input end of the error amplifier;

one end of the feedback resistor is connected with the inverting input end of the error amplifier;

and one end of the feedback capacitor is connected with the other end of the feedback resistor, and the other end of the feedback capacitor is connected with the output end of the error amplifier.

Preferably, the defibrillator further comprises a feedforward control circuit, the feedforward control circuit comprising:

one end of the timing resistor is connected with the second fixed end of the first charge and discharge switch;

one end of the timing capacitor is connected with the other end of the timing resistor, and the other end of the timing capacitor is connected with the second fixed end of the second charge and discharge switch;

the grid electrode of the MOS tube is connected with a clock signal end, the drain electrode of the MOS tube is connected with the common end of the timing resistor and the timing capacitor, and the source electrode of the MOS tube is grounded;

and the drain electrode of the MOS tube is used as the output end of the sawtooth wave generator.

Preferably, the MOS transistor is a PMOS transistor.

The positive progress effects of the invention are as follows: the invention adopts the defibrillator, and has the following advantages:

1. the defibrillator can charge the energy of the first energy storage capacitor to the maximum value before discharging, forms voltage through the second energy storage capacitor after receiving a discharging instruction, releases the voltage to a human body through the pair of electrodes to generate defibrillation current, smoothes defibrillation waveforms due to the addition of the second energy storage capacitor, and releases the voltage according to needs by utilizing the first charging and discharging switch, so that the defibrillation waveforms are conveniently generated.

2. Structurally, the watt-hour meter is added to detect the defibrillation voltage and the defibrillation current, the measurement result is more accurate, the released energy is irrelevant to the impedance of a human body, the transthoracic impedance of a patient does not need to be detected, and the structural compliance is better.

3. By adding a feedback control circuit, the defibrillation current can be controlled to a desired value.

4. By additionally arranging the feedforward control circuit, the voltage of the first energy storage capacitor immediately reacts when beginning to drop, so that the peak current of discharge can be effectively reduced, and the damage to the myocardial cells of a patient is avoided.

5. The dynamic regulation capability of the defibrillation current is remarkably improved according to the combination of the feedforward of the voltage of the first energy storage capacitor and the feedback of the output current. The defibrillation current is enabled to track the set current, and the defibrillation current can be changed by changing the set current. Thus, the defibrillation waveform can be varied according to clinical needs.

6. In the discharging process, the control variable is controlled by current, and the defibrillation effect has good correlation.

7. The released energy can be matched according to different impedance conditions of the patient, and individualized and accurate defibrillation is realized.

8. The invention is applicable to various external defibrillators.

Drawings

FIG. 1 is a schematic diagram of an overall construction of the present invention;

FIG. 2 is a schematic circuit diagram of the feedback control circuit of the present invention;

FIG. 3 is a circuit schematic of the feedforward control circuit of the present invention.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific drawings.

Referring to fig. 1, a defibrillator includes a dc power supply (not shown), a voltage converter 1, a rectifier circuit 2, a charge/discharge circuit 3, and a pair of electrodes 4, which are connected in this order.

The charging and discharging circuit 3 comprises a first charging and discharging switch K1, a second charging and discharging switch K2, a first energy storage capacitor C1, a diode D, a second energy storage capacitor C2 and an inductor L. Where the voltage VC represents the voltage across the first energy storage capacitor C1.

The first charge and discharge switch K1 has a first stationary end, a second stationary end and a movable end, the movable end of the first charge and discharge switch K1 can be switched between the first stationary end of the first charge and discharge switch K1 and the second stationary end of the first charge and discharge switch K1, for example, the first charge and discharge switch K1 adopts a switch with a switchable function, such as a single-pole double-throw switch or a field effect transistor, and the first stationary end (end 1) of the first charge and discharge switch K1 is connected with an output end of the rectification circuit 2. The second charge and discharge switch K2 has a first fixed end, a second fixed end and a movable end, the movable end of the second charge and discharge switch K2 can be switched between the first fixed end of the second charge and discharge switch K2 and the second fixed end of the second charge and discharge switch K2, for example, the second charge and discharge switch K2 adopts a switch with a switchable function, such as a single-pole double-throw switch or a field effect transistor, and the first fixed end (end 1) of the second charge and discharge switch K2 is connected with the other output end of the rectification circuit 2. One end of the first energy storage capacitor C1 is connected with the movable end of the first charge-discharge switch K1, and the other end of the first energy storage capacitor C1 is connected with the movable end of the second charge-discharge switch K2. The anode of the diode D is connected with the second stationary end (2 end) of the second charge-discharge switch K2, and the cathode of the diode D is connected with the second stationary end (2 end) of the first charge-discharge switch K1. One end of a second energy storage capacitor C2 is connected with the second immovable end of the first charge-discharge switch K1 through an inductor L, the other end of the second energy storage capacitor C2 is connected with the second immovable end of the second charge-discharge switch K2, and two ends of the second energy storage capacitor C2 are respectively connected with two electrodes 4.

In some embodiments, referring to fig. 1, the defibrillator has a charging process that is:

when defibrillation is started, the movable end of the first charge-discharge switch K1 is connected with the first immovable end of the first charge-discharge switch K1, the movable end of the second charge-discharge switch K2 is connected with the first immovable end of the second charge-discharge switch K2, the direct current low voltage provided by the direct current power supply is increased to the preset high voltage through the voltage converter 1, and the first energy storage capacitor C1 is charged after being rectified by the rectifying circuit 2. For example, the energy of the first energy storage capacitor C1 is charged to the maximum allowable value 360J after charging.

The defibrillator has a discharge process which is as follows:

after the defibrillator receives a discharge command, the movable end of the first charge-discharge switch K1 is connected with the second immovable end of the first charge-discharge switch K1, and the movable end of the second charge-discharge switch K2 is connected with the second immovable end of the second charge-discharge switch K2, so that the first energy-storage capacitor C1, the first charge-discharge switch K1, the inductor L, the diode D and the second energy-storage capacitor C2 form a typical buck converter. The inductor L is used for converting the electric energy of the first energy storage capacitor C1 into magnetic energy when the first charging and discharging switch K1 is switched on, and converting the magnetic energy into the electric energy to be supplied to the second energy storage capacitor C2 when the first charging and discharging switch K1 is switched off. The diode D functions to provide a current path for the inductor current. Thus, part of the energy of the first energy storage capacitor C1 is transferred to the second energy storage capacitor C2 through the first charge-discharge switch K1, the inductor L and the diode D, a voltage is formed in the second energy storage capacitor C2, and the voltage is released to the human body through the pair of electrodes 4 to generate defibrillation current.

In some embodiments, the charging/discharging circuit 3 further comprises a watt-second meter WS, the watt-second meter WS and the watt-second meter resistor R _ws Connected in series and in parallel with a second energy storage capacitor C2 to sense a defibrillation voltage and a defibrillation current across the pair of electrodes 4.

Among the variables that can be controlled in a defibrillator are voltage, current, and energy. The relationship between the three is:

wherein W is the defibrillation energy, U is the voltage across the pair of electrodes 4 that is output, and I is the defibrillation current. t0 is a discharge start time, and t1 is a discharge end time.

As can be seen from the equation, the released energy is independent of the impedance of the body. There is no need to measure transthoracic impedance nor to adjust the defibrillation energy.

In some embodiments, if the discharge energy is used as the control variable, after the defibrillator receives the discharge command, the wattmeter WS is driven to start the measurement or timing at t0, and when it is detected that the total energy measured reaches the preset target energy or reaches the preset time, the discharge is considered to stop so as not to cause the discharge pulse to be too wide. At this time, the active end of the first charge/discharge switch K1 is disconnected from the second inactive end thereof, the active end of the second charge/discharge switch K2 is disconnected from the second inactive end thereof, and after the second energy storage capacitor C2 releases all the energy to the pair of electrodes 4, the defibrillation discharge is completed.

The preset target energy or preset time can be input by a user in the manual defibrillator or can be a machine preset value of the automatic defibrillator.

The capacitance value of the second energy storage capacitor C2 is small, so that the error is less than 1%. The mode has the advantages of simple principle, accurate control, good compliance and fixed preset energy, does not need to measure the transthoracic impedance, and only needs to qualitatively judge the connection condition of the defibrillation electrode.

In some embodiments, controlling the defibrillation current may be accomplished by adjusting the closing time of the discharge switch. For example, the first charge/discharge switch K1 is switched at a fixed frequency of 100kHz or more, and when the first charge/discharge switch K1 is turned on (the movable end of the first charge/discharge switch K1 is connected to the second immovable end thereof), the first energy storage capacitor C1 transfers energy to the second energy storage capacitor C2 and also stores energy in the inductor L, and when the first charge/discharge switch K1 is turned off (the movable end of the first charge/discharge switch K1 is disconnected from the second immovable end thereof), the inductor L transfers the stored energy to the second energy storage capacitor C2 through the diode D. The longer the first charge-discharge switch K1 is turned on each time, the more energy is stored in the inductor L, the more energy is transferred from the first energy storage capacitor C1 to the second energy storage capacitor C2, the higher the voltage across the second energy storage capacitor C2 is, and the larger the defibrillation current is. Therefore, the defibrillation current can be changed by changing the on time of the first charge/discharge switch K1.

The invention can control the defibrillation current at a desired value through the feedback control circuit. Referring to fig. 2, the first charge and discharge switch K1 employs a field effect transistor, the drain of the first charge and discharge switch K1 is used as the active end thereof, the gate of the first charge and discharge switch K1 is used as the first inactive end thereof, and the source of the first charge and discharge switch K1 is used as the second inactive end thereof. The first charge/discharge switch K1 is preferably an N-channel fet, and more preferably a silicon carbide fet.

Referring to fig. 2, the feedback control circuit includes a current sampling resistor RS, an error amplifier EA, a comparator a1, a driver U1, a reference voltage terminal, and a sawtooth generator U2. Wherein the reference voltage terminal provides a reference voltage Vref.

The current sampling resistor RS is connected in series with a load resistor RL, and the load resistor RL is the equivalent resistance of a human body. Defibrillation current I _RL A feedback voltage VFB is generated at the current sampling resistor RS. The non-inverting input end of the error amplifier EA is connected with a reference voltage end, and the inverting input end of the error amplifier EA is connected with the common end of the current sampling resistor RS and the load resistor. The feedback voltage VFB is compared to the reference voltage Vref by an error amplifier EA that outputs a signal VX for adjusting the duty cycle of the PWM signal of driver U1. The feedback voltage VFB (representing the present output current) is subtracted from the reference voltage Vref in the error amplifier EA. Thus, the error amplifier EA performs a subtraction operation once.

The inverting input end of the comparator A1 is connected with the output end of the error amplifier EA, and the non-inverting input end of the comparator A1 is connected with the sawtooth wave generator U2. One end of the driver U1 is connected with the output end of the comparator A1, and the other end of the driver U1 is connected with the grid of the first charge-discharge switch K1. Driver U1 employs an isolation driver U1.

Referring to fig. 2, signal VX represents the difference between the defibrillation current generated feedback voltage VFB and the reference voltage Vref. At steady state, the average value of signal VX changes slowly. In the comparator A1, the signal VX is compared with the sawtooth wave VS generated by the sawtooth wave generator U2, if VS < VX, the comparator A1 outputs high level, the first charge-discharge switch K1 is turned on through the drive of the driver U1, and the first energy storage capacitor C1 discharges to the second energy storage capacitor C2. If VS is greater than VX, the comparator A1 outputs low level and the first charge-discharge switch K1 is closed, and the discharge is stopped. The higher the signal VX, the longer the sawtooth wave reaches VX and the longer the discharge time.

The working principle of closed-loop current stabilization is as follows: if the output current drops, the feedback voltage VFB is lower than the reference voltage Vref, which causes the error amplifier EA output voltage VX to rise. The rise of the voltage VX increases the time during which the comparator a1 outputs a high level, and the discharge time increases. The output current increases until VFB is Vref and vice versa.

In some embodiments, the feedback control circuit further comprises a first resistor R1, a feedback resistor RF, and a feedback capacitor CF. One end of the first resistor R1 is connected to a common end of the current sampling resistor RS and the load resistor RL, and the other end of the first resistor R1 is connected to an inverting input terminal of the error amplifier EA, that is, the inverting input terminal of the error amplifier EA is connected to a common end of the current sampling resistor RS and the load resistor RL via the first resistor R1. One end of the feedback resistor RF is connected to the inverting input terminal of the error amplifier EA. One end of the feedback capacitor CF is connected to the other end of the feedback resistor RF, and the other end of the feedback capacitor CF is connected to the output terminal of the error amplifier EA.

The first resistor R1, the feedback resistor RF, the feedback capacitor CF and the error amplifier EA form a Proportional Integral (PI) controller, also called a compensation circuit. Its effect is to improve the stability of the circuit to prevent the output current from swinging around the set value.

In the steady state: VFB Vref I _RL ×RS

The current sampling resistor RS is fixed, so that the defibrillation current I can be changed by changing Vref _RL 。

In some embodiments, referring to fig. 3, a feed forward method may be added when the discharge peak in the circuit is too high, i.e., the defibrillator of the present invention further comprises a feed forward control circuit comprising a timing resistor RT, a timing capacitor CT and a MOS transistor Q1.

One end of the timing resistor RT is connected with the second fixed end of the first charge-discharge switch K1. One end of the timing capacitor CT is connected with the other end of the timing resistor RT, and the other end of the timing capacitor CT is connected with a second fixed end of the second charge and discharge switch K2. The grid of MOS transistor Q1 is connected with the clock signal end, the drain of MOS transistor Q1 is connected with the common end of timing resistor RT and timing capacitor CT, and the source of MOS transistor Q1 is grounded. The drain of the MOS transistor Q1 is used as the output end of the sawtooth wave generator U2. The MOS transistor Q1 is preferably a PMOS transistor.

Referring to fig. 2 and 3, a voltage VC indicates a voltage across the first energy storage capacitor C1, and the comparator a1, the sawtooth wave generator U2, the MOS transistor Q1, and the clock signal terminal serve as a PWM circuit in which the clock signal generated at the clock signal terminal controls the frequency of the sawtooth wave. The operation of the feedforward control circuit is as follows:

after the timing capacitor CT voltage is cleared under the control of the clock signal, the comparator A1 outputs a high level, and the first charge-discharge switch K1 is turned on. The voltage on the timing capacitor CT starts to rise. The rising rate is related to the current of the timing resistor RT, and the higher the current of the timing resistor RT, the faster the rising rate. After the voltage on the timing capacitor CT reaches VX, the comparator A1 outputs low level, the first charge-discharge switch K1 is closed, and the discharging is finished at this time.

The timing resistor RT is connected to the voltage VC to directly sense the voltage across the first energy storage capacitor C1. The higher the voltage across the first energy storage capacitor C1, the faster the voltage across the first energy storage capacitor CT reaches VX, and the shorter the discharge time. When defibrillation is started, the voltage on the first energy storage capacitor C1 is high, each discharge time is short, and the average discharge speed is slow, so that the peak current of discharge can be effectively reduced.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. A defibrillator comprises a direct current power supply, a voltage converter, a rectifying circuit and a pair of electrodes which are connected in sequence;

characterized in that the defibrillator further comprises:

the charge and discharge circuit includes:

the first charge and discharge switch is provided with a first fixed end, a second fixed end and a movable end, the movable end can be switched between the first fixed end and the second fixed end, and the first fixed end of the first charge and discharge switch is connected with the output end of the rectifying circuit;

and one end of the second energy storage capacitor is connected with the second immovable end of the first charge-discharge switch through an inductor, the other end of the second energy storage capacitor is connected with the second immovable end of the second charge-discharge switch, and the two ends of the second energy storage capacitor are respectively connected with the two electrodes.

2. The defibrillator of claim 1, wherein the defibrillator has a charging process, the charging process being:

the defibrillator has a discharge process, which is:

3. The defibrillator of claim 2, wherein the charge and discharge circuit further comprises:

4. The defibrillator of claim 3, wherein the defibrillator is configured to drive the watt-hour meter to start metering or timing after receiving a discharge command, disconnect the movable end of the first charge-discharge switch from the second stationary end thereof and disconnect the movable end of the second charge-discharge switch from the second stationary end thereof when detecting that the total energy metered reaches a preset target energy or reaches a preset time, and terminate defibrillation discharge after the second energy storage capacitor releases all energy to the pair of electrodes.

5. The defibrillator according to any one of claims 1 to 4, wherein the first charge-discharge switch is a field effect transistor, a drain of the first charge-discharge switch is used as a moving end thereof, a gate of the first charge-discharge switch is used as a first immobile end thereof, and a source of the first charge-discharge switch is used as a second immobile end thereof;

6. The defibrillator of claim 5 wherein the first charge and discharge switch is an N-channel FET, preferably a silicon carbide FET.

7. The defibrillator of claim 5 wherein the driver is an isolated driver.

8. The defibrillator of claim 5, wherein the feedback control circuit further comprises:

9. The defibrillator of claim 5, wherein the defibrillator further comprises a feedforward control circuit, the feedforward control circuit comprising:

10. The defibrillator of claim 9 wherein the MOS transistor is a PMOS transistor.