defibrillator

Abstract

This invention belongs to the field of medical device technology, specifically relating to a defibrillator, comprising a DC power supply, a voltage converter, a rectifier circuit, a charging / discharging circuit, and a pair of electrodes connected in sequence. The charging / discharging circuit includes: a first charging / discharging switch, with its first stationary terminal connected to the output terminal of the rectifier circuit; a second charging / discharging switch, with its first stationary terminal connected to the other output terminal of the rectifier circuit; a first energy storage capacitor, with one end connected to the moving terminal of the first charging / discharging switch and the other end connected to the moving terminal of the second charging / discharging switch; a diode, with its positive terminal connected to the second stationary terminal of the second charging / discharging switch and its negative terminal connected to the second stationary terminal of the first charging / discharging switch; and a second energy storage capacitor, with one end connected to the second stationary terminal of the first charging / discharging switch and the other end connected to the second stationary terminal of the second charging / discharging switch, with both ends connected to the two electrodes respectively. This invention adds a second energy storage capacitor, resulting in a smoother defibrillation waveform, and utilizes the first charging / discharging switch for on-demand release, facilitating the generation of a defibrillation waveform.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, and specifically relates to a defibrillator. Background Technology

[0002] An external defibrillator (EDB) is a device that delivers electrical pulses to a patient's skin (external electrodes) or exposed heart (internal electrodes) via electrodes, thereby defibrillating the heart. It is used for emergency treatment of patients with ventricular fibrillation, ventricular tachycardia, or suspected cardiac arrest. The duration of an EDB pulse is typically 4–20 ms, with energy ranging from 40 to 360 J (joules). Pulse power can reach tens of kilowatts. The voltage amplitude is around 2000V. The defibrillation pulse is characterized by high voltage, high power, and short duration. EDBs are classified as Class III medical devices, requiring stable, reliable, precise, and safe defibrillation pulses.

[0003] A defibrillator is an energy storage and discharging device, typically composed of a low-voltage power supply, an energy storage capacitor, a high-voltage charging circuit, a discharging circuit, and electrodes. Currently, defibrillation discharge control can be divided into two methods: total discharge control and process control.

[0004] Total energy control refers to controlling the total amount of stored and released energy, without actively adjusting the release rate (discharge power) during the release process; it is left to its natural course. Therefore, the discharge waveform is generally an exponential wave. During defibrillation, the total stored energy is first determined according to a certain rule; this amount is called the preset energy. Examples include CN202010941353 Defibrillation Discharge Device and Defibrillation Method, CN202110778506 A Method and System for Automatically Adjusting External Defibrillation Current and Defibrillation Energy, and CN201810865883 A Defibrillator Bridge Discharge Circuit with Precise Control of Conduction Process. The control objective is to control the total released energy, indirectly controlling the released energy by controlling the stored energy. This can be achieved by changing the initial voltage of the energy storage capacitor. The advantage of the total energy control method is its good compliance. Its main disadvantages are:

[0005] The controlled variable does not match the variable responsible for defibrillation. The total quantity control method controls energy, but only the total energy, not the method of application. Numerous studies have shown that the variable that truly achieves defibrillation is current, not energy. Therefore, the vertical axis of a defibrillation waveform is current, and the horizontal axis is time. Energy equals the integral of power over time. If a 5V voltage is applied to a 50-ohm transthoracic resistor, resulting in a 0.1A current, and the pulse power is 0.5W, lasting 720s, then 360J of energy can be applied. Although the human body receives 360J of energy, defibrillation cannot be achieved with a 5V power supply because a 0.1A current is subthreshold stimulation. According to electrophysiological principles, under subthreshold stimulation, even a longer stimulation time will not cause tissue excitation, and therefore defibrillation cannot be achieved.

[0006] The process control method continuously adjusts the release rate during the current release process to obtain the desired waveform. For example, patent CN201210556832, "An H-bridge Circuit Defibrillator Output Stage and a Two-Phase Sawtooth Square Wave Defibrillation High-Voltage Discharge Method," employs the process control method. However, existing process control methods have relatively slow adjustment speeds and insufficient real-time performance, resulting in a sawtooth wave output. Summary of the Invention

[0007] This invention addresses the technical problems of poor defibrillation effect and poor real-time performance of existing defibrillators, and aims to provide a defibrillator.

[0008] A defibrillator includes a DC power supply, a voltage converter, a rectifier circuit, and a pair of electrodes connected in sequence.

[0009] The defibrillator also includes:

[0010] A charging / discharging circuit is located between the rectifier circuit and the electrode;

[0011] The charging and discharging circuit includes:

[0012] A first charge / discharge switch has a first stationary terminal, a second stationary terminal, and a moving terminal. The moving terminal can be switched between the first stationary terminal and the second stationary terminal. Its first stationary terminal is connected to the output terminal of the rectifier circuit.

[0013] A second charge / discharge switch has a first stationary terminal, a second stationary terminal, and a moving terminal. The moving terminal can be switched between the first stationary terminal and the second stationary terminal. Its first stationary terminal is connected to another output terminal of the rectifier circuit.

[0014] A first energy storage capacitor, one end of which is connected to the moving end of the first charge / discharge switch, and the other end of which is connected to the moving end of the second charge / discharge switch;

[0015] A diode, with its positive terminal connected to the second stationary terminal of the second charge / discharge switch and its negative terminal connected to the second stationary terminal of the first charge / discharge switch;

[0016] A second energy storage capacitor has one end connected to the second stationary terminal of the first charge / discharge switch via an inductor, and the other end connected to the second stationary terminal of the second charge / discharge switch. The two ends are respectively connected to the two electrodes.

[0017] As a preferred embodiment, the defibrillator has a charging process, which is as follows:

[0018] At the start of defibrillation, the moving terminal of the first charge-discharge switch is connected to its first stationary terminal, and the moving terminal of the second charge-discharge switch is connected to its first stationary terminal. The low DC voltage provided by the DC power supply is boosted to a preset high voltage by the voltage converter, and then rectified by the rectifier circuit to charge the first energy storage capacitor.

[0019] The defibrillator has a discharge process, which is as follows:

[0020] After receiving a discharge command, the defibrillator connects the moving end of the first charge-discharge switch to its second stationary end, and connects the moving end of the second charge-discharge switch to its second stationary end. The energy of the first energy storage capacitor is transferred to the second energy storage capacitor through the first charge-discharge switch, the inductor, and the diode. The second energy storage capacitor forms a voltage and is released to the human body through a pair of electrodes to generate a defibrillation current.

[0021] As a preferred embodiment, the charging and discharging circuit further includes:

[0022] A one-watt stopwatch, connected in series with a one-watt stopwatch resistor, is connected in parallel with the second energy storage capacitor to detect the defibrillation voltage and defibrillation current across a pair of electrodes.

[0023] As a preferred embodiment, after receiving a discharge command, the defibrillator drives the watt-second meter to start measuring or timing. When the total measured energy reaches the preset target energy or the preset time is reached, the moving end of the first charge-discharge switch is disconnected from its second stationary end, and the moving end of the second charge-discharge switch is disconnected from its second stationary end. After the second energy storage capacitor releases all the energy to the pair of electrodes, the defibrillation discharge ends.

[0024] As a preferred embodiment, the first charge-discharge switch is a field-effect transistor, with the drain of the first charge-discharge switch as its moving terminal, the gate of the first charge-discharge switch as its first stationary terminal, and the source of the first charge-discharge switch as its second stationary terminal.

[0025] The defibrillator further includes a feedback control circuit, the feedback control circuit comprising:

[0026] A current sampling resistor is connected in series with a load resistor, wherein the load resistor is the equivalent resistance of the human body;

[0027] An error amplifier, with its non-inverting input connected to the reference voltage terminal and its inverting input connected to the common terminal of the current sampling resistor and the load resistor;

[0028] A comparator, with its inverting input connected to the output of the error amplifier and its non-inverting input connected to a sawtooth wave generator;

[0029] A driver is connected at one end to the output of the comparator and at the other end to the gate of the first charge / discharge switch.

[0030] As a preferred embodiment, the first charge / discharge switch adopts an N-channel field-effect transistor, preferably a silicon carbide field-effect transistor.

[0031] As a preferred embodiment, the driver is an isolated driver.

[0032] As a preferred embodiment, the feedback control circuit further includes:

[0033] A first resistor, one end of which is connected to the common terminal of the current sampling resistor and the load resistor, and the other end of which is connected to the inverting input terminal of the error amplifier;

[0034] A feedback resistor, one end of which is connected to the inverting input terminal of the error amplifier;

[0035] A feedback capacitor is connected at one end to the other end of the feedback resistor and at the other end to the output terminal of the error amplifier.

[0036] As a preferred embodiment, the defibrillator further includes a feedforward control circuit, the feedforward control circuit comprising:

[0037] A constant-time resistor, one end of which is connected to the second stationary terminal of the first charge / discharge switch;

[0038] A timing capacitor is provided, with one end connected to the other end of the timing resistor and the other end connected to the second stationary terminal of the second charge / discharge switch.

[0039] A MOSFET, with its gate connected to the clock signal terminal, its drain connected to the common terminal of the timing resistor and the timing capacitor, and its source grounded;

[0040] The drain of the MOS transistor serves as the output terminal of the sawtooth wave generator.

[0041] As a preferred embodiment, the MOS transistor is a PMOS transistor.

[0042] The positive and progressive effects of this invention are as follows: This invention uses a defibrillator, which has the following advantages:

[0043] 1. The defibrillator of the present invention can charge the first energy storage capacitor to its maximum value before discharging. After receiving the discharge command, a voltage is formed through the second energy storage capacitor and released to the human body through a pair of electrodes to generate a defibrillation current. Due to the addition of the second energy storage capacitor, the defibrillation waveform is smooth, and the first charge and discharge switch is used to release the current as needed, which facilitates the generation of a defibrillation waveform.

[0044] 2. By adding a watt-second meter to the structure to detect defibrillation voltage and current, the measurement results are more accurate. The released energy is independent of human body impedance and does not require detection of the patient's transthoracic impedance, resulting in better structural compliance.

[0045] 3. By adding a feedback control circuit, the defibrillation current can be controlled at the desired value.

[0046] 4. By adding a feedforward control circuit, the system can react immediately when the voltage of the first energy storage capacitor begins to drop, which can effectively reduce the peak discharge current and avoid damage to the patient's myocardial cells.

[0047] 5. By combining the feedforward of the first energy storage capacitor voltage with the feedback of the output current, the dynamic adjustment capability of the defibrillation current is significantly improved. This allows the defibrillation current to track the set current; changing the set current alters the defibrillation current. Therefore, the defibrillation waveform can be modified according to clinical needs.

[0048] 6. During the discharge process, the control variable is controlled by the current, resulting in a good correlation between the defibrillation effect and the control variable.

[0049] 7. The energy released can be matched according to the patient's different impedance status to achieve personalized and precise defibrillation.

[0050] 8. This invention is applicable to all types of external defibrillators. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0052] Figure 2 This is a circuit schematic diagram of the feedback control circuit of the present invention;

[0053] Figure 3 This is a circuit schematic diagram of the feedforward control circuit of the present invention. Detailed Implementation

[0054] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific illustrations.

[0055] Reference Figure 1 A defibrillator includes a DC power supply (not shown), a voltage converter 1, a rectifier circuit 2, a charging and discharging circuit 3, and a pair of electrodes 4 connected in sequence.

[0056] The charging and discharging circuit 3 includes 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. The voltage VC represents the voltage across the first energy storage capacitor C1.

[0057] The first charge / discharge switch K1 has a first stationary terminal, a second stationary terminal, and a moving terminal. The moving terminal of the first charge / discharge switch K1 can be switched between the first stationary terminal and the second stationary terminal. For example, the first charge / discharge switch K1 can be a single-pole double-throw switch or a field-effect transistor (FET) or other switches with switchable functionality. The first stationary terminal (terminal 1) of the first charge / discharge switch K1 is connected to one output terminal of the rectifier circuit 2. The second charge / discharge switch K2 has a first stationary terminal, a second stationary terminal, and a moving terminal. The moving terminal of the second charge / discharge switch K2 can be switched between the first stationary terminal and the second stationary terminal. For example, the second charge / discharge switch K2 can be a single-pole double-throw switch or a field-effect transistor (FET) or other switches with switchable functionality. The first stationary terminal (terminal 1) of the second charge / discharge switch K2 is connected to the other output terminal of the rectifier circuit 2. One end of the first energy storage capacitor C1 is connected to the moving terminal of the first charge / discharge switch K1, and the other end of the first energy storage capacitor C1 is connected to the moving terminal of the second charge / discharge switch K2. The positive terminal of diode D is connected to the second stationary terminal (terminal 2) of the second charge / discharge switch K2, and the negative terminal of diode D is connected to the second stationary terminal (terminal 2) of the first charge / discharge switch K1. One end of the second energy storage capacitor C2 is connected to the second stationary terminal of the first charge / discharge switch K1 via inductor L, and the other end of the second energy storage capacitor C2 is connected to the second stationary terminal of the second charge / discharge switch K2. The two ends of the second energy storage capacitor C2 are respectively connected to two electrodes 4.

[0058] In some embodiments, refer to Figure 1 The defibrillator has a charging process, which is as follows:

[0059] At the start of defibrillation, the moving terminal of the first charge / discharge switch K1 is connected to its first stationary terminal, and the moving terminal of the second charge / discharge switch K2 is connected to its first stationary terminal. The low DC voltage provided by the DC power supply is boosted to a preset high voltage by the voltage converter 1, and then rectified by the rectifier circuit 2 to charge the first energy storage capacitor C1. For example, the energy of the first energy storage capacitor C1 is charged to the maximum allowable value of 360J.

[0060] Defibrillators have a discharge process, which is as follows:

[0061] After receiving a discharge command, the defibrillator connects the moving terminal of the first charge / discharge switch K1 to its second stationary terminal, and the moving terminal of the second charge / discharge switch K2 to its second stationary terminal. Thus, 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 constitute a typical step-down converter. The inductor L converts the electrical energy of the first energy storage capacitor C1 into magnetic energy when the first charge / discharge switch K1 is on, and converts the magnetic energy back into electrical energy to supply the second energy storage capacitor C2 when the first charge / discharge switch K1 is off. The diode D provides a current path for the inductor current. In this way, part of the energy in 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, forming a voltage in the second energy storage capacitor C2, which is then released to the human body through a pair of electrodes 4 to generate a defibrillation current.

[0062] In some embodiments, the charging / discharging circuit 3 further includes a watt-second meter WS, the watt-second meter WS being connected to a watt-second meter resistor R. ws After being connected in series, it is connected in parallel with the second energy storage capacitor C2 to detect the defibrillation voltage and defibrillation current across a pair of electrodes 4.

[0063] The controllable variables in a defibrillator are voltage, current, and energy. The relationship between these three is:

[0064]

[0065] Where W is the defibrillation energy, U is the voltage across the pair of electrodes 4, and I is the defibrillation current. t0 is the discharge start time, and t1 is the discharge end time.

[0066] As can be seen from the formula, the released energy is independent of the body's impedance. Therefore, it is not necessary to measure transthoracic impedance or adjust the defibrillation energy.

[0067] In some embodiments, if the released energy is used as the control variable, after the defibrillator receives the discharge command, the watt-second meter WS is driven to start measuring or timing from t0. When the total measured energy reaches the preset target energy or the preset time is reached, the discharge is considered to stop to avoid the discharge pulse being too wide. At this time, the moving end of the first charge-discharge switch K1 is disconnected from its second stationary end, and the moving end of the second charge-discharge switch K2 is disconnected from its second stationary end. After the second energy storage capacitor C2 releases all the energy to the pair of electrodes 4, the defibrillation discharge ends.

[0068] The preset target energy or preset time can be obtained from user input in a manual defibrillator or from the machine preset value of an automatic defibrillator.

[0069] Because the capacitance of the second energy storage capacitor C2 is relatively small, the resulting error is less than 1%. This method is simple in principle, precise in control, compliant with regulations, and has a fixed preset energy. It does not require measurement of transthoracic impedance; only a qualitative assessment of the defibrillation electrode connection status is needed.

[0070] In some embodiments, the defibrillation current can be controlled by adjusting the closing time of the discharge switch. For example, the first charge-discharge switch K1 switches at a fixed frequency above 100kHz. When the first charge-discharge switch K1 is on (the moving end of the first charge-discharge switch K1 is connected to its second stationary end), the first energy storage capacitor C1 transfers energy to the second energy storage capacitor C2 and simultaneously stores energy in the inductor L. When the first charge-discharge switch K1 is off (the moving end of the first charge-discharge switch K1 is disconnected from its second stationary end), 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 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, and the larger the defibrillation current. Therefore, the defibrillation current can be changed by altering the on-time of the first charge-discharge switch K1.

[0071] This invention uses a feedback control circuit to control the defibrillation current to the desired value. (See reference...) Figure 2 The first charge / discharge switch K1 is a field-effect transistor (FET). The drain of the first charge / discharge switch K1 serves as its moving terminal, the gate of the first charge / discharge switch K1 serves as its first stationary terminal, and the source of the first charge / discharge switch K1 serves as its second stationary terminal. The first charge / discharge switch K1 is preferably an N-channel FET, and more preferably a silicon carbide FET.

[0072] Reference Figure 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 wave generator U2. The reference voltage terminal provides a reference voltage Vref.

[0073] The current sampling resistor RS is connected in series with the load resistor RL, which is the equivalent resistance of the human body. Defibrillation current I RL A feedback voltage VFB is generated by the current sampling resistor RS. The non-inverting input of the error amplifier EA is connected to the reference voltage terminal, and the inverting input is connected to the common terminal of the current sampling resistor RS and the load resistor. The feedback voltage VFB is compared with the reference voltage Vref by the error amplifier EA, and the error amplifier EA outputs a signal VX, which is used to adjust the duty cycle of the PWM signal of the driver U1. The feedback voltage VFB (representing the current output current) is subtracted from the reference voltage Vref in the error amplifier EA. Therefore, the error amplifier EA performs a subtraction operation.

[0074] The inverting input terminal of comparator A1 is connected to the output terminal of error amplifier EA, and the non-inverting input terminal of comparator A1 is connected to sawtooth wave generator U2. One end of driver U1 is connected to the output terminal of comparator A1, and the other end of driver U1 is connected to the gate of first charge-discharge switch K1. Driver U1 uses isolation driver U1.

[0075] Refer to Figure 2 , signal VX represents the difference between feedback voltage VFB generated by defibrillation current and reference voltage Vref. In the steady state, the average value of signal VX changes slowly. Inside comparator A1, signal VX is compared with sawtooth wave VS generated by sawtooth wave generator U2. If VS < VX, comparator A1 outputs a high level, and through the drive of driver U1, first charge-discharge switch K1 is turned on, and first energy storage capacitor C1 discharges to second energy storage capacitor C2. If VS > VX, comparator A1 outputs a low level and first charge-discharge switch K1 closes, and the discharge stops. The higher signal VX is, the longer the time for the sawtooth wave to reach VX is, and the longer the discharge time is.

[0076] The working principle of closed-loop constant current is as follows: If the output current drops, feedback voltage VFB is lower than reference voltage Vref, which will cause the output voltage VX of error amplifier EA to rise. The rise of voltage VX increases the time for comparator A1 to output a high level, and the discharge time increases. The output current increases until VFB = Vref, and vice versa.

[0077] In some embodiments, the feedback control circuit further includes first resistor R1, feedback resistor RF, and feedback capacitor CF. One end of first resistor R1 is connected to the common terminal of current sampling resistor RS and load resistor RL, and the other end of first resistor R1 is connected to the inverting input terminal of error amplifier EA, that is, the inverting input terminal of error amplifier EA is connected to the common terminal of current sampling resistor RS and load resistor RL via first resistor R1. One end of feedback resistor RF is connected to the inverting input terminal of error amplifier EA. One end of feedback capacitor CF is connected to the other end of feedback resistor RF, and the other end of feedback capacitor CF is connected to the output terminal of error amplifier EA.

[0078] First resistor R1, feedback resistor RF, feedback capacitor CF, and error amplifier EA constitute a proportional integral (PI) controller, also called a compensation circuit. Its function is to improve the stability of the circuit to prevent the output current from oscillating near the set value.

[0079] In the steady state: VFB = Vref = I RL ×RS

[0080] Current sampling resistor RS remains unchanged, so changing Vref can change defibrillation current I RL .

[0081] In some embodiments, refer to Figure 3 When the discharge peak in the circuit is too high, a feedforward method can be added. That is, the defibrillator of the present invention also includes a feedforward control circuit, which includes a timing resistor RT, a timing capacitor CT and a MOSFET Q1.

[0082] One end of the timing resistor RT is connected to the second stationary terminal of the first charge / discharge switch K1. One end of the timing capacitor CT is connected to the other end of the timing resistor RT, and the other end of the timing capacitor CT is connected to the second stationary terminal of the second charge / discharge switch K2. The gate of the MOSFET Q1 is connected to the clock signal terminal, the drain of the MOSFET Q1 is connected to the common terminal of the timing resistor RT and the timing capacitor CT, and the source of the MOSFET Q1 is grounded. The drain of the MOSFET Q1 serves as the output terminal of the sawtooth wave generator U2. Preferably, the MOSFET Q1 is a PMOS transistor.

[0083] Reference Figure 2 and Figure 3 The voltage VC represents the voltage across the first energy storage capacitor C1. Comparator A1, sawtooth wave generator U2, MOSFET Q1, and the clock signal terminal form a PWM circuit. The clock signal generated at the clock signal terminal in this PWM circuit controls the frequency of the sawtooth wave. The operation of the feedforward control circuit is as follows:

[0084] After the clock signal resets the voltage of the timing capacitor CT to zero, comparator A1 outputs a high level, and the first charge / discharge switch K1 is turned on. The voltage on the timing capacitor CT begins to rise. The rate of rise is related to the current in the timing resistor RT; the larger the current in the timing resistor RT, the faster the rise. Once the voltage on the timing capacitor CT reaches VX, comparator A1 outputs a low level, the first charge / discharge switch K1 is turned off, and the current discharge ends.

[0085] The timing resistor RT is connected to the voltage VC point to directly sense the voltage on the first energy storage capacitor C1. The higher the voltage on the first energy storage capacitor C1, the faster the voltage on the first energy storage capacitor CT reaches VX, and the shorter the discharge time. At the start of defibrillation, the voltage on the first energy storage capacitor C1 is relatively high, the discharge time is short, and the average discharge rate is slower, which can effectively reduce the peak discharge current.

[0086] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A defibrillator, comprising a DC power supply, a voltage converter, a rectifier circuit, and a pair of electrodes connected in sequence; Its features are, The defibrillator also includes: A charging / discharging circuit is located between the rectifier circuit and the electrode; The charging and discharging circuit includes: A first charge / discharge switch has a first stationary terminal, a second stationary terminal, and a moving terminal. The moving terminal can be switched between the first stationary terminal and the second stationary terminal. Its first stationary terminal is connected to the output terminal of the rectifier circuit. A second charge / discharge switch has a first stationary terminal, a second stationary terminal, and a moving terminal. The moving terminal can be switched between the first stationary terminal and the second stationary terminal. Its first stationary terminal is connected to another output terminal of the rectifier circuit. A first energy storage capacitor, one end of which is connected to the moving end of the first charge / discharge switch, and the other end of which is connected to the moving end of the second charge / discharge switch; A diode, with its positive terminal connected to the second stationary terminal of the second charge / discharge switch and its negative terminal connected to the second stationary terminal of the first charge / discharge switch; A second energy storage capacitor, one end of which is connected to the second stationary terminal of the first charge-discharge switch via an inductor, and the other end of which is connected to the second stationary terminal of the second charge-discharge switch, with the two ends respectively connected to the two electrodes; A one-watt stopwatch, connected in series with a one-watt stopwatch resistor and then in parallel with the second energy storage capacitor, is used to detect the defibrillation voltage and defibrillation current across a pair of electrodes. The defibrillator has a discharge process, which is as follows: After receiving a discharge command, the defibrillator connects the moving end of the first charge-discharge switch to its second stationary end, and connects the moving end of the second charge-discharge switch to its second stationary end. The energy of the first energy storage capacitor is transferred to the second energy storage capacitor through the first charge-discharge switch, the inductor, and the diode. The second energy storage capacitor forms a voltage and is released to the human body through a pair of electrodes to generate a defibrillation current. After receiving a discharge command, the defibrillator drives the watt-second meter to start measuring or timing. When the total measured energy reaches the preset target energy or the preset time is reached, the moving end of the first charge-discharge switch is disconnected from its second stationary end, and the moving end of the second charge-discharge switch is disconnected from its second stationary end. After the second energy storage capacitor releases all the energy to the pair of electrodes, the defibrillation discharge ends.

2. The defibrillator as described in claim 1, characterized in that, The defibrillator has a charging process, which is as follows: At the start of defibrillation, the moving terminal of the first charge / discharge switch is connected to its first stationary terminal, and the moving terminal of the second charge / discharge switch is connected to its first stationary terminal. The low DC voltage provided by the DC power supply is boosted to a preset high voltage by the voltage converter, and then rectified by the rectifier circuit to charge the first energy storage capacitor.

3. The defibrillator as described in any one of claims 1 to 2, characterized in that, The first charge-discharge switch uses a field-effect transistor, with the drain of the first charge-discharge switch as its moving terminal, the gate of the first charge-discharge switch as its first stationary terminal, and the source of the first charge-discharge switch as its second stationary terminal. The defibrillator further includes a feedback control circuit, the feedback control circuit comprising: A current sampling resistor is connected in series with a load resistor, wherein the load resistor is the equivalent resistance of the human body; An error amplifier, with its non-inverting input connected to the reference voltage terminal and its inverting input connected to the common terminal of the current sampling resistor and the load resistor; A comparator, with its inverting input connected to the output of the error amplifier and its non-inverting input connected to a sawtooth wave generator; A driver is connected at one end to the output of the comparator and at the other end to the gate of the first charge / discharge switch.

4. The defibrillator as described in claim 3, characterized in that, The first charge / discharge switch uses an N-channel MOSFET.

5. The defibrillator as described in claim 4, characterized in that, The first charge / discharge switch uses a silicon carbide field-effect transistor.

6. The defibrillator as described in claim 3, characterized in that, The driver is an isolated driver.

7. The defibrillator as described in claim 3, characterized in that, The feedback control circuit also includes: A first resistor, one end of which is connected to the common terminal of the current sampling resistor and the load resistor, and the other end of which is connected to the inverting input terminal of the error amplifier; A feedback resistor, one end of which is connected to the inverting input terminal of the error amplifier; A feedback capacitor is connected at one end to the other end of the feedback resistor and at the other end to the output terminal of the error amplifier.

8. The defibrillator as described in claim 3, characterized in that, The defibrillator also includes a feedforward control circuit, which includes: A constant-time resistor, one end of which is connected to the second stationary terminal of the first charge / discharge switch; A timing capacitor is provided, with one end connected to the other end of the timing resistor and the other end connected to the second stationary terminal of the second charge / discharge switch. A MOSFET, with its gate connected to the clock signal terminal, its drain connected to the common terminal of the timing resistor and the timing capacitor, and its source grounded; The drain of the MOS transistor serves as the output terminal of the sawtooth wave generator.

9. The defibrillator as claimed in claim 8, characterized in that, The MOS transistor is a PMOS transistor.

Images