Boost circuit applied to implantable cardioverter defibrillator

Abstract

The invention belongs to the technical field of cardiovascular diseases, and discloses a booster circuit applied to an implantable cardioverter defibrillator, and the circuit system is composed of a BOOST booster circuit, a charge pump voltage doubling circuit, a high-voltage feedback and control circuit, and a high-voltage energy storage capacitor. According to the invention, the boost circuit is integrated with BOOST and charge pump voltage doubling technologies, and a switching device is accurately controlled through PWM, so that the input DC voltage can be greatly improved; the BOOST circuit lays a foundation for boosting, the charge pump voltage doubling circuit achieves secondary multiplication on the BOOST circuit, the voltage is increased by n + 1 times, n can be flexibly set according to a unit structure, the high-voltage feedback and control circuit monitors the voltage of an energy storage capacitor in real time, boosting starting and stopping are automatically controlled by comparing Vhv with Vref, it is ensured that the output voltage is accurate and stable, and the output voltage is stable. By means of the combination, the large step-up ratio is achieved, the step-up amplitude can be flexibly adjusted according to actual requirements, reliable high-voltage energy is provided for the ICD, and the strict requirements of defibrillation for high voltage and high energy are met.

Description

Technical Field

[0001] The present invention belongs to the technical field of cardiovascular diseases, and in particular relates to a boost circuit used in an implantable cardioverter-defibrillator. Background Art

[0002] In the field of cardiovascular disease, malignant ventricular arrhythmia is an extremely dangerous condition. It can cause serious cardiac hemodynamic disorders, resulting in the loss of the heart's normal pumping function, and thus adversely affecting the blood circulation throughout the body. Patients often experience serious clinical symptoms such as syncope and shock, and even worse, sudden death. Once a malignant ventricular arrhythmia attack lasts for more than 5 minutes, the chance of successful rescue will be greatly reduced. Implantable cardioverter defibrillator (ICD), as an important medical device to deal with this disease, can automatically identify and terminate malignant ventricular arrhythmia. ICD can detect the patient's abnormal heart rhythm in just a few seconds and quickly release low-energy or high-energy electrical pulses to achieve cardioversion or defibrillation, thereby effectively avoiding sudden death in patients.

[0003] The proper operation of an ICD relies on multiple key components, including a high-voltage boost circuit for defibrillation, consisting of a boost circuit and a charge pump voltage multiplier circuit. Furthermore, it requires a dedicated battery with strong output capability and a dedicated high-voltage energy storage capacitor. When the ICD's sensing system detects an arrhythmia, the pulse generator must quickly transfer the energy provided by the 2.8V battery and boost it to over 800V, storing it in the high-voltage energy storage capacitor. This places extremely high demands on the boost circuit, requiring not only high conversion efficiency, a large step-up ratio, and a fast step-up speed, but also a small size, as an implantable device. Currently, ICDs generally use a transformer-based boost solution, but this approach has numerous drawbacks. For example, the magnetic component is a transformer, which complicates the design process, requires customization, and is relatively large. The boost circuit employed in the present invention offers a simple structure, high efficiency, and a compact, inductor-based magnetic component, eliminating the need for customization. Furthermore, the diverse and diverse parameters available on the market significantly enhance design flexibility, better meeting the stringent requirements of ICDs for boost circuits. Summary of the Invention

[0004] The object of the present invention is to provide a boost circuit for use in an implantable cardioverter-defibrillator to solve the problems raised in the above background technology.

[0005] In order to achieve the above object, the present invention provides the following technical solutions: a boost circuit for an implantable cardioverter-defibrillator, the circuit system consisting of a BOOST boost circuit, a charge pump voltage multiplier circuit, a high-voltage feedback and control circuit, and a high-voltage energy storage capacitor;

[0006] BOOST boost circuit: The BOOST boost circuit is based on PWM technology. It uses the switching action of the high-frequency switching device MOSFET to control the input DC voltage to a higher output voltage. By regulating the switching frequency and duty cycle of the switching device, the output voltage value of the BOOST circuit can be flexibly adjusted.

[0007] Charge pump voltage doubler circuit: The charge pump voltage doubler circuit performs a secondary voltage doubler on the output voltage of the BOOST boost circuit, which can increase the voltage to n+1 times. n depends on the unit structure. The circuit is cascaded by n units, and the input of each unit is connected to Vboost. The nth unit outputs high voltage HV to charge the energy storage capacitor. It uses the characteristics of the diode to charge and discharge the capacitor and boost the voltage by the high and low changes of Vboost.

[0008] High-voltage feedback and control circuit: The PWM wave output is controlled by P_wave and comparator U1. P_wave determines the frequency and duty cycle, and U1 determines whether to output. When HV is 0, Vhv is less than Vref, U1 outputs high, Q2 turns on, and the output PWM wave controls the voltage boost. The voltage boost stops when Vhv equals Vref. Vref is calibrated by data and corresponds to the target HV value. If the target is met, the voltage boost is triggered.

[0009] High-voltage energy storage capacitor: ICD-specific wet tantalum capacitors are used. Wet tantalum capacitors have the characteristics of high capacitance density, low ESR, fast discharge and high reliability. High-voltage energy storage capacitors are used to store high-voltage energy. The defibrillation pulse energy is released from the high-voltage energy storage capacitor to the heart for defibrillation.

[0010] Preferably, the BOOST boost circuit includes:

[0011] (1) BOOST boost circuit principle: BOOST boost circuit uses pulse width modulation (PWM) technology and controls the switching action of high-frequency switching device MOSFET. Its main function is to boost the DC voltage of the input power supply to a higher output voltage.

[0012] (2) Output voltage adjustment method: The output voltage of the circuit can be adjusted by controlling the switching frequency and duty cycle of the MOSFET switching device.

[0013] Preferably, the charge pump voltage multiplier circuit includes:

[0014] (1) Function of the charge pump voltage doubler circuit: The function of the charge pump voltage doubler circuit is to perform a secondary voltage doubling process on the output voltage of the BOOST boost circuit, which can increase the voltage to n+1 times, where n is determined by the unit structure of the charge pump voltage doubler circuit. The final output high voltage HV will be input into the high voltage energy storage capacitor to achieve the purpose of boost charging;

[0015] (2) Structural composition of the charge pump voltage doubling circuit: The circuit is composed of n charge pump voltage doubling units in cascade, and the input of each unit is connected to the output Vboost of the BOOST boost circuit. There is a specific connection relationship between each level, that is, the Vout of the first-level charge pump voltage doubling unit is connected to the positive electrode of the capacitor Ca of the second-level charge pump voltage doubling unit, and so on, until the nth charge pump voltage doubling unit outputs high voltage HV, thereby doubling the output of the BOOST boost circuit.

[0016] (3) Working principle of the charge pump voltage doubling unit: The charge pump voltage doubling unit mainly uses the characteristics of the diode being forward-conducting and reverse-blocking to work. When the Vboost output by the BOOST boost circuit is a high voltage, the capacitor Ca is charged; when Vboost becomes a low voltage, the diode Da is reverse-blocked, and the capacitor Ca charges the capacitor Cb through the diode Db; when Vboost is in a high voltage state again, Vboost uses the capacitor Cb to boost the voltage and output Vout. Through this process, the voltage doubling operation is completed.

[0017] Preferably, the high-voltage feedback and control circuit includes:

[0018] (1) Control factors of PWM wave output: The output of PWM wave is controlled by P_wave and comparator U1. P_wave is generated by the controller and is a square wave with a specific frequency and duty cycle. It determines the frequency and duty cycle of the PWM wave, while comparator U1 determines whether the PWM wave can be output. The two work together to achieve control of PWM wave output.

[0019] (2) Working process of PWM wave controlled boost circuit: Under the boost charging demand, when the high voltage HV is 0 and Vhv is less than Vref, the comparator U1 outputs a high level to turn on Q2, and the controller outputs the P_wave waveform to make Q1 turn on synchronously. The 15V voltage is controlled by Q1 and Q2 to output a synchronous PWM wave with the same duty cycle to control the BOOST boost. When Vhv is equal to Vref, the comparator U1 outputs a low level, Q2 is turned off, the PWM wave stops outputting, and the boost circuit stops working.

[0020] (3) Determination of Vref reference value: The Vref reference value of the controller is derived from data calibration. The Vhv value after different HV voltage division is written. When the voltage is boosted to a specific target value, the controller outputs the corresponding Vref. Each target HV corresponds to a Vref. When Vhv reaches Vref, the comparator U1 outputs a high level, triggering the drive control circuit and starting the BOOST boost circuit.

[0021] Preferably, the high-voltage energy storage capacitor refers to the system using ICD-specific wet tantalum capacitors as high-voltage energy storage elements. Wet tantalum capacitors have high capacitance density, low equivalent series resistance (ESR), fast discharge and high reliability. High capacitance density can achieve large-capacity energy storage in a limited space, and low ESR effectively reduces energy loss; the fast discharge capability ensures that sufficient energy is released at the moment of defibrillation. These advantages enable the high-voltage energy storage capacitor to efficiently store high-voltage energy and accurately release the defibrillation pulse energy to the heart when needed, quickly terminate ventricular fibrillation, and ensure the efficiency and safety of the defibrillation action.

[0022] Preferably, the output voltage adjustment method further includes:

[0023] A. In the Boost circuit, the high-voltage feedback and PWM wave output by the control circuit control the switch S to turn on. At this time, the battery input voltage causes the inductor L to store energy.

[0024] B. The switch tube S is turned off by the PWM wave control, and the inductor L releases the stored energy. The output voltage is higher than the battery input voltage, completing the boost process.

[0025] Preferably, the structure of the charge pump voltage multiplier circuit also includes:

[0026] A. Using the unidirectional conduction characteristics of the diode, when the BOOST boost circuit outputs Vboost at a high voltage, the diode Da conducts forward, and current flows through Da to charge the capacitor Ca; when Vboost turns to a low voltage, the diode Da is reverse-cut off, and the capacitor Ca transfers the stored charge to the capacitor Cb through the forward-conducting diode Db, completing the energy transfer;

[0027] B. When Vboost returns to a high voltage again, the capacitor Cb is superimposed on the Vboost voltage. Through the bootstrap voltage boost mechanism, the driving current is output to the load through the conducting diode, and finally the output voltage from the output terminal Vout is higher than the initial Vboost, achieving a voltage doubling effect.

[0028] Preferably, the working process of the PWM wave controlled boost circuit further includes:

[0029] A. During the high-voltage energy storage capacitor's boost and energy storage process, the high-voltage feedback and control circuit continuously collects the voltage on the capacitor in real time, obtains the voltage divider amplitude Vhv through the voltage divider circuit, and accurately compares it with the preset target amplitude value Vref. This process continuously monitors voltage changes and provides a basis for subsequent control;

[0030] B. Based on the comparison result of Vhv and Vref, the output state of comparator U1 is controlled. When Vhv does not reach Vref, comparator U1 outputs a high-level signal to maintain the normal operation of the boost circuit. Once Vhv reaches or exceeds Vref, comparator U1 outputs a low-level signal to cut off the driving signal of the boost circuit, thereby stopping the boost process and ensuring that the voltage of the energy storage capacitor is stable at the target value.

[0031] The beneficial effects of the present invention are as follows:

[0032] 1. The present invention integrates BOOST boost and charge pump voltage doubling technologies through a boost circuit, and can significantly increase the input DC voltage through PWM precise control of switching devices. The BOOST boost circuit lays the foundation for boosting, and the charge pump voltage doubling circuit achieves secondary multiplication on this basis, increasing the voltage by n+1 times, and n can be flexibly set according to the unit structure. The high-voltage feedback and control circuit monitors the energy storage capacitor voltage in real time and automatically controls the boost start and stop by comparing Vhv and Vref to ensure accurate and stable output voltage. This combination not only achieves a large step-up ratio, but also allows the boost amplitude to be flexibly adjusted according to actual needs, providing reliable high-voltage energy for ICDs and meeting the stringent high-voltage and high-energy requirements of defibrillation.

[0033] 2. The present invention adopts an innovative design through the boost circuit. The charge pump voltage doubling unit is composed only of diodes and capacitors, without the need for complex magnetic components, which greatly simplifies the circuit structure and reduces the difficulty of design and production. At the same time, the key components of the circuit, such as inductors, switches, diodes, and capacitors, are respectively packaged in small sizes such as SMD, TO-252, SMAF, and 2220, effectively compressing the overall volume. Compared with the traditional transformer boost solution, this circuit is free from the limitations of large magnetic components and is more in line with the requirements of implantable devices for miniaturization and lightweight. It is easy to implant into the human body and reduces the impact on surrounding tissues, thereby improving the practicality of the equipment and the comfort of the patient.

[0034] 3. The present invention uses ICD-specific wet tantalum capacitors as high-voltage energy storage elements, which have the characteristics of high capacitance density, low ESR, fast discharge and high reliability, ensuring efficient energy storage in a limited space, reducing energy loss, and quickly and stably releasing energy at the moment of defibrillation to ensure the defibrillation effect. In addition, the circuit uses resistor voltage sampling and capacitor filtering, and cooperates with the comparator to accurately control the boost process, thereby enhancing system stability and safety. This boost circuit is not only suitable for implantable cardioverter defibrillators, but its excellent performance and design concept can also be expanded to other medical electronic equipment and portable instruments with strict boost requirements, and has broad application prospects and technical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a block diagram of the boost and control circuit system of the present invention;

[0036] Figure 2 This is the BOOST boost circuit diagram of the present invention;

[0037] Figure 3 This is a structural diagram of the charge pump voltage doubling circuit of the present invention;

[0038] Figure 4 This is a diagram of the charge pump voltage doubling unit of the present invention;

[0039] Figure 5 This is the BOOST triple boost voltage and charge trend diagram of the present invention;

[0040] Figure 6 is a structural diagram of the high-voltage feedback and control circuit of the present invention;

[0041] Figure 7 This is a control flow chart of the high-voltage feedback and control circuit of the present invention;

[0042] Figure 8 A diagram showing the energy trend of the inductor energy release of the present invention;

[0043] Figure 9 The second diagram shows the energy trend of the inductor energy release of the present invention;

[0044] Figure 10 Three diagrams showing the energy trend of the inductor energy release of the present invention;

[0045] Figure 11 A diagram showing the trend of triple voltage charge in the present invention;

[0046] Figure 12 The second figure is the trend of triple pressure charge of the present invention;

[0047] Figure 13 These are three diagrams showing the trend of triple voltage and charge in the present invention. DETAILED DESCRIPTION

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0049] like Figures 1 to 13 As shown, an embodiment of the present invention provides a boost circuit for an implantable cardioverter defibrillator. The circuit system is composed of a BOOST boost circuit, a charge pump voltage multiplier circuit, a high-voltage feedback and control circuit, and a high-voltage energy storage capacitor.

[0050] BOOST boost circuit: The BOOST boost circuit is based on PWM technology. It uses the switching action of the high-frequency switching device MOSFET to control the input DC voltage to a higher output voltage. By regulating the switching frequency and duty cycle of the switching device, the output voltage value of the BOOST circuit can be flexibly adjusted.

[0051] Charge pump voltage doubler circuit: The charge pump voltage doubler circuit performs a secondary voltage doubler on the output voltage of the BOOST boost circuit, which can increase the voltage to n+1 times. n depends on the unit structure. The circuit is cascaded by n units, and the input of each unit is connected to Vboost. The nth unit outputs high voltage HV to charge the energy storage capacitor. It uses the characteristics of the diode to charge and discharge the capacitor and boost the voltage by the high and low changes of Vboost.

[0052] High-voltage feedback and control circuit: The PWM wave output is controlled by P_wave and comparator U1. P_wave determines the frequency and duty cycle, and U1 determines whether to output. When HV is 0, Vhv is less than Vref, U1 outputs high, Q2 turns on, and the output PWM wave controls the voltage boost. The voltage boost stops when Vhv equals Vref. Vref is calibrated by data and corresponds to the target HV value. If the target is met, the voltage boost is triggered.

[0053] High-voltage energy storage capacitor: ICD-specific wet tantalum capacitors are used. Wet tantalum capacitors have the characteristics of high capacitance density, low ESR, fast discharge and high reliability. High-voltage energy storage capacitors are used to store high-voltage energy. The defibrillation pulse energy is released from the high-voltage energy storage capacitor to the heart for defibrillation.

[0054] like Figure 1 The technical solution of the present invention is to provide a high-step-up ratio DC-DC boost circuit for an implantable cardioverter defibrillator. The boost and control circuit system consists of a battery 101, a BOOST boost circuit 102, a charge pump voltage multiplier circuit 103, a high-voltage energy storage capacitor 104, and a high-voltage feedback and control circuit 105. Battery 101 adopts an ICD-specific battery, which is usually a silver-vanadium oxide chemical system. This chemical system has the characteristics of high capacitance, long cycle life, high safety, and excellent high-temperature performance.

[0055] Wherein, the BOOST boost circuit includes:

[0056] 1 BOOST boost circuit principle, BOOST boost circuit uses pulse width modulation PWM technology, with the help of high-frequency switching device MOSFET switching action to implement control, its main function is to increase the DC voltage of the input power supply to a higher output voltage;

[0057] 2 Output voltage adjustment method: the output voltage of the circuit can be adjusted by controlling the switching frequency and duty cycle of the MOSFET switching device.

[0058] like Figure 2 The BOOST circuit 102 is connected to the ICD battery, increasing the battery voltage by about 100 times. The circuit structure is characterized by including an inductor L201 and a switch tube S202. The inductor L201 is connected to the positive electrode of the battery, and the other end of the inductor L201 is connected to the drain of the switch tube S202. The PWM wave is supplied to the gate of the switch tube S to control the on and off of the switch tube. The source of the switch tube S is connected to the battery ground.

[0059] Figure 2 The Boost circuit controls the on and off of the switch tube S202 through the high-voltage feedback and PWM wave output by the control circuit 105, stores the energy released by the battery in the inductor L201 and then releases it, thereby achieving voltage boost. When the switch tube S202 is turned on, the battery input voltage stores energy through the inductor L201; when the switch tube S202 is turned off, the inductor L201 releases energy, and the output voltage is higher than the battery input voltage.

[0060] Wherein, the charge pump voltage multiplier circuit includes:

[0061] (1) Function of the charge pump voltage doubler circuit: The function of the charge pump voltage doubler circuit is to perform a secondary voltage doubling process on the output voltage of the BOOST boost circuit, which can increase the voltage to n+1 times, where n is determined by the unit structure of the charge pump voltage doubler circuit. The final output high voltage HV will be input into the high voltage energy storage capacitor to achieve the purpose of boost charging;

[0062] (2) Structural composition of the charge pump voltage doubling circuit: The circuit is composed of n charge pump voltage doubling units in cascade, and the input of each unit is connected to the output Vboost of the BOOST boost circuit. There is a specific connection relationship between each level, that is, the Vout of the first-level charge pump voltage doubling unit is connected to the positive electrode of the capacitor Ca of the second-level charge pump voltage doubling unit, and so on, until the nth charge pump voltage doubling unit outputs high voltage HV, thereby doubling the output of the BOOST boost circuit.

[0063] (3) Working principle of the charge pump voltage doubling unit: The charge pump voltage doubling unit mainly uses the characteristics of the diode being forward-conducting and reverse-blocking to work. When the Vboost output by the BOOST boost circuit is a high voltage, the capacitor Ca is charged; when Vboost becomes a low voltage, the diode Da is reverse-blocked, and the capacitor Ca charges the capacitor Cb through the diode Db; when Vboost is in a high voltage state again, Vboost uses the capacitor Cb to boost the voltage and output Vout. Through this process, the voltage doubling operation is completed.

[0064] like Figure 3As shown, the charge pump voltage doubling circuit performs a second voltage doubling on the output voltage of the BOOST boost circuit 102, increasing the voltage to n+1 times, where n depends on the unit structure of the charge pump voltage doubling circuit. The circuit is composed of n charge pump voltage doubling units in cascade;

[0065] like Figure 4 As shown in the figure, the basic working principle of the charge pump voltage doubling unit is: when the BOOST boost circuit outputs Vboost at a high voltage, the capacitor Ca is charged. When Vboost is at a low voltage, the diode Da is reversely cut off, and the capacitor Ca charges the capacitor Cb through the diode Db. When Vboost is at a high voltage again, Vboost is boosted to output Vout through the capacitor Cb.

[0066] like Figure 5 Taking 3x voltage as an example, after the output Vboost of the BOOST boost circuit is doubled by the voltage doubling unit, the output Vout is three times the voltage of Vboost. Vout is input to the high-voltage energy storage capacitor. The connection methods of other multi-voltage circuits are similar.

[0067] The present invention applies the charge pump principle, and the voltage doubling circuit adopts a new topology structure. In combination with the BOOST boost circuit, only two-stage voltage doubling units are needed to quickly boost 3V to 800V required for defibrillation. The circuit has a small size, a large boost ratio, and a fast boost speed.

[0068] Wherein, the high voltage feedback and control circuit includes:

[0069] 1. Control factors of PWM wave output: The output of PWM wave is controlled by P_wave and comparator U1. P_wave is generated by the controller and is a square wave with a specific frequency and duty cycle. It determines the frequency and duty cycle of the PWM wave, while comparator U1 determines whether the PWM wave can be output. The two work together to realize the control of PWM wave output.

[0070] 2. The working process of the PWM wave-controlled boost circuit: Under the boost charging demand, when the high voltage HV is 0 and Vhv is less than Vref, the comparator U1 outputs a high level to turn on Q2, and the controller outputs the P_wave waveform to make Q1 turn on synchronously. The 15V voltage is controlled by Q1 and Q2, and the PWM wave with the same duty cycle is output synchronously to control the BOOST boost. When Vhv is equal to Vref, the comparator U1 outputs a low level, Q2 is turned off, the PWM wave stops outputting, and the boost circuit stops working.

[0071] 3. Determination of Vref reference value: The Vref reference value of the controller comes from data calibration. The Vhv value after different HV voltage division is written. When the voltage is boosted to a specific target value, the controller outputs the corresponding Vref. Each target HV corresponds to a Vref. When Vhv reaches Vref, the comparator U1 outputs a high level, triggering the drive control circuit and starting the BOOST boost circuit.

[0072] as follows Figure 6 This is a high-voltage feedback and control circuit structure, consisting of a sampling circuit 501, a comparator U1502, a drive control circuit 503 for the BOOST circuit switch 202, and a controller 504. The sampling circuit 501 is composed of high-precision sampling resistors R1 and R2 and a filter capacitor C6. The high voltage HV is divided by the sampling resistors R1 and R2 to output the Vhv value. The drive control circuit 503 is composed of current-limiting resistors R3 and R4, pull-down resistors R5 and R6, and switches Q1 and Q2.

[0073] like Figure 7 As shown in the figure, under the boost charging demand, when the high voltage HV is 0 and Vhv is less than Vref, the comparator U1 outputs a high level to turn on Q2, and the controller outputs the P_wave waveform to make Q1 turn on synchronously. The 15V voltage is controlled by the PWM wave with the same duty cycle output by Q1 and Q2 to control the BOOST boost. When Vhv is equal to Vref, the comparator U1 outputs a low level, Q2 is turned off, the PWM wave stops being output, and the boost circuit stops working.

[0074] Among them, the high-voltage energy storage capacitor refers to the ICD-specific wet tantalum capacitor used as the high-voltage energy storage element in this system. The wet tantalum capacitor has the characteristics of high capacitance density, low equivalent series resistance (ESR), fast discharge and high reliability. The high capacitance density can achieve large-capacity energy storage in a limited space, and the low ESR effectively reduces energy loss; the fast discharge capability ensures that sufficient energy is released at the moment of defibrillation. These advantages enable the high-voltage energy storage capacitor to efficiently store high-voltage energy and accurately release the defibrillation pulse energy to the heart when needed, quickly terminate ventricular fibrillation, and ensure the efficiency and safety of the defibrillation action.

[0075] Example 1:

[0076] This embodiment describes a double voltage boost circuit. The charge pump circuit doubles the voltage output of the BOOST boost circuit. The specific details are as follows:

[0077] When PWM is low, Figure 8 The switch tube S is turned off, the inductor L releases energy, and the diodes Da and Db of the charge pump voltage doubler unit are forward biased. The released energy is given to Figure 8 The Ca, Cb capacitance of each charge pump voltage doubling unit is shown as Figure 8 The medium and high voltage energy storage capacitors are charged and boosted, such as Figure 8 , where the dotted line represents the direction of the charge Q, and formula ① represents the voltage at each point at this time, Vout = Vboost = VCa;

[0078] When PWM is high again, the inductor 201 stores energy. Due to the unidirectional conductivity of the diodes Da and Db, the voltage across the capacitor cannot change suddenly. As a result, the voltage at the end of the capacitor Ca connected to the anode DbL of the diode Db is the voltage value of the energy conversion released by the inductor last time. The voltage at the end of the capacitor Cb connected to the cathode (DbR) of the diode Db is also the voltage value of the energy conversion released by the inductor last time. Figure 9 , where the dotted line represents the direction of charge Q, and formula ② represents the voltage at each point at this time, Vout=VCa=VCb;

[0079] When PWM is low again, the switch tube S202 is turned off, and the inductor L201 releases energy again, charging and boosting the capacitors Ca, Cb of each charge pump voltage doubling unit and the high-voltage energy storage capacitor again. However, the voltage at the end of the capacitor Cb connected to the diode DbR is the superposition of the voltage value of the energy conversion released by the inductor last time and the voltage value of the energy conversion released by the inductor this time. The voltage value of the high-voltage energy storage capacitor is increased by a certain multiple, such as Figure 10 , where the dotted line represents the direction of charge Q, and formula ③ represents the voltage at each point at this time, Vout = Vboost + VCb;

[0080] In this way, the circuit continuously boosts and charges the high-voltage energy storage capacitor until the high voltage HV of the high-voltage energy storage capacitor meets the set value; through the charge pump circuit, the voltage output by the BOOST boost circuit is boosted, so that the output of the BOOST boost circuit is increased by a certain multiple, but the efficiency of the BOOST boost is not affected.

[0081] Example 2:

[0082] This embodiment is a triple voltage boost circuit. Figure 11 、 12 13 is the energy trend diagram of the triple voltage circuit during the boost process, and the energy trend diagram of the voltage doubler circuit with more units is as follows Figure 11 、 12 Taking the trend of 13 as an example,

[0083] ① Voltage at each point when the inductor releases energy: Vout = Vboost + VCa1 = VCa2 Figure 11 ;

[0084] ② Voltage at each point when the inductor stores energy: Vout=VCa1=VCb1=VCa2=VCb2 Figure 12 ;

[0085] ③ When the inductor releases energy again, the voltage at each point is: Vout=Vboost+VCb1=VCb2 Figure 13 .

[0086] The output voltage adjustment method further includes:

[0087] A. In the Boost circuit, the high-voltage feedback and PWM wave output by the control circuit control the switch S to turn on. At this time, the battery input voltage causes the inductor L to store energy.

[0088] B. The switch tube S is turned off by the PWM wave control, and the inductor L releases the stored energy. The output voltage is higher than the battery input voltage, completing the boost process.

[0089] In the Boost circuit, the high-voltage feedback and PWM wave output by the control circuit control the state of the switch tube S. When the PWM wave turns on the switch tube S, the battery input voltage stores energy through the inductor L. When the PWM wave controls the switch tube S to turn off, the inductor L releases energy, generating an output higher than the battery input voltage, thereby achieving a voltage boost.

[0090] The charge pump voltage multiplier circuit further comprises:

[0091] A. Using the unidirectional conduction characteristics of the diode, when the BOOST boost circuit outputs Vboost at a high voltage, the diode Da conducts forward, and current flows through Da to charge the capacitor Ca; when Vboost turns to a low voltage, the diode Da is reverse-cut off, and the capacitor Ca transfers the stored charge to the capacitor Cb through the forward-conducting diode Db, completing the energy transfer;

[0092] B. When Vboost returns to a high voltage again, the capacitor Cb is superimposed on the Vboost voltage. Through the bootstrap voltage boost mechanism, the driving current is output to the load through the conducting diode, and finally the output voltage from the output terminal Vout is higher than the initial Vboost, achieving a voltage doubling effect.

[0093] The charge pump voltage doubling unit works by utilizing the unidirectional conduction characteristics of the diode. When the Vboost output by the BOOST boost circuit is a high voltage, the diode Da is turned on and the current charges the capacitor Ca. When Vboost becomes a low voltage, the diode Da is cut off, and the diode Db is turned on. The capacitor Ca transfers the stored charge to the capacitor Cb, completing the energy transfer between the two capacitors. When Vboost becomes a high voltage again, the voltage on the capacitor Cb is superimposed on Vboost. With the help of the bootstrap boost mechanism, the driving current is output through the conducting diode, and finally a voltage higher than the initial Vboost is output from the Vout end, achieving a doubling effect on the input voltage.

[0094] The working process of the PWM wave controlled boost circuit also includes:

[0095] A. During the high-voltage energy storage capacitor's boost and energy storage process, the high-voltage feedback and control circuit continuously collects the voltage on the capacitor in real time, obtains the voltage divider amplitude Vhv through the voltage divider circuit, and accurately compares it with the preset target amplitude value Vref. This process continuously monitors voltage changes and provides a basis for subsequent control;

[0096] B. Based on the comparison result of Vhv and Vref, the output state of comparator U1 is controlled. When Vhv does not reach Vref, comparator U1 outputs a high-level signal to maintain the normal operation of the boost circuit. Once Vhv reaches or exceeds Vref, comparator U1 outputs a low-level signal to cut off the driving signal of the boost circuit, thereby stopping the boost process and ensuring that the voltage of the energy storage capacitor is stable at the target value.

[0097] When the high-voltage energy storage capacitor is boosting and storing energy, the high-voltage feedback and control circuit collects the capacitor voltage in real time, obtains Vhv through voltage division, and accurately compares it with the preset target value Vref, continuously monitors voltage changes, and provides data support for control; according to the comparison result of Vhv and Vref, the state of comparator U1 is controlled. When Vhv does not reach Vref, U1 outputs a high level to maintain the boost; when Vhv reaches or exceeds Vref, U1 outputs a low level to cut off the drive, terminate the boost, and ensure that the capacitor voltage is stable at the target value.

[0098] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0099] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A boost circuit for an implantable cardioverter-defibrillator, characterized in that: The circuit system consists of a BOOST voltage-boosting circuit, a charge pump voltage-doubling circuit, a high-voltage feedback and control circuit, and a high-voltage energy storage capacitor. BOOST boost circuit: The BOOST boost circuit is based on PWM technology. It uses the switching action of the high-frequency switching device MOSFET to control the input DC voltage to a higher output voltage. By regulating the switching frequency and duty cycle of the switching device, the output voltage value of the BOOST circuit can be flexibly adjusted. Charge pump voltage doubler circuit: The charge pump voltage doubler circuit performs a secondary voltage doubler on the output voltage of the BOOST boost circuit, which can increase the voltage to n+1 times. n depends on the unit structure. The circuit is cascaded by n units, and the input of each unit is connected to Vboost. The nth unit outputs high voltage HV to charge the energy storage capacitor. It uses the characteristics of the diode to charge and discharge the capacitor and boost the voltage by the high and low changes of Vboost. High-voltage feedback and control circuit: The PWM wave output is controlled by P_wave and comparator U1. P_wave determines the frequency and duty cycle, and U1 determines whether to output. When HV is 0, Vhv is less than Vref, U1 outputs high, Q2 turns on, and the output PWM wave controls the voltage boost. The voltage boost stops when Vhv equals Vref. Vref is calibrated by data and corresponds to the target HV value. If the target is met, the voltage boost is triggered. High-voltage energy storage capacitor: ICD-specific wet tantalum capacitors are used. Wet tantalum capacitors have the characteristics of high capacitance density, low ESR, fast discharge and high reliability. High-voltage energy storage capacitors are used to store high-voltage energy. The defibrillation pulse energy is released from the high-voltage energy storage capacitor to the heart for defibrillation.

2. The boost circuit for an implantable cardioverter-defibrillator according to claim 1, wherein: The BOOST boost circuit includes: (1) BOOST boost circuit principle: BOOST boost circuit uses pulse width modulation (PWM) technology and controls the switching action of high-frequency switching device MOSFET. Its main function is to boost the DC voltage of the input power supply to a higher output voltage. (2) Output voltage adjustment method: The output voltage of the circuit can be adjusted by controlling the switching frequency and duty cycle of the MOSFET switching device.

3. The boost circuit for an implantable cardioverter-defibrillator according to claim 1, wherein: The charge pump voltage multiplier circuit comprises: (1) Function of the charge pump voltage doubler circuit: The function of the charge pump voltage doubler circuit is to perform a secondary voltage doubling process on the output voltage of the BOOST boost circuit, which can increase the voltage to n+1 times, where n is determined by the unit structure of the charge pump voltage doubler circuit. The final output high voltage HV will be input into the high voltage energy storage capacitor to achieve the purpose of boost charging; (2) Structural composition of the charge pump voltage doubling circuit: The circuit is composed of n charge pump voltage doubling units in cascade, and the input of each unit is connected to the output Vboost of the BOOST boost circuit. There is a specific connection relationship between each level, that is, the Vout of the first-level charge pump voltage doubling unit is connected to the positive electrode of the capacitor Ca of the second-level charge pump voltage doubling unit, and so on, until the nth charge pump voltage doubling unit outputs high voltage HV, thereby doubling the output of the BOOST boost circuit. (3) Working principle of the charge pump voltage doubling unit: The charge pump voltage doubling unit mainly uses the characteristics of the diode being forward-conducting and reverse-blocking to work. When the Vboost output by the BOOST boost circuit is a high voltage, the capacitor Ca is charged; when Vboost becomes a low voltage, the diode Da is reverse-blocked, and the capacitor Ca charges the capacitor Cb through the diode Db; when Vboost is in a high voltage state again, Vboost uses the capacitor Cb to boost the voltage and output Vout. Through this process, the voltage doubling operation is completed.

4. The boost circuit for an implantable cardioverter-defibrillator according to claim 1, wherein: The high voltage feedback and control circuit comprises: (1) Control factors of PWM wave output: The output of PWM wave is controlled by P_wave and comparator U1. P_wave is generated by the controller and is a square wave with a specific frequency and duty cycle. It determines the frequency and duty cycle of the PWM wave, while comparator U1 determines whether the PWM wave can be output. The two work together to achieve control of PWM wave output. (2) Working process of PWM wave controlled boost circuit: Under the boost charging demand, when the high voltage HV is 0 and Vhv is less than Vref, the comparator U1 outputs a high level to turn on Q2, and the controller outputs the P_wave waveform to make Q1 turn on synchronously. The 15V voltage is controlled by Q1 and Q2 to output a synchronous PWM wave with the same duty cycle to control the BOOST boost. When Vhv is equal to Vref, the comparator U1 outputs a low level, Q2 is turned off, the PWM wave stops outputting, and the boost circuit stops working. (3) Determination of Vref reference value: The Vref reference value of the controller is derived from data calibration. The Vhv value after different HV voltage division is written. When the voltage is boosted to a specific target value, the controller outputs the corresponding Vref. Each target HV corresponds to a Vref. When Vhv reaches Vref, the comparator U1 outputs a high level, triggering the drive control circuit and starting the BOOST boost circuit.

5. The boost circuit for an implantable cardioverter-defibrillator according to claim 1, wherein: The high-voltage energy storage capacitor refers to the ICD-specific wet tantalum capacitor used as a high-voltage energy storage element in this system. The wet tantalum capacitor has high capacitance density, low equivalent series resistance (ESR), fast discharge, and high reliability. The high capacitance density enables large-capacity energy storage in a limited space, while the low ESR effectively reduces energy loss. The rapid discharge capability ensures that sufficient energy is released at the moment of defibrillation. These advantages enable the high-voltage energy storage capacitor to efficiently store high-voltage energy and accurately release the defibrillation pulse energy to the heart when needed, quickly terminating ventricular fibrillation and ensuring the efficiency and safety of defibrillation.

6. The boost circuit for an implantable cardioverter-defibrillator according to claim 2, wherein: The output voltage adjustment method also includes: A. In the Boost circuit, the high-voltage feedback and PWM wave output by the control circuit control the switch S to turn on. At this time, the battery input voltage causes the inductor L to store energy. B. The switch tube S is turned off by the PWM wave control, and the inductor L releases the stored energy. The output voltage is higher than the battery input voltage, completing the boost process.

7. The boost circuit for an implantable cardioverter-defibrillator according to claim 3, wherein: The structure of the charge pump voltage multiplier circuit also includes: A. Using the unidirectional conduction characteristics of the diode, when the BOOST boost circuit outputs Vboost at a high voltage, the diode Da conducts forward, and current flows through Da to charge the capacitor Ca; when Vboost turns to a low voltage, the diode Da is reverse-cut off, and the capacitor Ca transfers the stored charge to the capacitor Cb through the forward-conducting diode Db, completing the energy transfer; B. When Vboost returns to a high voltage again, the capacitor Cb is superimposed on the Vboost voltage. Through the bootstrap voltage boost mechanism, the driving current is output to the load through the conducting diode, and finally the output voltage from the output terminal Vout is higher than the initial Vboost, achieving a voltage doubling effect.

8. The boost circuit for an implantable cardioverter-defibrillator according to claim 4, wherein: The working process of the PWM wave controlled boost circuit also includes: A. During the high-voltage energy storage capacitor's boost and energy storage process, the high-voltage feedback and control circuit continuously collects the voltage on the capacitor in real time, obtains the voltage divider amplitude Vhv through the voltage divider circuit, and accurately compares it with the preset target amplitude value Vref. This process continuously monitors voltage changes and provides a basis for subsequent control; B. Based on the comparison result of Vhv and Vref, the output state of comparator U1 is controlled. When Vhv does not reach Vref, comparator U1 outputs a high-level signal to maintain the normal operation of the boost circuit. Once Vhv reaches or exceeds Vref, comparator U1 outputs a low-level signal to cut off the driving signal of the boost circuit, thereby stopping the boost process and ensuring that the voltage of the energy storage capacitor is stable at the target value.

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