A charging protection circuit

Abstract

The present invention discloses a charging protection circuit, which is applied to an electromagnetic focusing shock wave device, comprising: a charging circuit, connected to an external power supply, for charging a high-voltage capacitor in the electromagnetic focusing shock wave device; an output detection circuit, connected to the output end of the charging circuit, for detecting the output voltage of the charging circuit after a preset time when the charging circuit starts charging; a switch circuit, connected between the charging circuit and the loop of the external power supply; a self-locking protection circuit, comprising a logic gate circuit, the input end of the logic gate circuit is connected to the output end of the output detection circuit, the output end of the logic gate circuit is connected to the switch circuit, and is used to turn off the switch circuit when the output detection circuit detects that the output voltage of the charging circuit is lower than a preset threshold, thereby disconnecting the connection between the external power supply and the charging circuit. The present invention can realize the protection of the high-voltage capacitor during the charging process through the cooperation of the output detection circuit, the switch circuit and the logic gate circuit.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic focused shock waves, and more specifically to a charging protection circuit. Background Art

[0002] The principle of electromagnetic focusing shock wave is to use the propagation characteristics of electromagnetic waves and the focusing effect of shock waves to focus electromagnetic waves to a point through appropriate devices to generate shock waves. The commonly used electromagnetic focusing shock wave circuits are as follows: Figure 1 As shown, the impact energy mainly comes from the pulse current generated by the instantaneous discharge of the high-voltage capacitor C1 to the inductor coil L1, which forms a very strong pulse magnetic field, so that the diaphragm covered on the coil L1 induces a magnetic field, and the diaphragm magnetic field interacts with the coil magnetic field to generate a repulsive force, forming a shock wave on the other side of the diaphragm in the water medium, and focusing is achieved through a focusing lens or self-focusing, so that vibration and impact can be generated on the target object to achieve treatment or other application purposes, and the high-voltage capacitor C1 is charged by the V1 charging device. However, in the prior art, even if the high-voltage capacitor C1 is damaged or there is a fault in the capacitor charging end during charging, it can still be charged, which is easy to cause damage to the high-voltage capacitor C1, and in serious cases it will also endanger the personal safety of the user. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a charging protection circuit which can improve the safety of equipment during use.

[0004] In order to solve the above technical problems, the present invention provides a charging protection circuit, which is applied to an electromagnetic focusing shock wave device, and comprises:

[0005] A charging circuit, connected to an external power source, for charging a high-voltage capacitor in the electromagnetic focusing shock wave device;

[0006] an output detection circuit, connected to the output end of the charging circuit, and used to detect the output voltage of the charging circuit after a preset time when the charging circuit starts charging;

[0007] A switch circuit connected between the charging circuit and a loop of an external power supply;

[0008] The self-locking protection circuit includes a logic gate circuit, wherein the input end of the logic gate circuit is connected to the output end of the output detection circuit, and the output end of the logic gate circuit is connected to the switch circuit, and is used to turn off the switch circuit when the output detection circuit detects that the output voltage of the charging circuit is lower than a preset threshold, thereby disconnecting the external power supply from the charging circuit.

[0009] Compared with the prior art, the charging protection circuit of the present invention is provided with a switch circuit in the loop of the charging circuit and the external power supply, and an output detection circuit is also provided at the output end of the charging circuit. The output detection circuit can detect the output voltage of the charging circuit after a preset time when the charging circuit starts charging, and cooperate with the logic gate circuit in the self-locking protection circuit to turn off the switch circuit when the output voltage of the charging circuit is lower than a preset threshold value to disconnect the external power supply from the charging circuit, thereby protecting the charging process of the high-voltage capacitor when the high-voltage capacitor is damaged or the charging end fails, so as to improve the safety of the equipment and better protect the safety of the user; and further, charging overcurrent, overvoltage, undervoltage and overtemperature detection circuits are provided, which cooperate with the switch circuit and the self-locking protection circuit to form systematic protection, thereby better improving the safety of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a circuit diagram of an electromagnetic focusing shock wave circuit commonly used in the prior art;

[0011] Figure 2 It is a circuit block diagram of a specific embodiment of the charging protection circuit of the present invention;

[0012] Figure 3 It is a specific circuit diagram of a charging circuit, an LLC overcurrent detection circuit and an overtemperature detection circuit in the charging protection circuit of the present invention;

[0013] Figure 4 It is a specific circuit diagram of the start detection circuit in the charging protection circuit of the present invention;

[0014] Figure 5 It is a specific circuit diagram of the output detection circuit in the charging protection circuit of the present invention;

[0015] Figure 6 It is a specific circuit diagram of a switch circuit, a PFC circuit, a PFC overvoltage detection circuit and a PFC undervoltage detection circuit in the charging protection circuit of the present invention;

[0016] Figure 7 It is a specific circuit diagram of the alarm circuit in the charging protection circuit of the present invention. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to more clearly understand the objectives, technical solutions and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0018] Reference Figures 2 to 7 , Figures 2 to 7A specific embodiment of the charging protection circuit of the present invention is shown. The charging protection circuit of the present invention can be applied to an electromagnetic focusing shock wave device, and is used to protect the high-voltage capacitor C6 in the electromagnetic focusing shock wave device when it is charged. In the embodiment shown in the accompanying drawings, the charging protection circuit includes a charging circuit 10, an output detection circuit 20, a switch circuit 30 and a self-locking protection circuit 40, wherein the charging circuit 10 is connected to an external power supply V, and is used to charge the high-voltage capacitor C6 in the electromagnetic focusing shock wave device; the output detection circuit 20 is connected to the output end of the charging circuit 10, and is used to detect the output voltage of the charging circuit 10 after the charging circuit 10 starts charging for a preset time; the switch circuit 30 is connected between the charging circuit 10 and the loop of the external power supply V; the self-locking protection circuit 40 includes a logic gate circuit, the input end of the logic gate circuit is connected to the output end of the output detection circuit 20, and the output end of the logic gate circuit is connected to the switch circuit 30, and is used to turn off the switch circuit 30 when the output detection circuit 20 detects that the output voltage of the charging circuit 10 is lower than a preset threshold, thereby disconnecting the connection between the external power supply V and the charging circuit 10. Based on the above design, the high-voltage capacitor C6 can be protected during the charging process through the cooperation of the output detection circuit 20, the switch circuit 30 and the logic gate circuit, thereby improving the safety of the device and better protecting the safety of the user.

[0019] In some embodiments, the switch circuit 30 includes a second switch tube Q2 and a first optocoupler solid-state relay K1, and the logic gate circuit includes a logic gate chip and a control unit, wherein the anode and cathode of the light-emitting diode in the first optocoupler solid-state relay K1 are respectively connected to the power supply VCC and the drain of the second switch tube Q2, the source of the second switch tube Q2 is grounded, and the two main terminals of the bidirectional thyristor Q5 in the first optocoupler solid-state relay K1 are connected to the connection loop between the charging circuit 10 and the external power supply V, and an input end of the logic gate chip is connected to the output end of the output detection circuit 20; the control unit includes a thyristor Q5, the control electrode of the thyristor Q5 is connected to the output end of the logic gate chip, and its cathode is grounded, and the anode of the thyristor Q5 is connected to the power supply VCC and the gate of the second switch tube Q2, so that when the output detection circuit 20 detects that the output voltage of the charging circuit 10 is lower than the preset threshold, it is turned on to lower the level of the gate of the second switch tube Q2, so that the second switch tube Q2 is turned off, thereby disconnecting the circuit between the charging circuit 10 and the external power supply V. Based on the above design, the live wire of the external power supply V can be controlled by the second switch tube Q2 and the first optocoupler solid-state relay K1. When it is detected that the output voltage of the charging circuit 10 is lower than the preset threshold, the protection is triggered, the second switch tube Q2 is turned off, and the first optocoupler solid-state relay K1 is disconnected, thereby disconnecting the external power supply V, and the charging circuit 10 no longer works.

[0020] Continue to refer to Figure 1 In this embodiment, the output detection circuit 20 is used to output a low level when the output voltage of the detected charging circuit 10 is lower than a preset threshold value. The logic gate chip is a multi-channel AND gate chip. The control unit also includes a level flip circuit 42. The level flip circuit 42 is connected between the output end of the multi-channel AND gate chip and the control electrode of the thyristor Q5 to flip the level signal from the multi-channel AND gate chip so that the thyristor Q5 is turned on / off, thereby disconnecting / maintaining the loop between the charging circuit 10 and the external power supply V. Preferably, the level flip circuit 42 may include a NOT gate U11A, the output end of the NOT gate U11A is connected to the control electrode of the thyristor Q5 through a thirty-fourth resistor R34, and a thirty-fifth resistor R35 and a twelfth capacitor C12 are also connected between the control electrode and the cathode of the thyristor Q5. The logic gate chip may be a four-channel AND gate chip, wherein the output of the fourth channel AND gate U10A is connected to the first input end of the third channel AND gate U10D, the output end of the third channel AND gate U10D is connected to the first input end of the second channel AND gate U10C, the second input end of the second channel AND gate U10C is connected to the output end of the output detection circuit 20, the output end of the second channel AND gate U10C is connected to the first input end of the first channel AND gate U10B, and the output end of the first channel AND gate U10B is connected to the input end of the NOT gate U11A. Preferably, in this embodiment, the four-channel AND gate chip may be a chip with model HEF4081BT or SN74HC08. In this embodiment, when the output detection circuit 20 outputs a low level, it outputs a high level after passing through the NOT gate U11A, triggering the thyristor Q5 to be turned on all the time, turning off the second switch tube Q2, forming a self-locking protection.

[0021] Furthermore, combined with Figure 2 and Figure 4In the embodiment shown in the accompanying drawings, the charging protection circuit also includes a start-up detection circuit 50, and the self-locking protection circuit 40 also includes a first AND gate U15A, wherein the first input end of the first AND gate U15A is connected to the anode of the thyristor Q5, and the output end thereof is connected to the gate of the second switch tube Q2, and the start-up detection circuit 50 includes a detection circuit 52 and a delayed start circuit 53, wherein the detection circuit 52 includes a photocoupler U14 and a sixth switch tube Q6, and the sixth switch tube Q6 is an N-channel MOS tube, and the anode of the light-emitting diode in the photocoupler U14 is connected to a forty-seventh resistor R47, and a bidirectional voltage regulator diode D11 is connected between the forty-seventh resistor R47 and the cathode of the light-emitting diode in the photocoupler U14, and serves as the input side of the start-up detection circuit 50, and can be connected to an external power supply V through a start button P2, and the collector of the transistor in the photocoupler U14 is connected to the sixth switch The gate of the sixth switch tube Q6 is connected to the power supply VCC through a forty-fourth resistor R44, the emitter of the triode in the photocoupler U14 and the source of the sixth switch tube Q6 are grounded, the drain of the sixth switch tube Q6 is connected to the power supply VCC through a forty-first resistor R40, and is used as the output end of the detection circuit 52 and connected to the second input end of the first AND gate U15A; the delayed start circuit 53 includes a seventh switch tube Q7, a thirteenth capacitor C13, a tenth diode D10 and a forty-ninth resistor R49, the seventh switch tube Q7 is a P-channel MOS tube, the gate of the seventh switch tube Q7 is connected to the collector of the triode in the photocoupler U14, the source of the seventh switch tube Q7 is connected to the power supply VCC through a forty-first resistor R41, and is connected to the thirteenth capacitor C13 and one end of the forty-ninth resistor R49 through the tenth diode D10, the other end of the thirteenth capacitor C13 and the forty-ninth resistor R49 and the drain of the seventh switch tube Q7 are grounded. Understandably, the start button P2 can be a button switch or a connection terminal, or a switch at the software level. When working, first, the input side of the start detection circuit 50 can be connected to the external power supply V. When powered on, the photocoupler U14 is turned on, the sixth switch tube Q6 is turned off, and the power-on start signal NO is pulled high, and the second switch tube Q2 is driven to turn on through the first AND gate U15A, so that the first photocoupler solid-state relay K1 is turned on, and the charging circuit 10 works.

[0022] In this embodiment, Figure 5As shown, the output detection circuit 20 includes a fourth resistor voltage divider circuit 21, an isolation acquisition chip U8, a differential amplifier (U9A, U9B), a second comparison circuit and a second OR gate U1B, wherein the input end of the fourth resistor voltage divider circuit 21 is connected to the output end of the charging circuit 10, the isolation acquisition chip U8 is connected between the output end of the fourth resistor voltage divider circuit 21 and the input end of the differential amplifier (U9A, U9B), the second comparison circuit includes a second voltage follower U12B, a second voltage comparator U12A and a matching circuit 242, the input end of the second voltage follower U12B is connected to the output end of the differential amplifier (U9A, U9B), and the output end thereof is connected to the non-inverting input end of the second voltage comparator U12A through a forty-second resistor R42, the The matching circuit 242 includes a thirty-seventh resistor R37, a forty-third resistor R43 and a forty-eighth resistor R48, one end of the forty-third resistor R43 is connected to the inverting input end of the second voltage comparator U12A, and the other end thereof is connected to one end of the thirty-seventh resistor R37 and the forty-eighth resistor R48, the other ends of the thirty-seventh resistor R37 and the forty-eighth resistor R48 are respectively connected to the power supply VCC and the ground, the output end of the second voltage comparator U12A is connected to an input end of the second OR gate U1B, the other input end of the second OR gate U1B is connected to one end of the thirteenth capacitor C13 connected to the tenth diode D10, the output end of the second OR gate U1B serves as the output end of the output detection circuit 20, and is connected to the second input end of the second channel AND gate U10C in the logic gate chip. Specifically, the fourth resistor voltage divider circuit 21 includes a twentieth resistor R20 and a thirty-first resistor R31, one end of the twentieth resistor R20 is connected to the output end of the charging circuit 10, the other end of the twentieth resistor R20 is connected to one end of the thirty-first resistor R31 and the input end of the isolation acquisition chip U8, and the other end of the thirty-first resistor R31 is grounded. Preferably, in this embodiment, the model of the isolation acquisition chip U8 can be AMC1311BDWVR. It can be understood that the differential amplifier (U9A, U9B) and the second voltage follower U12B in the present invention can be implemented by differential amplifiers and voltage followers commonly used by those skilled in the art. The specific structure and working process are well known to those skilled in the art and will not be repeated here.Based on the above design, the output voltage of the charging circuit 10 is isolated and collected by the isolation acquisition chip U8, and then amplified by the differential amplifier (U9A, U9B), and then compared with the preset threshold in the second voltage comparator U12A after passing through the second voltage follower U12B. When it is detected that the output voltage of the charging circuit 10 still does not reach the set value after the preset time of charging is started, it is considered that there is a short circuit in the output, that is, the charging end is faulty, and the second OR gate U1B outputs a low-level HV_SC signal, thereby realizing short-circuit protection or undervoltage protection. When the charging protection circuit is working, in order to avoid the output detection circuit 20 from erroneously triggering the protection due to just starting, the delayed start circuit 53 of the start detection circuit 50 works when the power is on, and the signal NO_TP sent to the second OR gate U1B can be delayed through the thirteenth capacitor C13, thereby avoiding the problem of false protection at startup.

[0023] Continue to refer to Figure 2 and Figure 3 In some embodiments, the charging circuit 10 includes a PFC circuit 11, a half-bridge LLC circuit 12, a transformer 13 and a rectifier circuit 14 which are sequentially connected between the external power supply V and the high-voltage capacitor C6, wherein the half-bridge LLC circuit 12 includes an inverter bridge arm composed of a first switch tube Q1 and a fourth switch tube Q4, a first inductor L1, an eighth capacitor C8 and a ninth capacitor C9, the upper end of the inverter bridge arm is connected to the output end of the PFC circuit 11, the control end of the inverter bridge arm is connected to the external LLC drive, and the lower end thereof is grounded, specifically, as Figure 3 As shown, the gates of the first switch tube Q1 and the fourth switch tube Q4 are connected to LLC drive through resistors R24 and R30 respectively, the midpoint of the inverter bridge arm is also connected to resistor R24 ​​through resistor R22, and a resistor R32 is also connected between the gate and the source of the fourth switch tube Q4, one end of the first inductor L1 is connected to the midpoint of the inverter bridge arm, and the other end of the first inductor L1 is connected to the same-name end of the primary winding of the transformer 13, one end of the eighth capacitor C8 and the ninth capacitor C9 are both connected to the opposite-name end of the primary winding of the transformer 13, and the other ends of the eighth capacitor C8 and the ninth capacitor C9 are both grounded, and the secondary winding of the transformer 13 is connected to the rectifier circuit 14.

[0024] In some embodiments, the charging protection circuit further includes a PFC overvoltage detection circuit 70 and a PFC undervoltage detection circuit 80. Figure 6As shown, the PFC overvoltage detection circuit 70 includes a second resistor voltage divider circuit, a fourth voltage regulator U4 and a second photocoupler U2, wherein the second resistor voltage divider circuit is composed of a resistor R8 and a resistor R5, the input end of the second resistor voltage divider circuit is connected to the output end of the PFC circuit 11, the output end of the second resistor voltage divider circuit is connected to the reference electrode of the fourth voltage regulator U4, the cathode of the light emitting diode in the second photocoupler U2 is connected to the cathode of the fourth voltage regulator U4, and its anode is connected to the power supply through a third resistor R3, the collector of the transistor in the second photocoupler U2 is connected to the power supply VCC through a first resistor R1, and serves as the output end of the PFC overvoltage detection circuit 70, connected to the first input end of the fourth channel AND gate U10A in the logic gate chip, and its emitter and the anode of the fourth voltage regulator U4 are both grounded; the PFC undervoltage detection circuit 80 includes a third resistor voltage divider circuit, a fifth voltage regulator U5, a third photocoupler The third resistor voltage divider circuit is composed of a resistor R8 and a resistor R6, the input end of the third resistor voltage divider circuit is connected to the output end of the PFC circuit 11, the output end of the third resistor voltage divider circuit is connected to the reference electrode of the fifth voltage regulator U5, the cathode of the light emitting diode in the third photoelectric coupler U3 is connected to the cathode of the fifth voltage regulator U5, and the anode thereof is connected to the power supply through a fourth resistor R4, the collector of the transistor in the third photoelectric coupler U3 is connected to the power supply VCC through a second resistor R2, the emitter thereof, the anode of the fifth voltage regulator U5 and an input end of the first OR gate U1A are all grounded, the other input end of the first OR gate U1A is connected to one end of the thirteenth capacitor C13 connected to the tenth diode D10, and the output end of the first OR gate U1A is used as the output end of the PFC undervoltage detection circuit 80, and is connected to the second input end of the fourth channel AND gate U10A in the logic gate chip. Based on the above design, after the output voltage of the PFC circuit 11 is divided by the second resistor voltage divider circuit and the third resistor voltage divider circuit, the output voltage of the PFC circuit 11 is monitored by the circuit composed of U4 and U2 and the circuit composed of U5 and U3 respectively, and protection can be triggered in case of overvoltage / undervoltage.

[0025] Continue to refer to Figure 3Preferably, the charging protection circuit also includes an LLC overcurrent detection circuit 60, and the LLC overcurrent detection circuit 60 includes a through-type current transformer JP1, a third diode D3, a sixth voltage regulator diode D6, a rectifier bridge, a first resistor voltage divider circuit 63 and a first comparison circuit, wherein the primary side of the through-type current transformer JP1 is connected between the midpoint of the inverter bridge arm and the first inductor L1, the cathodes of the third diode D3 and the sixth voltage regulator diode D6 are connected between the secondary sides of the through-type current transformer JP1, and the anode of the third diode D3 is connected to the sixth an anode of the voltage-stabilizing diode D6; a first AC input terminal and a second AC input terminal of the rectifier bridge (D1, D2, D4, D5) are connected between the secondary side of the through-type current transformer JP1, a positive output terminal of the rectifier bridge (D1, D2, D4, D5) is connected to the first resistor voltage divider circuit 63, and a negative output terminal thereof is grounded; the first resistor voltage divider circuit 63 comprises a thirteenth resistor R13 and a fourteenth resistor R14, one end of the thirteenth resistor R13 is connected to the positive output terminal of the rectifier bridge (D1, D2, D4, D5), and the other end thereof is grounded through a seventeenth resistor R17, and One end of the fourteenth resistor R14 is connected, and the other end of the fourteenth resistor R14 is connected to the input end of the first comparison circuit; the first comparison circuit includes a first voltage follower U6B, a first voltage comparator U6A and an overcurrent matching circuit 663, the input end of the first voltage follower U6B is connected to the fourteenth resistor R14, and its output end is connected to the inverting input end of the first voltage comparator U6A, the overcurrent matching circuit 663 is used to match the overcurrent point, including a seventh resistor R7, an adjustable resistor R15 and a sixteenth resistor R16, and one end of the seventh resistor R7 is connected to the power supply VCC , the other end is connected to the adjustable resistor R15 and one end of the sixteenth resistor R16, and is connected to the adjustment end of the adjustable resistor R15, the other end of the adjustable resistor R15 is grounded, the in-phase input end of the first voltage comparator U6A is connected to the other end of the sixteenth resistor R16, and the output end thereof is connected to the second input end of the first channel AND gate U10B in the logic gate chip, so as to prompt the self-locking protection circuit 40 to turn off the switch circuit 30 when the output current of the half-bridge LLC circuit 12 detected exceeds the set current threshold, thereby disconnecting the external power supply V from the charging circuit 10.In this embodiment, when the half-bridge LLC circuit 12 is working, the signal can be collected through the through-type current transformer JP1, wherein D3 and D6 can be used for demagnetization, and the rectifier bridge composed of D1, D2, D4, and D5 can convert the AC signal of the through-type current transformer JP1 into a DC signal, and divide the voltage through R13 and R14, thereby converting the current signal into a voltage signal, and then passing through the first voltage follower U6B and comparing it with the current threshold set in the first voltage comparator U6A. When the set current threshold is exceeded, the first voltage comparator U6A outputs a low-level LLC_MAX signal, and when it does not exceed the LLC_MAX signal, the LLC_MAX signal is a high level. And because an adjustable resistor R15 is provided in the overcurrent matching circuit 663, the overcurrent point can be adjusted by adjusting the access resistance of the adjustable resistor R15.

[0026] In some embodiments, the charging protection circuit also includes an over-temperature detection circuit 90, and the over-temperature detection circuit 90 includes a temperature control switch TS and a photoelectric coupler U13. The temperature control switch TS is placed next to the charging circuit 10. Preferably, a heat sink TR can be set next to the inverter bridge arm of the charging circuit 10. The temperature control switch TS can be attached to the heat sink TR to detect the temperature of the charging circuit 10 when it is working. One end of the temperature control switch TS is connected to the power supply, and the other end is connected to the anode of the light-emitting diode in the photoelectric coupler U13. The cathode of the light-emitting diode and the emitter of the transistor in the photoelectric coupler U13 are grounded, and the collector of the transistor is connected to the power supply VCC through a thirty-ninth resistor R39, and as the output end of the over-temperature detection circuit 90, it is connected to the second input end of the third channel AND gate U10D in the logic gate chip. In this embodiment, the temperature control switch TS is usually in a normally open state. When the temperature of the heat sink TR is sensed to be greater than the operating temperature of the temperature control switch TS, the temperature control switch TS is closed, thereby turning on the photocoupler U13 and outputting a low-level TMEP signal, thereby triggering over-temperature protection.

[0027] Furthermore, the charging protection circuit also includes an alarm circuit 100, such as Figure 7As shown, the alarm circuit 100 includes a third switch tube Q3, a buzzer B1 and a second optocoupler solid-state relay U7, wherein the third switch tube Q3 is a P-channel MOS tube, the gate of the third switch tube Q3 is connected to the anode of the thyristor Q5, and the source thereof is connected to the negative terminal of the buzzer B1 and the cathode of the light-emitting diode in the second optocoupler solid-state relay U7 through a nineteenth resistor R19, the drain of the third switch tube Q3 is grounded, the positive terminal of the buzzer B1 and the anode of the light-emitting diode in the second optocoupler solid-state relay U7 are both connected to the power supply VCC, and the two ends of the transistor in the second optocoupler solid-state relay U7 are connected to an external host computer to pull down the level of the gate of the third switch tube Q3 when the thyristor Q5 is turned on, so that the third switch tube Q3 is turned on, thereby causing the buzzer B1 to alarm and the second optocoupler solid-state relay U7 to send an alarm signal to the external host computer. Based on the above design, after Q5 is turned on, the level of the gate of Q3 is pulled down, so that Q3 is turned on, causing the buzzer B1 to alarm. When a fault occurs and protection is generated, the second optocoupler solid-state relay U7 is also turned on and sends an alarm signal to the host computer.

[0028] It can be understood that when the charging protection circuit of the present invention works, first, the input side of the start detection circuit 50 is connected to the external power supply V and powered on, the photocoupler U14 is turned on, the sixth switch tube Q6 is turned off, and the power-on start signal NO is pulled high, and the second switch tube Q2 is driven to turn on through the first AND gate U15A, so that the first photocoupler solid-state relay K1 is turned on, and the PFC circuit 11 in the charging circuit 10 works to boost the voltage. At this time, the seventh switch tube Q7 in the delayed start circuit 53 is turned on, and the delayed output of the NO_TP signal is realized by charging the thirteenth capacitor C13. At the same time, the PFC overvoltage detection circuit 70 and the PFC undervoltage detection circuit 80 work. After a preset time, the PFC undervoltage detection circuit 80 detects the output of the PFC circuit 11. If the voltage has not risen to the specified voltage, a low-level PFC_MIX signal is output to the multi-channel logic gate chip, which triggers the protection, that is, the thyristor Q5 is turned on, the second switch tube Q2 is turned off, and the connection loop between the external power supply V and the PFC circuit 11 is cut off. At the same time, the third switch tube Q3 can be turned on, the buzzer B1 alarms, and the second optocoupler solid-state relay U7 is also turned on to send an alarm signal to the host computer to realize the PFC undervoltage protection function; and when the PFC overvoltage detection circuit 70 detects that the output voltage of the PFC circuit 11 is too high, it outputs a low-level PFC_MAX signal to the multi-channel logic gate chip, which also triggers the protection and realizes the PFC overvoltage protection function; and when the PFC circuit 11 is working normally, the delay 10 After ms, the LLC driver sends out a PWM voltage regulation signal to start the half-bridge LLC circuit 12. When the half-bridge LLC circuit 12 is working, the signal can be collected through the through-type current transformer JP1, and the AC signal of the through-type current transformer JP1 is converted into a DC signal through the rectifier bridge (D1, D2, D4, D5), and then compared with the set current threshold in the first comparison circuit after voltage division by R13 and R14. When the set current threshold is exceeded, a low-level LLC_MAX signal is output to trigger protection. When it does not exceed the set current threshold, the half-bridge LLC circuit 12 works normally and charges the high-voltage capacitor C6 through the rectifier circuit 14. At this time, the output voltage of the rectifier circuit 14 can also be isolated and collected through the isolation collection chip U8, and then It is then amplified by a differential amplifier (U9A, U9B), and then compared with a preset threshold in the second voltage comparator U12A after passing through the second voltage follower U12B. When it is detected that the output voltage of the charging circuit 10 still does not reach the set value after the preset time of charging is turned on, it is considered that there is a short circuit in the output, and the second OR gate U1B outputs a low-level HV_SC signal, thereby achieving short-circuit protection or under-voltage protection; and during the normal operation of the half-bridge LLC circuit 12, the temperature of the radiator TR can also be detected by the temperature control switch TS. When the temperature of the radiator TR is greater than the operating temperature of the temperature control switch TS, the temperature control switch TS is closed, so that the optocoupler U13 is turned on and the output is a low-level TMEP signal, thereby triggering the over-temperature protection.

[0029] In summary, the charging protection circuit of the present invention is provided with an output detection circuit 20, an LLC overcurrent detection circuit 60, a PFC overvoltage detection circuit 70, a PFC undervoltage detection circuit 80, an overtemperature detection circuit 90, a switch circuit 30 and a self-locking protection circuit 40. A variety of different protections can be performed during the charging process of the high-voltage capacitor C6, that is, when the output is short-circuited, the PFC circuit 11 outputs overvoltage or undervoltage, the half-bridge LLC circuit 12 is overcurrent, or the operating temperature is too high, the protection can be triggered, and the switch circuit 30 can be turned off, thereby disconnecting the external power supply V from the charging circuit 10, so as to improve the safety of the equipment and better protect the safety of the user. In addition, an alarm circuit 100 is also provided, which can give a prompt while triggering the protection to remind the user to lift the alarm as soon as possible.

[0030] The above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention in any form.

[0031] Those skilled in the art may make various equivalent changes and improvements based on the above embodiments. All equivalent changes or modifications made within the scope of the claims should fall within the protection scope of the present invention.

Claims

1. A charging protection circuit, applied to an electromagnetic focusing shock wave device, characterized in that: include: A charging circuit, connected to an external power supply, for charging a high-voltage capacitor in an electromagnetic focusing shock wave device, comprising a PFC circuit, a half-bridge LLC circuit, a transformer and a rectifier circuit, which are sequentially connected between the external power supply and the high-voltage capacitor, wherein the half-bridge LLC circuit comprises an inverter bridge arm composed of a first switch tube and a fourth switch tube, a first inductor, an eighth capacitor and a ninth capacitor, the upper end of the inverter bridge arm is connected to the output end of the PFC circuit, the control end of the inverter bridge arm is connected to an external LLC drive, and the lower end is grounded, one end of the first inductor is connected to the midpoint of the inverter bridge arm, the other end of the first inductor is connected to the same-name end of the primary winding of the transformer, one end of the eighth capacitor and the ninth capacitor are both connected to the opposite-name end of the primary winding of the transformer, the other ends of the eighth capacitor and the ninth capacitor are both grounded, and the secondary winding of the transformer is connected to the rectifier circuit; LLC overcurrent detection circuit, the LLC overcurrent detection circuit includes a through-type current transformer, a third diode, a sixth voltage-stabilizing diode, a rectifier bridge, a first resistor voltage-dividing circuit and a first comparison circuit, wherein the primary side of the through-type current transformer is connected between the midpoint of the inverter bridge arm and the first inductor, the cathodes of the third diode and the sixth voltage-stabilizing diode are connected between the secondary sides of the through-type current transformer, and the anode of the third diode is connected to the anode of the sixth voltage-stabilizing diode; the first AC input terminal and the second AC input terminal of the rectifier bridge are connected between the secondary sides of the through-type current transformer, the positive output terminal of the rectifier bridge is connected to the first resistor voltage-dividing circuit, and its negative output terminal is grounded; the first resistor voltage-dividing circuit includes a thirteenth resistor and a fourteenth resistor, one end of the thirteenth resistor is connected to the positive input terminal of the rectifier bridge output end, the other end of which is grounded through a seventeenth resistor and connected to one end of the fourteenth resistor, the other end of the fourteenth resistor is connected to the input end of the first comparison circuit; the first comparison circuit includes a first voltage follower, a first voltage comparator and an overcurrent matching circuit, the input end of the first voltage follower is connected to the fourteenth resistor, and the output end of the first voltage follower is connected to the inverting input end of the first voltage comparator, the overcurrent matching circuit includes a seventh resistor, an adjustable resistor and a sixteenth resistor, one end of the seventh resistor is connected to the power supply VCC, the other end is connected to the adjustable resistor and one end of the sixteenth resistor, and is connected to the adjustment end of the adjustable resistor, the other end of the adjustable resistor is grounded, the in-phase input end of the first voltage comparator is connected to the other end of the sixteenth resistor, and the output end of the first voltage comparator serves as the output end of the LLC overcurrent detection circuit; an output detection circuit, connected to the output end of the charging circuit, and used to detect the output voltage of the charging circuit after the charging circuit starts charging for a preset time; A switch circuit connected between the charging circuit and an external power supply circuit; The self-locking protection circuit includes a logic gate circuit, wherein the input end of the logic gate circuit is connected to the output end of the LLC overcurrent detection circuit and the output detection circuit, and the output end of the logic gate circuit is connected to the switch circuit, and is used to turn off the switch circuit when the output current of the half-bridge LLC circuit detected by the LLC overcurrent detection circuit exceeds a set current threshold or when the output detection circuit detects that the output voltage of the charging circuit is lower than a preset threshold, thereby disconnecting the external power supply from the charging circuit.

2. The charging protection circuit according to claim 1, characterized in that: The switch circuit includes a second switch tube, the drain and source of the second switch tube are connected between the charging circuit and the loop of the external power supply, and the logic gate circuit includes a logic gate chip and a control unit, wherein: An input end of the logic gate chip is connected to the output end of the output detection circuit; The control unit includes a thyristor, the control electrode of the thyristor is connected to the output end of the logic gate chip, the cathode of the thyristor is grounded, and the anode of the thyristor is connected to the power supply VCC and the gate of the second switch tube, so that when the output detection circuit detects that the output voltage of the charging circuit is lower than a preset threshold, the thyristor is turned on to lower the level of the gate of the second switch tube, so that the second switch tube is turned off, thereby disconnecting the loop between the charging circuit and the external power supply.

3. The charging protection circuit according to claim 2, characterized in that: The output detection circuit is used to output a low level when the output voltage of the detected charging circuit is lower than a preset threshold value. The logic gate chip is a multi-channel AND gate chip. The control unit also includes a level flipping circuit. The level flipping circuit is connected between the output end of the multi-channel AND gate chip and the control electrode of the thyristor to flip the level signal from the multi-channel AND gate chip so as to turn on / off the thyristor, thereby disconnecting / maintaining the loop between the charging circuit and the external power supply.

4. The charging protection circuit according to claim 2, characterized in that: The charging protection circuit also includes a start-up detection circuit, the self-locking protection circuit also includes a first AND gate, the first input end of the first AND gate is connected to the anode of the thyristor, and the output end is connected to the gate of the second switch tube, the start-up detection circuit includes a detection circuit and a delayed start circuit, wherein, The detection circuit includes a photocoupler U14 and a sixth switch tube, the sixth switch tube is an N-channel MOS tube, the anode and cathode of the light-emitting diode in the photocoupler U14 are connected to an external power supply through a start button, the collector of the triode in the photocoupler U14 is connected to the gate of the sixth switch tube, and its emitter and the source of the sixth switch tube are grounded, the drain of the sixth switch tube is connected to the power supply VCC through a 40th resistor, and serves as the output end of the detection circuit, and is connected to the second input end of the first AND gate; The delayed start circuit includes a seventh switch tube, a thirteenth capacitor, a tenth diode and a forty-ninth resistor. The seventh switch tube is a P-channel MOS tube. The gate of the seventh switch tube is connected to the collector of the transistor in the photocoupler U14, and the source is connected to the power supply VCC through a forty-first resistor, and is connected to one end of the thirteenth capacitor and the forty-ninth resistor through the tenth diode. The other ends of the thirteenth capacitor and the forty-ninth resistor and the drain of the seventh switch tube are grounded.

5. The charging protection circuit according to claim 4, characterized in that: The output detection circuit includes a fourth resistor voltage divider circuit, an isolation acquisition chip, a differential amplifier, a second comparison circuit and a second OR gate, wherein the input end of the fourth resistor voltage divider circuit is connected to the output end of the charging circuit, the isolation acquisition chip is connected between the output end of the fourth resistor voltage divider circuit and the input end of the differential amplifier, the second comparison circuit includes a second voltage follower, a second voltage comparator and a matching circuit, the input end of the second voltage follower is connected to the output end of the differential amplifier, and the output end thereof is connected to the non-inverting input end of the second voltage comparator, the matching circuit includes a thirty-seventh resistor, a forty-third resistor and a forty-eighth resistor, one end of the forty-third resistor is connected to the inverting input end of the second voltage comparator, and the other end thereof is connected to one end of the thirty-seventh resistor and the forty-eighth resistor, the other ends of the thirty-seventh resistor and the forty-eighth resistor are connected to the power supply VCC and the ground respectively, the output end of the second voltage comparator is connected to an input end of the second OR gate, the other input end of the second OR gate is connected to one end of the thirteenth capacitor connected to the tenth diode, and the output end of the second OR gate is used as the output end of the output detection circuit and connected to an input end of the logic gate chip.

6. The charging protection circuit according to claim 4, characterized in that: The charging protection circuit also includes a PFC overvoltage detection circuit and a PFC undervoltage detection circuit, wherein: The PFC overvoltage detection circuit comprises a second resistor voltage divider circuit, a fourth voltage stabilizer and a second photoelectric coupler, wherein the input end of the second resistor voltage divider circuit is connected to the output end of the PFC circuit, the output end of the second resistor voltage divider circuit is connected to the reference electrode of the fourth voltage stabilizer, the cathode of the light emitting diode in the second photoelectric coupler is connected to the cathode of the fourth voltage stabilizer, and the anode thereof is connected to the external power supply through a third resistor, the collector of the transistor in the second photoelectric coupler is connected to the power supply VCC through a first resistor, and serves as the output end of the PFC overvoltage detection circuit, connected to an input end of the logic gate chip, and the emitter thereof and the anode of the fourth voltage stabilizer are both grounded; The PFC undervoltage detection circuit includes a third resistor voltage divider circuit, a fifth voltage regulator, a third photoelectric coupler and a first OR gate, wherein the input end of the third resistor voltage divider circuit is connected to the output end of the PFC circuit, the output end of the third resistor voltage divider circuit is connected to the reference electrode of the fifth voltage regulator, the cathode of the light emitting diode in the third photoelectric coupler is connected to the cathode of the fifth voltage regulator, and the anode thereof is connected to the external power supply through a fourth resistor, the collector of the triode in the third photoelectric coupler is connected to the power supply VCC through a second resistor, the emitter thereof, the anode of the fifth voltage regulator and an input end of the first OR gate are all grounded, the other input end of the first OR gate is connected to one end of the thirteenth capacitor connected to the tenth diode, and the output end of the first OR gate is used as the output end of the PFC undervoltage detection circuit and connected to an input end of the logic gate chip.

7. The charging protection circuit according to claim 2, characterized in that: The charging protection circuit also includes an alarm circuit, which includes a third switch tube, a buzzer and a second optocoupler solid-state relay, wherein the third switch tube is a P-channel MOS tube, the gate of the third switch tube is connected to the anode of the thyristor, and the source of the third switch tube is connected to the negative terminal of the buzzer and the cathode of the light-emitting diode in the second optocoupler solid-state relay through a nineteenth resistor, the drain of the third switch tube is grounded, the positive terminal of the buzzer and the anode of the light-emitting diode in the second optocoupler solid-state relay are both connected to the power supply VCC, and the two ends of the transistor in the second optocoupler solid-state relay are connected to an external host computer to pull down the level of the gate of the third switch tube when the thyristor is turned on, so that the third switch tube is turned on, thereby causing the buzzer to alarm and the second optocoupler solid-state relay to send an alarm signal to the external host computer.

8. The charging protection circuit according to claim 2, characterized in that: The switch circuit also includes a first optocoupler solid-state relay, in which the anode and cathode of the light-emitting diode are respectively connected to the power supply VCC and the drain of the second switch tube, the two main terminals of the bidirectional thyristor in the first optocoupler solid-state relay are connected to the connection loop between the charging circuit and the external power supply, and the source of the second switch tube is grounded.

9. The charging protection circuit according to claim 2, characterized in that: The charging protection circuit also includes an over-temperature detection circuit, which includes a temperature control switch and a photoelectric coupler U13. The temperature control switch is placed next to the charging circuit, one end of the temperature control switch is connected to an external power supply, and the other end is connected to the anode of the light-emitting diode in the photoelectric coupler U13. The cathode of the light-emitting diode and the emitter of the transistor in the photoelectric coupler U13 are grounded, and the collector of the transistor is connected to the power supply VCC through a thirty-ninth resistor, and serves as the output end of the over-temperature detection circuit, connected to an input end of the logic gate chip.

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