High-voltage capacitive load switch control device

Abstract

The invention discloses a high-voltage capacitive load switch control device. The device is configured to comprise a first switching device; a second switching device; the current-limiting protection device is connected to two ends of the second switching device in parallel; the control signal is accessed to the first switching device for controlling the switching device to be switched on and switched off, and is accessed to the second switching device through the time delay circuit; the time delay circuit delays the accessed control signal for a preset time and then accesses the second switching device to control the switching device to be switched on and off; after a control signal is accessed to the device, the first switching device is switched on, and a power supply is accessed to the capacitive load through the first switching device and the current-limiting protection device; a control signal is connected to the time delay circuit at the same time, the time delay circuit delays a preset time and then enables the control signal to be connected with the second switching device, the current-limiting protection device is short-circuited, and the power supply is connected to the capacitive load through the first switching device and the second switching device. According to the device, capacitive load switch control is realized, and the problem of short-time large current when the capacitive load is started is effectively solved.

Description

Technical Field

[0001] The invention relates to a high-voltage capacitive load switch control device. Background Art

[0002] In the field of capacitive load control, the control is generally carried out by pre-charging or increasing the overload capacity of the control switch. The traditional pre-charging method is generally controlled by two sets of independent control switches, that is, one set of control switches pre-charges the capacitive load circuit through a current limiting resistor. When the capacitive load is charged to a certain level, the charging circuit is closed, and then another switch circuit is opened to charge the capacitive load; another method is to select a switching device with a larger overload capacity for application, and the switching device is capable of bearing the current impact when the capacitive load is switched.

[0003] The main problem of using two sets of independent control switches is that the system or equipment will be larger in size due to the need for two sets of control switches in the application, and the control process is more complicated, requiring the system to calculate and control; the main disadvantage of using the switch itself to withstand the current impact is that it is necessary to select a switch device with a larger margin for application, the product is large in size and high in cost, and is limited by capacitive loads and the consistency of switch devices, resulting in a generally short product life during application. When the capacitive load changes, it is very easy to cause the switch device to burn out. At the same time, when the capacitive load is too large, it is difficult to find a more suitable switch device. At the same time, this problem is particularly significant in high-voltage applications (above 1000V). Summary of the invention

[0004] In order to solve the technical problems existing in the prior art, the purpose of the present invention is to provide a high-voltage capacitive load switch control device, which can realize capacitive load switch control through a switching device, effectively solve the problem of short-term large current when the capacitive load is turned on, and can effectively reduce the size of the device, simplify the control method, etc.

[0005] To this end, the device is configured to include:

[0006] a first switching device;

[0007] a second switching device;

[0008] A current limiting protection device is connected in parallel to both ends of the second switch device;

[0009] Delay circuit,

[0010] The control signal is connected to the first switch device to control the switch device to be turned on or off, and is connected to the second switch device through the delay circuit; the delay circuit delays the connected control signal for a preset time and then connects to the second switch device to control the switch device to be turned on or off;

[0011] After the control signal is connected to the device, the first switch device is turned on, and the power supply is connected to the capacitive load through the first switch device and the current limiting protection device; the control signal is simultaneously connected to the delay circuit, and the delay circuit delays the control signal to the second switch device after a preset time to turn on the current limiting protection device, and the power supply is connected to the capacitive load through the first switch device and the second switch device.

[0012] In some embodiments, the device is further configured to include a driving protection circuit, and the control signal is connected to the first switching device via the driving protection circuit.

[0013] In some implementations, the control signal output by the delay circuit is connected to the second switch device via a driving protection circuit.

[0014] In some embodiments, the apparatus is further configured with a third switching device;

[0015] After the control signal is connected to the device, the first switch device and the third switch device are turned on, and the power supply is connected to the capacitive load through the first switch device, the third switch device and the current limiting protection device; the control signal is simultaneously connected to the delay circuit, and the delay circuit delays the control signal to the second switch device after a preset time, so that the current limiting protection device is short-circuited, and the power supply is connected to the capacitive load through the first switch device, the second switch device and the third switch device;

[0016] The first switch device, the second switch device and the third switch device perform multi-stage voltage boosting on the power supply to improve the withstand voltage of the device.

[0017] In some implementations, the control signal is connected to the third switch device via the driving protection circuit.

[0018] In some implementations, the control signal is simultaneously connected to the first switch device, the delay circuit, and the third switch device.

[0019] In some embodiments, the apparatus is further configured with a third switch device, wherein the second switch device is configured as a bidirectional switch device;

[0020] After the control signal is connected to the device, the first switch device or the third switch device is turned on, and the power supply is connected to the capacitive load through the first switch device and the current limiting protection device, or the power supply is connected to the capacitive load through the third switch device and the current limiting protection device; the control signal is simultaneously connected to the delay circuit, and the delay circuit delays the control signal to the second switch device after a preset time to turn on the current limiting protection device, and the power supply is connected to the capacitive load through the first switch device and the second switch device, or the power supply is connected to the capacitive load through the third switch device and the second switch device.

[0021] In some implementations, the control signal is connected to the third switch device via the driving protection circuit.

[0022] In some implementations, the control signal is simultaneously connected to the first switch device and the delay circuit.

[0023] In some embodiments, the driving and protection circuit is configured to include a diode D1, a resistor R2, a voltage-stabilizing diode D2, a resistor R3 and a transistor Q1; the diode D1, the resistor R3 and the transistor Q1 constitute a fast discharge circuit, and when the switching device is not working, they constitute a double protection for the switching device with the voltage-stabilizing diode D2, perform overvoltage protection, and prevent external interference from causing the voltage at the control terminal of the switching device to increase and cause misconduction; the voltage-stabilizing diode D2 provides overvoltage protection for the switching device when the switching device is working or not working.

[0024] The device is configured with a first switching device and a second switching device. The power state change of the capacitive load is realized by turning on and off the second switching device. When the second switching device is disconnected, the power connected to the capacitive load is limited by the current limiting protection device and is not in a full current access state; when the second switching device is connected, the current limiting protection device is short-circuited and the power connected to the capacitive load is in a full current state.

[0025] The technical effects that can be achieved by adopting this technical solution include at least:

[0026] 1) The device realizes capacitive load switch control through a switch (second switch device), effectively solving the problem of short-term high current when the capacitive load is turned on; and the configuration of a switch effectively reduces the size of the device.

[0027] 2) The device realizes delayed turning on of the second switch device through a delay circuit, which simplifies the control method and eliminates the need for a complex control mode.

[0028] 3) The configuration of multi-stage switching devices in the device improves the voltage resistance of the device and can realize the switch control function of high-voltage capacitive loads above 3000V.

[0029] 4) The device is configured with a first switching device to a third switching device, and the second switching device is a bidirectional switching device, thereby realizing bidirectional power supply. The power supply can be connected from the first switching device or the third switching device, which effectively solves the problem of the device being unusable due to incorrect power polarity connection, and has better practicality.

[0030] 5) The control signals of the device are simultaneously connected to the target devices / circuits, ensuring the synchronization of control. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings herein are incorporated into and constitute a part of the specification, showing embodiments consistent with the present invention, and together with the specification, are used to explain the principles of the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0032] Figure 1 A single-stage circuit structure diagram of the control device provided by the present invention;

[0033] Figure 2 A multi-stage circuit structure diagram of a control device provided by the present invention;

[0034] Figure 3 A bidirectional circuit structure diagram of a control device provided by the present invention;

[0035] Figure 4 A circuit structure diagram of the delay circuit described in the present invention;

[0036] Figure 5 This is a circuit structure diagram of the driving and protection circuit described in the present invention. DETAILED DESCRIPTION

[0037] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that the invention will be more comprehensive and complete and fully convey the concept of the example embodiments to those skilled in the art.

[0038] This device uses a switching device (such as MOSFET or IGBT or thyristor, etc.) in parallel with a current limiting resistor to form a controlled current limiting switch. The controlled current limiting circuit is composed of a control circuit, an isolation device, a delay circuit, and a drive protection circuit. When the device is working, the main switch circuit is turned on, and current limiting charging is performed through the series controlled current limiting circuit. After the delay circuit, it is converted to normal charging, which effectively solves the problem of short-term high current when the capacitive load is turned on, and realizes the functions of reducing the size of the device and simplifying the control.

[0039] At the same time, by adding a stage of series switch, the high-voltage capacitive load switch control function above 3000V can be realized.

[0040] This device includes the following structures:

[0041] Embodiment 1

[0042] The high voltage capacitive load switch control device of this embodiment is a single-stage structure. Figure 1As shown, the control circuit is connected to a first isolated driver device 1 and a second isolated driver device 2; the first isolated driver 1 is directly connected to the first switch device 3 or to the drive protection circuit 4, and then to the first switch device 4 (high-voltage MOSFET or IGBT or thyristor); the second isolated driver device 2 is connected to the delay circuit 5, and then to the second switch device 6, or the second isolated driver device 2 is connected to the drive protection circuit 4 via the delay circuit 6, and then to the second switch device 6 (high-voltage MOSFET or IGBT or thyristor); the drain and source of the second switch device 2 are respectively connected to the current limiting protection resistor R (taking MOSFET as an example).

[0043] When the device is working, the first switch device 3 is turned on first. At this time, the second switch device 6 is in the off state due to the influence of the delay circuit 5. At this time, the current limiting protection resistor R becomes the capacitive load charging limiting resistor, realizing the current limiting charging function; when the delay ends, the second switch device 6 is turned on, bypassing the current limiting protection resistor, and realizing full current charging. In this way, the capacitive load is first charged with current limiting, reducing the problem of excessive impact current in the initial stage.

[0044] The control signal is connected to the control circuit, and the control circuit is connected in series with the input side of the first isolation device 1 and the second isolation device 2 to achieve synchronization of the control circuit; or the control circuit is directly connected in series with the input side of the first switch device 2 and the delay circuit 5 to achieve synchronization of the control side. The output ends of the first switch device 3 and the second switch device 6 are connected in series (the current limiting protection resistor is connected in parallel with the output end of the second switch device 6). Due to the effect of the delay circuit 5, when the device is turned on, the current flows from the first switch device 3 through the current limiting protection resistor R to charge the capacitive load with limited current. When the delay ends, since the second switch device 6 is turned on, the current passes through the first switch device 3 and then directly through the second switch device 6 to charge the capacitive load, thereby achieving full current charging.

[0045] Embodiment 2

[0046] The high voltage capacitive load switch control device of this embodiment is a bidirectional structure. Figure 2 As shown, the structure adds a third isolation device 7 and a third switch device 8 on the basis of all the technical features of the first embodiment, and replaces the second switch device 6 with a bidirectional switch device (which can be a MOSFET, an IGBT in reverse series, or a unidirectional thyristor in anti-parallel, or a bidirectional thyristor), and the output end of the third switch device 8 is reversely connected in series with the second switch device 6 to achieve a bidirectional output.

[0047] The control circuit is connected in series with the input side of the first isolation device 1, the second isolation device 2 and the third isolation device 7 to achieve synchronization of the control circuit; or the control circuit is directly connected in series with the input side of the first switch device 3, the delay circuit 5 and the third switch device 8 to achieve control side synchronization.

[0048] The output side of the first isolation device 1 is connected to the driving and protection circuit 4 of the first switching device 3, and then to the first switching device 3; or the output side of the first isolation device 1 is directly connected to the first switching device 3 to realize the on / off control of the first switching device 3.

[0049] The output side of the second isolation device 6 is connected to the delay circuit 5 to achieve the delay effect on the control signal, thereby controlling the turn-on time of the second switch device 6 to achieve the control of the current limiting charging time; the output side of the delay circuit 5 is directly connected to the second switch device 6, or connected to the driving protection circuit 4 of the second switch device 6, and then connected to the second switch device 6 (bidirectional switch device), and the high-voltage current limiting protection resistor R is connected in parallel at both ends of the output of the bidirectional switch device.

[0050] The output side of the third isolation device 7 is connected to the driving protection circuit 4 of the third switch device 8, and then connected to the third switch device 8; or the output side of the third isolation device 7 is directly connected to the third switch device 8. Due to the bidirectional mode, the output side wiring of the third switch device 8 is opposite to the first switch device 3, wherein the isolation device side of the third switch device 8 and the driving and protection circuit should be connected in coordination with the third switch device 8.

[0051] In this embodiment, the output ends of the first switch device 3, the bidirectional switch device and the third switch device 8 are connected in series (the current limiting protection resistor is connected in parallel with the output end of the bidirectional switch device). Due to the effect of the delay circuit 5, when the device is turned on, the current flows from the first and third switch devices or the third and first switch devices (described here as: the current flows from the first switch device to the third switch device, or from the third switch device to the first switch device) through the current limiting protection resistor R to charge the capacitive load with limited current. When the delay ends, since the bidirectional switch device is turned on, the current passes through the first and third switch devices or the third and first switch devices and then directly passes through the bidirectional switch device to charge the capacitive load, thereby realizing full current charging.

[0052] Embodiment 3

[0053] The high voltage capacitive load switch control device of this embodiment is a multi-stage structure, such as Figure 3 As shown, the structure includes all the technical features of the first embodiment, and adds a third isolation device 7 and a third switch device 8; the third switch device 8 is connected in series with the circuit in the same way as the first switch device 3 to improve the withstand voltage of the device. If the switch device uses a 1700V high-voltage device, the third switch device is connected in series, so the maximum withstand voltage drop of the device is increased to 3400V. Similarly, this method can be used to continue to improve the withstand voltage of the device, not limited to 2-stage series connection, and the same method can be used to continue to connect the third stage or more stages.

[0054] The control circuit of the device of this embodiment is connected in series with the input side of the first isolation device 1, the second isolation device 2 and the third isolation device 7 to achieve synchronization of the control circuit; or the control circuit is directly connected in series with the input side of the first switching device 2, the delay circuit 5 and the third switching device 8 to achieve synchronization of the control side.

[0055] The output side of the second isolation device 2 is connected to the delay circuit 5 to achieve the delay effect on the control signal, thereby controlling the turn-on time of the second switch device 6 to achieve the control of the current limiting charging time. The delay circuit 5 is then connected to the driving protection circuit 4 of the second switch device 6, and then connected to the second switch device 6; or the output side of the second isolation device 2 is connected to the delay circuit 5, and the delay circuit 5 is directly connected to the second switch device 6; the output ends of the second switch device 6 are connected in parallel with a high-voltage current limiting protection resistor R.

[0056] The output side of the third isolation device 8 is connected to the driving protection circuit 4 of the third switch device 8 and then connected to the third switch device 8 , or the output side of the third isolation device 8 is directly connected to the third switch device 8 .

[0057] In this embodiment, the output ends of the first switch device 3, the second switch device 6 and the third switch device 8 are connected in series (the current limiting protection resistor R is connected in parallel with the output end of the second switch device 6). Due to the effect of the delay circuit 5, when the device is turned on, the current flows from the first switch device 3 through the current limiting protection resistor R and then through the third switch device 8 to charge the capacitive load with limited current; when the delay ends, since the second switch device 6 is turned on, the current flows through the first switch device 3 directly through the second switch device 6 and then through the third switch device 8 to charge the capacitive load, thereby realizing full current charging.

[0058] The delay circuit 5 described in the present disclosure may be configured as a 555 timer or as Figure 4 The RC circuit shown can adjust the delay time by adjusting the parameters of the resistor R1 and the capacitor C1 to achieve the desired delay time, and the separation components have strong anti-interference and stability.

[0059] Please refer to Figure 5, the driving protection circuit described in the present disclosure is configured to include a resistor R2 and a Zener diode D2, the control signal is connected to the switching device through the resistor R2, the Zener diode D2 is connected between the gate and the source of the switching device, or the Zener diode D2 is connected between the gate and the drain of the switching device; the Zener diode D2 protects the switching device from overvoltage when the device is working and not working. On this basis, the driving protection circuit is also configured to include a resistor R3, a diode D1 and a transistor Q1, and R3, D1 and Q1 form a fast discharge circuit. When the device is not working, the fast discharge circuit forms a dual protection effect with the Zener diode D2 to protect the switching device from overvoltage; wherein the fast discharge circuit can also prevent the gate voltage of the switching device from increasing due to external interference when the device is not working, resulting in misleading conduction.

[0060] The device can also be extended to low-voltage capacitive load applications by simply replacing the switch device with a low-voltage switch device.

[0061] When the capacitive load is connected, the device controls the charging current through the internally set delay time. After the delay ends, full current charging is performed, which can effectively prevent the problem of instantaneous high current when the capacitive load is connected. At the same time, through internal integration, the product can be miniaturized, the dependence on devices can be reduced, and the reliability and life of the devices can be improved. Moreover, the device can realize functions such as voltage doubling and bidirectional control according to the series connection method, which has good practicality.

[0062] In addition, the device has a simple circuit form and an obvious protective effect; it can realize capacitive load switch control applications above 1000V, or even above 4000V; because the impact of capacitive load current is reduced, excessive reliance on switching devices is reduced, and control functions can be achieved in a smaller volume; the volume and cost of such products are further reduced, thereby reducing the weight, volume, and cost of equipment and devices.

[0063] The present disclosure has been described by the above-mentioned relevant embodiments, but the above-mentioned embodiments are only examples for implementing the present disclosure. It must be pointed out that the disclosed embodiments do not limit the scope of the present disclosure. On the contrary, changes and modifications made without departing from the spirit and scope of the present disclosure are all within the scope of patent protection of the present disclosure.

Claims

1. A high voltage capacitive load switch control device, characterized in that: The device is configured to include: a first switching device; a second switching device; A current limiting protection device is connected in parallel to both ends of the second switch device; Delay circuit, The control signal is connected to the first switch device to control the switch device to be turned on or off, and is connected to the second switch device through the delay circuit; the delay circuit delays the connected control signal for a preset time and then connects to the second switch device to control the switch device to be turned on or off; After the control signal is connected to the device, the first switch device is turned on, and the power supply is connected to the capacitive load through the first switch device and the current limiting protection device; the control signal is simultaneously connected to the delay circuit, and the delay circuit delays the control signal to the second switch device after a preset time to turn on the current limiting protection device, and the power supply is connected to the capacitive load through the first switch device and the second switch device.

2. The high voltage capacitive load switch control device according to claim 1, characterized in that: The device is also configured to include a driving protection circuit, and the control signal is connected to the first switching device via the driving protection circuit.

3. The high voltage capacitive load switch control device according to claim 2, characterized in that: The control signal output by the delay circuit is connected to the second switch device via the driving protection circuit.

4. The high voltage capacitive load switch control device according to any one of claims 1 to 3, characterized in that: The apparatus is also configured with a third switching device; After the control signal is connected to the device, the first switch device and the third switch device are turned on, and the power supply is connected to the capacitive load through the first switch device, the third switch device and the current limiting protection device; the control signal is simultaneously connected to the delay circuit, and the delay circuit turns on the control signal second switch device after a preset time, the current limiting protection device is short-circuited, and the power supply is connected to the capacitive load through the first switch device, the second switch device and the third switch device; the first switch device, the second switch device and the third switch device perform multi-stage voltage boosting on the power supply to improve the voltage resistance of the device.

5. The high voltage capacitive load switch control device according to claim 4, characterized in that: The control signal is connected to the third switch device via the driving protection circuit.

6. The high voltage capacitive load switch control device according to claim 4, characterized in that: The control signal is respectively connected to the first switch device, the delay circuit and the third switch device at the same time.

7. The high voltage capacitive load switch control device according to any one of claims 1 to 3, characterized in that: The apparatus is also configured with a third switch device, the second switch device being configured as a bidirectional switch device; After the control signal is connected to the device, the first switch device or the third switch device is turned on, and the power supply is connected to the capacitive load through the first switch device and the current limiting protection device, or the power supply is connected to the capacitive load through the third switch device and the current limiting protection device; the control signal is simultaneously connected to the delay circuit, and the delay circuit delays the control signal to the second switch device after a preset time to turn on the current limiting protection device, and the power supply is connected to the capacitive load through the first switch device and the second switch device, or the power supply is connected to the capacitive load through the third switch device and the second switch device.

8. The high voltage capacitive load switch control device according to claim 7, characterized in that: The control signal is connected to the third switch device via the driving protection circuit.

9. The high voltage capacitive load switch control device according to claim 1, characterized in that: The control signal is respectively connected to the first switch device and the delay circuit at the same time.

10. The high voltage capacitive load switch control device according to claim 2 or 3 or 5 or 8, characterized in that: The driving and protection circuit is configured to include a diode D1, a resistor R2, a voltage-stabilizing diode D2, a resistor R3 and a transistor Q1; the diode D1, the resistor R3 and the transistor Q1 form a fast discharge circuit, and when the switching device is not working, they form a double protection for the switching device with the voltage-stabilizing diode D2, perform overvoltage protection, and prevent external interference from causing the voltage at the control end of the switching device to increase and cause misconduction; the voltage-stabilizing diode D2 provides overvoltage protection for the switching device when the switching device is working or not working.

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