Patent Publication Number: US-10784770-B2

Title: Conversion circuit

Description:
RELATED APPLICATIONS 
     This application is a Continuation-in-part of U.S. application Ser. No. 16/234,598, filed on Dec. 28, 2018, which claims priority of U.S. Provisional Application Ser. No. 62/628,692, filed on Feb. 9, 2018, and is also a Continuation-in-part of U.S. application Ser. No. 16/547,561, filed on Aug. 21, 2019, the entirety of which is incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates to a power supply device, and in particular, to a conversion circuit in the power supply device. 
     Description of Related Art 
     For existing conversion circuit for the power converters, the supplying voltage is designed in response to the rated voltage of the semiconductor device to be driven. Therefore, one or more additional voltage regulators are required to regulate the system supplying power to meet the voltage requirement of the conversion circuit and the semiconductor device. 
     SUMMARY 
     One aspect of the present disclosure is a conversion circuit. The conversion circuit includes a main device, a trigger circuit and a voltage control switching circuit. The main device includes a control terminal. The trigger circuit includes an output terminal and a sense terminal. The sense terminal of the trigger circuit is electrically connected to the control terminal of the main device. The voltage control switching circuit includes a first terminal, a second terminal and a control terminal. The first terminal is configured to receive an original signal. The second terminal is connected to the control terminal of the main device, and is configured to transmit a driving signal to drive the main device. The control terminal is connected to the second terminal of the main device and the output terminal of the trigger circuit. The driving signal has a first voltage level generated by the voltage control switching circuit in response to a voltage level at the control terminal of the voltage control switching circuit. 
     It is to be understood that both the foregoing general description and the following detailed description are by examples, and are intended to provide further explanation of the disclosure as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure can be more fully understood by reading the following detailed description of the embodiment, with reference made to the accompanying drawings as follows: 
         FIG. 1  is a schematic diagram of a conversion circuit in some embodiments of the present disclosure. 
         FIG. 2  is a voltage waveform diagram of the control terminal of main device in some embodiments of the present disclosure. 
         FIG. 3A  is a schematic diagram of a conversion circuit in some embodiments of the present disclosure. 
         FIG. 3B  is a schematic diagram of a conversion circuit in some embodiments of the present disclosure. 
         FIG. 4A  is a schematic diagram of a conversion circuit in some embodiments of the present disclosure. 
         FIG. 4B  is a schematic diagram of a conversion circuit in some embodiments of the present disclosure. 
         FIG. 4C  is a schematic diagram of a conversion circuit in some embodiments of the present disclosure. 
         FIG. 5A - FIG. 5B  are diagrams illustrating integration of the voltage control switching circuit, the main device and a trigger circuit according to some embodiments of the present disclosure. 
         FIG. 6A  and  FIG. 6B  are diagrams illustrating integration of the driving signal generator and the voltage control switching circuit according to some embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     For the embodiment below is described in detail with the accompanying drawings, embodiments are not provided to limit the scope of the present disclosure. Moreover, the operation of the described structure is not for limiting the order of implementation. Any device with equivalent functions that is produced from a structure formed by a recombination of elements is all covered by the scope of the present disclosure. Drawings are for the purpose of illustration only, and not plotted in accordance with the original size. 
     It will be understood that when an element is referred to as being “connected to” or “coupled to”, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element to another element is referred to as being “directly connected” or “directly coupled,” there are no intervening elements present. As used herein, the term “and/or” includes an associated listed items or any and all combinations of more. 
     Reference is made to  FIG. 1 .  FIG. 1  is a diagram illustrating a conversion circuit  100  according to some embodiments of the present disclosure. As shown in  FIG. 1 , the conversion circuit  100  includes a voltage control switching circuit  140 , a main device  160  and a trigger circuit  180 . 
     In structural, the main device  160  includes a first terminal  160   a , a second terminal  160   b  and a control terminal  160   c . The second terminal  160   b  is electrically connected to a reference terminal Nr. The control terminal  160   c  is configured to receive a driving signal S 1 , so that the main device  160  is driven in response to a first voltage level of the driving signal S 1 . The main device  160  operates in a first state (e.g., a normal working state) and is configured to perform power switching. In various embodiments of the present disclosure, the main device  160  may be the power switching element applied in various switching power supply devices, such as a buck converter, a boost converter, a buck-boost converter or any other devices having power switches. For example, the main device  160  may include a Gallium Nitride (GaN) switching device, a MOSFET switching device, an Insulated Gate Bipolar Transistor (IGBT) switching device, a bipolar junction transistor (BJT) switching device, a Silicon Carbide (SIC) switching device, a relay switching device, or any combination thereof. 
     The voltage control switching circuit  140  is electrically connected to the main device  160  so as to provide the driving signal S 1  to the main device  160 . In some embodiments, the voltage control switching circuit  140  includes a first terminal  140   a , a second terminal  140   b  and a control terminal  140   c . The first terminal  140   a  is configured to receive a original signal S 0 . The second terminal  140   b  is connected to the control terminal  160   c  of the main device  160 , and is configured to transmit a driving signal to drive the main device according to the original signal S 0 . The control terminal  140   c  is connected to the second terminal  140   b . The driving signal has a first voltage level generated by the voltage control switching circuit  140 . 
     In some embodiments, the conversion circuit  100  further includes a driving signal generator  120  to generate the original signal S 0 . The driving signal generator  120  is electrically connected to the first terminal  140   a  of the voltage control switching circuit  140 . The driving signal generator  120  includes a logic circuit  122  and a driver buffer  124 , and is configured to receive an input voltage VDD from a voltage source and generate the original signal S 0 . Details will be explained in the following paragraphs. 
     The trigger circuit  180  is configured to modify the voltage level at the control terminal  140   c , so that the voltage level of the driving signal S 1  (i.e., the voltage level of the control terminal  160   c ) is changed accordingly. For example, the voltage level of the driving signal S 1  is temporarily decreased from the first voltage level to the second voltage level. 
     In some embodiments, the trigger circuit  180  is electrically connected between the control terminal  160   c  and the control terminal  140   c . The trigger circuit  180  includes an output terminal  180   a  and a sense terminal  180   b . The output terminal  180   a  of the trigger circuit  180  is electrically connected to the control terminal  140   c  of the voltage control switching circuit  140 , and the sense terminal  180   b  of the trigger circuit  180  is electrically connected to the control terminal  160   c  of the main device  160 . 
     In some embodiments, when the main device  160  is configured to perform power switching according to the driving signal S 1  is having the first voltage level, the trigger circuit  180  is configured to turn on in response to a voltage level of the control terminal  160   c , to modify a voltage level at the control terminal  140   c , so that the voltage control switching circuit  140  is configured to output the driving signal S 1  having a second voltage level. The second voltage level is less than the first voltage level. 
     Accordingly, at the moment when the main device  160  is turned on in response to the driving signal S 1 , the trigger circuit  180  may turn on in response to the voltage level of the control terminal  160   c  so as to pull low the voltage level at the control terminal  140   c . At this time, the voltage control switching circuit  140  may decrease the voltage level of the driving signal S 1  (e.g., from first voltage level to the second voltage level). Therefore, the main device  160  may perform power switching in a second state, and be protected from damage due to abnormal states (e.g., the abnormal large voltage or the large current). In summary, the trigger circuit  180  causes the voltage level of the driving signal S 1  to have a “two-stage” change. Thus, in the present disclosure, the main device  160  is prevented from being damaged by abnormal states such as gate voltage spike without affecting the driving speed of the main device  160 . 
     In some embodiments, the trigger circuit  180  includes a first capacitance C 1 , a first switching unit T 1  and a first resistance R 1 . The first capacitance C 1  is electrically connected to the control terminal  160   c  of the main device  160 . The first switching unit T 1  is electrically between the control terminal  140   c  of the voltage control switching circuit  140  and a reference terminal Nr (e.g., ground), and a control terminal of the first switching unit T 1  is electrically connected to the first capacitance C 1 . 
     Referring to the  FIG. 2 ,  FIG. 2  is a waveform diagram of the voltage level change at the control terminal  160   c . The horizontal axis represents the voltage value between the first resistor R 1  and the first capacitor, and the vertical axis represents the voltage value of control terminal  160   c . When the main device  160  is turned on in response to the first voltage level of the driving signal S 1 , the first capacitor begins to be charged, and the control terminal of the first switching unit T 1  conducts to the control terminal  160   c . In a first charging period P 1 , when the voltage level between the first resistor R 1  and the first capacitance C 1  reaches to the threshold voltage of the first switching unit T 1 , the first switching unit T 1  will be turned on according to the voltage level of the control terminal  160   c . At this time, since the control terminal  140   c  is pulled low to the reference terminal Nr, the voltage level of the driving signal S 1  outputted by the voltage control switching circuit  140  may be controlled into the second voltage level V 2 . 
     After a second charging period P 2 , the capacitor C 1  is fully charged, the first switching unit T 1  is turned off. At this time, the control terminal  140   c  returns to a predetermined level, and the voltage level of the driving signal S 1  outputted by the voltage control switching circuit  140  may be controlled into the first voltage level V 1 . Through the foregoing features, the problem that the main device  160  is damaged due to the voltage spike of the driving signal S 1  can be avoided when the voltage control switching circuit  140  is beginning to output the signal S 1  having the first voltage level V 1 . The length of time of the first charging period P 1  and the second charging period P 2  depends on the first capacitance R 1  and the first resistance C 1 . 
     The driving signal S 1  is generated by the voltage control switching circuit  140  in response to the voltage level at the control terminal  140   c  of the voltage control switching circuit  140 . The voltage control switching circuit  140  can use a variety of circuit structures. In some embodiments, the voltage control switching circuit  140  includes a voltage control switch  141 . The a voltage control switch  141  includes a drain terminal, a source terminal and a gate terminal. The drain terminal is coupled to the first terminal  140   a  of the voltage control switching circuit  140 . The source terminal is coupled to the second terminal  140   b  of the voltage control switching circuit  140 . The gate terminal is coupled to the control terminal  140   c  of the voltage control switching circuit  140 . 
     The voltage control switching circuit  140  is normally-on in response to a zero gate-source voltage at the control terminal  140   c . The voltage control switch  141  may include a depletion type metal-oxide-semiconductor field-effect transistor (MOSFET) switching device to achieve the normally-on operation in response to the zero gate-source voltage at the reference terminal, but the present disclosure is not limited thereto. In some other embodiments, the voltage control switch  141  may include other suitable semiconductor devices having similar channel current to gate voltage characteristics to achieve the voltage control switch  141 . Alternatively stated, the voltage control switch  141  may include a depletion type MOSFET switching device, an enhancement type MOSFET switching device, or any combination thereof. 
     In some embodiments, the voltage control switching circuit  140  further includes a clamping circuit  142 . A first terminal  142   a  of the clamping circuit  142  is electrically connected to the gate terminal of the voltage control switch  140 . A second terminal  142   c  of the clamping circuit  142  is electrically connected to a reference terminal Nr. A voltage across the first terminal  142   a  and the second terminal  142   b  of the clamping circuit  142  is clamped to a predetermined level. In some embodiments, the clamping circuit  142  comprises at least two Zener diodes Da, Db connected in series. The control terminal  140   c  is between two Zener diodes Da, Db. The threshold voltage of the voltage control switching circuit  140  is negative, and the voltage control switching circuit  140  is configured to be off on the condition that the gate-source voltage is smaller than the negative threshold voltage Vth. In some embodiments, the threshold voltage is the threshold voltage of the MOSFET switching device. For example, in some embodiments, the threshold voltage of the normally-on device is between −0.1 volts and −20 volts. 
     Accordingly, the voltage level of the driving signal S 1  will be clamped by the voltage control switching circuit  140  in response to the threshold voltage of the voltage control switching circuit  140  on the condition that the voltage level of the original signal S 0  is higher than a specific value. Alternatively stated, the voltage level of the original signal S 0  is higher than the voltage level of the driving signal S 1  since the voltage level of the driving signal S 1  is clamped by the voltage control switching circuit  140 . 
     Reference is made to  FIG. 3A  and  FIG. 3B .  FIG. 3A  and  FIG. 3B  are diagrams illustrating the voltage control switching circuit according to some other embodiments of the present disclosure. With respect to the embodiments of  FIG. 3A  and  FIG. 3B , like elements in  FIG. 1  are designated with the same reference numbers for ease of understanding. The specific operations of similar elements, which are already discussed in detail in the above paragraphs, are omitted herein for the sake of brevity, unless there is a need to introduce the co-operation relationship with the elements shown in  FIG. 3A  and  FIG. 3B . 
     In some other embodiments, referring the  FIG. 3A , the voltage control switching circuit  240  includes a first terminal  240   a , a second terminal  240   b  and a control terminal  240   c , and the voltage control switching circuit  240  further includes a clamping circuit. The clamping circuit includes multiple clamping unit D 1 , D 2  connected in series, and the trigger circuit  180  is electrically connected to the control terminal  240   c  (i.e., a node between two of the clamping unit D 1 , D 2 ). In some alternative embodiments, the clamping unit D 1 , D 2  can be implemented by diodes or Zener diodes. In some other embodiments, the clamping circuit may be realized by multiple MOSFETs electrically coupled to each other. The gate terminal of one of the MOSFETs is electrically coupled to the source terminal or the drain terminal of another one of the MOSFETs. The number of the diode units or the MOSFETs may be adjusted according to actual needs and thus the present disclosure is not limited to examples shown in  FIG. 3A . The original signal S 0  is clamped by the clamping circuit of the voltage control switching circuit  240 , and forms the driving signal S 1 . When the trigger circuit  180  is turned on, the control terminal  160   c  conducts to the reference terminal Nr, so the voltage level of the driving signal S 1  will change accordingly. 
     In some other embodiments, referring the  FIG. 3B , the voltage control switching circuit  340  includes a first terminal  340   a , a second terminal  340   b  and a control terminal  340   c , and the voltage control switching circuit  340  further includes a buffer  341  and a regulator circuit  342 . The buffer  341  is electrically connected to the control terminal  160   c . The regulator circuit  342  is electrically connected to the buffer  341 . A control terminal of the regulator circuit  342  as the control terminal  340   c  of the voltage control switching circuit  340 , and is electrically connected to the trigger circuit  180 . The regulator circuit  342  is output a control voltage Sc to a positive control terminal of the buffer  341  to control the voltage level of the driving signal S 1  outputted by the buffer  341 . When the trigger circuit  180  is turned on, the control terminal of the regulator circuit  342  conducts to the reference Nr, so the voltage level of the control terminal of the regulator circuit  342  is decreased. At this time, the voltage level of the control voltage Sc is modified in response to a voltage level of the control terminal of the regulator circuit  342 . Since the person in the art can understand the operation of the regulator circuit  342 , it is not explained here. 
     In addition, referring to  FIG. 1 , in some embodiments, the driving signal generator  120  includes a logic circuit  122  and a driver buffer  124 , and is configured to receive an input voltage VDD from a voltage source and generate an original signal S 0 . Specifically, the input voltage VDD is provided to the logic circuit  122  and the driver buffer  124  to supply the required power. In some embodiments, the logic circuit  122  is configured to generate the original signal S 0  according to a pulse-width modulation (PWM) signal PWM. 
     For example, as shown in  FIG. 1 , the logic circuit  122  may include a Schmitt trigger ST 1 , an Under-Voltage Lockout (UVLO) circuit UVLO 1 , and an AND gate AND 1 . The Schmitt trigger is ST 1  configured to receive the pulse-width modulation (PWM) signal PWM, and output a signal DSx, in which the value of the signal DSx retains the value until the pulse-width modulation signal PWM at the input terminal changes sufficiently to trigger a change. 
     The Under-Voltage Lockout (UVLO) circuit UVLO 1  is configured to monitor the input voltage VDD and provide a protection signal PS 1  on the condition that under voltage occurs. The AND gate AND 1  is coupled to the Schmitt trigger ST 1 , and the Under-Voltage Lockout (UVLO) circuit UVLO 1  at the input side, and perform an AND operation correspondingly to output the original signal S 0  in response to the received signals. The original signal S 0  is transmitted to the driver buffer  124  coupled to the logic circuit  122 , and the driver buffer  124  is configured to output the original signal S 0  via an output terminal. However, the structure of the driving signal generator  120  is not limited to this. 
     In the foregoing embodiment, the trigger circuit  180  is turned on in response to a voltage level of the control terminal  160   c . However, in some other embodiments, the trigger circuit  180  may turn on in response to a voltage level of other terminals of the main device  160 . Reference is made to  FIG. 4A .  FIG. 4A  is a diagram illustrating a conversion circuit  100  according to some embodiments of the present disclosure. With respect to the embodiments of  FIG. 4A , like elements in  FIG. 1  are designated with the same reference numbers for ease of understanding. The specific operations of similar elements, which are already discussed in detail in above paragraphs, are omitted herein for the sake of brevity, unless there is a need to introduce the co-operation relationship with the elements shown in  FIG. 4A . 
     As shown in  FIG. 4A , in structural, the conversion circuit  100  includes the driving signal generator  120 , the main device  160 , the voltage control switching circuit  140  and a trigger circuit  280 . The trigger circuit  280  is electrically connected between the first terminal  160   a  of the main device  160  and the control terminal  140   c  of the voltage control switching circuit  140 . In some other embodiments, the trigger circuit  280  includes an output terminal  280   a  and a sense terminal  280   b . The output terminal  280   a  of the trigger circuit  280  is electrically connected to the control terminal  140   c  of the voltage control switching circuit  140 , and the sense terminal  280   b  of the trigger circuit  180  is electrically connected to the first terminal  160   a  of the main device  160 . 
     When the main device  160  operates in the first state, and the first terminal  160   a  has a predetermined voltage level, the voltage control switching circuit  140  is configured to output the driving signal S 1  having a first voltage level to the main device  160 . The main device is configured to perform power switching according to the first voltage level of the driving signal S 1 . On the other hand, when the first terminal  160   a  of the main device  160  has an operation voltage level different from the predetermined voltage level, for example, the operation voltage level is much larger than the predetermined voltage level, or a large current through the main device  160 , at this time, the trigger circuit  280  is configured to turn on in response to the operation voltage level of the first terminal  160   a , to modify a voltage level at the control terminal  140   c  so that the voltage control switching circuit  140  is configured to output the driving signal S 1  having a second voltage level, the second voltage level is less than the first voltage level. 
     Accordingly, in the situation that the main device  160  operates in the first state and performs power switching, if there is a large current, which exceeding a preset range, through the main device  160 , the trigger circuit  280  may turn on in response to the voltage level of the first terminal  160   a  so as to pull low the voltage level at the control terminal  140   c . At this time, the voltage control switching circuit  140  may decrease the voltage level of the driving signal S 1  (e.g., from first voltage level to the second voltage level). Therefore, the main device  160  may perform power switching in a second state, and be protected from damage due to the gate voltage spike or the abnormal large current. Same as the previous embodiment, the trigger circuit  280  causes the voltage level of the driving signal S 1  to have a “two-stage” change. That is, the voltage level of the driving signal S 1  maintains to the second voltage level until the first terminal  160   a  return to the predetermined voltage level and the trigger circuit  280  is turned off accordingly. 
     Referring to the  FIG. 4A , in some embodiments, the trigger circuit  280  includes a second switching unit T 2 , a third switching unit T 3 , and a second resistance R 2 . The second switching unit T 2  is electrically connected between the first terminal  160   a  and the reference terminal Nr. A control terminal of the second switching unit T 2  is electrically connected to the second terminal  140   b . The third switching unit T 3  is electrically connected between the control terminal of the voltage control switching circuit  140   c  and the reference terminal Nr. A control terminal of the third switching unit T 3  is electrically connected to the second switching unit T 2 . In some embodiments, the second switching unit T 2  is further electrically connected to the reference terminal Nr through the second resistance R 2 . The control terminal of the third switching unit T 3  is further electrically connected to the reference terminal Nr through the second resistance R 2 . 
     Since the voltage across the second switching unit T 2  is same as the main device  160 , the main device  160  and the second switching unit T 2  may turn on and turn off synchronously. When the first terminal  160   a  has an operation voltage level different from the predetermined voltage level, the third switching unit T 3  may turn on to decrease the voltage level of the control terminal  140   c  of the voltage control switching circuit  140 . Then, the voltage level of the driving signal S 1  may be modified to the second voltage level, and the main device  160  is protected from damage due to the large current. 
     With respect to the embodiments of  FIG. 4B-4C , like elements in  FIG. 1  are designated with the same reference numbers for ease of understanding. The specific operations of similar elements, which are already discussed in detail in above paragraphs, are omitted herein for the sake of brevity, unless there is a need to introduce the co-operation relationship with the elements shown in  FIG. 4B-4C . Referring to  FIG. 4B , in other some embodiments, the voltage control switching circuit  240  includes a first terminal  240   a , a second terminal  240   b  and a control terminal  240   c . The trigger circuit  380  includes an output terminal  380   a  and a sense terminal  380   b . The output terminal  380   a  of the trigger circuit  380  is electrically connected to the control terminal  240   c  of the voltage control switching circuit  240 , and the sense terminal  380   b  of the trigger circuit  380  is electrically connected to the first terminal  160   a  of the main device  160 . 
     The trigger circuit  380  includes a rectifier T 4 . The rectifier T 4  is electrically connected between the first terminal  160   a  of the main device  160  and the control terminal  240   c  of the voltage control switching circuit  240 . When a voltage across the rectifier T 4  is larger than a forward voltage, the rectifier T 4  is configured to turn on. For example, in the situation that the main device  160  is inverse turned on, if the current through the main device  160  become larger so as to the first terminal  160   a  has an operation voltage level different from the predetermined voltage level, the rectifier T 4  may turn on to modify (e.g., decrease) the voltage level of the control terminal  240   c . The rectifier T 4  may be a diode, a rectifying element or a single throw switch, but not limited to this. 
     Referring to  FIG. 4C , the trigger circuit  380  can be applied to the mentioned voltage control switching circuit  340 . The voltage control switching circuit  340  includes a first terminal  340   a , a second terminal  340   b  and a control terminal  340   c . Similarly, in the embodiments shown in  FIGS. 4A-4C , the trigger circuit  280 ,  380  can be applied to the voltage control switching circuit  140 , the voltage control switching circuit  240  or the voltage control switching circuit  340 . Alternatively stated, the voltage control switching circuit  140  shown in  FIG. 4A  (or the voltage control switching circuit  240 ,  340  as shown in  FIG. 4B-4C ) is merely one example of various embodiments of the present disclosure and not meant to limit the circuit structure of the voltage control switching circuit. The voltage control switching circuit in the conversion circuit can be implemented by the other circuit structure, such as the voltage control switching circuit  140 ,  240 ,  340  shown in  FIG. 4A - FIG. 4C . 
     Reference is made to  FIG. 5A - FIG. 5B .  FIG. 5A - FIG. 5B  are diagrams illustrating integration of the voltage control switching circuit  140 , the main device  160  and the trigger circuit  180  according to some embodiments of the present disclosure. 
     Corresponding to the embodiments shown in  FIG. 1 , as shown in  FIG. 7A , in some embodiments, the normally-on voltage control switch  141 , the main device  160  and the trigger circuit  180  are integrated or packaged together with System on Chip (SoC) on a substrate  610   a  to form a chip  600   a . As shown in  FIG. 5B , in some embodiments, the normally-on voltage control switch  141 , the main device  160  and the trigger circuit  180  are integrated or packaged together with System in Package (SiP) on a substrate  610   b  to form a package  600   b . In various embodiments, SiP dies may be stacked vertically or tiled horizontally and internally connected by wires that are bonded to the package. 
     In other words, in various embodiments, the voltage control switching circuit  140 , the main device  160  and the trigger circuit  180  may be integrated or packaged together with System in Package, System on Chip, three-dimensional integrated circuit (3D IC), etc. 
     Reference is made to  FIG. 6A  and  FIG. 6B .  FIG. 6A  and  FIG. 6B  are diagrams illustrating integration of the driving signal generator  120  and the voltage control switching circuit  140  according to some embodiments of the present disclosure. 
     Corresponding to the embodiments shown in  FIG. 1 , as shown in  FIG. 6A , in some embodiments, the logic circuit  122 , the driver buffer  124 , and the voltage control switching circuit  140  are integrated or packaged together with System on Chip (SoC) on a substrate  710   a  to form a chip  700   a . As shown in  FIG. 6B , in some embodiments, the logic circuit  122 , the driver buffer  124 , and the voltage control switching circuit  140  are integrated or packaged together with System in Package (SiP) on a substrate  710   b  to form a package  700   b.    
     In other words, in various embodiments, similar to the integration applied to the voltage control switching circuit  140  and the main device  160 , in some embodiments, the driving signal generator  120  and the voltage control switching circuit  140  may be integrated or packaged together with System in Package, System on Chip, 3D IC, etc. 
     In some other embodiments, the driving signal generator  120 , the voltage control switching circuit  140 , the main device  160  and the trigger circuit  180  may also be integrated or packaged together with System in Package, System on Chip, 3D IC, etc, and further explanation is omitted herein for the sake of brevity. 
     In addition, the elements in the above embodiments may be implemented by various digital or analog circuits, and may also be implemented by different integrated circuit chips. Each element may also be integrated in a single chip. It is noted that, in an actual implementation, the circuits may be realized by a microcontroller unit (MCU), or by be realized in various ways such as by a digital signal processor (DSP), a field-programmable gate array (FPGA), etc. The switches and transistors may be realized by proper devices. For example, the switches may be implemented by power semiconductor devices including but not limited to Insulated Gate Bipolar Transistors (IGBTs), bipolar junction transistors (BJTs), SiC metal-oxide-semiconductor field-effect transistors (MOSFET), or mechanical switches, such as various types of relays. The normally-on switching devices may be GaN transistors or semiconductors devices with similar I-V characteristics. Transformer, diodes, resistors, capacitor units and/or inductors units may be realized by suitable electronic elements. The above list is merely exemplary and is not meant to be limitations of the present disclosure. 
     The elements, method steps, or technical features in the foregoing embodiments may be combined with each other, and are not limited to the order of the specification description or the order of the drawings in the present disclosure. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present disclosure without departing from the scope or spirit of the present disclosure. In view of the foregoing, it is intended that the present disclosure cover modifications and variations of this present disclosure provided they fall within the scope of the following claims.