Hybrid switching circuit with bidirectional double-base bipolar junction transistor

Abstract

A hybrid switching circuit for coupling two circuit terminals together is disclosed. The hybrid switching circuit includes a set of bidirectional switching devices coupled between a first circuit terminal and a second circuit terminal. The hybrid switching circuit also includes a set of unidirectional switching devices also coupled between the first circuit terminal and the second circuit terminal. In some cases, the set of bidirectional switching devices may be implemented using bidirectional double-base bipolar junction transistors, while the set of unidirectional switching devices may be implemented using wide bandgap transistors. In response to de-assertion of the switching signal, the control circuit may turn off the set of bidirectional switching devices and turn off the set of unidirectional switching devices after a period of time has elapsed.

Description

[0001] Cross-citation of related applications

[0002] This application claims the benefit of U.S. Patent Application No. 18 / 458,790, filed August 30, 2023, entitled "Hybrid Switch Circuit with Bidirectional Double-Base Bipolar Junction Transistors." The application is incorporated herein by reference as if reproduced in its entirety below. Technical Field

[0003] This disclosure relates to electrically controlled switches, and more specifically, to hybrid switches comprising bidirectional double-base bipolar junction transistors (“BDBBJT”). Background Technology

[0004] Many electrical systems utilize high voltage and current. Such systems can be used in a wide range of applications, from electric vehicles to consumer appliances. For example, in some electric vehicles, approximately 1200 volts can be used to power the electric motor.

[0005] During the operation of such electrical systems, it may be necessary to disconnect or decouple the load circuit from a high-voltage source. This can be achieved using an electronically controlled switch. In response to an assertion of a switching signal, the electronically controlled switch can couple the power supply to the load circuit. The electronically controlled switch can also decouple the load circuit from the power supply in response to a release assertion of a switching signal. Summary of the Invention

[0006] Various embodiments of a hybrid switching circuit are disclosed. Broadly speaking, a hybrid switching circuit may include a first set of bidirectional switching devices configured to couple a first terminal to a second terminal in response to an assertion of a plurality of first control signals. The hybrid switching circuit may further include a second set of unidirectional switching devices configured to couple the first terminal to the second terminal in response to an assertion of a plurality of second control signals. A control circuit may be configured to deassert the plurality of first control signals in response to a deassertion of the switching signals, and to deassert the plurality of second control signals after a period of time has elapsed since the deassertion of the plurality of first control signals.

[0007] In some embodiments, the first set of bidirectional switching devices may include a plurality of double-base bipolar junction transistors coupled in parallel between the first terminal and the second terminal.

[0008] In other embodiments, the second set of unidirectional switching devices may include a plurality of wide-bandgap transistors coupled in series between the first terminal and the second terminal. BRIEF DESCRIPTION OF DRAWINGS

[0009] For a detailed description of example embodiments, reference will now be made to the accompanying drawings in which:

[0010] Figure 1 is a block diagram of an embodiment of a hybrid switching circuit.

[0011] Figure 2 is a block diagram of an embodiment of a unidirectional switch.

[0012] Figure 3 is a block diagram of an embodiment of a bidirectional switch.

[0013] Figure 4 is a block diagram of an embodiment of a bidirectional switching device.

[0014] Figure 5 illustrates example waveforms associated with operation of a hybrid switching circuit.

[0015] Figure 6 is a block diagram of a control circuit included in a hybrid switching circuit.

[0016] Figure 7 is a flowchart of an embodiment of a method for operating a hybrid switching circuit.

[0017] Figure 8 is a flowchart of an embodiment of a different method for operating a hybrid switching circuit.

[0018] Figure 9 is a block diagram of various embodiments of a system that can include a hybrid switching circuit.

[0019] Many of the electrical connections in the drawings are shown as direct connections, but in actual practice, the connections can be indirect connections, through intervening devices and connections. In the following discussion, the term "directly coupled" is used to indicate a direct connection, but the term "coupled" is used to indicate an indirect connection, through intervening devices and connections.

[0020] DEFINITIONS

[0021] Various terminology is used to refer to particular components. Different companies may refer to components by different names — this document does not intend to distinguish between components that differ in name but not in function. In the following discussion and in the claims, the terms "including" and "comprising" are used in an open-ended fashion, and thus should be interpreted to mean "including, but not limited to...." Also, the term "couple" is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection can be through a direct connection, or through an indirect connection via other devices and connections.

[0022] As used herein, "a" and "an" refer to both the singular and plural, unless the context clearly indicates otherwise. By way of example, a "processor" programmed to perform various functions refers to one processor programmed to perform each and every function, or more than one processor collectively programmed to perform each of the functions.

[0023] With respect to electrical devices, whether standalone or as part of an integrated circuit, the terms "input" and "output" refer to electrical connections to the electrical device and should not be interpreted as verbs requiring action. For example, a differential amplifier (e.g., an operational amplifier) can have a first differential input and a second differential input, and these "inputs" define electrical connections to the operational amplifier and should not be interpreted to require inputting a signal to the operational amplifier.

[0024] "Asserted" shall mean creating or maintaining a first predetermined state of a Boolean signal. Depending on the choice of the circuit designer, the Boolean signal can be asserted as high, or having a higher voltage, and the Boolean signal can be asserted as low, or having a lower voltage. Similarly, "de-asserted" shall mean creating or maintaining a second predetermined state of a Boolean signal, opposite the asserted state.

[0025] "FET" shall mean field effect transistor, such as a junction gate FET (JFET) or a metal oxide semiconductor field effect transistor (MOSFET).

[0026] "Closed" with respect to an electrically controlled switch (e.g., a FET) shall mean making the electrically controlled switch conductive. For example, closed as used for a FET used as an electrically controlled switch can mean driving the FET to a fully conductive state.

[0027] "Open" with respect to an electrically controlled switch (e.g., a FET) shall mean making the electrically controlled switch non-conductive.

[0028] "Bilateral double base bipolar junction transistor" shall mean a junction transistor having a base and a collector-emitter on a first face or side of a bulk region, and a base and a collector-emitter on a second face or side of the bulk region. The base and collector-emitter on the first side are different from the base and collector-emitter on the second side.

[0029] "Upper collector-emitter" shall mean a terminal of a bilateral double base bipolar junction transistor connected to a collector-emitter on a first side of a bulk region of the transistor, and should not be interpreted to imply a position of the collector-emitter relative to gravity.

[0030] "Lower collector-emitter" shall mean the terminal connected to the collector-emitter of the bidirectional double-base bipolar junction transistor on the second side of the transistor opposite the first side, and shall not be construed to imply the position of the collector-emitter with respect to gravity.

[0031] "Upper base" shall mean the terminal connected to the base of the bidirectional double-base bipolar junction transistor on the first side of the transistor, and shall not be construed to imply the position of the base with respect to gravity.

[0032] "Lower base" shall mean the terminal connected to the base of the bidirectional double-base bipolar junction transistor on the second side of the transistor opposite the first side, and shall not be construed to imply the position of the base with respect to gravity.

[0033] "Controller" or "controller circuit" shall mean, individually or in combination, individual circuit components, application specific integrated circuits (ASICs), microcontrollers with control software, reduced instruction set computing (RISC) with control software, digital signal processors (DSPs), processors with control software, programmable logic devices (PLDs), field programmable gate arrays (FPGAs), or programmable system on a chip (PSOC) configured to read inputs and drive outputs in response to the inputs. DETAILED DESCRIPTION

[0034] The following discussion relates to various embodiments of the application. Although one or more of these embodiments can be preferred, the disclosed embodiments should not be construed as limiting the scope of the disclosure, including the claims. In addition, one skilled in the art will appreciate that the following description has broad application and is not intended to limit the scope of the disclosure, including the claims, to any one embodiment.

[0035] In various applications, switching of high voltages and currents can be required. For example, in some electric vehicles, it can be common to couple and decouple a load circuit with a high voltage supply (e.g., 1200V). In many systems, silicon carbide (SiC) switches are employed. To handle large currents, many SiC switches can be coupled together in parallel, such that each SiC handles only a fraction of the total current.

[0036] However, using multiple SiC switches can result in large circuit area and higher cost. In addition, increased drive capability needs to be added to the switch control signals used to control the multiple SiC switches, increasing power consumption and reducing the efficiency of the switching subsystem.

[0037] To reduce the number of SiC switches required, the hybrid switch includes both SiC switches and bidirectional double-base bipolar junction transistors. The higher current carrying capability of the bidirectional double-base bipolar junction transistors enables fewer total switching circuit elements to be used for a given current. However, the bidirectional double-base bipolar junction transistors transition from an off state to an on state more slowly than SiC switches. During this time, there is a large voltage across the bidirectional double-base bipolar junction transistors in addition to the current flowing through the bidirectional double-base bipolar junction transistors, resulting in undesirable power dissipation, which reduces the efficiency of the switching sub-system.

[0038] Embodiments described herein can provide techniques for operating a hybrid switch to reduce power dissipation and improve efficiency. In response to receiving an indication to turn off, the hybrid switch can turn off the bidirectional double-base bipolar junction transistors while leaving the SiC switches on. With the SiC switches on, the voltage across the bidirectional double-base bipolar junction transistors decreases while it transitions from on to off. After a period of time, the hybrid switch turns off the SiC switches. Since the SiC switches have a relatively fast transition time, the time during which the hybrid switch dissipates power is reduced.

[0039] In Figure 1 a block diagram of an embodiment of a hybrid switch circuit is depicted. As illustrated, the hybrid switch circuit 100 includes a control circuit 101, a unidirectional switch 102, and a bidirectional switch 103.

[0040] The bidirectional switch 103 is configured to couple the terminal 104 to the terminal 105 in response to the bidirectional control signals 107 being placed in a particular state. It should be noted that in some embodiments, one or more of the bidirectional control signals 107 can be electrically floating. As described below, the bidirectional switch 103 can include multiple BDB BJT devices, which can be in different operating states or modes. In some embodiments, the different modes can include multiple off and on modes, which can be selected based on the application in which the hybrid switch circuit 100 is employed. In various embodiments, each mode can correspond to a particular state of the bidirectional control signals 107.

[0041] In a similar manner, the unidirectional switch 102 is configured to couple the terminal 104 to the terminal 105 in response to an assertion of the unidirectional control signal 106. It should be noted that although both the bidirectional control signals 107 and the unidirectional control signal 106 are depicted as single wires, in various embodiments, each of the bidirectional control signals 107 and the unidirectional control signal 106 can include multiple wires for transmitting different voltages and / or currents to the unidirectional switch 102 and the bidirectional switch 103.

[0042] When the one-way switch 102 and the bi-directional switch 103 are closed, current 109 can flow between the terminal 104 and the terminal 105. It should be noted that although the current 109 is depicted as flowing from the terminal 104 to the terminal 105, in other embodiments different arrangements of the circuit coupled to the terminals 104 and 105 can result in the current 109 flowing in the opposite direction.

[0043] The control circuit 101 is configured to place the bi-directional control signal 107 in a state corresponding to an open mode of the bi-directional switch 103 in response to the de-assertion of the switch signal 108. In various embodiments, the control circuit 101 is further configured to de-assert the one-way control signal 106 after a time period 110 has elapsed since the bi-directional switch 103 was placed in the open mode.

[0044] Furthermore, the control circuit 101 is also configured to assert the one-way control signal 106 to close the one-way switch 102 and place the bi-directional control signal 107 in a state corresponding to a closed mode of the bi-directional switch 103 in response to the assertion of the switch signal 108. Once the one-way switch 102 and the bi-directional switch 103 are closed, the current 109 can flow between the terminals 104 and 105. In some embodiments, the control circuit 101 can be further configured to change the respective state of the bi-directional control signal 107 to activate a "diode mode" of the bi-directional switch 103 to allow the current 109 to flow in only a single direction in response to the assertion of the switch signal 108.

[0045] As described below, the control circuit 101 can include an isolation circuit and a driver circuit. In various embodiments, the control circuit 101 can additionally include a microcontroller, a state machine, or any other suitable timing logic circuit.

[0046] Turning to Figure 2 , a block diagram of the one-way switch 102 is depicted. As illustrated, the one-way switch 102 includes a one-way switch device 201 and a one-way switch device 202. Although only two one-way switch devices are depicted, in other embodiments any suitable number of one-way switch devices can be employed.

[0047] The one-way switch device 201 is coupled between the terminal 104 and a node 206 and is controlled by a control signal 205. In a similar manner, the one-way switch device 202 is coupled between the node 206 and the terminal 105 and is controlled by a control signal 204. In various embodiments, the control signals 204 and 205 can be included in the one-way control signal 106 as depicted in Figure 1

[0048] ​In response to assertion of control signal 205, unidirectional switch device 201 is configured to enable current to pass between terminal 104 and node 206. Depending on the orientation of unidirectional switch device 201, current can flow from terminal 104 to node 206, or from node 206 to terminal 104. In a similar manner, unidirectional switch device 202 is configured to enable current to pass between node 206 and terminal 105 in response to assertion of control signal 204.

[0049] It is noted that unidirectional switch device 201 and unidirectional switch device 202 are depicted with their drains coupled together. In other embodiments, different arrangements of unidirectional switch device 201 and unidirectional switch device 202 are possible and contemplated. For example, in some embodiments, the drain of unidirectional switch device 201 can be coupled to the source of unidirectional switch device 202.

[0050] In various embodiments, unidirectional switch device 201 and unidirectional switch device 202 can be implemented using silicon carbide (SiC) devices, insulated gate bipolar transistors (IGBTs), gallium nitride (GaN) transistors, or any other suitable wide bandgap transistors. In some embodiments, unidirectional switch device 201 and 202 can be implemented using SiC devices or GaN transistors, and a JFET arranged in a common-source common-gate configuration.

[0051] Turning to Figure 3 , a block diagram of bidirectional switch 103 is depicted. As illustrated, bidirectional switch 103 includes bidirectional switch devices 301A-301C. As described below, each of bidirectional switch devices 301A-301C can include at least one double-base bipolar device. Although only three bidirectional switch devices are depicted in the embodiment of Figure 3 , in other embodiments, any suitable number of bidirectional switch devices can be employed. In some embodiments, the number of bidirectional switch devices included in bidirectional switch 103 can be based on a desired current level to be switched by bidirectional switch 103.

[0052] Each of bidirectional switch devices 301A-301C is coupled between terminal 104 and terminal 105. Bidirectional switch device 301A is controlled by control signal 302A, while bidirectional switch devices 301B and 301C are controlled by control signals 302B and 302C, respectively. In some embodiments, the use of different control signals for each of bidirectional switch devices 301A-301C enables different ones of bidirectional switch devices 301A-301C to be independently opened and closed.

[0053] It should be noted that while control signals 302A-C are depicted as single wires, in various embodiments, control signals 302A-C can include multiple wires for controlling different elements using bidirectional switching devices 301A-C.

[0054] In Figure 4 A block diagram depicting an embodiment of a bidirectional switching device is depicted in FIG. 4. As illustrated, bidirectional switching device 400 includes BDB BJT 401, switch 402, and switch 403. In various embodiments, BDB BJT 401 can be implemented as a B-TRAN™ available from Ideal Power Inc. of Austin, Texas. While BDB BJT 401 is depicted as a PNP device, in other embodiments, BDB BJT 401 can also be implemented as an NPN device. Further, one example BDB BJT 401 can be a device as described in U.S. Provisional Patent Application No. 63 / 382,924, entitled “METHOD AND SYSTEMS OF OPERATING A PNP BI-DIRECTIONAL DOUBLE-BASE BIPOLAR JUNCTION TRANSISTOR (B-TRAN),” filed November 9, 2022, in which the main load current flows through the base connection. To avoid confusion, for the purposes of this disclosure and claims, the main load current is considered to flow to and through the collector-emitter, and the control current is applied to the base, even though from a physical perspective of the BJT device, the BJT is utilized as in the aforementioned provisional application.

[0055] Switch 402 is coupled between terminal 104 and upper collector-emitter 410, and is configured to interrupt current flow between terminal 104 and upper collector-emitter 410 based on control signal 404. In various embodiments, switch 402 can be implemented using a FET or any other suitable switching device.

[0056] Switch 403 is coupled between terminal 105 and lower collector-emitter 411, and is configured to interrupt current flow between terminal 105 and lower collector-emitter 411 based on control signal 407. In various embodiments, switch 403 can be implemented using a FET or any other suitable switching device.

[0057] The BDB BJT 401 is configured to conduct current through the upper collector-emitter 410 and lower collector-emitter 411 based on the states of the control signals 405 and 406. In various embodiments, different modes of operation of the BDB BJT 401 can be achieved by varying the states of the control signals 405 and 406 as well as the states of the switches 402 and 403. For example, the BDB BJT 401 can be placed in a "passive off' state by floating the control signal 405, which in turn floats the upper base 408. At the same time, the upper collector-emitter 410 is coupled to the terminal 104 via the switch 402. In addition, the control signal 406 is coupled to the terminal 105, which couples the lower base 409 to the terminal 105. Furthermore, the lower collector-emitter 411 is electrically floated by de-asserting the control signal 407 and opening the switch 403.

[0058] Alternatively, the BDB BJT 401 can be placed in a "passive on' state by floating the control signal 405 to electrically float the upper base 408, while the control signal 404 is asserted to close the switch 402 to couple the upper collector-emitter 410 to the terminal 104. In addition, the lower base 409 can be electrically floated by placing the control signal 406 in a high impedance state, the control signal 407 is asserted to close the switch 403 to couple the lower collector-emitter 411 to the terminal 105.

[0059] In various embodiments, the control signals 404 through 407 can be included in the bidirectional control signal 107 as depicted in FIG. 1 B. It should be noted that in addition to the "passive on' and "passive off' states, there are an additional four states of operation, and any suitable subset of the states of operation can be employed during operation of the hybrid switching circuit 100 out of the six possible states of operation of the BDB BJT 401. Figure 1

[0060] Figure 5 Example waveforms associated with operation of a hybrid switching circuit, such as the hybrid switching circuit 100 as depicted in FIG. 1 B, are illustrated in FIG. 2. It should be noted that the waveforms depicted in FIG. 2 are merely examples, and different relative timing between the various signals can be employed in other embodiments. Figure 1 Figure 5

[0061] ​​​​At time tO, the switch signal 108 is not asserted, which causes the unidirectional control signal 106 to remain de-asserted, resulting in the unidirectional switch 102 being open, and the bidirectional control signal 107 being in a state corresponding to the bidirectional switch 103 being open. With both the unidirectional switch 102 and the bidirectional switch 103 open, the current 109 is equal to or near zero. It should be noted that in some embodiments, both the unidirectional switch 102 and the bidirectional switch 103 can allow a small amount of leakage current to flow even in their open state. Thus, even though both switches are open, the current 109 can be non-zero.

[0062] At time tl, the switch signal 108 is asserted, which activates the unidirectional control signal 106, which closes the unidirectional switch 102. In addition, the bidirectional control signal 107 is placed in a state that closes the bidirectional switch 103. Once the unidirectional switch 102 and the bidirectional switch 103 are closed, the current 109 can flow.

[0063] At time t2, the switch signal 108 is de-asserted, which places the bidirectional control signal 107 in a state that opens the bidirectional switch 103. It should be noted that at this time, the unidirectional control signal 106 remains asserted, maintaining the closed state of the unidirectional switch 102. With the unidirectional switch 102 closed, the difference in the respective voltages of the terminals 104 and 105 is minimized, thus minimizing the power dissipated by the bidirectional switch 103 when it is closed, improving the efficiency of the hybrid switch circuit 100.

[0064] At time t3, the unidirectional control signal 106 is de-asserted, closing the unidirectional switch 102. When the unidirectional switch 102 is closed, the current 109 decreases as the voltage between the terminals 104 and 105 rises. The unidirectional switch 102 is dissipating power until the current 109 stops flowing. As described above, the switching speed of the unidirectional switch 102 is faster than the switching speed of the bidirectional switch 103, thus the time during which the hybrid switch circuit 100 dissipates power is minimized.

[0065] Figure 5 The waveforms illustrated in FIG. 6 depict a single turn-on / off cycle. In various embodiments, multiple turn-on / off cycles can be performed continuously. The respective durations of the turn-on time and the turn-off time of any of the multiple turn-on / off cycles can vary.

[0066] Turning to Figure 6 , a block diagram of an embodiment of the control circuit 101 is depicted. As illustrated, the control circuit 101 includes an isolation circuit 601, a controller 602, a driver circuit 603, a comparator circuit 604, a transformer 605, and an AC-DC converter 606.

[0067] The primary winding of transformer 605 is coupled to input AC voltage 611. Transformer 605 is configured to generate isolated AC voltage 612 on its secondary winding based on input AC voltage 611. In some embodiments, transformer 605 can include a core made of ferrous material and / or one or more taps on the secondary winding. Although a single transformer is depicted in the embodiment of FIG. 6, in other embodiments, multiple transformers can be employed to provide different AC voltages to AC-DC converter 606. Figure 6

[0068] AC-DC converter 606 is configured to generate bus voltage 610 using isolated AC voltage 612. In various embodiments, bus voltage 610 can include multiple voltage levels (e.g., 3.3 V, 5 V, 12 V, etc.) for use by controller 602 and driver circuit 603 to generate voltages for various bidirectional control signals 107 to change the operating state of bidirectional switching devices 301A-C. In some embodiments, AC-DC converter 606 can be implemented using a rectifier circuit, one or more capacitors, one or more power converter circuits (e.g., a buck converter), or any other suitable circuit components or sub-circuits.

[0069] In various embodiments, control circuit 101 can be in a different electrical domain than the circuit that generates switching signals 108. To account for the difference in electrical domains, isolation circuit 601 is employed. In various embodiments, isolation circuit 601 is configured to generate signal 607 based on switching signals 108 such that signal 607 is in a different electrical domain than switching signals 108. In some embodiments, isolation circuit 601 can be implemented using an optocoupler, a capacitive isolation device, or any other circuit configured to convert a signal from one electrical domain to another.

[0070] Comparator circuit 604 is configured to generate signal 609 based on the respective voltage levels of terminals 104 and 105. In various embodiments, the voltage level of signal 609 can indicate which of terminals 104 and 105 has a higher voltage level. For example, in some cases, a particular voltage level of signal 609 can indicate that the voltage level of terminal 104 is greater than the voltage level of terminal 105, while a different voltage level of signal 609 can indicate that the voltage level of terminal 104 is less than the voltage level of terminal 105. In various embodiments, comparator circuit 604 can be implemented using a differential amplifier circuit, a Schmitt trigger circuit, or any other suitable circuit configured to generate an output signal whose voltage level is based on a comparison of the respective voltage levels of at least two input signals.

[0071] ​The controller 602 is configured to generate the signal 608 and the unidirectional control signal 106 based on the signal 607. As described above, in response to the de-assertion of the switch signal 108 and the corresponding change in the signal 607, the controller 602 can be configured to change the state of the signal 608 via the bidirectional control signal 107 to place the bidirectional switching devices 301A-C in a closed state. The controller 602 is further configured to change the state of the unidirectional control signal 106 to close the unidirectional switch 102 after a time period 110 has elapsed since the bidirectional switching devices 301A-C were placed in the closed state.

[0072] In various embodiments, to generate the signal 608 and the unidirectional control signal 106, the controller 602 can be further configured to generate the signal 608 and the unidirectional control signal 106 using one or more of the voltage levels included in the bus voltage 610. As described below, the signal 608 is used to operate various switches within the driver circuit 603 to change the operating state or mode of the bidirectional switching devices 301A-C via the bidirectional control signal 107.

[0073] In various embodiments, the controller 602 can be implemented using individual circuit components, an application specific integrated circuit (ASIC), a microcontroller configured to execute software or program instructions, a reduced instruction set computer (RISC), a digital signal processor (DSP) circuit, a processor or processor core configured to execute software or program instructions, a programmable logic device (PLD), a field programmable gate array (FPGA), a programmable system on a chip (SoC), or any suitable combination thereof.

[0074] The driver circuit 603 is configured to generate the bidirectional control signal 107 using the signal 608 and one or more of the voltage levels included in the bus voltage 610. As described above with respect to Figure 4 different ones of the bidirectional control signal 107 can be in a high impedance state, thereby allowing different terminals of the DB DBJT 401 to float. In other cases, the driver circuit 603 can be configured to couple different ones of the bidirectional control signal 107 to the terminal 104 or the terminal 105, or to set others of the bidirectional control signal 107 to particular voltage levels, all under the control of the signal 608. In various embodiments, the driver circuit 603 can be implemented using a plurality of switches, FETs, or any other suitable switching devices.

[0075] Turning to Figure 7 , a flowchart depicting an embodiment of a method for operating a hybrid switching circuit is illustrated. The method, which begins at block 701, can be applied to various hybrid switching circuits including the hybrid switching circuit 100 as depicted in Figure 1

[0076] ​The method includes opening a first set of bidirectional switching devices in response to changing a state of a switch signal (block 702). In various embodiments, the first set of bidirectional switching devices is coupled between the first terminal and the second terminal. In various embodiments, opening the first set of bidirectional switching devices can include generating a plurality of first switch signals using a control signal. In this case, the method can further include opening the first set of bidirectional switching devices using a corresponding one of the plurality of first switch signals.

[0077] In some cases, the voltage levels of the control signals associated with different logic states are not compatible with the voltage levels switched through the hybrid switch. In this case, generating the plurality of first switch signals can include electrically isolating the control signal from control circuitry included in the hybrid switch, where the control circuitry is configured to generate the first plurality of switch signals. In various embodiments, electrically isolating the control signal can include coupling the control signal from a first circuit domain to a second circuit domain via a transformer or other suitable circuit element.

[0078] In some cases, the first set of bidirectional switching devices includes a plurality of bidirectional double-base bipolar junction transistors coupled in parallel between the first terminal and the second terminal. The plurality of bidirectional double-base bipolar junction transistors can be implemented using an NPN structure, a PNP structure, or any other suitable bidirectional bipolar junction transistor structure.

[0079] The method further includes opening a second set of unidirectional switching devices after a time period has elapsed since the first set of bidirectional switching devices was opened (block 703). In some embodiments, opening the second set of unidirectional switching devices includes generating a delay corresponding to the time period using a delay circuit, a counter circuit, or any other suitable circuit.

[0080] In various embodiments, the second set of unidirectional switching devices is also coupled between the first terminal and the second terminal. In some embodiments, the second set of unidirectional switching devices can include a plurality of unidirectional switching devices coupled in series between the first terminal and the second terminal. In different embodiments, the plurality of unidirectional switching devices can be implemented using a common-source common-gate JFET, a silicon carbide (SiC) device, an insulated gate bipolar transistor (IGBT), or any other suitable wide-bandgap transistor.

[0081] In some cases, opening the second set of unidirectional switching devices can include generating a plurality of second switch signals using a control signal. In various embodiments, the method can further include opening the second set of unidirectional switching devices using a corresponding one of the plurality of second switch signals.

[0082] In some embodiments, the method can further include closing a particular subset of the first set of bidirectional switching devices in response to the switch signal being asserted. In addition, the method can further include closing the second set of unidirectional switching devices in response to the switch signal being asserted. The method ends in block 704.

[0083] As described above, a bidirectional switch can allow current to flow through the switch in either direction depending on the respective voltage at the terminals of the hybrid switch. In some applications (e.g., rectification), it can be desirable to limit the direction of current flow through the hybrid switch to a single direction while still maintaining the advantages of using a dual-base bipolar junction transistor. This can be accomplished by activating a "diode mode" of the bidirectional switch device, in which current can only flow through the bidirectional switch device in a single direction. In Figure 8 A flowchart depicting embodiments of different methods for operating a hybrid switch is illustrated in FIG. 8. The method, which can be applied to various hybrid switch circuits including the hybrid switch circuit 100, begins at block 800.

[0084] The method includes closing a first set of bidirectional switch devices in a unidirectional mode (or "diode mode") in response to assertion of a switch signal (block 802). In various embodiments, the first set of bidirectional switch devices is coupled between the first terminal and the second terminal. In some embodiments, closing the first set of bidirectional switch devices in the unidirectional mode can include activating a subset of a plurality of control signals coupled to the first set of bidirectional switch devices in response to assertion of the switch signal. In other embodiments, the method can further include determining a particular subset of a plurality of subsets of the plurality of control signals to activate based on one or more configuration bits.

[0085] As described above, the first set of bidirectional switch devices can include a plurality of dual-base bipolar junction transistors coupled in parallel between the first terminal and the second terminal. In some cases, the closing of individual ones of the first set of bidirectional devices can be staggered to avoid a large current surge.

[0086] The method also includes closing a second set of unidirectional switch devices in response to assertion of the switch signal (block 803). In various embodiments, the second set of unidirectional switch devices is coupled between the first terminal and the second terminal.

[0087] As described above, the second set of unidirectional switch devices can be implemented using any suitable wide bandgap device, and can be coupled in series between the first terminal and the second terminal. In various embodiments, the orientation of the second set of unidirectional switch devices can be determined so as to match the direction of current flow through the first set of bidirectional switch devices operating in the unidirectional mode.

[0088] Although the steps of blocks 802 and 803 are depicted as being performed sequentially, in other embodiments, the steps of blocks 802 and 803 can be performed substantially simultaneously. It should be noted that in various embodiments, the opening of the first set of bidirectional switch devices and the second set of unidirectional switch devices can be performed in a similar manner as described in the flowchart illustrated in FIG. 7. The method ends at block 804. Figure 7 The method described in the flowchart illustrated in FIG. 8 can be performed in a similar manner as described in the flowchart illustrated in FIG. 7. The method ends at block 804.

[0089] Turning to Figure 9, illustrating various types of systems that can include any of the circuits, devices, or systems discussed above. Systems or devices 900 that can incorporate or otherwise utilize one or more of the techniques described herein can be utilized in a wide array of fields. For example, systems or devices 900 can be utilized as consumer appliances 903, such as refrigerators, freezers, electric ranges and ovens, heating, ventilation, and air conditioning (HVAC) equipment, etc.

[0090] Similarly, the disclosed elements can be utilized in medical equipment 905. Such medical equipment can include x-ray machines, magnetic resonance imaging (MRI) equipment, computed axial tomography (CAT) scan equipment, etc. Other types of devices are also contemplated, including any medical application in which high current or voltage switching is required.

[0091] Systems or devices 900 can also be employed in other contexts. For example, systems or devices 900 can be utilized in the context of solar / wind power inverters 901 or uninterruptible power supplies (UPS) 904. Further, systems or devices 900 can be used in electric vehicles 902 (e.g., electric cars, electric bikes, electric scooters, etc.).

[0092] Figure 9 The applications illustrated in the above-described embodiments are merely examples and are not intended to limit potential future applications of the disclosed systems and devices.

[0093] The present disclosure includes reference to“an embodiment” or“a group of embodiments.” As used herein, an embodiment is a different implementation of an example of the disclosed concept. References to“an embodiment,”“some embodiments,” etc. do not necessarily refer to the same embodiment. Numerous embodiments are possible and contemplated, including those not explicitly disclosed, as well as modifications or alternatives to the embodiments within the spirit or scope of the present disclosure.

[0094] The above disclosure is intended to be illustrative and not limiting of the principles and various embodiments of the disclosed concept. Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be construed to include all such variations and modifications.

Claims

1. An apparatus comprising: A first set of bidirectional switching devices is configured to couple a first terminal to a second terminal in response to a plurality of first control signals being placed in a first state; A second set of unidirectional switching devices is configured to couple the first terminal to the second terminal in response to an assertion of a plurality of second control signals; and The control circuit is configured to respond to a release assertion of a switching signal: Place the plurality of first control signals into a second state corresponding to the open state of the first group of bidirectional switching devices; and After a period of time has elapsed since the plurality of first control signals were placed in the second state, the assertion of the plurality of second control signals is released.

2. The device according to claim 1, wherein the first set of bidirectional switching devices comprises a plurality of double-base bipolar junction transistors coupled in parallel between the first terminal and the second terminal.

3. The device of claim 1, wherein the second set of unidirectional switching devices comprises a plurality of wide-bandgap transistors coupled in series between the first terminal and the second terminal.

4. The device of claim 1, wherein the control circuit is further configured to electrically isolate the switching signal from the controller circuit and driver circuit coupled to the first set of bidirectional switching devices.

5. The device of claim 1, wherein the first set of bidirectional switching devices is coupled to a corresponding subset of the plurality of first control signals, and wherein a given bidirectional switching device of the first set of bidirectional switching devices is configured to couple the first terminal to the second terminal in response to a corresponding subset of the plurality of first control signals being placed in the first state.

6. The device of claim 1, wherein the control circuitry is further configured to sequentially place a plurality of subsets of the plurality of first control signals in the first state in response to an assertion of the switching signal.

7. A method comprising: In response to a change in the state of a control signal, the first set of bidirectional switching devices is disconnected, wherein the first set of bidirectional switching devices is coupled between a first terminal and a second terminal; and After a period of time since the first set of bidirectional switches was disconnected, the second set of unidirectional switches is disconnected, wherein the second set of unidirectional switches is coupled between the first terminal and the second terminal.

8. The method of claim 7, wherein the first set of bidirectional switches comprises a plurality of double-base bipolar junction transistors coupled in parallel between the first terminal and the second terminal.

9. The method of claim 7, wherein the second set of unidirectional switching devices comprises a plurality of wide-bandgap transistors coupled in series between the first terminal and the second terminal.

10. The method of claim 7, wherein disconnecting the first set of bidirectional switching devices comprises: The control signal is used to generate a plurality of first switching signals; and The first set of bidirectional switching devices is disconnected using the corresponding of the plurality of first switching signals.

11. The method of claim 10, wherein generating the plurality of first switching signals comprises electrically isolating the control signal from control circuitry configured to generate the plurality of first switching signals.

12. The method of claim 7, wherein disconnecting the second set of unidirectional switching devices comprises generating a plurality of second switching signals using the control signal.

13. The method of claim 7, further comprising: A specific subset of the first set of bidirectional switching devices is closed in response to the assertion of the control signal; and The second set of one-way switching devices is closed in response to the assertion of the control signal.

14. An apparatus comprising: First terminal; Second terminal; and A hybrid switching circuit coupled between the first terminal and the second terminal, wherein the hybrid switching circuit includes a first set of bidirectional switching devices and a second set of unidirectional switching devices, wherein the hybrid switching circuit is configured to: The first set of bidirectional switching devices is disconnected in response to a change in the state of the control signal. and After a period of time has elapsed since the first set of bidirectional switching devices was disconnected, the second set of unidirectional switching devices is disconnected.

15. The device of claim 14, wherein the first set of bidirectional switching devices comprises a plurality of double-base bipolar junction transistors coupled in parallel between the first terminal and the second terminal.

16. The device of claim 14, wherein the second set of unidirectional switching devices comprises a plurality of wide-bandgap transistors coupled in series between the first terminal and the second terminal.

17. The device of claim 14, wherein, in order to disconnect the first set of bidirectional switching devices, the hybrid switching circuit is further configured to: The control signal is used to generate a plurality of first switching signals; and The first set of bidirectional switching devices is disconnected using the corresponding of the plurality of first switching signals.

18. The device of claim 14, wherein the hybrid switching circuit includes control circuitry configured to generate the plurality of first switching signals, and wherein, in order to generate the plurality of first switching signals, the hybrid switching circuitry is configured to electrically isolate the control signals from the control circuitry.

19. The device of claim 14, wherein, in order to disconnect the second set of unidirectional switching devices, the hybrid switching circuit is configured to generate a plurality of second switching signals using the control signal.

20. The device of claim 14, wherein the hybrid switching circuit is further configured to: In response to the assertion of the control signal, a specific subset of the first set of bidirectional switching devices is closed; and The second set of unidirectional switching devices is closed in response to the assertion of the control signal.

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