Unidirectional conduction protection circuit, sealed transistor, monolithic integrated chip and electronic equipment

Abstract

The invention provides a one-way conduction protection circuit, a sealed transistor, a monolithic integrated chip and electronic equipment. The circuit comprises at least one normally open transistor and at least one normally closed transistor, the normally-open transistors and the normally-closed transistors are in source-drain connection in sequence according to a preset sequence to form a series circuit; the grid electrode of each normally-open transistor is connected to the series circuit, at least one target normally-open transistor exists, and the grid electrode of the target normally-open transistor is connected to a potential point of which the potential is lower than that of the source electrode of the target normally-open transistor in the series circuit; the grid electrode of any normally-closed transistor is connected to the drain electrode of the normally-closed transistor, or a potential point of which the potential is higher than that of the drain electrode of the normally-closed transistor in the series circuit, and the circuit can realize unidirectional conduction and overcurrent, over-temperature and under-voltage protection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic circuit, in particular to a one-way conduction protection circuit, a hermetically sealed transistor, a monolithic integrated chip and an electronic device. BACKGROUND

[0002] When a circuit fails or an abnormality occurs, such as a load short circuit, overload or control circuit failure, a large current far exceeding the rated current of the device will be generated in the circuit. If the current of the circuit cannot be reduced or the circuit is not cut off in time, the power device will soon be burned out due to the large current. In order to limit the current or cut off the circuit in time to protect the device from being damaged, an overcurrent protection element or device is usually configured in the circuit.

[0003] Common overcurrent protection methods include fuses, overcurrent protection circuits based on operational amplifiers, etc. Fuses can be generally divided into self-recovery fuses and non-recovery fuses. However, the self-recovery fuse has a slow disconnection time, a large conduction resistance, an inaccurate overcurrent point, and is greatly affected by the environment temperature, etc. The non-recovery fuse needs human intervention and needs to be replaced with a new fuse after each work, which has a high maintenance cost. The overcurrent protection circuit based on the operational amplifier includes an operational amplifier, a sampling resistor, a controller and a switching element, and the circuit is complex and the response speed still cannot meet the changing actual needs. SUMMARY

[0004] In order to solve the above problems in the prior art, the present application provides a one-way conduction protection circuit, a hermetically sealed transistor, a monolithic integrated chip and an electronic device. Specifically, it comprises:

[0005] In a first aspect, the present application provides a one-way conduction protection circuit, comprising:

[0006] at least one normally-on transistor and at least one normally-off transistor;

[0007] Each normally-on transistor and each normally-off transistor is connected in source-drain connection in a preset order to form a series circuit;

[0008] The gate of each normally-on transistor is connected to the series circuit, and there is at least one target normally-on transistor, and the gate of the target normally-on transistor is connected to a potential point in the series circuit which has a potential lower than the source potential of the target normally-on transistor;

[0009] The gate of any normally-off transistor is connected to the drain of the normally-off transistor, or a potential point in the series circuit which has a potential higher than the drain potential of the normally-off transistor.

[0010] In a second aspect, the present application also provides a hermetically sealed transistor comprising any one-way conduction protection circuit provided in the first aspect.

[0011] In a third aspect, the present application provides an electronic device comprising any hermetic transistor provided in the second aspect.

[0012] In a fourth aspect, the present application provides a monolithic integrated chip comprising any unidirectional conduction protection circuit provided in the first aspect.

[0013] Advantages of the present application:

[0014] The unidirectional conduction protection circuit, hermetic transistor, monolithic integrated chip and electronic device provided by the present application comprise at least one normally-on transistor and at least one normally-off transistor; each normally-on transistor and each normally-off transistor are connected in source-drain sequence to form a series circuit; the gate of each normally-on transistor is connected to the series circuit, and there is at least one target normally-on transistor, the gate of the target normally-on transistor is connected to a potential point in the series circuit having a potential lower than the source potential of the target normally-on transistor; the gate of any normally-off transistor is connected to the drain of the normally-off transistor, or a potential point in the series circuit having a potential higher than the drain potential of the normally-off transistor, which can achieve the effects of unidirectional conduction, overcurrent protection, overtemperature protection and undervoltage protection.

[0015] The present application will be further described in detail below with reference to the accompanying drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A structural schematic diagram of a unidirectional conduction protection circuit provided by the present application;

[0017] Figure 2 A structural schematic diagram of another unidirectional conduction protection circuit provided by the present application;

[0018] Figure 3 A structural schematic diagram of still another unidirectional conduction protection circuit provided by the present application;

[0019] Figure 4 A structural schematic diagram of still another unidirectional conduction protection circuit provided by the present application;

[0020] Figure 5 A structural schematic diagram of still another unidirectional conduction protection circuit provided by the present application;

[0021] Figure 6 A structural schematic diagram of still another unidirectional conduction protection circuit provided by the present application;

[0022] Figure 7 A structural schematic diagram of still another unidirectional conduction protection circuit provided by the present application;

[0023] Figure 8Another structure schematic diagram of the one-way conducting protection circuit provided by the present application is provided.

[0024] Figure 9 Another structure schematic diagram of the one-way conducting protection circuit provided by the present application is provided.

[0025] Figure 10 Another structure schematic diagram of the one-way conducting protection circuit provided by the present application is provided.

[0026] Figure 11 Another structure schematic diagram of the one-way conducting protection circuit provided by the present application is provided.

[0027] Figure 12 Another structure schematic diagram of the one-way conducting protection circuit provided by the present application is provided.

[0028] Figure 13 Another structure schematic diagram of the one-way conducting protection circuit provided by the present application is provided.

[0029] Figure 14 Another structure schematic diagram of the one-way conducting protection circuit provided by the present application is provided.

[0030] Figure 15 Another structure schematic diagram of the one-way conducting protection circuit provided by the present application is provided.

[0031] Figure 16 Another structure schematic diagram of the one-way conducting protection circuit provided by the present application is provided.

[0032] Figure 17 Another structure schematic diagram of the one-way conducting protection circuit provided by the present application is provided. DETAILED DESCRIPTION

[0033] The present application will be further described in conjunction with specific embodiments, but the embodiments of the present application are not limited thereto.

[0034] The present application provides a one-way conducting protection circuit, which comprises:

[0035] At least one normally-on transistor and at least one normally-off transistor.

[0036] Each normally-on transistor and each normally-off transistor are connected in source-drain sequence to form a series circuit.

[0037] The gate of each normally-on transistor is connected to the series circuit, and there is at least one target normally-on transistor, the gate of the target normally-on transistor being connected to a potential point in the series circuit which has a lower potential than the source potential of the target normally-on transistor.

[0038] The gate of any normally-off transistor is connected to the drain of the normally-off transistor, or the potential point in the series circuit which has a higher potential than the drain potential of the normally-off transistor.

[0039] Specifically, the normally-on transistor and the normally-off transistor in the circuit are connected in series, the drain of the normally-off transistor is connected to the source of the normally-on transistor which has a higher drain potential than the normally-off transistor, or the source of another normally-off transistor which has a higher drain potential than the normally-off transistor, or the highest potential point in the circuit.

[0040] The gate of the normally-on transistor which is closest to the highest potential end in the circuit is connected to the potential point in the circuit which has a lower source potential than the normally-on transistor, which is usually the source of a normally-off transistor which has a lower source potential than the normally-on transistor, or the source of another normally-on transistor which has a lower source potential than the normally-on transistor, or the lowest potential point in the circuit.

[0041] The gate of the normally-off transistor which is closest to the lowest potential end in the circuit is connected to the potential point in the circuit which has a higher drain potential than the normally-off transistor, which is usually the drain of a normally-on transistor which has a higher drain potential than the normally-off transistor, or the drain of another normally-off transistor which has a higher drain potential than the normally-off transistor, or the highest potential point in the circuit.

[0042] Optionally, the unidirectional conduction protection circuit comprises a normally-on transistor and a normally-off transistor; the source of the normally-on transistor is connected to the drain of the normally-off transistor; the gate of the normally-on transistor is connected to the source of the normally-off transistor; the gate of the normally-off transistor is connected to the drain or source of the normally-on transistor; the drain of the normally-on transistor is the highest potential end of the unidirectional conduction protection circuit, and the source of the normally-off transistor is the lowest potential end of the unidirectional conduction protection circuit.

[0043] In order to better understand the circuit provided by the present application, the present application takes a normally-on transistor and a normally-off transistor as an example, and provides the following multiple examples.

[0044] It should be noted that the above examples are only for illustration, and are not exhaustive, and any circuit structure which can be obtained or deduced according to the circuit provided by the present application belongs to the protection scope of the present application.

[0045] For example, Figure 1 The structure diagram of the unidirectional conduction protection circuit provided by the present application is shown in the following figure, Figure 1As shown, the circuit includes: normally open transistor U1 and normally closed transistor U2, the source of U1 and the drain of U2 are connected to form a series circuit, the drain of U1 is the highest potential end of the series circuit, the source of U2 is the lowest potential end of the series circuit, the gate of U1 is connected with the source of U2, and the gate of U2 is connected with the drain of U1.

[0046] As shown in the circuit, U1 and U2 jointly play a role in limiting current when the current in the circuit increases, and U2 further limits the current flow, realizing one-way conduction of the circuit. Figure 1

[0047] The following will make a further detailed description of the circuit principle combined with the characteristics of the device:

[0048] The normally open transistor and the normally closed transistor are both three-terminal devices, one end of the device is the drain, which is usually connected with the relatively high potential end in the circuit; one end is the source, which is usually connected with the relatively low potential end in the circuit; the other end is the gate, which usually controls the resistance (i.e. the internal resistance of the transistor) between the other two ends (i.e. the source and the drain of the device) when connected to different potentials. The gate-source bias of the transistor has a certain adjusting effect on the internal resistance of the transistor. Under normal circumstances, when the gate of the normally open transistor is at the same potential as the source, the source and the drain are in a low-resistance conduction state, and when a certain potential is applied to the gate, the resistance can be increased or decreased, and the maximum resistance can be increased to infinity (i.e. the transistor is turned off), but the resistance can only be slightly smaller than the resistance in the conduction state. Under normal circumstances, when the gate of the normally closed transistor is at the same potential as the source, the source and the drain are in a high-resistance off state, and when a certain potential is applied to the gate, the resistance can be increased or decreased, and the resistance can be decreased to a very low resistance (i.e. the transistor is turned on), but the resistance can only be slightly higher than the resistance in the off state.

[0049] As shown in the circuit, U1 and U2 jointly play a role in limiting current when the current in the circuit increases, and U2 further limits the current flow, realizing one-way conduction of the circuit. Figure 1 ​In the shown circuit, the unidirectional conducting protection circuit is connected in series in the total circuit loop. When the unidirectional conducting protection circuit is normally connected, i.e. the actual potential of the highest potential end of the unidirectional conducting protection circuit is higher than the actual potential of the lowest potential end of the unidirectional conducting protection circuit, at this time, the electric charge can flow from the high potential end of the unidirectional conducting protection circuit into the unidirectional conducting protection circuit, and then pass through the normally open transistor U1 to the drain of the normally closed transistor U2, at the same time, the current passing through the high potential end of the unidirectional conducting protection circuit and the gate of the normally closed transistor U2 charges the gate of the normally closed transistor U2 until the voltage difference between the gate and the source of the normally closed transistor U2 reaches the opening voltage of the normally closed transistor U2 (even if the normally closed transistor U2 enters the low resistance conducting state), and then the current flows through the drain of the normally closed transistor U2 to the source of the normally closed transistor U2 (i.e. the low potential end of the unidirectional conducting protection circuit), so that the unidirectional conducting protection circuit is in the normally conducting state. However, when the actual potential of the highest potential end of the unidirectional conducting protection circuit is lower than the actual potential of the lowest potential end of the unidirectional conducting protection circuit, the normally closed transistor U2 in the circuit cannot form an effective opening gate-source voltage difference between the gate and the source, so the normally closed transistor U2 is in the high resistance off state, i.e. the unidirectional conducting protection circuit is in the off state, and the current in the circuit cannot normally flow, i.e. the current in the circuit is cut off. It can be seen that the unidirectional conducting protection circuit only allows the current to flow in one direction, and the reverse current will be prevented by the transistor combination, which has the characteristic of unidirectional current conduction.

[0050] Further, when the unidirectional protection circuit is normally connected, the voltage drop generated by the current on the internal resistance of the normally-off transistor U2 is fed back to the gate of the normally-on transistor U1 through the source of the normally-off transistor U2 (i.e. the low potential end of the unidirectional protection circuit), so that a negative voltage difference is generated between the gate and the source of the normally-on transistor U1. As the current in the circuit increases, the voltage drop generated by the current on the internal resistance of the normally-off transistor U2 also increases (i.e. the negative voltage difference between the gate and the source of the normally-on transistor U1 also increases). When the negative voltage difference increases to the off voltage of the normally-on transistor U1, the internal resistance of the normally-on transistor U1 will increase sharply until the conduction channel between the source and the drain of the normally-on transistor U1 is turned off. Before the conduction channel between the source and the drain of the normally-on transistor U1 is reopened, the charge on the source of the normally-on transistor U1 will still be discharged to the source of the normally-off transistor U2 (i.e. the low potential end of the unidirectional protection circuit) through the normally-off transistor U2, but the voltage drop on the internal resistance of the normally-off transistor U2 will gradually decrease (i.e. the voltage difference between the source of the normally-on transistor U1 and the source of the normally-off transistor U2 gradually decreases), that is, the negative voltage difference between the gate of the normally-on transistor U1 and the source of the normally-on transistor U1 gradually decreases. When the negative voltage difference decreases to a value that is insufficient to support the normally-on transistor U1 to remain in the high-resistance off state, the normally-on transistor U1 will be turned on and enter a low-resistance on state. If the current in the circuit is still large at this time, the above process will occur repeatedly. The current value at the moment when the normally-on transistor U1 is triggered to enter the off state is the current limiting value set by the unidirectional protection circuit. The current in the circuit will maintain this limiting value (i.e. small fluctuations below this limiting value) until the current in the circuit returns to normal, and the unidirectional protection circuit also returns to the normal working state.

[0051] As can be seen, based on the characteristics of the normally-on transistor and the normally-off transistor, the unidirectional protection circuit can respond to the increase in current in the circuit in almost real time, that is, by adjusting the resistance value of the unidirectional protection circuit in real time to adjust the current in the circuit. This real-time adjustment of the resistance value is not a linear change in resistance value, but when the circuit current is less than the set limit current, the resistance value changes less, and when the circuit current approaches the set limit current, the resistance value increases sharply. Therefore, the current in the circuit can be controlled within a predetermined limit at all times, achieving the effect of current limiting. This not only protects the device itself from being damaged by excessive current for a long time, but also protects other components in the circuit. Furthermore, the on-resistance of the transistor itself is small when it is normally working in series in the circuit, and the overcurrent point is accurate and less affected by environmental temperature. Due to the use of semiconductor technology, the consistency of the components is good and they can be easily interchanged under the same specification, and the components have long service life and high stability and are not prone to aging.

[0052] For example,Figure 2 A schematic diagram of another unidirectional protection circuit provided by the present invention is shown in FIG. Figure 2 As shown, the circuit includes: a normally-on transistor U1' and a normally-off transistor U2', the source of U1' and the drain of U2' are connected to form a series circuit, the drain of U1' is the highest potential end of the series circuit, the source of U2' is the lowest potential end of the series circuit, the gate of U1' is connected to the source of U2', and the gate of U2' is connected to the source of U1'.

[0053] exist Figure 2 In the circuit shown, U1' and U2' work together to limit the current when the current in the circuit increases. U2' further limits the current flow to achieve unidirectional current conduction.

[0054] The following is a further detailed explanation of the circuit principle in combination with device characteristics:

[0055] like Figure 2 In the circuit shown, when the unidirectionally conducting protection circuit is connected normally, that is, when the actual potential at the highest potential terminal of the unidirectionally conducting protection circuit is higher than the actual potential at its lowest potential terminal, current flows through U1' to the source of U2'. Simultaneously, the current path between the source of U1' and the gate of U2' charges the gate of U2' until the voltage difference between the gate and source of U2' reaches the turn-on voltage of U2'. Current then flows through the drain of U2', through U2', and to the source of U2', at which point the unidirectionally conducting protection circuit is in a normal conduction state. However, when the actual potential at the highest potential terminal of the unidirectionally conducting protection circuit is lower than the actual potential at the lowest potential terminal, no effective turn-on gate-source voltage difference can be formed between the gate and source of U2'. Consequently, U2' is in a high-impedance off state, and current in the circuit cannot flow normally, thereby achieving the purpose of unidirectional current conduction.

[0056] Furthermore, when the unidirectionally conducting protection circuit is connected normally, the voltage drop generated by the current across the internal resistance of U2' is fed back to the gate of U1' through the source of U2', resulting in a negative voltage difference between the gate and source of U1'. As the current in the circuit increases, the voltage drop across the internal resistance of U2' also increases. When this negative voltage difference increases to the cut-off voltage of U1', the internal resistance of U1' will increase sharply until the conductive channel between the source and drain of U1' is shut off. Before the conductive channel between the source and drain of U1' is reopened, the charge on the source of U1' will still be discharged to the source of U2' through U2', but the voltage drop across the internal resistance of U2' will gradually decrease, that is, the negative voltage difference between the gate and source of U1' will gradually decrease. When this negative voltage difference decreases to a level that is insufficient to support U1' in the high-resistance off state, U1' will turn on and enter the low-resistance on state. If the current in the circuit is still large at this time, the above process will repeat, thereby achieving the current limiting effect.

[0057] Further, the transistors with the same working mode in the series circuit can be connected in series adjacently or can be connected in series with the transistors with different working modes.

[0058] The working mode includes the normally-on type and the normally-off type.

[0059] In other words, when there is more than one normally-on transistor in the series circuit, the more than one normally-on transistors can be connected in sequence or can be connected after being separated by several normally-off transistors.

[0060] Optionally, the unidirectional conduction protection circuit includes a plurality of normally-on transistors and at least one normally-off transistor; the plurality of normally-on transistors and the at least one normally-off transistor are connected in source-drain series to form a series circuit, wherein a first transistor at the highest potential of the series circuit is a normally-off transistor, and a second transistor adjacent to the first transistor is a normally-on transistor, and a gate of the second transistor is connected to the lowest potential of the series circuit, or a third transistor at the lowest potential of the series circuit is a normally-off transistor, or the first transistor at the highest potential of the series circuit is a normally-on transistor, and the third transistor at the lowest potential of the series circuit is also a normally-on transistor.

[0061] In order to better understand the circuit provided by the present application, the present application takes two normally-on transistors and one normally-off transistor as an example, and provides the following multiple examples.

[0062] It should be noted that this is only an example and is not exhaustive, and any circuit structure that can be derived or deduced from the circuit provided by the present application belongs to the protection scope of the present application.

[0063] Exemplarily, Figure 3 Another unidirectional conduction protection circuit provided by the present application has a structure as shown in Figure 3 The circuit includes a normally-on transistor U3, a normally-on transistor U4, and a normally-off transistor U5. The U3, the U4, and the U5 are connected in source-drain series to form a series circuit, a drain of the U3 is a highest potential end of the series circuit, a source of the U5 is a lowest potential end of the series circuit, a gate of the U3 and a gate of the U4 are connected to the source of the U5, and a gate of the U5 is connected to the drain of the U3.

[0064] In the circuit shown in Figure 3 U3, U4, and U5 jointly play a role of current limiting when the current in the circuit increases, and U5 further limits the current flow, thereby realizing unidirectional conduction of the circuit. Among them, U3 and U5 can constitute a current limiting circuit, and U4 and U5 can also constitute a current limiting circuit. Figure 1 Figure 3 ​In the circuit shown, multiple current limiting can be achieved by setting different current limiting values for U3 and U4, further ensuring the current limiting function of the protection circuit.

[0065] Specifically, in Figure 3 When the unidirectional conduction protection circuit is normally connected, i.e. when the actual potential of the highest potential end of the unidirectional conduction protection circuit is higher than the actual potential of the lowest potential end thereof, the current flows through U3 to the drain of U4, then through U4 to the drain of U5, and at the same time, the current path between the high potential end of the unidirectional conduction protection circuit and the gate of U5 is also used to charge the gate of U5 until the voltage difference between the gate and the source of U5 reaches the turn-on voltage of U5, i.e. U5 is in a low resistance conduction state, the current flows through the drain of U5 to the source of U5 through U5, and the unidirectional conduction protection circuit is in a normal conduction state. However, when the actual potential of the highest potential end of the unidirectional conduction protection circuit is lower than the actual potential of the lowest potential end thereof, the effective gate-source voltage difference cannot be formed between the gate and the source of U5 in the circuit, and therefore U5 is in a high resistance off state, and the current in the circuit cannot flow normally, thereby achieving the purpose of unidirectional conduction of the current.

[0066] Further, when Figure 3 When the unidirectional conduction protection circuit is normally connected, the voltage drop generated by the current on the internal resistance of U5 is fed back to the gates of U3 and U4 through the source of U5, respectively, so that a negative voltage difference is generated between the gate and the source of U3 and between the gate and the source of U4, respectively. As the current in the circuit increases, the voltage drop generated on the internal resistance of U5 also increases, further causing the negative voltage difference between the gate and the source of U3 and U4 to increase. When the negative voltage difference increases to the off voltage of any normally-on transistor, it can be understood that, under normal circumstances, the normally-on transistor with a high current limiting value will first play a current limiting role, and there can be some abnormal cases in which the normally-on transistor with a low current limiting value will first play a current limiting role. The internal resistance of the corresponding normally-on transistor will increase sharply until the conduction channel between its source and drain is turned off. Before the conduction channel between the source and the drain of the normally-on transistor is re-opened, the charge on the source will still be released to the source of U5 through the normally-off transistor U5, but the voltage drop on the internal resistance of U5 will gradually decrease, i.e. the negative voltage difference between the gate and the source of the normally-on transistor will gradually decrease. When the negative voltage difference is insufficient to support the normally-on transistor to maintain a high resistance off state, the normally-on transistor will be turned on and enter a low resistance conduction state. If the current in the circuit is still large at this time, the above process will occur repeatedly, thereby achieving current limiting.

[0067] For example, Figure 4 Another structure of the unidirectional conduction protection circuit provided by the present application is shown in FIG. 4. Figure 4As shown, the circuit comprises normally-on transistors U6, U7 and normally-off transistor U8. U6, U7 and U8 are connected in series in the order of source-drain, with the drain of U6 being the highest potential end of the series circuit, the source of U8 being the lowest potential end of the series circuit, the gate of U6 being connected to the source of U8, the gate of U7 being connected to the source of U7, and the gate of U8 being connected to the drain of U6.

[0068] In Figure 4 As shown, U6, U7 and U8 jointly function as current limiters when the current in the circuit increases, wherein U7 functions as a resistor for dividing the voltage in the circuit. U8 further limits the current flow, thereby realizing unidirectional conduction of the circuit.

[0069] When Figure 4 As shown, when the unidirectional conduction protection circuit is normally connected, current flows from the drain of U6 into the unidirectional conduction protection circuit, and then flows through U6, U7 and U8 in sequence. The voltage drop generated by the internal resistance of U7 and the internal resistance of U8 is fed back to the gate of U6 through the source of U8, so that a negative voltage difference is generated between the gate and the source of U6. As the current in the circuit increases, the voltage drop generated by the internal resistance of U7 and the internal resistance of U8 also increases. When the negative voltage difference increases to the off voltage of U6, the internal resistance of U6 will increase sharply until the conduction path between the source and the drain of U6 is turned off. Before the conduction path between the source and the drain of U6 is turned on again, the charge on the source of U6 will still be discharged to the source of U8 through U7 and U8, but the voltage drop across the internal resistance of U7 and the internal resistance of U8 will gradually decrease, i.e., the negative voltage difference between the gate and the source of U6 will gradually decrease. When the negative voltage difference is insufficient to support U6 to maintain a high-resistance off state, U6 will be turned on and enter a low-resistance on state. If the current in the circuit is still large at this time, the above process will occur repeatedly, thereby realizing current limiting.

[0070] For details of how the normally-off transistor U8 functions as a unidirectional conduction device, please refer to the relevant content in the above embodiment. To save space, no further description is given here.

[0071] For example, Figure 5 Another unidirectional conduction protection circuit provided by the present application has the structure shown in FIG. 4. Figure 5 As shown, the circuit comprises normally-on transistors U9, U10 and normally-off transistor U11. U9, U10 and U11 are connected in series in the order of source-drain, with the drain of U9 being the highest potential end of the series circuit, the source of U11 being the lowest potential end of the series circuit, the gates of U9 and U10 being connected to the drain of U11, and the gate of U11 being connected to the drain of U11.

[0072] In Figure 5In the shown circuit, U9 and U10 jointly function as a current limiter when the current in the circuit increases, and U11 limits the current flow, thereby realizing unidirectional conduction of the circuit.

[0073] Specifically, in Figure 5 When the unidirectional conduction protection circuit is normally connected, the current reaches the drain of U10 through U9, then reaches the drain of U11 through U10, and at the same time charges the gate of U11 through the current path between the source of U10 and the gate of U11 until the voltage difference between the gate and the source of U11 reaches the turn-on voltage of U11, and the current flows through the drain of U11 to the source of U11, so that the unidirectional conduction protection circuit is in a normally on state. However, when the actual potential of the highest potential end of the unidirectional conduction protection circuit is lower than the actual potential of the lowest potential end, the effective gate-source turn-on voltage difference between U11 in the circuit cannot be formed, so U11 is in a high-resistance off state, and the current in the circuit cannot normally flow, thereby achieving the purpose of unidirectional conduction of the current.

[0074] Further, when Figure 5 When the unidirectional conduction protection circuit is normally connected, the voltage drop generated by the internal resistance of U10 is fed back to the gate of U9 through the source of U10, so that a negative voltage difference is generated between the gate and the source of U9. As the current in the circuit increases, the voltage drop generated by the internal resistance of U10 also increases, further causing the negative voltage difference between the gate and the source of U9 to increase. When the negative voltage difference increases to the cutoff voltage of U9, the internal resistance of U9 will increase sharply until the conduction path between the source and the drain of U9 is turned off. Before the conduction path between the source and the drain of U9 is reopened, the charge on the source of U9 will still be released to the source of U10 through U10, but the voltage drop on the internal resistance of U10 will gradually decrease, i.e., the negative voltage difference between the gate and the source of U9 will gradually decrease. When the negative voltage difference is insufficient to support U9 to remain in a high-resistance off state, U9 will turn on and enter a low-resistance on state. If the current in the circuit is still large at this time, the above process will occur repeatedly, thereby realizing current limiting.

[0075] Exemplarily, Figure 6 Another unidirectional conduction protection circuit provided by the present application has the structure shown in the structural diagram. Figure 6 The circuit includes a normally off transistor U12 and normally on transistors U13 and U14. U12, U13, and U14 are connected in series in the order of source-drain, the drain of U12 is the highest potential end of the series circuit, the source of U14 is the lowest potential end of the series circuit, the gate of U12 is connected to the drain of U12, and the gates of U13 and U14 are connected to the source of U14.

[0076] In Figure 6In the circuit shown, the normally-off transistor U12 plays a role of unidirectional conduction, and the normally-on transistors U13 and U14 play a role of current limiting when the current in the circuit increases.

[0077] when Figure 6 When the unidirectional conduction protection circuit shown is connected normally, the voltage drop generated by the current on the internal resistance of U14 is fed back to the gate of U13 through the source of U14, resulting in a negative voltage difference between the gate and source of U13. As the current in the circuit increases, the voltage drop generated on the internal resistance of U14 also increases, further causing the negative voltage difference between the gate and source of U13 to increase. When this negative voltage difference increases to the cut-off voltage of U13, the internal resistance of U13 will increase sharply until the conductive channel between its source and drain is turned off. Before the conductive channel between the source and drain of U13 is reopened, the charge on the source of U13 will still be released to the source of U14 through U14, but the voltage drop on the internal resistance of U14 will gradually decrease, that is, the negative voltage difference between the gate and source of U13 will gradually decrease. When this negative voltage difference is reduced to a level that is not enough to support U13 to continue to maintain the high-resistance off state, U13 will turn on and enter the low-resistance on state. If the current in the circuit is still large at this time, the above process will occur repeatedly, thereby achieving current limiting.

[0078] The detailed process of how the normally-off transistor U12 performs the unidirectional conduction function can be found in the relevant contents of the above embodiments, and will not be elaborated here to save space.

[0079] For example, Figure 7 A structural diagram of another unidirectional conductive protection circuit provided by the present invention is shown as follows: Figure 7 As shown, the circuit includes: normally-on transistors U15 and U17 and a normally-off transistor U16. U15, U17, and U16 are sequentially connected in series with their sources and drains to form a series circuit. The drain of U15 is the highest potential end of the series circuit, and the source of U17 is the lowest potential end of the series circuit. The gates of U15 and U17 are both connected to the source of U17, and the gate of U16 is connected to the drain of U16.

[0080] exist Figure 7 In the circuit shown, U15, U16, and U17 work together to limit current as the current increases. U16 acts as a resistor in the circuit's voltage divider. U16 further limits the current flow, ensuring unidirectional conduction.

[0081] when Figure 7When the unidirectional conduction protection circuit is normally connected, the current flows from the drain of U15 into the unidirectional conduction protection circuit, and then flows through U15, U16 and U17 in sequence. The voltage drop generated on the internal resistance of U16 and the internal resistance of U17 is fed back to the gate of U15 through the source of U17, so that a negative voltage difference is generated between the gate and the source of U15. With the increase of the current in the circuit, the voltage drop generated on the internal resistance of U16 and the internal resistance of U17 also increases. When the negative voltage difference increases to the off voltage of U15, the internal resistance of U15 will increase sharply until the conduction path between the source and the drain of U15 is turned off. Before the conduction path between the source and the drain of U15 is turned on again, the charge on the source of U15 will still be discharged to the source of U17 through U16 and U17, but the voltage drop on the internal resistance of U16 and U17 will gradually decrease, that is, the negative voltage difference between the gate and the source of U15 gradually decreases. When the negative voltage difference is insufficient to support U15 to maintain a high resistance off state, U15 will be turned on and enter a low resistance conduction state. If the current in the circuit is still large at this time, the above process will occur repeatedly, thereby achieving current limiting.

[0082] For details of how the normally-off transistor U16 functions as a unidirectional conduction, please refer to the relevant content in the above embodiment. To save space, no further description is given here.

[0083] As can be seen, the unidirectional conduction protection circuit provided by the present application can realize unidirectional conduction of the circuit due to the inclusion of the normally-off transistor, and can form a current limiting circuit due to the presence of the target normally-on transistor, thereby playing a role in limiting current when the current in the circuit increases.

[0084] In addition, the unidirectional conduction protection circuit provided by the present application can also achieve under-voltage protection. When the voltage in the circuit suddenly drops, the output power of the load generally remains unchanged, so the drop in voltage must result in an increase in current, that is, the current flowing through the unidirectional conduction protection circuit will increase sharply. Since the unidirectional conduction protection circuit provided by the present application can achieve overcurrent protection, the current can also be limited when it increases due to under-voltage, which is equivalent to achieving the function of under-voltage protection. In addition, it is easy to understand that there is at least one normally-off transistor in the unidirectional conduction protection circuit provided by the present application, so when the gate-source bias of the normally-off transistor does not meet a certain threshold condition, the unidirectional conduction protection circuit will also cut off the current path. Therefore, when the voltage in the circuit is too low to cause the normally-off transistor to fail to conduct, the circuit will also enter an off state, which is equivalent to the circuit also having the function of under-voltage protection.

[0085] In addition, the one-way conduction protection circuit can also realize under-current protection. When the circuit current suddenly decreases, the gate-source voltage of the normally-off transistor is obtained from the voltage division of the internal resistance of all the transistors between the drain of the normally-off transistor and the highest potential point of the series circuit and the internal resistance of the normally-off transistor. When the current decreases to a certain value, the voltage division is lower than the threshold of the normally-off transistor, so that the normally-off transistor is in the off state or close to the off state. At this time, the circuit current is rapidly reduced or even completely cut off, which is equivalent to accelerating the circuit cut-off when the under-current occurs, thereby realizing the under-current warning and protection functions.

[0086] Furthermore, in any circuit structure provided by the present application, the normally-off transistor is used to realize the current limiting function. The temperature control current function can also be realized, that is, the current limit value of the circuit is reduced with the increase of the temperature. When the temperature of the protection circuit increases, the internal resistance of the normally-off transistor also increases. In the same current condition, the potential difference between the drain and the source of the normally-off transistor is larger when the temperature is higher. According to the above analysis of the current limiting process, the gate-source negative bias of the target normally-on transistor is also larger, so that the normally-on transistor is more likely to be in the off state when the temperature of the circuit increases, thereby reducing the current limit value of the circuit, which is equivalent to the temperature control current function.

[0087] Optionally, a thermistor can be connected in series in the series circuit, or a thermistor or a thermosensitive sensor can be added to the single-pole double-throw switch circuit, so as to increase the sensitivity of the series protection circuit to the temperature and further enhance the over-temperature protection function of the series protection circuit.

[0088] Optionally, at least one resistive device is connected in series between the first potential point connected to the source of the target normally-on transistor and the second potential point connected to the gate of the target normally-on transistor in the series circuit.

[0089] In order to better understand the circuit provided by the present application, the present application provides the following multiple examples.

[0090] It should be noted that the above examples are only for illustration and are not exhaustive. Any circuit structure obtained or derived from the circuit description provided by the present application belongs to the protection scope of the present application.

[0091] For example, Figure 8 For another one-way conduction protection circuit provided by the present application, the structure schematic diagram is shown in the following figure. Figure 8 In the circuit shown in the figure, U1 is the target normally-on transistor, point A is the first potential point, point B is the second potential point, and the resistance R1 is the resistive device connected in series between the first potential point and the second potential point.

[0092] As a variant of the structure of Figure 8 , the resistor R1 can also be connected in series between the point C and the point B, or on the basis of the original structure, a resistive device is added between the point C and the point B. Figure 8

[0093] Exemplarily, Figure 9 Another structure of the one-way conduction protection circuit provided by the present application is shown in the following figure. Figure 9 In the circuit shown in the figure, U3 and U4 are both target normally-on transistors, A1 and A2 are both first potential points, B is a second potential point, and R1 is a resistive device connected in series between the first potential point A2 and the second potential point B.

[0094] As a variant of the structure of Figure 9 , the resistor R1 can also be connected in series between the point A1 and the point C, or between the point D and the point B, or on the basis of the original structure, a resistive device is added between the point A1 and the point C and / or between the point D and the point B. Figure 9

[0095] By connecting the first potential point connected to the source of the target normally-on transistor and the second potential point connected to the gate of the target normally-on transistor in series in the series circuit, at least one resistive device is connected in series between the two potential points, which can increase the voltage division resistance in the circuit, increase the attenuation amplitude of the voltage on the series circuit, and further increase the negative voltage difference between the gate and the source of the target normally-on transistor and the change thereof, thereby improving the current-limiting response efficiency and speed and enhancing the circuit protection capability.

[0096] Optionally, the gate of any first normally-off transistor in the at least one normally-off transistor is connected in series with a resistive device and / or a capacitive device and / or an inductive device, and the drain of the first normally-off transistor or a potential point in the series circuit having a potential higher than that of the drain of the first normally-off transistor is connected.

[0097] In order to better understand the circuit provided by the present application, the present application provides the following examples.

[0098] It should be noted that this is only an example and is not exhaustive, and any circuit structure that can be derived or deduced from the circuit description provided by the present application belongs to the protection scope of the present application.

[0099] Exemplarily, Figure 10 Another structure of the one-way conduction protection circuit provided by the present application is shown in the following figure. Figure 10 In the circuit shown in the figure, the gate of the normally-off transistor U2 is connected in series with the device U3 and then connected to the drain of the normally-on transistor U1, wherein Ua is a resistive device and / or a capacitive device and / or an inductive device. See Figure 10 ​​It can be seen that the drain of U1 is located in the series circuit, and the potential thereof is higher than that of the drain of U2.

[0100] Exemplarily, Figure 11 Another structure schematic diagram of the one-way conduction protection circuit provided by the present application is shown in the following figure. Figure 11 In the circuit shown in the figure, the gate of the normally-off transistor U16 is connected to the drain of the normally-on transistor U16 in series with the device U3, wherein Ua is a resistive device and / or a capacitive device and / or an inductive device.

[0101] When the single resistive device (R), capacitive device (C), inductive device (L) or the series-parallel combination circuit of at least two devices in RCL is connected in series between the loop between the gate and the drain of the normally-off transistor, the main scenario in which it plays a role is when the normally-off device is a PGaN gate GaN HEMT device, because there will be gate-source leakage between the gate and the source of the PGaN gate GaN HEMT device, and by adding the RCL device or the combination thereof, the function of adjusting and stabilizing the gate-source voltage of the normally-off device can be achieved.

[0102] Optionally, after the gate of the target normally-on transistor is connected in series with the resistive device and / or the capacitive device and / or the inductive device, the connection is connected to the potential point in the series circuit which is lower than the potential of the source of the target normally-on transistor.

[0103] In order to better understand the circuit provided by the present application, the present application provides a plurality of examples as follows.

[0104] It should be noted that this is only an example and is not exhaustive, and any circuit structure that can be derived or deduced from the circuit description provided by the present application belongs to the protection scope of the present application.

[0105] Exemplarily, Figure 12 Another structure schematic diagram of the one-way conduction protection circuit provided by the present application is shown in the following figure. Figure 12 In the circuit shown in the figure, the gate of the target normally-on transistor U1 is connected to the source of the normally-off transistor U2 in series with the device U6, wherein Ub is a resistive device and / or a capacitive device and / or an inductive device. See Figure 12 It can be seen that the potential of the source of U2 is lower than that of the source of U1.

[0106] Exemplarily, Figure 13 Another structure schematic diagram of the one-way conduction protection circuit provided by the present application is shown in the following figure. Figure 13 In the circuit shown in the figure, the gate of the target normally-on transistor U3 is connected to the source of the normally-off transistor U5 in series with the device U6, wherein Ub is a resistive device and / or a capacitive device and / or an inductive device. See Figure 13 It can be seen that the potential of the source of U5 is lower than that of the source of U3.

[0107] As Figure 13 a variant structure, Ub can also be connected in series between the gate of U4 and the source of U5, or, on the basis of the original structure, a resistive device and / or a capacitive device and / or an inductive device is connected in series between the gate of U4 and the source of U5. Figure 13

[0108] Optionally, after connecting a resistive device and / or a capacitive device and / or an inductive device in series at the gate of any first normally-on transistor other than the target normally-on transistor, the potential point in the series circuit lower than or equal to the potential of the source of the first normally-on transistor is connected.

[0109] In order to better understand the circuit provided by the present application, the present application provides a plurality of examples as follows.

[0110] It should be noted that this is only an example and is not exhaustive, and any circuit structure that can be derived or deduced from the description of the circuit provided by the present application belongs to the protection scope of the present application.

[0111] Exemplarily, Figure 14 the structure diagram of another one-way conduction protection circuit provided by the present application is shown in the circuit as Figure 14 shown, the gate of the non-target normally-on transistor U7 is connected to the source of U7 through a resistive device and / or a capacitive device and / or an inductive device Uc, wherein Uc is a resistive device and / or a capacitive device and / or an inductive device.

[0112] Exemplarily, Figure 15 the structure diagram of another one-way conduction protection circuit provided by the present application is shown in the circuit as Figure 15 shown, the gate of the non-target normally-on transistor U17 is connected to the source of U17 through a resistive device and / or a capacitive device and / or an inductive device Uc, wherein Uc is a resistive device and / or a capacitive device and / or an inductive device.

[0113] When the RCL three devices or the series-parallel combination of at least two of the three devices are connected in series between the gate and the source of the normally-on transistor, the main function is to generate an impedance effect when the gate-source capacitor of the normally-on transistor is charged, so that the gate voltage change of the normally-on transistor produces a delay phase, and the source voltage change of the normally-on transistor is real-time, thus accelerating the turn-off speed of the normally-on transistor.

[0114] ​The single RCL or the series-parallel combination circuit of at least two devices in the RCL functions to generate an equivalent resistance or an equivalent RC / LC oscillation circuit, in other words, to provide impedance for the corresponding circuit. The impedance provided thereby can also serve as a detection resistance to provide information about the change of the relevant voltage in the unidirectional conduction protection circuit to an external detection device or circuit, so that the external detection device or circuit judges the state of the unidirectional conduction protection circuit and triggers corresponding actions, such as turning off the unidirectional conduction protection circuit or turning off a system in which the unidirectional conduction protection circuit is embedded, based on the judgment result.

[0115] Optionally, the unidirectional conduction protection circuit provided by the application further comprises at least one single-pole double-throw switch, the fixed end of each single-pole double-throw switch is connected to the gate of a normally-off transistor, the normally-closed end is connected to a potential point in the series circuit which is higher than or equal to the potential of the drain of the corresponding normally-off transistor, and the normally-open end is connected to a potential point in the series circuit which is lower than or equal to the potential of the source of the corresponding normally-off transistor; the single-pole double-throw switch is used to adjust the topology of the unidirectional conduction protection circuit by switching the contact.

[0116] The single-pole double-throw switch can be triggered by a sensor arranged on the single-pole double-throw switch, at this time, the single-pole double-throw switch is a single-pole double-throw switch with a sensor, which can switch the contact to adjust the topology of the unidirectional conduction protection circuit according to the change of the detected target signal. Specifically, the sensor on the single-pole double-throw switch with a sensor can be a temperature sensor, a humidity sensor, a pressure sensor, etc.

[0117] The single-pole double-throw switch can also be triggered by an external control signal, thereby achieving the effect of adjusting the topology of the unidirectional conduction protection circuit by the external control signal. For example, the single-pole double-throw switch can be manually switched by a person according to the demand; or the contact of the single-pole double-throw switch can be switched by an external controller based on a set condition, for example, the timer reaches a preset time result to send a control signal to the single-pole double-throw switch to switch the contact of the single-pole double-throw switch.

[0118] It should be noted that the single-pole double-throw switch can be a mechanical structure or a control circuit composed of several transistors.

[0119] It is easy to understand that the single-pole double-throw switch is only used to make a charging and discharging path on the gate of the normally-off transistor, so it does not need to bear a large current. At the same time, the temperature change of the single-pole double-throw switch is related to the overall temperature change of the circuit. The single-pole double-throw switch can be arranged on the gate of any normally-off device.

[0120] It can be understood that when the unidirectional conduction protection circuit provided by the present application is connected in series in other circuits to form a new circuit structure, the fixed end of the single-pole double-throw switch used to switch the topology of the unidirectional conduction protection circuit through the switching contact is connected to the gate of a normally-off transistor; the normally-closed end is connected to a potential point in the new circuit structure that is higher than or equal to the potential of the drain of the corresponding normally-off transistor, and the potential point is not limited to the potential point in the series circuit that is higher than or equal to the potential of the drain of the corresponding normally-off transistor; and the normally-open end is connected to a potential point in the new circuit structure that is lower than or equal to the potential of the source of the corresponding normally-off transistor, and the potential point is not limited to the potential point in the series circuit that is lower than or equal to the potential of the source of the corresponding normally-off transistor.

[0121] Optionally, the unidirectional conduction protection circuit provided by the present application further comprises: at least one single-pole double-throw switch; the fixed end of each single-pole double-throw switch is connected to the gate of a normally-off transistor, the normally-closed end is connected to a potential point in the series circuit that is higher than or equal to the potential of the drain of the corresponding normally-off transistor, and the normally-open end is connected to a potential point in the series circuit that is lower than or equal to the potential of the source of the corresponding normally-off transistor; and the single-pole double-throw switch is used to switch the topology of the unidirectional conduction protection circuit through the switching contact.

[0122] Further, the way to restore the circuit topology can be to restore the circuit topology by using a bounce-back mechanism, for example, when it is detected that the trigger condition cannot be met, the single-pole double-throw switch automatically disconnects the fixed end and the normally-open end, and connects the fixed end and the normally-closed end, thereby restoring the circuit topology; the way to restore the circuit topology can also be to manually switch the closing mode of the single-pole double-throw switch. In addition, a self-restoring single-pole double-throw switch with a sensor can also be selected, which requires manual intervention to keep the fixed end and the normally-open end conducting for a long time. Further, the closing mode of the single-pole double-throw switch can also be automatically triggered by an external control signal. It should be noted that the present application does not specifically limit the way to restore the circuit topology.

[0123] As can be seen, the unidirectional conduction protection circuit based on a single-pole double-throw switch provided by the present application has recoverability, and its maintenance cost is lower than that of the fuse-type fuse in the prior art.

[0124] In order to better understand the circuit provided by the present application, the present application provides the following multiple examples.

[0125] It should be noted that this is only an example and is not exhaustive, and any circuit structure that can be derived or deduced from the circuit description provided by the present application belongs to the protection scope of the present application.

[0126] For example, Figure 16 For another unidirectional conduction protection circuit provided by the present application, a structure diagram is shown in FIG. 4, which is similar to the structure diagram shown in FIG. 3, and the difference is that the normally-closed end of the single-pole double-throw switch is connected to a potential point in the series circuit that is lower than or equal to the potential of the source of the corresponding normally-off transistor, and the normally-open end is connected to a potential point in the series circuit that is higher than or equal to the potential of the drain of the corresponding normally-off transistor. Figure 16The circuit shown, Figure 16 In Figure 1 The circuit shown, further comprising a single-pole double-throw switch K1, the fixed end a of K1 is connected with the gate of normally-off transistor U2, the normally-closed end b is connected with the drain of normally-on transistor U1, and the normally-open end c is connected with the source of normally-off transistor U2. Referring to Figure 16 It can be seen that the potential of the source of U1 is higher than that of the drain of U2.

[0127] In normal operation, the fixed end a of K1 is connected with the normally-closed end b, and the fixed end a is disconnected with the normally-open end c, at this time, the gate of U2 is connected with the drain of U1, and U2 meets the conduction condition because the potential of the drain of U1 (the potential of the gate of U2) is higher than that of the source of U2. When the switching condition of K1 is detected, the fixed end a of K1 is disconnected with the normally-closed end b, and the fixed end a is connected with the normally-open end c, so that the gate of U2 is disconnected with the drain of U1, and the gate of U2 is connected with the source of U2, achieving the effect of changing the circuit topology. At this time, U2 cannot meet the conduction condition, and will enter the off state.

[0128] Exemplary, Figure 17 Another structure of the one-way conduction protection circuit provided by the present application is shown in the figure, Figure 17 The circuit shown, Figure 17 In Figure 7 The circuit shown, further comprising a single-pole double-throw switch K1, the fixed end a of K1 is connected with the gate of normally-off transistor U2, the normally-closed end b is connected with the drain of normally-off transistor U15, and the normally-open end c is connected with the source of normally-on transistor U17. Referring to Figure 17 It can be seen that the potential of the source of U17 is lower than that of the source of U16.

[0129] In normal operation, the fixed end a of K1 is connected with the normally-closed end b, and the fixed end a is disconnected with the normally-open end c, at this time, the gate of U16 is connected with the source of U15, and U16 meets the conduction condition because the potential of the source of U15 (the potential of the gate of U16) is higher than that of the source of U16. When the switching condition of K1 is detected, the fixed end a of K1 is disconnected with the normally-closed end b, and the fixed end a is connected with the normally-open end c, so that the gate of U16 is disconnected with the source of U15, and the gate of U16 is connected with the source of U17, achieving the effect of changing the circuit topology. At this time, the potential of the source of U17 (the potential of the gate of U16) is lower than that of the source of U16, resulting in that U16 cannot meet the conduction condition, and will enter the off state.

[0130] Through the setting, in normal circumstances, the fixed end and the normally closed end of the single-pole double-throw switch are conducted, at which time the gate and the source of the corresponding normally-off transistor are normally conducted; when the temperature / humidity and the like change and reach the triggering condition, the fixed end and the normally closed end of the single-pole double-throw switch are disconnected, and the fixed end and the normally open end are conducted, at which time the gate and the source of the corresponding normally-off transistor do not meet the conduction condition, and enter the off state, thereby disconnecting the current path of the entire circuit, so as to achieve the effect of over-temperature protection, avoid the device from being burned out, and improve the reliability of the circuit.

[0131] Optionally, the unidirectional conduction protection circuit comprises at least one normally-on GaN HEMT, or at least one normally-on GaN HEMT and at least one normally-off GaN HEMT.

[0132] In other words, when the unidirectional conduction protection circuit only comprises one normally-on transistor, the normally-on transistor is a normally-on GaN HEMT (GaN High electron mobility transistor); when the unidirectional conduction protection circuit comprises multiple normally-on transistors, at least one of the normally-on transistors is a normally-on GaN HEMT. When the unidirectional conduction protection circuit comprises normally-off transistors, the types of the normally-off transistors are not specifically limited, and can all be normally-off GaN HEMTs, can be partially normally-off GaN HEMTs, or can all not be normally-off GaN HEMTs.

[0133] The normally-on GaN HEMT has a natural bidirectional blocking capability, that is, in the case that the gate voltage is lower than the source voltage by a certain gate-source off threshold, the normally-on GaN HEMT will close the conductive channel at the gate-source end, and when the value by which the gate voltage is lower than the source voltage is higher than the gate-source off threshold, the normally-on GaN HEMT is in a conduction state, but when the drain voltage is higher than the gate voltage by a certain gate-drain off threshold, the normally-on GaN HEMT will also close the conductive channel at the gate-drain end.

[0134] When the drain voltage of the normally-on GaN HEMT in the unidirectional conduction protection circuit suddenly rises, the gate voltage of the normally-on GaN HEMT has not yet changed, at which time the normally-on GaN HEMT will close the conductive channel at the gate-drain end, so that the unidirectional conduction protection circuit enters an off state to cut off the current path of the circuit, until the difference between the drain voltage and the gate voltage of the normally-on GaN HEMT is restored to be below the gate-drain off threshold of the normally-on GaN HEMT, and the unidirectional conduction protection circuit is re-conducted, so that the unidirectional conduction protection circuit adopting the normally-on GaN HEMT can also play a role in over-voltage protection.

[0135] It is easy to understand that the GaN HEMT device has the characteristics of small gate capacitance, no body diode, no tail current in the opening and closing process, high working frequency, and the unidirectional conduction protection circuit based on the GaN HEMT device has the characteristics of more stable performance and higher response speed.

[0136] The application further provides a packaged transistor comprising the unidirectional conduction protection circuit according to any one of the above embodiments.

[0137] The packaged transistor only comprises one output terminal and one input terminal, and has simple external pins, facilitating wiring design and low application difficulty.

[0138] The application further provides a monolithic integrated chip comprising the unidirectional conduction protection circuit according to any one of the above embodiments.

[0139] The application further provides an electronic device comprising any one of the packaged transistor and / or the monolithic integrated chip according to the application.

[0140] For example, the packaged transistor and / or the monolithic integrated chip according to the application can be used as an electronic fuse (eFuse). The eFuse can embed various functions for the system embedded therein to protect the system from surge current, overcurrent, overvoltage, reverse current, reverse polarity and short circuit faults. The eFuse is more accurate and faster, and can be self-repaired without user intervention. Its characteristics include but are not limited to no replacement, reduced maintenance cost and time, higher accuracy, accurate degree, integrated function and space saving.

[0141] The above is a further detailed description of the application in combination with specific preferred embodiments, and the specific implementation of the application cannot be limited to these descriptions. For ordinary skilled persons in the technical field to which the application belongs, some simple deductions or replacements can be made without departing from the concept of the application, and all of them shall be regarded as falling within the protection scope of the application.

Claims

1. A unidirectional conduction protection circuit, characterized by comprising: The single-direction-conducting protection circuit comprises at least one normally-on transistor and at least one normally-off transistor. The source and drain of each of the normally-on transistors and each of the normally-off transistors are connected in series to form a series circuit. The gate of each of the normally-on transistors is connected to the series circuit, and there is at least one target normally-on transistor, the gate of which is connected to a potential point in the series circuit that has a lower potential than the source potential of the target normally-on transistor. The gate of any of the normally-off transistors is connected to the drain of the normally-off transistor, or the potential point in the series circuit that has a higher potential than the drain potential of the normally-off transistor. The single-direction-conducting protection circuit further comprises at least one single-pole double-throw switch.

2. The circuit of claim 1, wherein, The fixed end of each of the single-pole double-throw switches is connected to the gate of a normally-off transistor, the normally closed end is connected to a potential point in the series circuit that has a higher or equal potential than the drain potential of the corresponding normally-off transistor, and the normally open end is connected to a potential point in the series circuit that has a lower or equal potential than the source potential of the corresponding normally-off transistor. The single-pole double-throw switch is used to adjust the topology of the single-direction-conducting protection circuit by switching the contact. The single-direction-conducting protection circuit comprises at least one normally-on gallium nitride transistor (GaN HEMT) or at least one normally-on gallium nitride transistor (GaN HEMT) and at least one normally-off gallium nitride transistor (GaN HEMT). Transistors with the same working mode in the series circuit can be connected in series adjacent to each other or can be connected in series with transistors having different working modes, and the working modes include normally-on and normally-off.

3. The circuit of claim 2, wherein, The single-direction-conducting protection circuit comprises one normally-on transistor and one normally-off transistor.

4. The circuit according to any of claims 1 to 3, characterized in that The source of the normally-on transistor is connected to the drain of the normally-off transistor.

5. The circuit according to any of claims 1-3, characterized in that The gate of the normally-on transistor is connected to the source of the normally-off transistor. The gate of the normally-off transistor is connected to the drain or source of the normally-on transistor. The drain of the normally-on transistor is the highest potential end of the single-direction-conducting protection circuit, and the source of the normally-off transistor is the lowest potential end of the single-direction-conducting protection circuit. The single-direction-conducting protection circuit comprises a plurality of normally-on transistors and at least one normally-off transistor. The plurality of normally-on transistors and the at least one normally-off transistor are connected in series to form the series circuit, wherein, 6. The circuit according to any one of claims 1 to 3, characterized in that The first transistor at the highest potential of the series circuit is a normally-off transistor, and the second transistor adjacent to the first transistor is a normally-on transistor, and the gate of the second transistor is connected to the lowest potential of the series circuit. Alternatively, The third transistor at the lowest potential of the series circuit is a normally-off transistor. Alternatively, The first transistor at the highest potential of the series circuit is a normally-on transistor, and the third transistor at the lowest potential of the series circuit is also a normally-on transistor. There is at least one resistive device connected in series between the first potential point connected to the source of the target normally-on transistor and the second potential point connected to the gate of the target normally-on transistor in the series circuit. ​ 7. The circuit according to any of claims 1-3, characterized in that ​ 8. The circuit according to any of claims 1-3, characterized in that connecting the drain of the first normally-off transistor or a potential point in the series circuit higher than the potential of the drain of the first normally-off transistor after the gate of any first normally-off transistor of the at least one normally-off transistor is connected in series with a resistive device and / or a capacitive device and / or an inductive device.

9. The circuit according to any of claims 1-3, characterized in that connecting a potential point in the series circuit lower than the potential of the source of the target normally-on transistor after the gate of the target normally-on transistor is connected in series with a resistive device and / or a capacitive device and / or an inductive device.

10. The circuit according to any one of claims 1 to 3, characterized in that connecting a potential point in the series circuit lower than or equal to the potential of the source of any first normally-on transistor except the target normally-on transistor after the gate of the first normally-on transistor is connected in series with a resistive device and / or a capacitive device and / or an inductive device.

11. A hermetic transistor, characterized by, a unidirectional conduction protection circuit comprising any one of claims 1-10.

12. A monolithically integrated chip, characterized by a unidirectional conduction protection circuit comprising any one of claims 1-10.

13. An electronic device, comprising: a chip comprising any one of the normally-on transistors of claim 11 and / or any one of the monolithic integrated chips of claim 12.

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