Substrate potential management circuit

Abstract

The utility model provides a kind of substrate potential management circuit, applied in bidirectional switch device, comprising: first diode, anode connects the substrate of bidirectional switch device, cathode connects the drain of bidirectional switch device;Second diode, anode connects the substrate of bidirectional switch device, cathode connects the source of bidirectional switch device;Third diode, anode connects the substrate of bidirectional switch device, cathode connects the gate of bidirectional switch device.Through the substrate potential management circuit provided by the utility model, the problem that the substrate bias effect caused by the direct connection of substrate and drain or source in the prior art bidirectional switch device is solved.

Description

Technical Field

[0001] This utility model relates to the field of integrated circuit design technology, and in particular to a substrate potential management circuit. Background Technology

[0002] In traditional gallium nitride-based power devices, the substrate is mostly directly connected to the source via a TGV (Through GaN Via); therefore, there is no substrate bias effect. However, in recent years, bidirectional devices, namely bidirectional switching (BDS) devices, have been developed based on lateral power devices. In these devices, the substrate cannot be directly connected to the drain or source, otherwise a substrate bias effect will occur.

[0003] Taking the direct connection between the substrate and the source as an example, for applications where the drain is at a low voltage end and the source is at a high voltage end, this connection method will generate a substrate bias effect, thereby affecting the device threshold and on-resistance. Therefore, how to reduce the substrate bias effect of bidirectional switching devices through substrate potential management design has become a technical problem that those skilled in the art urgently want to solve.

[0004] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this utility model and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this utility model. Utility Model Content

[0005] In view of the shortcomings of the prior art described above, the purpose of this utility model is to provide a substrate potential management circuit to solve the problem of substrate bias effect caused by the direct connection of the substrate to the drain or source in the bidirectional switching device in the prior art.

[0006] To achieve the above and other related objectives, this utility model provides a substrate potential management circuit for use in a bidirectional switching device, comprising a first diode, a second diode, and a third diode, wherein:

[0007] The anode of the first diode is connected to the substrate of the bidirectional switching device, and the cathode of the first diode is connected to the drain of the bidirectional switching device;

[0008] The anode of the second diode is connected to the substrate of the bidirectional switching device, and the cathode of the second diode is connected to the source of the bidirectional switching device;

[0009] The anode of the third diode is connected to the substrate of the bidirectional switching device, and the cathode of the third diode is connected to the gate of the bidirectional switching device.

[0010] Optionally, the first diode is implemented using a transistor, wherein the gate and source of the transistor are shorted together as the anode, and the drain of the transistor is implemented as the cathode; or, the first diode is implemented using a Schottky diode.

[0011] Optionally, the second diode is implemented using a transistor, wherein the gate and source of the transistor are shorted together as the anode, and the drain of the transistor is implemented as the cathode; or, the second diode is implemented using a Schottky diode.

[0012] Optionally, the third diode is implemented using a transistor, wherein the gate and source of the transistor are shorted together as the anode, and the drain of the transistor is implemented as the cathode; or, the third diode is implemented using a Schottky diode.

[0013] Optionally, each diode is implemented in the same way; wherein, when each diode is implemented using a transistor, the structure of each transistor is consistent with the structure of the bidirectional switching device.

[0014] Optionally, in the bidirectional switching device, when the source is used as a low potential terminal, the substrate potential corresponding to the device's off state and on state is the same, satisfying the formula VSUB=VS+VF, where VSUB is the substrate potential, VS is the source potential, and VF is the forward voltage drop of the diode.

[0015] Optionally, in the bidirectional switching device, when the drain is used as a low potential terminal, the substrate potential corresponding to the device's off state and on state is the same, satisfying the formula VSUB=VD+VF, where VSUB is the substrate potential, VD is the drain potential, and VF is the forward voltage drop of the diode.

[0016] Optionally, the first diode, the second diode, and the third diode are monolithically integrated into the bidirectional switching device.

[0017] Optionally, the bidirectional switching device includes a gallium nitride-based bidirectional switching device.

[0018] Optionally, the bidirectional switching device includes a high electron mobility transistor.

[0019] As described above, the substrate potential management circuit of this invention, through the design of three diodes, enables the substrate potential of the bidirectional switching device to remain consistent and close to a low potential regardless of the application or state of the bidirectional switching device. This reduces the substrate bias effect, decreases the device threshold and on-resistance, and better meets the requirements of bidirectional applications. Attached Figure Description

[0020] Figure 1The diagram shown is a schematic of a substrate potential management circuit in an embodiment of this utility model, wherein each diode is implemented using a Schottky diode.

[0021] Figure 2 This is a schematic diagram of another structure of the substrate potential management circuit in an embodiment of the present invention, wherein each diode is implemented using a transistor.

[0022] Figure 3 (a) and (b) are shown as Figure 1 The diagram shows the equivalent structure of the bidirectional switching device in the off state in the first application.

[0023] Figure 4 (a) and (b) are shown as Figure 1 The diagram shows the equivalent structure of the bidirectional switching device in the on state in the first application.

[0024] Figure 5 (a) and (b) are shown as Figure 1 The diagram shows the equivalent structure of the bidirectional switching device in the off state in the second application.

[0025] Figure 6 (a) and (b) are shown as Figure 1 The diagram shows the equivalent structure of the bidirectional switching device in the on state in the second application.

[0026] Component labeling explanation: 100 Substrate potential management circuit. Detailed Implementation

[0027] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model.

[0028] Please see Figures 1 to 6 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this utility model. Therefore, the illustrations only show the components related to this utility model and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the shape, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0029] like Figure 1 and Figure 2As shown, this embodiment provides a substrate potential management circuit 100, including a first diode D1, a second diode D2, and a third diode D3; wherein, the substrate potential management circuit 100 is applied in a bidirectional switching device MT to manage the substrate potential of the bidirectional switching device MT, thereby reducing the substrate bias effect.

[0030] The anode of the first diode D1 is connected to the substrate (i.e., the SUB terminal) of the bidirectional switching device MT, and the cathode of the first diode D1 is connected to the drain (i.e., the D terminal) of the bidirectional switching device MT.

[0031] In one implementation, such as Figure 1 As shown, the first diode D1 is implemented using a Schottky diode. In another embodiment, as... Figure 2 As shown, the first diode D1 is implemented using a transistor; for example, this transistor is referred to as the first transistor, wherein the gate and source of the first transistor are shorted together as the anode of the first diode D1, and the drain of the first transistor is used as the cathode of the first diode D1.

[0032] The anode of the second diode D2 is connected to the substrate (i.e., the SUB terminal) of the bidirectional switching device MT, and the cathode of the second diode D2 is connected to the source (i.e., the S terminal) of the bidirectional switching device MT.

[0033] In one implementation, such as Figure 1 As shown, the second diode D2 is implemented using a Schottky diode. In another embodiment, as... Figure 2 As shown, the second diode D2 is implemented using a transistor; for example, this transistor is referred to as the second transistor, wherein the gate and source of the second transistor are shorted together as the anode of the second diode D2, and the drain of the second transistor is used as the cathode of the second diode D2.

[0034] The anode of the third diode D3 is connected to the substrate (i.e., the SUB terminal) of the bidirectional switching device MT, and the cathode of the third diode D3 is connected to the gate (i.e., the G terminal) of the bidirectional switching device MT.

[0035] In one implementation, such as Figure 1 As shown, the third diode D3 is implemented using a Schottky diode. In another embodiment, as... Figure 2 As shown, the third diode D3 is implemented using a transistor; for example, this transistor is referred to as the third transistor, wherein the gate and source of the third transistor are shorted together as the anode of the third diode D3, and the drain of the third transistor is used as the cathode of the third diode D3.

[0036] In practical applications, diodes D1, D2, and D3 are typically implemented in the same way to simplify manufacturing; for example, each diode may be implemented using a Schottky diode, such as... Figure 1 As shown, for example, each diode is implemented using a transistor, such as... Figure 2 As shown. In addition, the first diode D1, the second diode D2, and the third diode D3 are all monolithically integrated into the bidirectional switching device MT to complete the circuit design during front-end device manufacturing.

[0037] When all diodes are implemented using Schottky diodes, the forward voltage drop of Schottky diodes is relatively small, i.e., the VF value is small. This allows the substrate potential of the bidirectional switching device MT to fluctuate less, bringing it closer to a low potential, thus better meeting the requirements of bidirectional applications. However, the process technology of Schottky diodes is slightly incompatible with that of bidirectional switching devices MT, which may require some additional process steps during device manufacturing, thereby affecting manufacturing costs.

[0038] When each diode is implemented using transistors, the structure of each transistor is consistent with that of the bidirectional switching device (MT), and they share the same substrate. As an alternative, the bidirectional switching device (MT) includes gallium nitride-based bidirectional switching devices; of course, other material-based bidirectional switching devices, such as silicon-based devices, are also feasible. Furthermore, the bidirectional switching device (MT) includes high electron mobility transistors (HEMTs). Correspondingly, each transistor is also a gallium nitride-based HEMT. Although using transistors to construct diodes results in a slightly larger forward voltage drop compared to Schottky diodes, the transistor manufacturing process is compatible with that of the bidirectional switching device (MT), allowing for simultaneous manufacturing without incurring additional manufacturing costs.

[0039] The substrate potential management circuit 100 in this embodiment has excellent symmetry characteristics. Regardless of the application or state of the bidirectional switching device MT, it can keep the substrate potential of the bidirectional switching device MT consistent and always close to the low potential, thereby reducing the substrate bias effect and better meeting the requirements of bidirectional applications.

[0040] For the first application, in the bidirectional switching device MT, the source (i.e., the S terminal) is used as the low potential terminal, and the drain (i.e., the D terminal) is used as the high potential terminal.

[0041] When the bidirectional switching device MT is in the off state (i.e., off-state), the gate potential is low and can be considered the same as the source potential; at this time, the substrate potential management circuit 100 can be equivalent to Figure 3 As shown in (a), further, it can be equivalent to Figure 3As shown in (b), RD1 is the reverse conduction resistance of the first diode D1; correspondingly, the substrate potential satisfies the formula VSUB=VS+VF_D2, where VSUB is the substrate potential of the bidirectional switching device MT, VS is the source potential of the bidirectional switching device MT, and VF_D2 is the forward conduction voltage drop of the second diode D2.

[0042] When the bidirectional switching device MT is in the ON state (i.e., the ON state), ignoring the on-resistance of the bidirectional switching device MT, the drain potential is pulled down to the same level as the source potential, while the gate potential is high. At this time, the substrate potential management circuit 100 can be equivalent to... Figure 4 As shown in (a), further, it can be equivalent to Figure 4 As shown in (b), RD3 is the reverse conduction resistance of the third diode D3; correspondingly, the substrate potential satisfies the formula VSUB=VS+VF_D2.

[0043] For the second application, in the bidirectional switching device MT, the drain (i.e., D terminal) is used as the low potential terminal, and the source (i.e., S terminal) is used as the high potential terminal.

[0044] When the bidirectional switching device MT is in the off state (i.e., off state), the gate potential is low and can be considered the same as the drain potential. At this time, the substrate potential management circuit 100 can be equivalent to... Figure 5 As shown in (a), further, it can be equivalent to Figure 5 As shown in (b), RD2 is the reverse conduction resistance of the second diode D2; correspondingly, the substrate potential satisfies the formula VSUB=VD+VF_D1, where VSUB is the substrate potential of the bidirectional switching device MT, VD is the drain potential of the bidirectional switching device MT, and VF_D1 is the forward conduction voltage drop of the first diode D1.

[0045] When the bidirectional switching device MT is in the ON state (i.e., the ON state), ignoring the on-resistance of the bidirectional switching device MT, the source potential is pulled down to the same level as the drain potential, while the gate potential is high. At this time, the substrate potential management circuit 100 can be equivalent to... Figure 6 As shown in (a), further, it can be equivalent to Figure 6 As shown in (b), RD3 is the reverse conduction resistance of the third diode D3; correspondingly, the substrate potential satisfies the formula VSUB=VD+VF_D1.

[0046] Regarding the first application, regardless of whether the bidirectional switching device MT is in the off or on state, its corresponding substrate potential is consistent, satisfying the formula VSUB=VS+VF_D2; regarding the second application, regardless of whether the bidirectional switching device MT is in the off or on state, its corresponding substrate potential is consistent, satisfying the formula VSUB=VD+VF_D1; in both applications, the source potential VS and drain potential VD are both low potentials and can be considered the same, i.e., VS=VD=VL. In addition, the forward voltage drop of the first diode D1 and the forward voltage drop of the second diode D2 can be considered the same, i.e., VF_D1=VF_D2=VF.

[0047] Therefore, regardless of the application or state of the bidirectional switching device MT, its corresponding substrate potential remains consistent, satisfying the formula VSUB = VL + VF, where VL is the low potential and VF is the forward voltage drop of the diode. In practical applications, since the value of VF is very small, VSUB ≈ VL can be considered.

[0048] In summary, the substrate potential management circuit of this invention, through the design of three diodes, ensures that the substrate potential of the bidirectional switching device remains consistent and close to a low potential regardless of the application or state of the device. This reduces the substrate bias effect, decreases the device threshold and on-resistance, and better meets the requirements of bidirectional applications. Therefore, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0049] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A substrate potential management circuit, applied in a bidirectional switching device, characterized in that, It includes a first diode, a second diode, and a third diode, wherein: The anode of the first diode is connected to the substrate of the bidirectional switching device, and the cathode of the first diode is connected to the drain of the bidirectional switching device; The anode of the second diode is connected to the substrate of the bidirectional switching device, and the cathode of the second diode is connected to the source of the bidirectional switching device; The anode of the third diode is connected to the substrate of the bidirectional switching device, and the cathode of the third diode is connected to the gate of the bidirectional switching device.

2. The substrate potential management circuit according to claim 1, characterized in that, The first diode is implemented using a transistor, wherein the gate and source of the transistor are shorted together to form the anode, and the drain of the transistor forms the cathode; or, the first diode is implemented using a Schottky diode.

3. The substrate potential management circuit according to claim 1, characterized in that, The second diode is implemented using a transistor, wherein the gate and source of the transistor are shorted together to serve as the anode, and the drain of the transistor serves as the cathode; or, the second diode is implemented using a Schottky diode.

4. The substrate potential management circuit according to claim 1, characterized in that, The third diode is implemented using a transistor, wherein the gate and source of the transistor are shorted together to serve as the anode, and the drain of the transistor serves as the cathode; or, the third diode is implemented using a Schottky diode.

5. The substrate potential management circuit according to claim 2, 3 or 4, characterized in that, Each diode is implemented in the same way; when each diode is implemented using a transistor, the structure of each transistor is consistent with the structure of the bidirectional switching device.

6. The substrate potential management circuit according to claim 1, characterized in that, In the bidirectional switching device, when the source is used as a low potential terminal, the substrate potential corresponding to the device's off state and on state is the same, satisfying the formula VSUB=VS+VF, where VSUB is the substrate potential, VS is the source potential, and VF is the forward voltage drop of the diode.

7. The substrate potential management circuit according to claim 1, characterized in that, In the bidirectional switching device, when the drain is used as a low potential terminal, the substrate potential corresponding to the device's off state and on state is the same, satisfying the formula VSUB=VD+VF, where VSUB is the substrate potential, VD is the drain potential, and VF is the forward voltage drop of the diode.

8. The substrate potential management circuit according to claim 1, characterized in that, The first diode, the second diode, and the third diode are monolithically integrated into the bidirectional switching device.

9. The substrate potential management circuit according to claim 1, characterized in that, The bidirectional switching device includes a gallium nitride-based bidirectional switching device.

10. The substrate potential management circuit according to claim 9, characterized in that, The bidirectional switching device includes a high electron mobility transistor.

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