CN117240277B

CN117240277B - Substrate selection circuit and electronic equipment

Info

Publication number: CN117240277B
Application number: CN202311522197.0A
Authority: CN
Inventors: 王晨皓; 熊志鹏; 杨志斌; 虞少平; 王敏
Original assignee: Zhejiang Geoforcechip Technology Co Ltd
Current assignee: Zhejiang Geoforcechip Technology Co Ltd
Priority date: 2023-11-15
Filing date: 2023-11-15
Publication date: 2024-02-09
Anticipated expiration: 2043-11-15
Also published as: CN117240277A

Abstract

The application relates to the field of circuits and discloses a substrate selection circuit and electronic equipment, wherein the substrate selection circuit comprises: a power device and a substrate switch module; the drain electrode of the power device is connected with the voltage input end of the substrate switch module, the source electrode of the power device is connected with the voltage output end of the substrate switch module, and the back gate electrode of the power device is connected with the back gate connection end of the substrate switch module; under the condition that the input voltage of the voltage input end is larger than the output voltage of the voltage output end, the substrate switch module controls the back gate connecting end to be connected with the voltage output end; and under the condition that the input voltage is smaller than the output voltage, the substrate switch module controls the back gate connecting end to be connected with the voltage input end. The substrate selection circuit has simple and practical structure, can avoid the defect that the series reverse connection prevention scheme is applied to the power device and has larger layout, and can also avoid the nonlinear change caused by the use of the comparator, thereby reducing the layout area, and ensuring that the production and manufacturing cost of the substrate selection circuit are lower and the practicability is stronger.

Description

Substrate selection circuit and electronic equipment

Technical Field

The present disclosure relates to the field of circuits, and more particularly, to a substrate selection circuit and an electronic device.

Background

The MOS transistor (MOSFET) is a metal oxide semiconductor field effect transistor, and the power MOS transistor is a high-power MOS device. Along with the development of electronic power technology, the power MOS tube has the advantages of good high-frequency performance, small switching loss, high input impedance, small driving power, simple driving circuit and the like, and is widely used as a switch in a switching power supply circuit for power supplies, motors, automobile electronics and other equipment.

However, in the practical application process, the reverse connection phenomenon of the power MOS tube may occur, so that the power MOS tube is likely to be damaged, and a potential safety hazard is brought, so that the power MOS tube needs to be applied to a reverse connection prevention circuit. However, the existing reverse connection preventing circuit for the power MOS tube is complex, so that the cost is high, the area of a circuit layout is large, and a higher integration effect cannot be realized.

In view of the foregoing, it is desirable to provide a substrate selection circuit and an electronic device capable of reducing the layout area.

Disclosure of Invention

The application provides a substrate selection circuit and electronic equipment, which can reduce the area of a circuit layout on the basis of reducing the reverse connection risk of a power MOS tube.

In a first aspect, the present application proposes a substrate selection circuit comprising: a power device and a substrate switch module;

the drain electrode of the power device is connected with the voltage input end of the substrate switch module, the source electrode of the power device is connected with the voltage output end of the substrate switch module, and the back grid electrode of the power device is connected with the back grid connection end of the substrate switch module;

when the input voltage of the voltage input end is larger than the output voltage of the voltage output end, the substrate switch module controls the back gate connecting end to be connected with the voltage output end;

and under the condition that the input voltage is smaller than the output voltage, the substrate switch module controls the back gate connecting end to be connected with the voltage input end.

Optionally, the substrate switch module includes a first switch circuit and a second switch circuit, a voltage input end of the first switch circuit is connected with a voltage input end of the second switch circuit, and a voltage output end of the first switch circuit is connected with a voltage output end of the second switch circuit; the back gate connecting end of the first switch circuit is connected with the back gate connecting end of the second switch circuit;

when the input voltage is larger than the output voltage, the second switch circuit is disconnected, and the first switch circuit controls the circuit between the back gate connecting end of the first switch circuit and the voltage output end of the first switch circuit to be conducted;

and under the condition that the input voltage is smaller than the output voltage, the first switch circuit is disconnected, and the second switch circuit controls the circuit conduction between the back gate connecting end of the second switch circuit and the voltage input end of the second switch circuit.

Optionally, the first switching circuit includes a first switching unit, and the first switching unit includes a first switch;

the first switch is respectively connected with the voltage input end, the voltage output end and the back grid electrode, and is conducted under the condition that the input voltage of the voltage input end is larger than a first preset threshold value, so that the voltage output end is conducted with the back grid electrode.

Optionally, the first switch unit further comprises a first unidirectional subcircuit;

the first unidirectional subcircuit is respectively connected with the voltage input end, the first switch and the grounding end, and under the condition that the input voltage of the voltage input end is larger than a second preset threshold value, the current conducting direction is from the voltage input end to the grounding end.

Optionally, the first switching circuit further includes a second switching unit, and the second switching unit includes a second switch and a third switch;

the third switch is respectively connected with the voltage input end, the voltage output end and the second switch;

the second switch is respectively connected with the voltage output end and the back gate connecting end, and under the condition that the second switch is conducted, the connection between the voltage output end and the back gate connecting end is controlled.

Optionally, the second switching unit further comprises a second unidirectional subcircuit;

the second unidirectional subcircuit is arranged between the third switch and the ground terminal and between the third switch and the second switch; and under the condition that the second unidirectional subcircuit is conducted, protecting the second switch and controlling the second switch to be turned off.

Optionally, the second switch unit further includes a third unidirectional sub-circuit, where the third unidirectional sub-circuit is disposed between the voltage output end of the first switch circuit and the back gate connection end of the first switch circuit, and the current conducting direction is from the back gate connection end of the first switch circuit to the voltage output end of the first switch circuit;

the third unidirectional subcircuit is connected with the voltage output end and the back gate connecting end respectively.

Optionally, the second switching circuit includes a fourth switch;

the fourth switch is connected with the voltage input end, the voltage output end and the back gate connecting end respectively.

Optionally, the second switching circuit further includes: a fourth unidirectional subcircuit;

the fourth unidirectional subcircuit is respectively connected with the back gate connecting end and the voltage output end, and under the condition that the voltage of the back gate connecting end is larger than the voltage output end, the current of the back gate connecting end is controlled to be discharged to the voltage output end.

In a second aspect, there is also provided an electronic device comprising the substrate selection circuit of any of the first aspects.

The application has the advantages that: the substrate switch module that this application used can be under the condition that input voltage is less than output voltage, control back gate link and voltage input end are connected, under the condition that input voltage is greater than output voltage, control back gate link and voltage output end are connected for the back gate link can be connected with voltage input end (input voltage) and voltage output end (output voltage) in the less one of voltage all the time, thereby avoids the reverse connection, can avoid back gate link to be connected with the great one of voltage in the two, has realized the anti-reverse connection function of power MOS pipe. The structure is not added with complex elements such as a comparator, so that nonlinear variation generated by logic 0 or logic 1 output by the comparator can be avoided, nonlinear control is not required to be added in a circuit, the design difficulty of a circuit is reduced, and the required layout area of the part is reduced. In addition, the substrate switch module can enable the back grid electrode of the power device to be connected with the lowest voltage in the voltage input end and the voltage output end through the back grid connection end under most conditions, so that other circuits are not required to be introduced to deal with special conditions, the area of a circuit layout can be further reduced, and the universality is stronger.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the application. Also, like reference numerals are used to designate like parts throughout the figures. In the drawings:

FIG. 1a is a schematic diagram of a power device;

FIG. 1b is a schematic diagram of the connection terminals of the poles of a power device;

FIG. 2 is a schematic diagram of a substrate selection circuit provided in an embodiment of the present application;

FIG. 3 is a schematic diagram of a substrate switch module of a substrate selection circuit provided in an embodiment of the present application;

fig. 4 is a schematic diagram of an operation principle of a first switch circuit of a substrate selection circuit according to an embodiment of the present application;

fig. 5 is a schematic structural diagram of a first switch unit 111 of a substrate selection circuit according to an embodiment of the present application;

fig. 6 is a schematic structural diagram of a second switch unit of the substrate selection circuit according to the embodiment of the present application;

fig. 7 is a schematic structural diagram of a second switch circuit of the substrate selection circuit according to the embodiment of the present application.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

It is noted that unless otherwise indicated, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this application belongs.

Fig. 1a is a typical power device MN0, i.e. a power MOS transistor, including an N-type power MOS transistor with four connection ends, and fig. 1b is a typical connection mode of the power device MN0 as a load switch transistor (power switch transistor). Wherein V is _IN For voltage input terminal, V _OUT G is the gate (switch control end) of the power device MN0, B is the back gate (substrate electrical connection end) of the power device MN0, D is the drain of the power device MN0, and S is the source of the power device MN0. For power device MN0, the desired voltage transmission path is from voltage input terminal V _IN To voltage output terminal V _OUT The remaining transmission paths, e.g. from voltage output terminal V _OUT To voltage input terminal V _IN From voltage output terminal V _OUT Via back gate connection end V _SUB To voltage input terminal V _IN From the back gate connection end V _SUB To voltage input terminal V _IN And the like, are all undesirable voltage transmission paths. Therefore, to achieve the above desired transmission path, it is necessary to secure the back gate connection terminal V _SUB Always select voltage input terminal V _IN And a voltage output terminal V _OUT The lower end of the medium voltage is connected.

The voltage input terminal V is realized by complex circuits such as a comparator in a traditional mode _IN And a voltage output terminal V _OUT And the voltage is selected. Taking the anti-reverse connection scheme of the active comparator as an example, the voltage input end V in the figure 1b is realized due to the introduction of the comparator _IN And a voltage output terminal V _OUT Comparison of the levels, thereby connecting the back gate connection terminal V _SUB Is connected to the voltage input terminal V _IN And a voltage output terminal V _OUT And the output of the comparator is either a logic 0 or a logic 1, whether "0-1" or "1-0", is a nonlinear variable. The nonlinear variable quantity needs to introduce nonlinear control, so that the difficulty of line design is increased, and additional layout area is needed.

The existing other method is a series reverse connection preventing scheme, however, when the series reverse connection preventing channel is applied to a special condition of a power device, which has high power output and low on-resistance, a larger layout area is necessarily introduced, and the layout area is generally four times that of a circuit without reverse connection preventing.

Therefore, the existing scheme for preventing reverse connection of the power device not only can increase the difficulty of circuit design, but also needs larger layout area.

In order to solve the above problems, a substrate selection circuit and an electronic device are provided in an embodiment of the present application. The substrate switch module can enable the back grid of the power device to be connected with the lowest voltage of the voltage input end and the voltage output end through the back grid connecting end under all conditions, and controls the back grid connecting end to be connected with the voltage input end so as to avoid reverse connection under the condition that the input voltage is smaller than the output voltage; therefore, the reverse connection prevention scheme of other circuits for coping with special situations is not required to be introduced, nonlinear change is avoided, the layout area is reduced, nonlinear change quantity caused by logic 0 or logic 1 output generated by using a comparator is avoided, nonlinear control is not required to be added in the circuit, the design difficulty of the circuit is reduced, and the layout area required by the part is reduced. The voltage input end, the voltage output end and the back grid connecting end of the substrate switch module are respectively connected with the drain electrode, the source electrode and the back grid of the power device, and the circuit connection is simple.

Example 1

As shown in fig. 2, a schematic diagram of a substrate selection circuit according to an embodiment of the present application is provided, where the substrate selection circuit includes: a power device MN0 and a substrate switch module 100. The drain electrode of the power device MN0 is connected to the voltage input end of the substrate switch module 100, the source electrode of the power device MN0 is connected to the voltage output end of the substrate switch module 100, and the back gate electrode (back gate end) of the power device MN0 is connected to the back gate connection end of the substrate switch module 100; in the case that the input voltage of the voltage input terminal is greater than the output voltage of the voltage output terminal, the substrate switch module 100 controls the back gate connection terminal to be connected with the voltage output terminal; in the case where the input voltage is less than the output voltage, the substrate switch module 100 controls the back gate connection to connect with the voltage input.

The power device may be any power mosfet, optionally an N-type power mosfet, and the back gate (Body pin) of the power device may be understood as a pin for controlling the working state of the power MOS transistor to implement a specific function, and the substrate switch module may be a circuit structure for adjusting the back gate connection end connected to the back gate of the power device and the voltage output end or the voltage input end, and the specific structure of the embodiment is not limited as long as the connection between the back gate connection end and the voltage output end or the voltage input end can be adjusted.

The substrate switch module 100 can control the back gate connection terminal to be connected with the voltage input terminal when the input voltage of the voltage input terminal is smaller than the output voltage of the voltage output terminal, and control the back gate connection terminal to be connected with the voltage output terminal when the input voltage of the voltage input terminal is larger than the output voltage of the voltage output terminal, so that the back gate connection terminal can be always connected with the smaller one of the voltage input terminal and the voltage output terminal, thereby realizing the anti-reverse connection function of the power MOS tube. The non-linear variable quantity generated by logic 0 or logic 1 output by the comparator can be avoided because the comparator is not used, so that non-linear control is not required to be added in a circuit, the design difficulty of a circuit can be reduced, and the layout area required by a non-linear control part can be reduced. In addition, the substrate switch module 100 of the present application can make the back gate of the power device MN0 be connected with the lowest voltage of the voltage input end and the voltage output end through the back gate connection end in most cases, so that other circuits do not need to be introduced to cope with special situations, thereby further reducing the area of the circuit layout and having stronger universality.

Fig. 3 is a schematic diagram of a substrate switch module 100 of a substrate selection circuit according to an embodiment of the present application, where, as shown in fig. 3, the substrate switch module 100 includes a first switch circuit 101 and a second switch circuit 102, a voltage input terminal of the first switch circuit 101 is connected to a voltage input terminal of the second switch circuit 102, and a voltage output terminal of the first switch circuit 101 is connected to a voltage output terminal of the second switch circuit 102; the back gate connection terminal of the first switch circuit 101 is connected to the back gate connection terminal of the second switch circuit 102. In the case where the input voltage is greater than the output voltage, the second switch circuit 102 is turned off, and the first switch circuit 101 controls the circuit between the back gate connection terminal of the first switch circuit 101 and the voltage output terminal of the first switch circuit 101 to be turned on. In the case where the input voltage is smaller than the output voltage, the first switch circuit 101 is turned off, and the second switch circuit 102 controls the circuit between the back gate connection terminal of the second switch circuit 102 and the voltage input terminal of the second switch circuit 102 to be turned on.

In this embodiment, the substrate switch module 100 including the first switch circuit 101 and the second switch circuit 102 is provided, where the first switch circuit 101 may conduct the voltage output terminal with the back gate connection terminal when the input voltage of the voltage input terminal is greater than the output voltage of the voltage output terminal, and the second switch circuit 102 may conduct the voltage input terminal with the back gate connection terminal when the output voltage of the voltage output terminal is greater than the input voltage of the voltage input terminal, so that the connection between the back gate of the power device and the end with lower voltage is achieved through the two switch circuits, and the structure of the substrate circuit is more stable and safer.

Fig. 4 shows a schematic diagram of the operation principle of the first switch circuit 101 of the substrate selection circuit provided in the embodiment of the present application, and fig. 5 shows a schematic diagram of the structure of the first switch unit 111 of the substrate selection circuit provided in the embodiment of the present application, where, as shown in fig. 4 and fig. 5, the first switch circuit 101 includes the first switch unit 111, and the first switch unit 111 includes the first switch. The first switch is connected to the voltage input terminal VIN, the voltage output terminal VOUT, and the back gate B (back gate connection terminal V _SUB ) Is connected with voltage inputWhen the input voltage of the terminal VIN is greater than the first preset threshold, the first switch is turned on, so that the voltage output terminal VOUT is turned on with the back gate B. The first preset threshold is a value capable of conducting the first switch.

In practical application, the first switch circuit 101 including the first switch unit 111 is provided, where the first switch unit 111 may switch on the voltage output terminal and the back gate connection terminal when the input voltage of the voltage input terminal is greater than the output voltage of the voltage output terminal, and disconnect the voltage output terminal and the back gate connection terminal when the output voltage of the voltage output terminal is greater than the input voltage of the voltage input terminal, so that when the voltage of the voltage output terminal is lower, the back gate of the power device is connected with the voltage output terminal, and when the input voltage of the voltage input terminal is lower, the back gate of the power device is disconnected from the voltage output terminal, and one end with a larger voltage is prevented from being switched on with the back gate connection terminal, so as to protect the power device MN0.

In some embodiments, as shown in fig. 5, the first switching unit 111 further includes a first unidirectional sub-circuit. The first unidirectional sub-circuit is respectively connected with the voltage input end V _IN The first switch is connected with the ground GND, the voltage input terminal V _IN Under the condition that the input voltage of the voltage transformer is larger than a second preset threshold value, the current conducting direction is a voltage input end V _IN To ground GND. The ground GND may be the 0 point potential of the substrate selection circuit of the present application. Specifically, the first switch unit 111 includes a fifth NMOS transistor MN5, and a gate and a voltage input terminal V of the fifth NMOS transistor MN5 _IN Is connected with the connecting end V of the source electrode and the back gate _SUB Is connected with the drain electrode and the voltage output end V _OUT Is connected with each other. The gate of the fifth NMOS transistor MN5 is also connected with the first unidirectional subcircuit. The second preset threshold is a value capable of conducting the first unidirectional sub-circuit and keeping the first unidirectional sub-circuit in a conducting state.

The ground terminal is understood to mean the lowest potential of the substrate selection circuit, which is not necessarily directly grounded, but may be connected to a negative bus or a zero voltage, etc.

The first unidirectional subcircuit is used for realizing a back gate connecting terminalV _SUB To voltage output terminal V _OUT Short circuit (unidirectional low resistance effect) and can be used as voltage output terminal V _OUT Opposite back gate connecting end V _SUB The first switching unit 111 is more stable.

Specifically, the first unidirectional subcircuit comprises at least two PMOS tubes connected in series. Taking the example that the first unidirectional sub-circuit comprises a first PMOS tube MP1 and a second PMOS tube MP2 which are connected in series, the source stage of the first PMOS tube MP1 and a voltage input end V _IN The grid electrode and the drain electrode are connected with the source stage of the second PMOS tube MP 2; the gate and the drain of the second PMOS tube MP2 are grounded.

It should be understood that the structure of the first unidirectional sub-circuit is just one implementation of the present embodiment, and the present embodiment is not limited thereto, and for example, a plurality of diodes may also be used in series.

The plurality of PMOS tubes connected in series in the first unidirectional sub-circuit form a diode string, but because the area of the PMOS tube is smaller than that of the diode in the process, the layout area of the branch circuit can be reduced on the premise of not influencing the function, the static power consumption is reduced, and meanwhile, the third PMOS tube MP3 can be protected through current limiting, and the third PMOS tube MP3 is prevented from being thermally damaged.

In other embodiments, the first switch circuit 101 may further include a third PMOS transistor MP3, where the third PMOS transistor MP3 is disposed between the first unidirectional sub-circuit and the ground GND. The source of the third PMOS tube MP3 is connected with the grid and the drain of the second PMOS tube MP2, the drain is connected with the grounding end GND, and the grid is connected with the voltage output end V _OUT Is connected with each other.

At voltage input terminal V _IN Is greater than the voltage output terminal V _OUT Under the condition of (1), the third PMOS tube MP3 is started to be connected with the slave voltage input end V _IN The charge of the input first switch unit 111 is discharged. The partial pressure and the current limiting function of the first unidirectional subcircuit can also protect the third PMOS tube MP3 and prevent the third PMOS tube MP3 from being thermally damaged.

Further, the first switch circuit 101 may further include a first resistor R1, the first resistor R1 being disposed at the voltage input terminal V _IN With the first unidirectional sub-electricBetween the ways. One end of the first resistor R1 and the voltage input end V _IN The other end of the first PMOS tube MP1 is connected with the source stage of the first PMOS tube MP 1. The first resistor R1 is used for inputting voltage V _IN Clamping and current limiting are performed on the input voltage of the first switch, so that the opening of the first switch is controlled more stably.

When the voltage is input to V _IN Is connected to an external power supply terminal, a voltage output terminal V _OUT When floating (not connecting any level) or having low resistance to the ground GND, the fifth NMOS transistor MN5 of the first switch is turned on to make the voltage output terminal V _OUT With the back gate connecting end V _SUB And the conduction is realized, so that the function of selecting a lower level by the substrate selection circuit is realized. When the voltage output terminal V _OUT Is connected to an external power supply terminal, a voltage input terminal V _IN When floating (not receiving any level) or having low resistance to ground GND, i.e. voltage output terminal V _OUT Is greater than the voltage input terminal V _IN When the voltage is input, the fifth NMOS transistor MN5 of the first switch is turned off to make the voltage output terminal V _OUT With the back gate connecting end V _SUB And (5) disconnecting.

Fig. 6 shows a schematic structural diagram of a second switching unit 112 of a substrate selection circuit according to an embodiment of the present application, and as shown in fig. 4 and 6, the first switching circuit 101 further includes the second switching unit 112, and the second switching unit 112 includes a second switch and a third switch. Third switch and voltage input terminal V _IN Voltage output terminal V _OUT And the second switch is connected with the voltage output end V _OUT And controlling the conduction of the third switch, and controlling the second switch to be turned off when the third switch is turned on. The second switch is respectively connected with the voltage output terminal V _OUT Back gate connection terminal V _SUB Is connected with the second switch, and controls the voltage output terminal V under the condition of conduction _OUT With the back gate connecting end V _SUB Is conducted between them.

A second switching unit 112 comprising a second switch and a third switch is provided at the voltage output terminal V _OUT Under the condition that the level of the voltage is gradually increased, the third switch and the second switch are sequentially conducted to enable the voltage output terminal V _OUT With the back gate connecting end V _SUB On, thus, at the voltage output terminal V, through two switches _OUT Is gradually close to the voltage input terminal V _IN Under the condition, the back grid electrode of the power device is connected with the end with lower voltage, and the structure of the substrate circuit is more stable.

Specifically, the second switch includes a sixth PMOS transistor MP6, and source stages of the sixth PMOS transistor MP6 are respectively connected to the voltage output terminal V _OUT The output end of the third unidirectional sub-circuit and the third switch are connected, the grid electrode is connected with the output end of the second unidirectional sub-circuit, and the drain electrode is respectively connected with the input end of the third unidirectional sub-circuit and the back grid connection end V _SUB Is connected with each other.

The third switch comprises a sixth NMOS transistor MN6, and a drain electrode and a voltage input end V of the sixth NMOS transistor MN6 _IN Is connected with the source stage of the sixth PMOS tube, the third unidirectional sub-circuit and the voltage output end V respectively _OUT And the source stage is connected with the input end of the second unidirectional subcircuit.

When the voltage is input to V _IN Is connected to an external power supply terminal, a voltage output terminal V _OUT When floating (not connecting any level) or having low resistance to the ground end GND, the sixth NMOS transistor MN6 of the third switch is turned off to turn on the sixth PMOS transistor MP6 of the second switch, thereby enabling the voltage output end V _OUT With the back gate connecting end V _SUB The function of selecting a lower level by the substrate selection circuit is realized by conducting the sixth PMOS tube MP 6. When the voltage output terminal V _OUT Is connected to an external power supply terminal, a voltage input terminal V _IN When floating (not receiving any level) or having low resistance to ground GND, i.e. voltage output terminal V _OUT Is greater than the voltage input terminal V _IN When the voltage is input, the sixth NMOS tube MN6 of the third switch is turned on, the sixth PMOS tube MP6 of the second switch is turned off, and the voltage output end V _OUT With the back gate connecting end V _SUB And (5) disconnecting.

In some embodiments, as shown in fig. 6, the second switching unit 112 may further include a second unidirectional sub-circuit. The second unidirectional subcircuit is arranged between the third switch and the ground terminal GND as well as the second switch; and under the condition that the second unidirectional subcircuit is turned on, protecting the second switch and controlling the second switch to be turned off.

Second one-wayThe sub-circuit can realize the back gate connection end V _SUB To voltage output terminal V _OUT Short circuit (unidirectional low resistance effect) and can be used as voltage output terminal V _OUT Opposite back gate connecting end V _SUB The second switching unit 112 is more stable.

The second unidirectional subcircuit comprises at least two PMOS tubes connected in series. Taking the example that the second unidirectional subcircuit comprises a fourth PMOS tube MP4 and a fifth PMOS tube MP5 which are connected in series, the source stage of the fourth PMOS tube MP4 is connected with the source stage of a sixth NMOS tube MN6, and the grid electrode and the drain electrode are connected with the source stage of the fifth PMOS tube MP 5; the gate and the drain of the fifth PMOS tube MP5 are grounded, and the gate and the drain of the fifth PMOS tube MP5 are also connected with the gate of the sixth PMOS tube MP 6. One or more PMOS tubes connected in series can be further added between the fourth PMOS tube MP4 and the fifth PMOS tube MP 5.

It should be understood that the structure of the second unidirectional sub-circuit is just one implementation of the present embodiment, and the present embodiment is not limited thereto, and for example, a plurality of diodes may also be used in series.

The plurality of PMOS tubes connected in series in the second unidirectional sub-circuit form a diode string, but because the area of the PMOS tube is smaller than that of the diode in the process, the layout area of the branch circuit can be reduced on the premise of not influencing the function, the static power consumption is reduced, and meanwhile, the voltage drop of the MP6 grid electrode of the sixth PMOS tube can be protected through current limiting.

Further, as shown in fig. 6, the second switching unit 112 further includes a third unidirectional sub-circuit. The third unidirectional sub-circuit is arranged at the voltage output terminal V of the first switch circuit 101 _OUT And a back gate connection terminal V of the first switch circuit 101 _SUB The current conduction direction is the back gate connection end V of the first switch circuit 101 _SUB To the voltage output terminal V of the first switch circuit 101 _OUT . The third unidirectional sub-circuit is respectively connected with the voltage output terminal V _OUT Back gate connection terminal V _SUB Is connected with each other.

At the back gate connecting end V _SUB Is greater than the voltage output terminal V _OUT When the third unidirectional subcircuit is turned on, the back gate connection terminal V is controlled _SUB Is discharged toVoltage output terminal V _OUT Thereby protecting the circuit and the power device MN0.

The third unidirectional sub-circuit comprises a first diode D1. Cathode of first diode D1 and voltage output terminal V _OUT Is connected with the anode and the back grid connecting end V _SUB Is connected with each other.

The on-state voltage drop of the diode is approximately in the range of 0.5V to 0.6V. Due to the back gate connection end V _SUB Is likely to be greater than the voltage output terminal V _OUT Therefore, not only the back gate connection terminal V can be discharged through the first diode D1 in the third unidirectional sub-circuit _SUB Can also carry out voltage clamping to realize the back gate connecting terminal V _SUB Voltage-to-voltage output terminal V of (2) _OUT Is provided for the voltage following of the voltage.

In other embodiments, the second switch unit 112 further includes a second resistor R2, the second resistor R2 is disposed at the voltage input terminal V _IN And the second unidirectional subcircuit. One end of the second resistor R2 is connected with the voltage input end V _IN The other end of the first PMOS tube is connected with the source stage of the fourth PMOS tube MP 4.

A second resistor R2 for inputting voltage V _IN Clamping and current limiting are performed on the input voltage of the transformer.

Further, the second switch unit 112 further includes a fourth resistor R4, and the fourth resistor R4 is disposed between the ground GND and the second unidirectional sub-circuit. One end of the fourth resistor R4 is connected with the ground end GND, and the other end of the fourth resistor R4 is connected with the drain electrode of the fifth PMOS tube MP 5.

The fourth resistor R4 can reduce the voltage and current on the line, thereby protecting the gate of the sixth PMOS MP 6.

Fig. 7 is a schematic structural diagram of a second switch circuit 102 of a substrate selection circuit according to an embodiment of the present application, where, as shown in fig. 7, the second switch circuit 102 includes a fourth switch. Fourth switch respectively having voltage input terminal V _IN Voltage output terminal V _OUT Back gate connection terminal V _SUB Is connected with each other.

At voltage output terminal V _OUT Is greater than the voltage of the voltage input terminal V _IN In the case of (a), the voltage output terminal V _OUT Control the fourth switch to turn on, and control the voltage input terminal V to turn on _IN With the back gate connecting end V _SUB And the back grid electrode of the power device is connected with the end with lower voltage by conduction.

Specifically, the fourth switch includes a first NMOS transistor MN1 and a second NMOS transistor MN2 connected in parallel. The gates of the first NMOS transistor MN1 and the second NMOS transistor MN2 are both connected with the voltage output end V _OUT The sources of the first NMOS tube MN1 and the second NMOS tube MN2 are connected with the back gate connecting end V _SUB The drains of the first NMOS tube MN1 and the second NMOS tube MN2 are connected with the voltage input end V _IN Is connected with each other.

Wherein, the back gate of the second NMOS transistor MN2 and the voltage output terminal V _OUT Is connected with each other; the back gate of the first NMOS transistor MN1 is connected to the source thereof.

When the back gate connecting end V _SUB Is greater than the voltage of the voltage input terminal V _IN When, and when the voltage output terminal V _OUT Is greater than the voltage of the voltage input terminal V _IN When (reverse connection time), back gate connecting end V _SUB The current of (2) can flow to the voltage input terminal V through the first NMOS transistor MN1 _IN Thereby connecting end V of back gate _SUB The current of (2) is rapidly discharged to protect the power device MN0. Meanwhile, the second NMOS transistor MN2 can be arranged at the voltage output end V _OUT Is greater than the voltage of the voltage input terminal V _IN In the case of (2), always maintain the back gate connection terminal V _SUB And a voltage input terminal V _IN And the back grid electrode of the power device is connected with the end with lower voltage.

As shown in fig. 7, the second switching circuit 102 further includes a fourth unidirectional sub-circuit. The fourth unidirectional subcircuit is respectively connected with the back gate connecting end V _SUB Voltage output terminal V _OUT Is connected with each other.

At the back gate connecting end V _SUB The voltage is greater than the voltage output terminal V _OUT In the case of (2), the fourth unidirectional sub-circuit enables the back gate connection terminal V to be made _SUB Is discharged to the voltage output terminal V _OUT Thereby protecting the power device MN0.

In particular, the fourth unidirectional sub-circuit may comprise a second diode D2 in parallel, a thirdAn NMOS transistor MN3 and a fourth NMOS transistor MN4. The anode of the second diode D2, the drain electrode of the third NMOS tube MN3 and the drain electrode of the fourth NMOS tube MN4 are all connected with the back gate connecting end V _SUB The cathode of the second diode D2, the source of the third NMOS transistor MN3 and the source of the fourth NMOS transistor MN4 are connected with the voltage output terminal V _OUT Is connected with each other; the gate of the third NMOS transistor MN3 and the voltage output terminal V _OUT Is connected with the grid electrode of the fourth NMOS tube MN4 and the voltage input end V _IN Is connected with each other.

The third NMOS tube MN3, the fourth NMOS tube MN4 and the second diode D2 in the fourth unidirectional subcircuit can realize the back gate connection end V under different conditions _SUB To voltage output terminal V _OUT Is provided with a unidirectional low resistance function, namely, a back gate connecting end V _SUB And a voltage output terminal V _OUT Unidirectional conduction and short circuit, and simultaneously, the second diode D2 can also be used as a voltage output end V _OUT Opposite back gate connecting end V _SUB Electrostatic discharge protection (ESD protection). At voltage input terminal V _IN Is greater than the voltage output terminal V _OUT And the back gate connecting end V _SUB Is also greater than the voltage output terminal V _OUT In the case of (1), the fourth NMOS transistor MN4 is conducted to realize the back gate connection end V _SUB And protects the second diode D2 by dividing the voltage shunt. At voltage output terminal V _OUT Is greater than the voltage of the voltage input terminal V _IN And the back gate connecting end V _SUB Is greater than the voltage output terminal V _OUT In the case of (1), the third NMOS transistor MN3 is turned on to realize the back gate connection terminal V _SUB And protects the second diode D2 by dividing the voltage shunt.

In other embodiments, the second switching circuit 102 further includes a third resistor R3. The third resistor R3 is arranged at the output end and the voltage output end V of the fourth unidirectional sub-circuit _OUT (the source of the third NMOS transistor MN3, the source of the fourth NMOS transistor MN4, and the cathode of the second diode D2).

The third resistor R3 can slow down the back gate connection V realized by the second diode D2 _SUB Level follower voltage output terminal V _OUT The response speed of the level and the voltage division are performed, thereby protecting the fourth unidirectional sub-circuit.

The third NMOS transistor MN3 can be regarded as the voltage output terminal V _OUT Opposite back gate connecting end V _SUB The forward diode of (2) has a voltage output terminal V due to the third resistor R3 _OUT Opposite back gate connecting end V _SUB There is a unidirectional weak conduction branch. Because the grid electrode of the third NMOS tube MN3 is connected with the source electrode of the third NMOS tube MN3 through the third resistor R3, and the source electrode of the third NMOS tube MN3 is in short circuit with the back grid electrode B thereof, the physical characteristics of the MOS tube enable the source electrode to the drain electrode of the third NMOS tube MN3 to present a PN junction, and the PN junction is a parasitic diode of the back grid electrode B to the drain electrode, thereby realizing that a unidirectional weak conduction branch exists from the source electrode to the drain electrode of the third NMOS tube MN 3.

When the voltage is input to V _IN Is connected to an external power supply terminal, a voltage output terminal V _OUT When floating (not connecting any level) or grounding end GND is low-resistance, the first NMOS tube MN1 and the second NMOS tube MN2 of the fourth switch are both turned off, the third NMOS tube MN3 in the fourth unidirectional subcircuit is also turned off, but the fourth NMOS tube MN4 is turned on, so that the back gate connecting end V is caused _SUB Through the fourth NMOS transistor MN4 and the voltage output terminal V _OUT Conducting, when the back gate connecting end V _SUB Is greater than the voltage output terminal V _OUT During the process, the back gate connecting end V _SUB Is discharged through the second diode D2 and the fourth NMOS transistor MN4 in the fourth unidirectional sub-circuit. When the voltage output terminal V _OUT Is connected to an external power supply terminal, a voltage input terminal V _IN When floating (not connecting any level) or having low resistance to the ground end GND, the fourth unidirectional subcircuit is turned off, and the first NMOS transistor MN1 and the second NMOS transistor MN2 of the fourth switch are both turned on, so that the voltage input end V _IN With the back gate connecting end V _SUB And the conduction is realized, so that the function of selecting a lower level by the substrate selection circuit is realized.

The substrate selection circuit for a power device according to the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

For the power device MN0, when the drain D and the voltage input terminal V are connected _IN Is connected with a source S and a voltage output terminal V _OUT Is connected with the back grid B and the back grid connecting end V _SUB When connected, if the voltage output terminal V _OUT And a voltage input terminal V _IN A high-resistance path is arranged between the voltage output terminals V _OUT To voltage input terminal V _IN No current exists between the two; if the back gate connecting end V _SUB And a voltage input terminal V _IN A high-resistance passage is arranged between the back gate connecting ends V _SUB To voltage input terminal V _IN There is no current in between.

During normal power-up of the device (i.e. input voltage through voltage input terminal V _IN Input to substrate selection circuit), voltage output terminal V _OUT And back gate connection end V _SUB Due to voltage input terminal V _IN High resistance, low level, with voltage input terminal V _IN The fifth NMOS transistor MN5 in the first switch is turned on to conduct, and the voltage output terminal V _OUT Opposite back gate connecting end V _SUB The low resistance path of (a) enables the substrate switch module 100 to select a lower level. At the same time, as shown in fig. 5, the fourth NMOS MN4 in the second unidirectional sub-circuit is turned on, and the back gate terminal V is connected _SUB To voltage output terminal V _OUT Exhibiting a low resistance path. When the gate G level of the power device MN0 is raised, the voltage output terminal V is in a conducting state when the power device MN0 is in a conducting state _OUT Is gradually close to the voltage input terminal V _IN The sixth PMOS tube MP6 of the second switch is turned on to turn on the voltage output terminal V _OUT Opposite back gate connecting end V _SUB Is provided. Meanwhile, the fourth NMOS transistor MN4 of the third unidirectional sub-circuit is due to the voltage output terminal V _OUT Is gradually close to the voltage input terminal V _IN Also from an on-state to an off-state. When the gate G level of the power device MN0 drops until the power device MN0 is turned off, the voltage output terminal V _OUT The level drops, the fifth NMOS tube MN5 of the first switch and the fifth PMOS tube MP5 of the second unidirectional sub-circuit still keep on conduction, and meanwhile, the first diode D1 of the third unidirectional sub-circuit can enable the back gate connecting end V to be conducted _SUB Level-follower voltage output terminal V of (2) _OUT Is set to a level of (2).

When the device is abnormal, i.e. voltage output terminal V _OUT Is connected to an external power supply terminal, a voltage input terminal V _IN When floating (not connecting any level) or having low resistance to ground GND, voltage output terminal V _OUT High level, voltage input terminal V _IN The first NMOS tube MN1 and the second NMOS tube MN2 of the fourth switch are turned on and turned on at low level, and the voltage input end V _IN Opposite back gate connecting end V _SUB Low-resistance pass voltage input terminal V _IN With the back gate connecting end V _SUB Is connected so as to realize the function of selecting a lower level by the substrate selection circuit.

The first diode D1 in the third unidirectional sub-circuit and the second diode D2 in the fourth unidirectional sub-circuit both serve as the back gate connection terminal V _SUB To voltage output terminal V _OUT Is used for unidirectional low resistance, i.e. the two diodes both serve to connect the back gate to the terminal V _SUB And a voltage output terminal V _OUT Unidirectional conduction and short circuit, and simultaneously, the first diode D1 and the second diode D2 can also be used as a voltage output end V _OUT Opposite back gate connecting end V _SUB Electrostatic discharge protection (ESD protection). The third resistor R3 can slow down the back gate connection V realized by the second diode D2 _SUB Level follower voltage output terminal V _OUT Response speed of the level.

Example two

The application also provides an electronic device comprising a substrate selection circuit as described above. The electronic device may be, but not limited to, a circuit board, a chip, etc. including the substrate selection circuit, for example, a single chip microcomputer, or other electronic products including the substrate selection circuit, which is not specifically limited in this embodiment.

The electronic device provided in this embodiment, which applies the substrate selection circuit and is based on the same concept as the substrate selection circuit, can at least achieve the above-mentioned beneficial effects, and any of the above-mentioned embodiments can be applied to the electronic device provided in this embodiment, and will not be described here again.

It should be noted that the above-mentioned embodiments illustrate rather than limit the application, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the embodiments, and are intended to be included within the scope of the claims and description. In particular, the technical features mentioned in the various embodiments can be combined in any way as long as there is no structural conflict

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The application may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The use of the words first, second, third, etc. do not denote any order. These words may be interpreted as names.

The foregoing is merely a preferred embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions easily conceivable by those skilled in the art within the technical scope of the present application should be covered in the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A substrate selection circuit for a power device, comprising: a power device and a substrate switch module;

when the input voltage is smaller than the output voltage, the substrate switch module controls the back gate connecting end to be connected with the voltage input end;

the substrate switch module comprises a first switch circuit and a second switch circuit, wherein the voltage input end of the first switch circuit is connected with the voltage input end of the second switch circuit, and the voltage output end of the first switch circuit is connected with the voltage output end of the second switch circuit; the back gate connecting end of the first switch circuit is connected with the back gate connecting end of the second switch circuit;

2. The substrate selection circuit of claim 1, wherein the first switching circuit comprises a first switching unit comprising a first switch;

3. The substrate selection circuit of claim 2, wherein the first switching unit further comprises a first unidirectional subcircuit;

4. The substrate selection circuit of claim 1, wherein the first switching circuit further comprises a second switching unit comprising a second switch and a third switch;

5. The substrate selection circuit of claim 4, wherein the second switching unit further comprises a second unidirectional subcircuit;

6. The substrate selection circuit of claim 4, wherein the second switching unit further comprises a third unidirectional sub-circuit disposed between the voltage output terminal of the first switching circuit and the back gate connection terminal of the first switching circuit, the current conduction direction being from the back gate connection terminal of the first switching circuit to the voltage output terminal of the first switching circuit;

7. The substrate selection circuit of claim 1, wherein the second switching circuit comprises a fourth switch;

8. The substrate selection circuit of claim 7, wherein the second switching circuit further comprises: a fourth unidirectional subcircuit;

9. An electronic device comprising the substrate selection circuit of any one of claims 1-8.