CN219436642U - Reverse current protection circuit, electronic device and vehicle - Google Patents
Reverse current protection circuit, electronic device and vehicle Download PDFInfo
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- CN219436642U CN219436642U CN202320440229.1U CN202320440229U CN219436642U CN 219436642 U CN219436642 U CN 219436642U CN 202320440229 U CN202320440229 U CN 202320440229U CN 219436642 U CN219436642 U CN 219436642U
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Abstract
The present disclosure relates to a reverse current protection circuit, an electronic device, and a vehicle, the circuit including: the switching device comprises a switching unit, a first transistor, a second transistor, a first resistor and a second resistor; the first node of the switch unit is connected with the output end of the first transistor, the output end of the first transistor is grounded through the first resistor, the control end of the first transistor is connected with the control end of the second transistor, the output end of the second transistor is grounded through the second resistor, the control end of the second transistor is connected with the output end of the second transistor, the input end of the first transistor is connected with the second node of the switch unit, and the input end of the second transistor is connected with the third node of the switch unit. The scheme of the present disclosure has the characteristics of simple circuit and low cost.
Description
Technical Field
The disclosure relates to the technical field of circuits, and in particular relates to a reverse current protection circuit, electronic equipment and a vehicle.
Background
At present, electronic components on an automobile, such as a Body Controller (BCM), may need to output a voltage to external equipment, such as 5V or 3.3V, and the vehicle power supply of the automobile is mostly 12V or 24V, if the electronic components are mistakenly powered to the vehicle power supply by 5V, the electronic components of the automobile can be burnt out due to reverse current caused by overvoltage under the condition of lack of protection.
In order to avoid this, it is conventional practice to add a separate LDO or DCDC to supply power to the outside for protection, but in doing so, the circuit is complex and the cost is high.
Disclosure of Invention
The embodiment of the disclosure aims to provide a reverse current protection circuit, electronic equipment and a vehicle, wherein the circuit can automatically disconnect an internal circuit from an external circuit under the condition that the external voltage is larger than the internal voltage, so that internal circuit components are protected from being burnt by the reverse current.
To achieve the above object, in a first aspect, the present disclosure provides a reverse current protection circuit, comprising: the switching device comprises a switching unit, a first transistor, a second transistor, a first resistor and a second resistor;
the first node of the switch unit is connected with the output end of the first transistor, the output end of the first transistor is grounded through the first resistor, the control end of the first transistor is connected with the control end of the second transistor, the output end of the second transistor is grounded through the second resistor, the control end of the second transistor is connected with the output end of the second transistor, the input end of the first transistor is connected with the second node of the switch unit, and the input end of the second transistor is connected with the third node of the switch unit.
Optionally, the second node of the switch unit is connected to an external voltage, and the third node of the switch unit is connected to an internal voltage; the internal voltage and the external voltage are both smaller than the maximum withstand voltage of the switch unit, and the external voltage is larger than or equal to the internal voltage.
Optionally, the switch unit includes a PMOS tube.
Optionally, the first node is a gate of the PMOS transistor, the second node is a source of the PMOS transistor, and the third node is a drain of the PMOS transistor.
Optionally, the first transistor and the second transistor each include a PNP transistor.
Optionally, the input end is an emitter of the PNP triode, the output end is a collector of the PNP triode, and the control end is a base of the PNP triode.
Optionally, the threshold voltage range of the switching unit is greater than or equal to 1V and less than or equal to half of the internal voltage.
Optionally, the resistance of the first resistor is less than half of the resistance of the second resistor.
In a second aspect, an embodiment of the present disclosure provides an in-vehicle electronic device, including any one of the reverse current protection circuits described in the first aspect.
In a third aspect, an embodiment of the present disclosure provides a vehicle, including the in-vehicle electronic device of the second aspect.
Through the above technical scheme, the beneficial effects that the embodiment of the disclosure can achieve can include: the embodiment of the disclosure provides a reverse current protection circuit, which comprises a switch unit, a first transistor, a second transistor, a first resistor and a second resistor; the first node of the switch unit is connected with the output end of the first transistor, the output end of the first transistor is grounded through a first resistor, the control end of the first transistor is connected with the control end of the second transistor, the output end of the second transistor is grounded through a second resistor, the control end of the second transistor is connected with the output end of the second transistor, the input end of the first transistor is connected with the second node of the switch unit, and the input end of the second transistor is connected with the third node of the switch unit. The circuit can disconnect the switch unit under the condition that the external voltage is larger than the internal voltage, so that the connection between the internal circuit and the external circuit is automatically disconnected, and the components of the internal circuit are protected from being burnt by reverse current.
Additional features and advantages of the present disclosure will be set forth in the detailed description which follows.
Drawings
The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification, illustrate the disclosure and together with the description serve to explain, but do not limit the disclosure. In the drawings:
fig. 1 is a schematic diagram of an application scenario of a reverse current protection circuit according to an embodiment of the present disclosure;
FIG. 2 is a schematic block diagram of a reverse current protection circuit shown in accordance with one embodiment of the present disclosure;
fig. 3 is a schematic diagram of a reverse current protection circuit shown according to one embodiment of the present disclosure.
Detailed Description
Specific embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating and illustrating the disclosure, are not intended to limit the disclosure.
Before describing the reverse current protection circuit provided by the embodiments of the present disclosure, first, application scenarios related to the present disclosure are described, and fig. 1 is a schematic diagram of an implementation scenario related to various embodiments of the present disclosure, where the implementation scenario may include: at least one reverse current protection circuit, at least one internal voltage module, at least one external voltage module, wherein in various embodiments of the present disclosure, "at least one" may be understood as one or more, the implementation scenario of the present disclosure is illustrated by way of example with respect to one reverse current protection circuit, one internal voltage module, one external voltage module, see fig. 1, the one reverse current protection circuit may be a reverse current protection circuit 100, the one internal voltage module may be an internal voltage 200, and the one external voltage module may be an external voltage 300. Wherein the internal voltage 200 is connected to the external voltage 300 through the reverse current protection circuit 100. For example, the internal voltage 200 may be a voltage of a Body Controller (BCM) entertainment navigation electronic device, which is typically 5V or 3.3V, the external voltage 300 may be an on-board power supply of a vehicle, which is typically 12V or 24V, if the internal voltage 200 and the external voltage 300 are directly connected due to a malfunction without the existence of the reverse current protection circuit 100, since the voltage of the external voltage 300 is higher than that of the internal voltage 200, a situation that an external current flows backward into the internal voltage module to damage electronic components within the internal voltage module may occur, and in case that the reverse current protection circuit 100 exists between the internal voltage 200 and the external voltage 300, the reverse current protection circuit 100 immediately disconnects the external voltage 300 from the internal voltage 200 when the external voltage 300 is greater than the internal voltage 200, thereby protecting the electronic components within the internal voltage module from the reverse current.
Fig. 2 is a schematic block diagram of a reverse current protection circuit according to one embodiment of the present disclosure, as shown in fig. 2, the reverse current protection circuit 100 includes: the switching device includes a switching unit S1, a first transistor Q1, a second transistor Q2, a first resistor R1, and a second resistor R2.
The first node 1 of the switching unit S1 is connected to the output terminal 6 of the first transistor Q1, the output terminal 6 of the first transistor Q1 is grounded through a first resistor R1, the control terminal 5 of the first transistor Q1 is connected to the control terminal 8 of the second transistor Q2, the output terminal 9 of the second transistor Q2 is grounded through a second resistor R2, the control terminal 8 of the second transistor Q2 is connected to the output terminal 9 of the second transistor Q2, the input terminal 4 of the first transistor Q1 is connected to the second node 2 of the switching unit S1, and the input terminal 7 of the second transistor Q2 is connected to the third node 3 of the switching unit S1.
The third node 3 of the switching unit S1 is connected to the internal voltage 200, and the second node 2 of the switching unit S1 is connected to the external voltage 300.
The working principle of the circuit is as follows:
since the control terminal 8 of the second transistor Q2 is pulled to the ground by the second resistor R2, the control terminal 8 of the second transistor Q2 is at a low level, the second transistor Q2 is turned on, the internal voltage 200, the second transistor Q2, and the second resistor R2 are turned on to the circuit, the voltage of the control terminal 8 of the second transistor Q2 is at a high level (close to the voltage of the internal voltage 200) when the current passes through the second resistor R2, and since the voltage of the control terminal 8 of the second transistor Q2 is equal to the voltage of the control terminal 5 of the first transistor Q1, the level of the control terminal 5 of the first transistor Q1 is pulled up.
When the voltage of the external voltage 300 is the same as the voltage of the internal voltage 200, the first transistor Q1 is turned off, the first node 1 (control terminal) of the switching unit S1 is pulled to the ground by the first resistor R1, and the switching unit S1 is turned on, and the internal voltage 200 is connected to the external voltage 300, and the external voltage 300 and the internal voltage 200 are equivalent at this time, so that no reverse current flows into the internal voltage module, and no electronic component in the internal voltage module is burned by the reverse current.
When the voltage of the external voltage 300 is greater than the voltage of the internal voltage 200, since the voltage difference between the input terminal 4 and the control terminal 5 of the first transistor Q1 is greater than the on voltage of the first transistor, the first transistor Q1 is turned on at this time, a voltage drop occurs in the first resistor R1 when a current passes through the first resistor R1, the voltage drop of the first resistor R1 approaches the voltage of the external voltage 300, the first node 1 (control terminal) of the switch unit S1 is pulled high, at this time, the switch unit S1 is turned off, the internal voltage 200 is turned off from the external voltage 300, and at this time, the external voltage 300 and the internal voltage 200 are turned off, so that no reverse current flows into the internal voltage module, and no internal electronic component of the internal voltage module is burned by the reverse current.
In summary, embodiments of the present disclosure provide a reverse current protection circuit, including a switching unit, a first transistor, a second transistor, a first resistor, and a second resistor; the first node of the switch unit is connected with the output end of the first transistor, the output end of the first transistor is grounded through a first resistor, the control end of the first transistor is connected with the control end of the second transistor, the output end of the second transistor is grounded through a second resistor, the control end of the second transistor is connected with the output end of the second transistor, the input end of the first transistor is connected with the second node of the switch unit, and the input end of the second transistor is connected with the third node of the switch unit. The circuit can disconnect the switch unit under the condition that the external voltage is larger than the internal voltage, so that the connection between the internal circuit and the external circuit is automatically disconnected, and the components of the internal circuit are protected from being burnt by reverse current.
Fig. 3 is a schematic diagram of a reverse current protection circuit according to one embodiment of the present disclosure, as shown in fig. 3, the reverse current protection circuit 100 includes: PMOS transistor Q3, PNP transistor Q1, PNP transistor Q2, first resistor R1, and second resistor R2.
The grid G of the PMOS transistor Q3 is connected with the collector of the PNP transistor Q1, the collector of the PNP transistor Q1 is grounded through a first resistor R1, the base of the PNP transistor Q1 is connected with the base of the PNP transistor Q2, the collector of the PNP transistor Q2 is grounded through a second resistor R2, the base of the PNP transistor Q2 is connected with the collector of the PNP transistor Q2, the emitter of the PNP transistor Q1 is connected with the source S of the PMOS transistor Q3, and the emitter of the PNP transistor Q2 is connected with the drain D of the PMOS transistor Q3.
The drain electrode D of the PMOS tube Q3 is connected with the internal voltage VDD1, and the source electrode S of the PMOS tube Q3 is connected with the external voltage VDD2.
The working principle of the circuit is as follows:
since the base of the PNP transistor Q2 is pulled to the ground by the second resistor R2, the base of the PNP transistor Q2 is at a low level, at this time, the PNP transistor Q2 is turned on, the internal voltage VDD1, the PNP transistor Q2, and the second resistor R2 are turned on to the circuit, and when a voltage drop occurs in the second resistor R2 due to a current passing through the second resistor, the base voltage of the PNP transistor Q2 is at a high level (a voltage close to the internal voltage VDD 1), and since the base voltage of the PNP transistor Q2 is equal to the base voltage of the PNP transistor Q1, the base level of the PNP transistor Q1 is pulled high. The circuit operation is analyzed in two cases:
first case: at this time, the voltage of the external voltage VDD2 is the same as the voltage of the internal voltage VDD1, so that the PNP transistor Q1 is also turned on (because the base voltage of Q1 is the same as the base voltage of Q2, and Q2 is turned on, and Q1 is also turned on), and at this time, the voltage vg=ic1×r1 of the gate G (control terminal) of the PMOS transistor Q3.
Since Q1 and Q2 are transistors of the same type, having the same amplification factor, and the base current is also the same ib1=ib2, there is ic1=ic2.
The current IR2 = IC2+ IB1+ IB2 of the resistor R2, since the base currents IB1, IB2 of the transistors Q1 and Q2 are very small, IC2 +.ir 2 = VB2/R2 = (VDD 1-0.7)/R2, where VB2 is the voltage of the base of Q2 and VDD1 is the internal voltage.
Then vg= [ (VDD 1-0.7)/R2 ] r1≡vdd1×r1/R2. Since R1 is smaller than half of R2, the gate voltage VG of the PMOS transistor Q3 is smaller than half of the internal voltage VDD1, and at this time, the internal voltage VDD 1=the external voltage VDD2, and since the threshold voltage of the PMOS transistor Q3 is smaller than half of the internal voltage VDD1, the voltage difference between the source voltage of the PMOS transistor Q3 and the gate voltage VG is larger than the threshold voltage, at this time, the PMOS transistor Q3 is turned on, and the internal voltage VDD1 is communicated with the external voltage VDD2, and since the external voltage VDD2 is equivalent to the internal voltage VDD1, no reverse current flows into the internal voltage module, and no internal electronic component of the internal voltage module is burned by the reverse current.
Second case: at this time, the voltage of the external voltage VDD2 is greater than the voltage of the internal voltage VDD1, and since the voltage difference between the emitter and the base of the PNP transistor Q1 is greater than the turn-on voltage of the PNP transistor, the PNP transistor Q1 is turned on at this time, the voltage drop of the first resistor R1 is close to the voltage of the external voltage VDD2 and is smaller than the voltage of the external voltage VDD2 by a PN junction turn-on voltage drop of 0.7V, at this time, the gate (control end) of the PMOS transistor Q3 is pulled up to a high level, the voltage difference between the source S and the gate G of the PMOS transistor Q3 is 0.7V and less than the threshold voltage (the threshold voltage is 1V at the minimum), at this time, the PMOS transistor Q3 is turned off, the internal voltage VDD1 is turned off from the external voltage VDD2, and since the external voltage VDD2 and the internal voltage VDD1 are turned off at this time, there is no reverse current flowing into the internal voltage module, and no internal electronic components of the internal voltage module are burned out by the reverse current.
The external voltage VDD2 and the internal voltage VDD1 are both smaller than the maximum withstand voltage of the PMOS transistor Q3, so as to ensure that the PMOS transistor Q3 is not broken down.
In summary, the embodiment of the disclosure provides a reverse current protection circuit, which includes a PMOS transistor Q3, a PNP transistor Q1, a PNP transistor Q2, a first resistor R1, and a second resistor R2. The grid G of the PMOS transistor Q3 is connected with the collector of the PNP transistor Q1, the collector of the PNP transistor Q1 is grounded through a first resistor R1, the base of the PNP transistor Q1 is connected with the base of the PNP transistor Q2, the collector of the PNP transistor Q2 is grounded through a second resistor R2, the base of the PNP transistor Q2 is connected with the collector of the PNP transistor Q2, the emitter of the PNP transistor Q1 is connected with the source S of the PMOS transistor Q3, and the emitter of the PNP transistor Q2 is connected with the drain D of the PMOS transistor Q3. The drain electrode D of the PMOS tube Q3 is connected with the internal voltage VDD1, and the source electrode S of the PMOS tube Q3 is connected with the external voltage VDD2. The circuit can disconnect the PMOS tube Q3 under the condition that the external voltage VDD2 is larger than the internal voltage VDD1, thereby automatically disconnecting the internal circuit from the external circuit and protecting the components of the internal circuit from being burnt by reverse current.
The embodiment of the disclosure also provides a vehicle-mounted electronic device, which includes the reverse current protection circuit described in the previous embodiment, and the reverse current protection circuit is used for protecting electronic components inside the device from external voltage.
The embodiment of the disclosure also provides a vehicle, which comprises the vehicle-mounted electronic device described in the previous embodiment, wherein the electronic device can avoid reverse current by external voltage.
The preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, but the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the scope of the technical concept of the present disclosure, for example, the switching unit may be changed to an NMOS transistor, and the first transistor and the second transistor may be changed to an NPN transistor, which all fall within the scope of protection of the present disclosure.
In addition, the specific features described in the foregoing embodiments may be combined in any suitable manner, and the various possible combinations are not described in detail in this disclosure.
Moreover, any combination between the various embodiments of the present disclosure is possible as long as it does not depart from the spirit of the present disclosure, which should also be construed as the disclosure of the present disclosure.
Claims (10)
1. A reverse current protection circuit, comprising: the switching device comprises a switching unit, a first transistor, a second transistor, a first resistor and a second resistor;
the first node of the switch unit is connected with the output end of the first transistor, the output end of the first transistor is grounded through the first resistor, the control end of the first transistor is connected with the control end of the second transistor, the output end of the second transistor is grounded through the second resistor, the control end of the second transistor is connected with the output end of the second transistor, the input end of the first transistor is connected with the second node of the switch unit, and the input end of the second transistor is connected with the third node of the switch unit.
2. The circuit of claim 1, wherein a second node of the switching unit is connected to an external voltage and a third node of the switching unit is connected to an internal voltage;
the internal voltage and the external voltage are both smaller than the maximum withstand voltage of the switch unit, and the external voltage is larger than or equal to the internal voltage.
3. The circuit of claim 2, wherein the switching unit comprises a PMOS transistor.
4. The circuit of claim 3, wherein the first node is a gate of the PMOS transistor, the second node is a source of the PMOS transistor, and the third node is a drain of the PMOS transistor.
5. The circuit of claim 4, wherein the first transistor and the second transistor each comprise a PNP transistor.
6. The circuit of claim 5, wherein the input terminal is an emitter of the PNP transistor, the output terminal is a collector of the PNP transistor, and the control terminal is a base of the PNP transistor.
7. The circuit of claim 2, wherein the threshold voltage range of the switching unit is greater than or equal to 1V and less than or equal to half the internal voltage.
8. The circuit of claim 2, wherein the first resistor has a resistance less than half the resistance of the second resistor.
9. An in-vehicle electronic device comprising the reverse current protection circuit according to any one of claims 1 to 8.
10. A vehicle comprising the in-vehicle electronic apparatus according to claim 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320440229.1U CN219436642U (en) | 2023-03-08 | 2023-03-08 | Reverse current protection circuit, electronic device and vehicle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320440229.1U CN219436642U (en) | 2023-03-08 | 2023-03-08 | Reverse current protection circuit, electronic device and vehicle |
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| Publication Number | Publication Date |
|---|---|
| CN219436642U true CN219436642U (en) | 2023-07-28 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202320440229.1U Active CN219436642U (en) | 2023-03-08 | 2023-03-08 | Reverse current protection circuit, electronic device and vehicle |
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| CN (1) | CN219436642U (en) |
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- 2023-03-08 CN CN202320440229.1U patent/CN219436642U/en active Active
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