Sensor output signal conversion circuit

Abstract

The utility model belongs to the technical field of sensors, and discloses a sensor output signal conversion circuit. The circuit comprises a first conversion unit, a first short-circuit protection unit and a first shunting unit. The first conversion unit is used for being respectively connected with the output end of the NPN type sensor and an output load, and is connected to a power supply voltage through the first short-circuit protection unit, so that an output signal of the NPN type sensor is converted into an output signal of the PNP type sensor, and the output signal is output to the output load; the first short-circuit protection unit is connected with the power supply voltage and the first conversion unit so as to control the first conversion unit to be disconnected during short circuit; the first shunting unit is connected with the first conversion unit and the first short-circuit protection unit so as to shunt short-circuit current during short circuit. The output signal of the NPN type sensor can be converted into the output signal of the PNP type sensor to be output to the load, the output mode of the NPN type sensor is expanded, and the technical problem that the application scene of the NPN type sensor is single is solved.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and in particular to a sensor output signal conversion circuit. Background Art

[0002] At present, the output circuit of most sensors is in the form of an open collector output signal, that is, an NPN transistor collector output and a PNP transistor collector output. For most sensors, considering the production cost and volume of the sensor, usually only one output mode is designed, that is, one of the NPN transistor collector output and the PNP transistor collector output. The corresponding sensors can be called NPN sensors and PNP sensors. However, the problem with a single NPN sensor or PNP sensor is that the scope of use of the sensor is limited. For example, an NPN sensor cannot be used in a scenario where a PNP transistor collector output signal is received. Similarly, a PNP sensor cannot be used in a scenario where an NPN transistor collector output signal is received. Utility Model Content

[0003] In view of the above problems, the present application provides a sensor output signal conversion circuit to solve the above technical problems.

[0004] In a first aspect, the present application provides a sensor output signal conversion circuit, comprising a first conversion unit, a first short-circuit protection unit, and a first shunt unit;

[0005] The first conversion unit is used to connect the output end of the NPN sensor and the output load respectively, and to connect to the power supply voltage through the first short-circuit protection unit, to convert the output signal of the NPN sensor into the output signal of the PNP sensor and output it to the output load;

[0006] The first short-circuit protection unit is connected to the power supply voltage and the first conversion unit respectively to control the first conversion unit to be disconnected when a short circuit occurs;

[0007] The first shunt unit is connected to the first conversion unit and the first short-circuit protection unit respectively to shunt the short-circuit current when a short circuit occurs.

[0008] In some embodiments, the first conversion unit includes a first resistor, a second resistor and a first transistor;

[0009] The first end of the first resistor is used to connect to the output end of the NPN sensor, and the second end of the first resistor is connected to the control end of the first transistor;

[0010] The first end of the second resistor is connected to the first end of the first transistor and the first shunt unit respectively, and the second end of the second resistor is used to connect the output load;

[0011] The control end of the first transistor is also connected to the first short-circuit protection unit so that the first short-circuit protection unit controls the first transistor to be cut off in case of a short circuit. The second end of the first transistor is connected to the first short-circuit protection unit so as to be connected to the power supply voltage via the first short-circuit protection unit.

[0012] In some embodiments, the first short circuit protection unit includes a first capacitor, a third resistor, a fourth resistor, a fifth resistor, a second transistor and a third transistor;

[0013] The first end of the first capacitor is connected to the power supply voltage, the second end of the first capacitor is connected to the second end of the second transistor and the first end of the third resistor respectively, and the second end of the third resistor is connected to the control end of the third transistor;

[0014] The first end of the fourth resistor is connected to the power supply voltage, the second end of the fourth resistor is respectively connected to the first end of the fifth resistor and the second end of the third transistor, and the second end of the fifth resistor is respectively connected to the first conversion unit and the first shunt unit;

[0015] The control end of the second transistor is connected to the first end of the third transistor and is connected to the first conversion unit to control the first conversion unit to be disconnected, and the first end of the second transistor is suspended.

[0016] In some embodiments, the first flow dividing unit comprises:

[0017] A fourth transistor, wherein the control end of the fourth transistor is connected to the first conversion unit, the first end of the fourth transistor is connected to the first short-circuit protection unit to shunt the short-circuit current in the event of a short circuit, and the second end of the fourth transistor is used to connect the output load.

[0018] In some embodiments, the sensor output signal conversion circuit provided in the present application further includes: a first bidirectional transient suppression diode, connected to the power supply voltage and used to connect to the output load.

[0019] In a second aspect, the present application provides a sensor output signal conversion circuit, including a second conversion unit, a second short-circuit protection unit, and a second shunt unit;

[0020] The second conversion unit is used to respectively connect the output end of the PNP sensor and the output load, and is grounded through the second short-circuit protection unit, so as to convert the output signal of the PNP sensor into the output signal of the NPN sensor and output it to the output load;

[0021] The second short-circuit protection unit is connected to the second conversion unit and grounded to control the second conversion unit to be disconnected when a short circuit occurs;

[0022] The second shunt unit is connected to the second conversion unit and the second short-circuit protection unit respectively to shunt the short-circuit current when a short circuit occurs.

[0023] In some embodiments, the second conversion unit includes a sixth resistor, a seventh resistor and a fifth transistor;

[0024] The first end of the sixth resistor is used to connect to the output end of the PNP sensor, and the second end of the sixth resistor is connected to the control end of the fifth transistor;

[0025] The first end of the seventh resistor is connected to the first end of the fifth transistor and the second current dividing unit respectively, and the second end of the seventh resistor is used to connect the output load;

[0026] The control end of the fifth transistor is also connected to the second short-circuit protection unit so that the second short-circuit protection unit controls the fifth transistor to be cut off in case of short circuit. The second end of the fifth transistor is connected to the second short-circuit protection unit so as to be grounded via the second short-circuit protection unit.

[0027] In some embodiments, the second short circuit protection unit includes a second capacitor, an eighth resistor, a ninth resistor, a tenth resistor, a sixth transistor and a seventh transistor;

[0028] A first end of the second capacitor is grounded, a second end of the second capacitor is connected to a second end of the sixth transistor and a first end of the eighth resistor respectively, and a second end of the eighth resistor is connected to a control end of the seventh transistor;

[0029] The first end of the ninth resistor is grounded, the second end of the ninth resistor is respectively connected to the first end of the tenth resistor and the second end of the seventh transistor, and the second end of the tenth resistor is respectively connected to the second conversion unit and the second shunt unit;

[0030] The control end of the sixth transistor is connected to the first end of the seventh transistor and is connected to the second conversion unit to control the second conversion unit to be disconnected, and the first end of the sixth transistor is suspended.

[0031] In some embodiments, the second flow dividing unit comprises:

[0032] An eighth transistor, wherein the control end of the eighth transistor is connected to the second conversion unit, the first end of the eighth transistor is connected to the second short-circuit protection unit to shunt the short-circuit current in the event of a short circuit, and the second end of the eighth transistor is used to connect the output load.

[0033] In some embodiments, the sensor output signal conversion circuit provided by the present application further includes: a second bidirectional transient suppression diode, which is grounded and used to connect the output load.

[0034] The present application provides a sensor output signal conversion circuit, which receives the output signal of an NPN sensor, forms a loop from the power supply voltage to the output load through a first conversion unit, thereby converting the output signal of the NPN sensor into the output signal of a PNP sensor, and provides a first short-circuit protection unit to disconnect the first conversion unit when the circuit is short-circuited, and to shunt the large current caused by the short circuit through a first shunt unit to protect the circuit when the circuit is short-circuited. The present application can convert the output signal of an NPN sensor into the output signal of a PNP sensor and output it to the load, thereby expanding the output mode of the NPN sensor and solving the technical problem of the single application scenario of the NPN sensor.

[0035] The present application also provides a sensor output signal conversion circuit, which receives the output signal of a PNP sensor, forms a loop of an output load and a ground through a second conversion unit, thereby converting the output signal of the PNP sensor into the output signal of an NPN sensor, and setting a second short-circuit protection unit to disconnect the second conversion unit when the circuit is short-circuited, and shunts the large current caused by the short circuit through a second shunt unit to protect the circuit when the circuit is short-circuited. The present application can convert the output signal of a PNP sensor into the output signal of an NPN sensor and output it to a load, expands the output mode of a PNP sensor, and solves the technical problem of a single application scenario of a PNP sensor.

[0036] These and other aspects of the present application will become more clearly understood in the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 A module schematic diagram of a sensor output signal conversion circuit provided in an embodiment of the present application is shown.

[0039] Figure 2A schematic diagram of the structure of a sensor output signal conversion circuit provided in an embodiment of the present application is shown.

[0040] Figure 3 Another structural schematic diagram of the sensor output signal conversion circuit provided in an embodiment of the present application is shown.

[0041] Figure 4 A module schematic diagram of a sensor output signal conversion circuit provided in an embodiment of the present application is shown.

[0042] Figure 5 A schematic diagram of the structure of a sensor output signal conversion circuit provided in an embodiment of the present application is shown.

[0043] Figure 6 Another structural schematic diagram of the sensor output signal conversion circuit provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0044] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0045] In the embodiments of the present application, it should be noted that, in this article, relational terms such as first and second, etc. are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0046] Moreover, the terms "comprises," "comprising," or any other variation thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0047] In addition, the "plurality" in the embodiments of the present application refers to two or more than two. In view of this, the "plurality" in the embodiments of the present application can also be understood as "at least two". "At least one" can be understood as one or more, for example, one, two or more. For example, including at least one means including one, two or more, and there is no limit on which ones are included. For example, including at least one of A, B and C, then A, B, C, A and B, A and C, B and C, or A, B and C can be included.

[0048] It should be noted that in the embodiments of the present application, "connection" can be understood as electrical connection, and the connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be either a direct connection between A and B or an indirect connection between A and B through one or more other electrical components.

[0049] The following first explains the output signals of NPN sensors and PNP sensors.

[0050] NPN type sensor: When a signal is triggered, the collector of the NPN transistor is connected to the 0V line (through the emitter), that is, the load is connected to the collector and power supply of the NPN transistor respectively, which is equivalent to outputting a low level.

[0051] Normally open NPN sensor: When a signal is triggered, the collector of the NPN transistor is connected to the ground (through the emitter) and the output is a low level.

[0052] For a normally closed NPN sensor, when there is no signal trigger, the collector of the NPN transistor is connected to the ground (through the emitter) and the output is a low level.

[0053] PNP type sensor: When a signal is triggered, the collector of the PNP transistor is connected to the power line (through the emitter), that is, the load is connected to the collector and ground of the NPN transistor respectively, which is equivalent to outputting a high level.

[0054] Normally open PNP sensor: When a signal is triggered, the collector of the PNP transistor is connected to the power line (through the emitter) and outputs a high level.

[0055] Normally closed PNP sensor: When there is no signal trigger, the collector of the PNP transistor is connected to the power line (through the emitter) and the output is high.

[0056] The present application embodiment provides a sensor output signal conversion circuit, Figure 1 The module schematic diagram of the sensor output signal conversion circuit provided in the embodiment of the present application is shown as follows: Figure 1 As shown, the circuit includes a first conversion unit 110, a first short-circuit protection unit 210 and a first shunt unit 310;

[0057] The first conversion unit 110 is used to respectively connect the output end of the NPN sensor and the output load, and is connected to the power supply voltage through the first short-circuit protection unit, so that a loop from the power supply voltage VCC to the output load is formed through the first conversion unit, thereby converting the output signal of the NPN sensor into the output signal of the PNP sensor and outputting it to the output load.

[0058] It can be understood that when the NPN sensor is used, its output signal needs to be output to the load, that is, the output load used to connect to the first conversion circuit in the embodiment of the present application. The embodiment of the present application does not limit the form of the output load. For example, the output load can be a PLC device, MCU and other signal processing modules. For example, the output load can also be an indication circuit (such as an indicator light, a buzzer, etc.) for receiving signals to output different indication states.

[0059] The first short-circuit protection unit 210 is connected to the power supply voltage VCC and the first conversion unit 110, respectively, to control the first conversion unit 110 to disconnect when a short circuit occurs. Optionally, when a circuit is short-circuited, a large current flows through the first conversion unit 110, and the first short-circuit protection unit 210 disconnects the first conversion unit 110 when a large current flows through the first conversion unit 110 to achieve the purpose of protecting the circuit.

[0060] The first shunt unit 310 is connected to the first conversion unit 110 and the first short-circuit protection unit 210 respectively to shunt the short-circuit current in case of a short circuit. Optionally, the first short-circuit protection unit 210 is also connected to the first shunt unit 310, so that the first shunt unit 310 shares the large current on the first conversion unit 110 in case of a short circuit, further protecting the circuit.

[0061] It can be understood that when the sensor output signal conversion circuit provided in the embodiment of the present application is applied to an NPN type sensor, the output end of the NPN type sensor is connected to the first conversion unit 110, and the positive pole (power supply end) and negative pole (ground end) of the NPN type sensor should also be connected to the power supply voltage VCC and the ground GND, respectively.

[0062] In some embodiments, a diode is further connected between the positive electrode (power supply terminal) of the NPN sensor and the power supply voltage VCC, the cathode of the diode is connected to the NPN sensor, and the anode is connected to the power supply voltage VCC to achieve reverse polarity protection.

[0063] The sensor output signal conversion circuit provided in the embodiment of the present application can convert the output signal of an NPN sensor into the output signal of a PNP sensor and output it to a load, thereby expanding the output mode of the NPN sensor and solving the technical problem of the single application scenario of the NPN sensor.

[0064] In some embodiments, Figure 2 The structure diagram of the sensor output signal conversion circuit provided in the embodiment of the present application is shown as follows: Figure 2 As shown, the first conversion unit 110 includes a first resistor R1, a second resistor R2 and a first transistor Q1.

[0065] The first end of the first resistor R1 is used to connect the output end of the NPN type sensor, and the second end of the first resistor R1 is connected to the control end of the first transistor Q1; the first end of the second resistor R2 is respectively connected to the first end of the first transistor Q1 and the first shunt unit 310, and the second end of the second resistor R2 is used to connect the output load; the control end of the first transistor Q1 is also connected to the first short-circuit protection unit 210, so that the first short-circuit protection unit 210 controls the first transistor Q1 to be cut off when a short circuit occurs, and the second end of the first transistor Q1 is connected to the first short-circuit protection unit 210, so as to be connected to the power supply voltage VCC via the first short-circuit protection unit 210.

[0066] Optionally, in an embodiment of the present application, the control end of the first transistor Q1 is the base, the first end is the collector, and the second end is the emitter. The first transistor Q1 receives a low-level signal output by the NPN transistor and is turned on, that is, the collector of the first transistor Q1 is connected to the power supply voltage VCC through the first short-circuit protection unit 210. At this time, the signal output by the first transistor Q1 to the output load is the high-level signal output by the PNP transistor. In the first conversion unit 110, the first resistor R1 and the second resistor R2 are current limiting resistors.

[0067] In some embodiments, Figure 2 As shown, the first transistor Q1 is preferably a PNP transistor. In fact, the first transistor Q1 can also use an NPN transistor, but it should be clear that converting the PNP transistor into an NPN transistor in the circuit requires changing the circuit to conform to the NPN transistor connection method. This change in connection method is a conventional technical means in the circuit field, so this embodiment of the present application does not explain this.

[0068] In some embodiments, Figure 2 As shown, the first short circuit protection unit 210 includes a first capacitor C1, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a second transistor Q2 and a third transistor Q3.

[0069] The first end of the first capacitor C1 is connected to the power supply voltage VCC, the second end of the first capacitor C1 is respectively connected to the second end of the second transistor Q2 and the first end of the third resistor R3, and the second end of the third resistor R3 is connected to the control end of the third transistor Q3; the first end of the fourth resistor R4 is connected to the power supply voltage VCC, the second end of the fourth resistor R4 is respectively connected to the first end of the fifth resistor R5 and the second end of the third transistor Q3, and the second end of the fifth resistor R5 is respectively connected to the first conversion unit 110 (i.e., the second end of the first transistor Q1) and the first shunt unit 310; the control end of the second transistor Q2 is connected to the first end of the third transistor Q3, and is connected to the first conversion unit 110 (i.e., the second end of the first resistor and the control end of the first transistor Q1) to control the first conversion unit 110 to be disconnected, and the first end of the second transistor Q2 is suspended.

[0070] Optionally, in the embodiment of the present application, the control end base of the second transistor Q2 and the third transistor Q3 has a first end as a collector and a second end as an emitter. When the circuit is short-circuited, a large current flows through the first transistor Q1, and the voltage division on the fourth resistor R4 and the fifth resistor R5 increases. The first capacitor C1 starts to charge and discharge periodically, thereby causing the second transistor Q2 and the third transistor Q3 to be turned on. The base of the second transistor Q2 and the collector of the third transistor Q3 are both connected to the base of the first transistor Q1, and current is output to the base of the first transistor Q1, thereby raising the base voltage of the first transistor Q1 and cutting off the first transistor Q1, wherein the collector of the second transistor Q2 is suspended, thereby causing more current to flow from the emitter to the base of the second transistor Q2.

[0071] In some embodiments, the first terminal of the second transistor Q2 may also be grounded.

[0072] In some embodiments, Figure 2 As shown, the second transistor Q2 and the third transistor Q3 are preferably PNP transistors. In fact, the second transistor Q2 and the third transistor Q3 can also use NPN transistors, but it should be clear that converting the PNP transistor into the NPN transistor in the circuit requires changing the circuit to conform to the NPN transistor connection method. This change in connection method is a conventional technical means in the circuit field, so this embodiment of the present application does not explain this.

[0073] The sensor output signal conversion circuit provided in the embodiment of the present application forms a short-circuit protection circuit based on a transistor. Compared with the traditional short-circuit protection circuit using a recoverable fuse, the short-circuit protection circuit based on the transistor can avoid damage and failure of the first conversion unit.

[0074] In some embodiments, Figure 2 As shown, the first flow dividing unit 310 includes:

[0075] The fourth transistor Q4, the control end of the fourth transistor Q4 is connected to the first conversion unit 110 (i.e., the first end of the first transistor Q1), the first end of the fourth transistor Q4 is connected to the first short-circuit protection unit 210 (i.e., the second end of the fifth resistor R5) to shunt the short-circuit current in the event of a short circuit, and the second end of the fourth transistor Q4 is used to connect the output load.

[0076] Optionally, in the embodiment of the present application, the control terminal base of the fourth transistor Q4 has a first end as a collector and a second end as an emitter. When the circuit is short-circuited, the first short-circuit protection unit 210 controls the first conversion unit 110 to be cut off, and also diverts most of the short-circuit current to the fourth transistor Q4. Because the first capacitor C1 is periodically charged and discharged during a short circuit, even if periodic conduction occurs between the fourth transistor Q4 and the output load, its output signal will not be determined as the output signal of a PNP sensor.

[0077] In some embodiments, Figure 2 As shown, the fourth transistor Q4 is preferably an NPN transistor. In fact, the fourth transistor Q4 can also use an NPN transistor, but it should be clear that converting the NPN transistor into a PNP transistor in the circuit requires modifying the circuit to conform to the PNP transistor connection method. This change in connection method is a conventional technical means in the circuit field, so this embodiment of the present application does not explain this.

[0078] The sensor output signal conversion circuit provided in the embodiment of the present application is further provided with a first shunt unit 310 to shunt the short-circuit current, thereby further improving the safety of the circuit.

[0079] In some embodiments, Figure 3 Another structural schematic diagram of the sensor output signal conversion circuit provided in the embodiment of the present application is shown. Figure 3 As shown, the sensor output signal conversion circuit provided in the embodiment of the present application also includes a first bidirectional transient suppression diode D1, one end of the diode D1 is connected to the power supply voltage VCC, and the other end is used to connect the output load to resist surge voltage and current that may occur in the circuit.

[0080] It should be clear that in the embodiment of the present application, the specific value of the power supply voltage VCC is determined by the power supply voltage supported by the NPN sensor. For example, if the power supply voltage supported by the NPN sensor is 12V, then in the embodiment of the present application, the power supply voltage VCC is 12V. If the power supply voltage supported by the NPN sensor is 24V, then in the embodiment of the present application, the power supply voltage VCC is 24V.

[0081] The embodiment of the present application also provides a sensor output signal conversion circuit, Figure 4 The module schematic diagram of the sensor output signal conversion circuit provided in the embodiment of the present application is shown as follows: Figure 4 As shown, the circuit includes a second conversion unit 120, a second short-circuit protection unit 220 and a second shunt unit 320;

[0082] The second conversion unit 120 is used to respectively connect the output end of the PNP sensor and the output load, and is grounded GND through the second short-circuit protection unit 220, so that a loop between the output load and the ground is formed through the second conversion unit 120, thereby converting the output signal of the PNP sensor into the output signal of the NPN sensor and outputting it to the output load.

[0083] It can be understood that when a PNP type sensor is used, its output signal needs to be output to a load, that is, an output load connected to a first conversion circuit in an embodiment of the present application. The embodiment of the present application does not limit the form of the output load. For example, the output load may be a signal processing module such as a PLC device or an MCU. For example, the output load may also be an indication circuit (such as an indicator light, a buzzer, etc.) for receiving signals to output different indication states.

[0084] The second short-circuit protection unit 220 is connected to the second conversion unit 120 and grounded to GND to control the second conversion unit 120 to disconnect when a short circuit occurs. Optionally, when a circuit is short-circuited, a large current flows through the second conversion unit 120. When a large current flows through the second conversion unit 120, the second short-circuit protection unit 220 disconnects the second conversion unit 120 to achieve the purpose of protecting the circuit.

[0085] The second shunt unit 320 is connected to the second conversion unit 120 and the second short-circuit protection unit 220 respectively to shunt the short-circuit current in case of a short circuit. Optionally, the second short-circuit protection unit 220 is also connected to the second shunt unit 320, so that the second shunt unit 320 shares the large current on the second conversion unit 120 in case of a short circuit, further protecting the circuit.

[0086] It can be understood that when the sensor output signal conversion circuit provided in the embodiment of the present application is applied to a PNP type sensor, the output end of the PNP type sensor is connected to the second conversion unit 120, and the positive pole (power supply end) and negative pole (ground end) of the PNP type sensor should also be connected to the power supply voltage and the ground, respectively.

[0087] In some embodiments, a diode is connected between the positive electrode (power supply terminal) of the PNP sensor and the power supply voltage VCC, the cathode of the diode is connected to the PNP sensor, and the anode is connected to the power supply voltage VCC to achieve reverse polarity protection.

[0088] The sensor output signal conversion circuit provided in the embodiment of the present application can convert the output signal of a PNP sensor into the output signal of an NPN sensor and output it to a load, thereby expanding the output mode of the PNP sensor and solving the technical problem of the single application scenario of the PNP sensor.

[0089] In some embodiments, Figure 5 The structure diagram of the sensor output signal conversion circuit provided in the embodiment of the present application is shown as follows: Figure 5 As shown, the second conversion unit 120 includes a sixth resistor R6, a seventh resistor R7 and a fifth transistor Q5.

[0090] The first end of the sixth resistor R6 is used to connect the output end of the PNP type sensor, and the second end of the sixth resistor R6 is connected to the control end of the fifth transistor Q5; the first end of the seventh resistor R7 is respectively connected to the first end of the fifth transistor Q5 and the second shunt unit 320, and the second end of the seventh resistor R7 is used to connect the output load; the control end of the fifth transistor Q5 is also connected to the second short-circuit protection unit 220 so that the second short-circuit protection unit 220 controls the fifth transistor Q5 to be cut off in the event of a short circuit, and the second end of the fifth transistor Q5 is connected to the second short-circuit protection unit 220 so as to be grounded via the second short-circuit protection unit 220.

[0091] Optionally, in an embodiment of the present application, the control end of the fifth transistor Q5 is the base, the first end is the collector, and the second end is the emitter. The fifth transistor Q5 receives the high-level signal output by the PNP transistor and is turned on, that is, the collector of the fifth transistor Q5 is grounded GND through the second short-circuit protection unit 220. At this time, the signal output by the fifth transistor Q5 to the output load is the low-level signal output by the NPN transistor. In the second conversion unit 120, the sixth resistor R6 and the seventh resistor R7 are current limiting resistors.

[0092] In some embodiments, Figure 4 As shown, the fifth transistor Q5 is preferably an NPN transistor. In fact, the fifth transistor Q5 can also use a PNP transistor, but it should be clear that converting the NPN transistor into a PNP transistor in the circuit requires changing the circuit to conform to the PNP transistor connection method. This change in connection method is a conventional technical means in the circuit field, so the embodiments of the present application will not explain this.

[0093] In some embodiments, Figure 5 As shown, the second short circuit protection unit 220 includes a second capacitor C2, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a sixth transistor Q6 and a seventh transistor Q7.

[0094] The first end of the second capacitor C2 is grounded GND, the second end of the second capacitor C2 is respectively connected to the second end of the sixth transistor Q6 and the first end of the eighth resistor R8, and the second end of the eighth resistor R8 is connected to the control end of the seventh transistor Q7; the first end of the ninth resistor R9 is grounded, the second end of the ninth resistor R9 is respectively connected to the first end of the tenth resistor R10 and the second end of the seventh transistor Q7, and the second end of the tenth resistor R10 is respectively connected to the second conversion unit 120 (i.e., the second end of the fifth transistor Q5) and the second shunt unit 320; the control end of the sixth transistor Q6 is connected to the first end of the seventh transistor Q7, and is connected to the second conversion unit 120 (i.e., the second end of the sixth resistor R6) to control the second conversion unit 120 to be disconnected, and the first end of the sixth transistor Q6 is suspended.

[0095] Optionally, in the embodiment of the present application, the control end base of the sixth transistor Q6 and the seventh transistor Q7 has a first end as a collector and a second end as an emitter. When the circuit is short-circuited, a large current flows through the fifth transistor Q5, and the voltage division on the ninth resistor R9 and the tenth resistor R10 increases. The second capacitor C2 starts to charge and discharge periodically, thereby causing the sixth transistor Q6 and the seventh transistor Q7 to be turned on. The base of the sixth transistor Q6 and the collector of the seventh transistor Q7 are both connected to the base of the fifth transistor Q5, and current is drawn from the base of the fifth transistor Q5, thereby lowering the base voltage of the fifth transistor Q5, and the fifth transistor Q5 is cut off, wherein the collector of the sixth transistor Q6 is suspended, so that the emitter of the sixth transistor Q6 draws more current from the base.

[0096] In some embodiments, the first terminal of the sixth transistor Q6 may also be connected to a power source.

[0097] In some embodiments, Figure 5 As shown, the sixth transistor Q6 and the seventh transistor Q7 are preferably NPN transistors. In fact, the sixth transistor Q6 and the seventh transistor Q7 can also use PNP transistors, but it should be clear that converting the NPN transistor into a PNP transistor in the circuit requires changing the circuit to conform to the connection method of the PNP transistor. This change in the connection method is a conventional technical means in the circuit field, so this is not explained in the embodiments of the present application.

[0098] The sensor output signal conversion circuit provided in the embodiment of the present application forms a short-circuit protection circuit based on a transistor. Compared with the traditional short-circuit protection circuit using a recoverable fuse, the short-circuit protection circuit based on the transistor can avoid damage and failure of the second conversion unit.

[0099] In some embodiments, Figure 5 As shown, the second flow dividing unit 320 includes:

[0100] The eighth transistor Q8, the control end of the eighth transistor Q8 is connected to the second conversion unit 120 (i.e., the first end of the fifth transistor Q5), the first end of the eighth transistor Q8 is connected to the second short-circuit protection unit 220 (i.e., the second end of the tenth resistor R10) to shunt the short-circuit current in the event of a short circuit, and the second end of the eighth transistor Q8 is used to connect to the output load.

[0101] Optionally, in the embodiment of the present application, the control terminal base of the eighth transistor Q8 has a first end as a collector and a second end as an emitter. When the circuit is short-circuited, the second short-circuit protection unit 220 controls the second conversion unit 120 to be cut off, and also diverts most of the short-circuit current to the eighth transistor Q8. Because the second capacitor C2 is periodically charged and discharged during a short circuit, even if periodic conduction occurs between the eighth transistor Q8 and the output load, its output signal will not be judged as the output signal of the NPN sensor.

[0102] In some embodiments, Figure 5 As shown, the eighth transistor Q8 is preferably a PNP transistor. In fact, the eighth transistor Q8 can also use a PNP transistor, but it should be clear that converting the PNP transistor into an NPN transistor in the circuit requires modifying the circuit to conform to the NPN transistor connection method. This change in connection method is a conventional technical means in the circuit field, so the embodiments of the present application will not explain this.

[0103] The sensor output signal conversion circuit provided in the embodiment of the present application further provides a second shunt unit 320 to shunt the short-circuit current, thereby further improving the safety of the circuit.

[0104] In some embodiments, Figure 6 Another structural schematic diagram of the sensor output signal conversion circuit provided in the embodiment of the present application is shown. Figure 6 As shown, the sensor output signal conversion circuit provided in the embodiment of the present application also includes a second bidirectional transient suppression diode D2, one end of the diode D2 is grounded GND, and the other end is used to connect the output load to resist surge voltage and current that may occur in the circuit.

[0105] The above contents are further detailed descriptions of the present application in combination with specific implementation methods, and it cannot be determined that the specific implementation of the present application is limited to these descriptions. For ordinary technicians in the technical field to which the present application belongs, several simple deductions or substitutions can be made without departing from the concept of the present application, which should be regarded as the protection scope of the present application.

Claims

1. A sensor output signal conversion circuit, characterized in that: It includes a first conversion unit, a first short-circuit protection unit and a first shunt unit; The first conversion unit is used to connect the output end of the NPN sensor and the output load respectively, and is connected to the power supply voltage through the first short-circuit protection unit to convert the output signal of the NPN sensor into the output signal of the PNP sensor and output it to the output load; The first short-circuit protection unit is connected to the power supply voltage and the first conversion unit respectively to control the first conversion unit to be disconnected when a short circuit occurs; The first shunt unit is connected to the first conversion unit and the first short-circuit protection unit respectively to shunt the short-circuit current when a short circuit occurs.

2. The sensor output signal conversion circuit according to claim 1, characterized in that: The first conversion unit includes a first resistor, a second resistor and a first transistor; The first end of the first resistor is used to connect to the output end of the NPN sensor, and the second end of the first resistor is connected to the control end of the first transistor; The first end of the second resistor is connected to the first end of the first transistor and the first shunt unit respectively, and the second end of the second resistor is used to connect the output load; The control end of the first transistor is also connected to the first short-circuit protection unit so that the first short-circuit protection unit controls the first transistor to be cut off when a short circuit occurs. The second end of the first transistor is connected to the first short-circuit protection unit so as to be connected to the power supply voltage via the first short-circuit protection unit.

3. The sensor output signal conversion circuit according to claim 1, characterized in that: The first short-circuit protection unit includes a first capacitor, a third resistor, a fourth resistor, a fifth resistor, a second transistor and a third transistor; The first end of the first capacitor is connected to the power supply voltage, the second end of the first capacitor is connected to the second end of the second transistor and the first end of the third resistor respectively, and the second end of the third resistor is connected to the control end of the third transistor; The first end of the fourth resistor is connected to the power supply voltage, the second end of the fourth resistor is respectively connected to the first end of the fifth resistor and the second end of the third transistor, and the second end of the fifth resistor is respectively connected to the first conversion unit and the first shunt unit; The control end of the second transistor is connected to the first end of the third transistor and is connected to the first conversion unit to control the first conversion unit to be disconnected, and the first end of the second transistor is suspended.

4. The sensor output signal conversion circuit according to claim 1, characterized in that: The first flow dividing unit comprises: A fourth transistor, wherein the control end of the fourth transistor is connected to the first conversion unit, the first end of the fourth transistor is connected to the first short-circuit protection unit to shunt the short-circuit current in the event of a short circuit, and the second end of the fourth transistor is used to connect the output load.

5. The sensor output signal conversion circuit according to claim 1, characterized in that: Also includes: The first bidirectional transient suppression diode is connected to the power supply voltage and is used to connect the output load.

6. A sensor output signal conversion circuit, characterized in that: It includes a second conversion unit, a second short-circuit protection unit and a second current shunting unit; The second conversion unit is used to respectively connect the output end of the PNP sensor and the output load, and is grounded through the second short-circuit protection unit, so as to convert the output signal of the PNP sensor into the output signal of the NPN sensor and output it to the output load; The second short-circuit protection unit is connected to the second conversion unit and grounded to control the second conversion unit to be disconnected when a short circuit occurs; The second shunt unit is connected to the second conversion unit and the second short-circuit protection unit respectively to shunt the short-circuit current when a short circuit occurs.

7. The sensor output signal conversion circuit according to claim 6, characterized in that: The second conversion unit includes a sixth resistor, a seventh resistor and a fifth transistor; The first end of the sixth resistor is used to connect to the output end of the PNP sensor, and the second end of the sixth resistor is connected to the control end of the fifth transistor; The first end of the seventh resistor is connected to the first end of the fifth transistor and the second current dividing unit respectively, and the second end of the seventh resistor is used to connect the output load; The control end of the fifth transistor is also connected to the second short-circuit protection unit so that the second short-circuit protection unit controls the fifth transistor to be cut off in case of short circuit. The second end of the fifth transistor is connected to the second short-circuit protection unit so as to be grounded via the second short-circuit protection unit.

8. The sensor output signal conversion circuit according to claim 6, characterized in that: The second short-circuit protection unit includes a second capacitor, an eighth resistor, a ninth resistor, a tenth resistor, a sixth transistor and a seventh transistor; A first end of the second capacitor is grounded, a second end of the second capacitor is connected to a second end of the sixth transistor and a first end of the eighth resistor respectively, and a second end of the eighth resistor is connected to a control end of the seventh transistor; The first end of the ninth resistor is grounded, the second end of the ninth resistor is respectively connected to the first end of the tenth resistor and the second end of the seventh transistor, and the second end of the tenth resistor is respectively connected to the second conversion unit and the second shunt unit; The control end of the sixth transistor is connected to the first end of the seventh transistor and is connected to the second conversion unit to control the second conversion unit to be disconnected, and the first end of the sixth transistor is suspended.

9. The sensor output signal conversion circuit according to claim 6, characterized in that: The second flow dividing unit comprises: An eighth transistor, wherein the control end of the eighth transistor is connected to the second conversion unit, the first end of the eighth transistor is connected to the second short-circuit protection unit to shunt the short-circuit current in the event of a short circuit, and the second end of the eighth transistor is used to connect the output load.

10. The sensor output signal conversion circuit according to claim 6, characterized in that: Also includes: A second bidirectional TVS diode is grounded and used for connecting the output load.

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