CN203489891U

CN203489891U - Signal detecting device

Info

Publication number: CN203489891U
Application number: CN201320390875.8U
Authority: CN
Inventors: 柯友恒; 秦峰; 胡卓敏
Original assignee: Continental Automotive Wuhu Co Ltd
Current assignee: Continental Automotive Body Electronic System Wuhu Co Ltd
Priority date: 2013-07-02
Filing date: 2013-07-02
Publication date: 2014-03-19
Anticipated expiration: 2023-07-02
Also published as: TWI652450B; TW201516380A; WO2015001412A1

Abstract

The utility model discloses a signal detecting device. The signal detecting device comprises the following components: a power end, a signal receiving end, a signal transmitting end, a control end and a detecting circuit. The detecting circuit comprises a first end, a second end and a third end, wherein, the first end is connected with the power end; the second end is connected with the signal receiving end and the signal transmitting end therebetween; and the third end is connected with the control end. The control end is used for receiving the control signal. When the control signal is in a first state, the resistance between the first end and the second end is a first resistance; and when the control signal is in a second state, the resistance between the first end and the second end is a second resistance, wherein the first resistance is not equal with the second resistance. The signal detecting device settles a problem that a resistance signal is affected by ground voltage difference caused by separation from ground, and realizes a technical effect of accurately detecting a to-be-detected resistance represented by the resistance signal.

Description

Signal detection device

Technical Field

The utility model relates to a signal detection field particularly, relates to a signal detection device.

Background

The vehicle sensor is an input device of a vehicle-mounted electronic control system, and is used for sensing various working condition information in the running process of the motor vehicle, such as the vehicle speed, the temperature of various media, the engine running condition and the like, converting the information into electric signals and sending the electric signals to the control system, so that the vehicle is in the optimal working state. The working principle of the sensors such as the oil pressure sensor, the water temperature sensor, the air temperature sensor and the like is that a resistance-type sensitive element such as a piezoresistor or a thermistor is utilized to convert a corresponding measured value into a resistance value signal, and the resistance value signal is sent out through the output end of the sensor, wherein the resistance value signal is used for representing the resistance value between the output end of the sensor and the ground of the sensor. Therefore, accurately detecting the resistance value to be detected represented by the resistance value signal sent by the resistance sensor is an important link in vehicle control.

In the prior art, the resistance signal is usually directly acquired by a data acquisition module such as a microprocessor. In this operating mode, the premise for accurately detecting the resistance value to be detected represented by the resistance value signal is that the sending device and the collecting device of the resistance value signal are grounded, for example, for vehicle control, each sensor and a data collecting module in the vehicle-mounted electronic control system are required to be grounded. However, when the vehicle body ground is separated from the sensor ground, a voltage difference generally exists between each sensor and the ground of the data acquisition module. In this case, the resistance signal input to the processor is usually affected by the voltage difference between the grounds, and thus the resistance value to be measured cannot be accurately represented. The above-described problems are also widely present in the field of signal detection, outside the field of vehicle control.

In view of the above problems, no effective solution has been proposed.

SUMMERY OF THE UTILITY MODEL

An embodiment of the utility model provides a signal detection device to at least, solve among the prior art because the resistance signal that ground separation caused receives the problem that the poor influence of ground voltage.

In order to solve the technical problem, the utility model discloses a signal detection device includes: the detection circuit comprises a first end, a second end and a third end, wherein the first end is connected to the power supply end, the power supply end is used for being connected with a power supply, and the voltage value between the power supply and a first ground is constant; the second terminal is connected between the signal receiving terminal and the signal transmitting terminal, the signal receiving terminal is configured to receive a resistance signal, the resistance signal is configured to indicate a resistance value to be measured between the signal receiving terminal and a second ground, the signal transmitting terminal is configured to transmit a voltage signal, the voltage signal is configured to indicate a voltage value between the signal transmitting terminal and the first ground, and a voltage difference exists between the first ground and the second ground; the third terminal is connected to the control terminal, the control terminal is configured to receive a control signal, when the control signal is in a first state, a resistance between the first terminal and the second terminal is a first resistance, and when the control signal is in a second state, a resistance between the first terminal and the second terminal is a second resistance, where the first resistance is not equal to the second resistance.

Preferably, the signal detection device further includes: and a processor, an input end of which is connected to the signal transmitting end, and configured to obtain the resistance value to be measured according to the first resistance value, the second resistance value, a first voltage value and a second voltage value, where the first voltage value is a voltage value of the voltage signal when the control signal is in the first state, and the second voltage value is a voltage value of the voltage signal when the control signal is in the second state.

Preferably, the processor is configured to obtain the resistance value to be measured according to the following formula:

wherein R is a value representing the resistance to be measured, E is a value representing a voltage of the power supply with respect to the first ground, and V_{_on}For indicating the first voltage value, V_{_off}For indicating the above-mentioned second voltage value, Z_{_on}For representing the first resistance value, Z_{_off}For indicating the second resistance value.

Preferably, an output terminal of the processor is connected to the control terminal, and is configured to send the control signal to the control terminal.

Preferably, the detection circuit includes: and a switching circuit and a first resistor, the switching circuit and the first resistor being connected in series or in parallel between the first terminal and the second terminal, wherein a control input terminal of the switching circuit is connected to the third terminal, the switching circuit is turned on when the control signal is in the first state, and the switching circuit is turned off when the control signal is in the second state.

Preferably, the detection circuit further includes: and a second resistor connected in parallel between the first terminal and the second terminal with respect to a combination of the switch circuit and the first resistor when the switch circuit and the first resistor are connected in series between the first terminal and the second terminal, and connected in series between the first terminal and the second terminal with respect to a combination of the switch circuit and the first resistor when the switch circuit and the first resistor are connected in parallel between the first terminal and the second terminal.

Preferably, the detection circuit further includes: one or more third resistors connected in parallel to both ends of the first resistor.

Preferably, the signal detection device includes: and a heat dissipation mechanism adjacent to the first resistor and the third resistor.

Preferably, the switching circuit includes a transistor switching circuit.

Preferably, the detection circuit further comprises at least one of: a current limiting unit connected between the second terminal and the signal transmitting terminal; a pull-up resistor, one end of which is connected between the second terminal and the signal transmitting terminal, and the other end of which is connected to the power supply terminal; a clamp circuit having one end connected between the second end and the signal transmitting terminal, the other end connected to the first ground, and the other end connected to the power supply terminal; a first capacitor having one end connected between the second end and the signal transmitting end and the other end connected to the first ground; a second capacitor having one end connected between the signal receiving terminal and the second terminal and the other end connected to the first ground; and a fourth resistor, one end of which is connected between the signal receiving terminal and the second terminal, and the other end of which is connected to the first ground.

The embodiment of the utility model provides an in, utilize the partial pressure effect between the equivalent resistance that the resistance signal that detection circuitry formed corresponds that this detection circuitry received to await measuring the resistance value formed, through the resistance value to the equivalent resistance that this detection circuitry formed under the first state under with the second state, and to the acquisition of the voltage value at the equivalent resistance both ends that this detection circuitry formed, the above-mentioned technical effect of the above-mentioned resistance value that awaits measuring that accurate detection above-mentioned resistance signal represents has been realized, and then the technical problem of the influence of the voltage difference that above-mentioned resistance signal received existence between above-mentioned first ground and above-mentioned second ground has been solved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without undue limitation to the invention. In the drawings:

fig. 1 is a preferred circuit diagram of a signal detection device according to an embodiment of the present invention;

fig. 2 is a preferred schematic diagram of a signal detection device according to an embodiment of the present invention;

fig. 3 is another preferred schematic diagram of a signal detection device according to an embodiment of the present invention;

fig. 4 is an equivalent circuit diagram of a preferred connection mode between the signal detection device and the sending device of the resistance signal according to the embodiment of the present invention;

fig. 5 is a preferred circuit diagram of the detection circuit of the signal detection device according to the embodiment of the present invention;

fig. 6 is another preferred circuit diagram of the detection circuit of the signal detection apparatus according to the embodiment of the present invention;

fig. 7 is another preferred circuit diagram of the detection circuit of the signal detection apparatus according to the embodiment of the present invention;

fig. 8 is another preferred circuit diagram of the detection circuit of the signal detection apparatus according to the embodiment of the present invention;

fig. 9 is a preferred block diagram of a signal detection device according to an embodiment of the present invention;

fig. 10 is another preferred circuit diagram of a signal detection device according to an embodiment of the present invention;

fig. 11 is an equivalent circuit diagram of another preferred connection method between the signal detection device and the resistance signal transmission device according to the embodiment of the present invention.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings in conjunction with embodiments. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

The embodiment of the utility model provides a preferred signal detection device, as shown in FIG. 1, the device includes detection circuitry 110, and this detection circuitry 110 includes following link: a first terminal 112, a second terminal 114 and a third terminal 116, wherein the first terminal 112 is connected to the power terminal 108, the second terminal 114 is connected between the signal receiving terminal 102 and the signal transmitting terminal 104, and the third terminal 116 is connected to the control terminal 106.

As shown in fig. 2, the power terminal 108 is for connection to a power source. As a preferred embodiment, the power supply may be a vehicle-mounted low-voltage dc power supply, and the voltage value between the power supply and the ground of the vehicle, i.e., the first ground, is constant.

As shown in fig. 2, the signal receiving terminal 102 is used for receiving a resistance value signal. Preferably, the signal receiving end 102 may be connected to an output end of a resistive sensor, which may be, but not limited to, an on-board resistive oil pressure sensor, a water temperature sensor, an air temperature sensor, or the like. In the above scenario, the resistance signal is used to represent a resistance value to be measured between the output terminal of the resistive sensor and the sensor ground, that is, a resistance value between the signal receiving terminal 102 and a second ground, where a voltage difference exists between the second ground and the first ground.

As shown in fig. 2, the signal transmitting terminal 104 is used for outputting a voltage signal. Preferably, as shown in fig. 3, the signal transmitting terminal 104 may be connected to an input terminal of a processor 180, and the processor 180 may be, but is not limited to, an on-board microprocessor or an electronic control unit, etc., and is connected to the power source terminal 108 in common. In the above scenario, the voltage signal is read by the processor 180 and is used to indicate a voltage value between the input terminal of the processor 180 and the processor ground, that is, a voltage value between the signal transmitting terminal 104 and the first ground.

As shown in fig. 2, the control terminal 106 is used for receiving a control signal. Preferably, as shown in fig. 3, the control terminal 106 may be connected to the output terminal of the processor 180, i.e., the processor 180 outputs the control signal. In particular, the control terminal may be a terminal or a contact. Preferably, the control signal may be a periodic high/low level signal, a contact on/off signal, or the like. The control signal can be an active signal or a passive signal, and the utility model discloses do not limit to this.

In this embodiment, when the control signal is in a first state, the resistance between the first end 112 and the second end 114 of the detection circuit 110 is a first resistance, and when the control signal is in a second state, the resistance between the first end 112 and the second end 114 is a second resistance, where the first resistance and the second resistance are not equal. In the above scenario, since the resistance value between the first end 112 and the second end 114 of the detection circuit 110 and the equivalent resistance formed by the resistance value to be measured form a voltage division function between the power supply and the second ground, when the resistance value of the detection circuit 110 changes and changes from the first resistance value to the second resistance value, the voltage signal also changes and changes from the first voltage value to the second voltage value. The difference between the first voltage value and the second voltage value can eliminate the influence of the voltage difference between the first ground and the second ground on the resistance signal received by the signal receiving terminal 102.

The principle of eliminating the influence of the ground voltage difference on the resistance signal by the difference between the first voltage value and the second voltage value will be described in detail below. In the equivalent circuit shown in fig. 4, a power supply voltage, which is a voltage value of the power supply with respect to the first ground, may be represented as E, a ground voltage difference, which is a voltage value of the second ground with respect to the first ground, may be represented as S, the voltage signal, which is a voltage value of the signal transmitting terminal 104 with respect to the first ground, may be represented as V, a resistance value between the first terminal 112 and the second terminal 114 of the detection circuit 110 may be represented as Z, the resistance value to be measured may be represented as R, a voltage value applied across the equivalent resistor 136 of the resistance value to be measured may be represented as U, a current value applied across the equivalent resistor 136 may be represented as I, and the positive directions of the voltage value U and the current value I are shown in fig. 4, wherein one end of the equivalent resistor 136 is connected to the second ground. A value of a current passing between the first terminal 112 and the second terminal 114 may be considered to be equal to a value of a current applied to the equivalent resistor 136, regardless of a load of a circuit or a device to which the signal transmitting terminal 104 is connected.

When the control signal is in the first state, a first resistance value Z, which is a resistance value between the first terminal 112 and the second terminal 114, may be set as the first resistance value_{_on}The first voltage value represented by the voltage signal may be represented by V_{_on}The voltage value loaded by the equivalent resistor 136 can be represented by U_{_on}The current value can be represented by I_{_on}To indicate. From the circuit configuration and the circuit principle in fig. 4, it can be derived that:

\{\begin{matrix} U_{_on} = V_{_on} - S \\ I_{_on} = \frac{E - V_{_on}}{Z_{_on}} \end{matrix}

when the control signal is in the second state, a resistance value between the first terminal 112 and the second terminal 114, i.e., a second resistance value, may be represented by Z_{_off}The first voltage value represented by the voltage signal may be represented by V_{_off}The voltage value loaded by the equivalent resistor 136 can be represented by U_{_off}The current value can be represented by I_{_off}To indicate. From the circuit configuration and the circuit principle in fig. 4, it can be derived that:

\{\begin{matrix} U_{_off} = V_{_off} - S \\ I_{_off} = \frac{E - V_{_off}}{Z_{_off}} \end{matrix}

under the condition that the resistance value to be measured is relatively stable in the two states, the calculation formula of the resistance value to be measured can be obtained according to ohm's law and the characteristic of the resistor as a linear element:

therefore, the relation between the voltage value and the current value loaded by the two groups of equivalent resistors can be obtained:

and

as can be seen from the above equation, in the present embodiment, the first voltage value V is used_{_on}And the second voltage value V_{_off}The difference between the first ground and the second ground can eliminate the influence of the voltage difference S existing between the first ground and the second ground on the resistance value signal.

Preferably, the processor 180 may further include an operation unit, configured to obtain the resistance value to be detected according to the first voltage value, the second voltage value, the power voltage, the first resistance value, and the second resistance value, so as to further achieve a technical effect of accurately detecting the resistance value to be detected. Furthermore, the measured value of the sensor indicated by the resistance value to be measured may be displayed by a display device, which may be an in-vehicle display, an instrument panel, or the like. As an alternative embodiment, the display device is not shown in the drawings. It should be understood by those skilled in the art that the above-mentioned arithmetic unit is not necessary, and the resistance value to be measured can also be obtained by means of an arithmetic circuit or the like.

Specifically, as an optional implementation manner of the present invention, accurate reading of the oil pressure signal of the vehicle can be realized through the above-mentioned signal detection device, wherein the oil pressure signal can be output by the output end of the resistive oil pressure sensor, the oil pressure sensor can be installed inside or outside the automobile or the motorcycle separately from other vehicle-mounted electronic devices, for detecting the oil pressure of the vehicle, and the sensor ground of the oil pressure sensor has a voltage difference with the system ground of the vehicle-mounted electronic control unit ecu (electronic control unit). In the embodiment of the present invention, the output end of the oil pressure sensor may be connected to the signal receiving end 102 of the signal detecting device through a wire, so as to transmit the oil pressure signal to the signal detecting device; the signal transmitting terminal 104 of the signal detection device may be connected to an input terminal of the processor 180 through a wire, and is configured to transmit the voltage signal output by the signal detection device to the processor 180; the output end of the processor 180 may be connected to the control end 106 of the signal detection device through a wire, and is used for transmitting the control signal to the signal detection device; the processor 180 may be a microprocessor mcu (micro Control unit), and the Control signal output by the output end may be a square wave signal with a period of 1ms or a pulse Width modulation (pwm) signal. In the above-described scenario, the control signal may be at a high level as the first state, and the control signal may be at a low level as the second state, and the resistance value between the first end 112 and the second end 114 of the detection circuit 110 in the signal detection device in the first state and the second state, that is, the first resistance value and the second resistance value may be respectively denoted as Z_{_on}And Z_{_off}The first state and the second state are transmitted from the signal transmitting end 104 of the signal detection deviceThe voltage values of the voltage signals, namely the first voltage value and the second voltage value, are respectively marked as V_{_on}And V_{_off}Therefore, the value of the oil pressure signal can be accurately obtained according to the following calculation formula:

R = \frac{V_{_on} - V_{_off}}{\frac{E - V_{_on}}{Z_{_on}} - \frac{E - V_{_off}}{Z_{_off}}}

wherein R is a resistance value corresponding to the hydraulic signal, and E is a voltage value of a power supply mounted on the vehicle and supplying power to the ECU with respect to a system ground of the ECU. Further, the actual oil pressure value may be obtained according to the resistance value corresponding to the oil pressure signal and a calibration table or a calibration formula between the resistance value of the preset or calibrated oil pressure signal and the actual oil pressure value, wherein the conversion between the resistance value of the oil pressure signal and the actual oil pressure value may also be completed by the MCU. Of course, the above is only a preferred embodiment of the present invention, and should not be construed as constituting any limitation to the present invention.

Preferably, the detection circuit 110 includes a switch circuit 120 and a first resistor 130, and the switch circuit 120 and the first resistor 130 are connected in series or in parallel between the first end 112 and the second end 114, as shown in fig. 5 and 6, respectively. The control input terminal of the switch circuit 120 is connected to the third terminal 116, and is configured to receive the control signal. When the control signal is in the first state, the switch circuit 120 is turned on, and when the control signal is in the second state, the switch circuit 120 is turned off. In this embodiment, for the case that the switch circuit 120 and the first resistor 130 are connected in series between the first end 112 and the second end 114, when the switch circuit 120 is turned on, the resistance between the first end 112 and the second end 114 is the resistance of the first resistor 130, and when the switch circuit 120 is turned off, the resistance between the first end 112 and the second end 114 is an open circuit, which can be regarded as infinite. For the case where the switch circuit 120 and the first resistor 130 are connected in parallel between the first end 112 and the second end 114, when the switch circuit 120 is turned on, the resistance between the first end 112 and the second end 114 is zero, and when the switch circuit 120 is turned off, the resistance between the first end 112 and the second end 114 is the resistance of the first resistor 130.

It should be understood by those skilled in the art that the above-mentioned constituent structure of the detection circuit 110 described in the present embodiment is not exclusive, and for example, the combination of the above-mentioned switch circuit 120 and the above-mentioned first resistor 130 may also be a partial structure in the detection circuit 110, or the detection circuit may include a variable resistor controlled by an electric signal, or the like.

Preferably, as shown in fig. 7 and 8, the detection circuit 110 may further include a second resistor 132 for more flexibly setting the first resistance value and the second resistance value.

As a preferred embodiment, for the case where the switch circuit 120 and the first resistor 130 are connected in series between the first end 112 and the second end 114, the second resistor 132 may be connected in parallel between the first end 112 and the second end 114 with respect to the combination of the switch circuit 120 and the first resistor 130, as shown in fig. 7. In the above scenario, when the switch circuit 120 is turned on, the resistance between the first end 112 and the second end 114 is the resistance of the parallel circuit of the first resistor 130 and the second resistor 132, and when the switch circuit 120 is turned off, the resistance between the first end 112 and the second end 114 is the resistance of the second resistor 132.

As another preferred embodiment, for the case where the switch circuit 120 and the first resistor 130 are connected in parallel between the first end 112 and the second end 114, the second resistor 132 may be connected in series between the first end 112 and the second end 114 with respect to the combination of the switch circuit 120 and the first resistor 130, as shown in fig. 8. In the above scenario, when the switch circuit 120 is turned on, the resistance between the first end 112 and the second end 114 is the resistance of the second resistor 132, and when the switch circuit 120 is turned off, the resistance between the first end 112 and the second end 114 is the resistance of the series circuit of the first resistor 130 and the second resistor 132.

Preferably, as shown in fig. 9, the detection circuit further includes one or more third resistors 134, and the third resistors 134 are connected in parallel to two ends of the first resistor 130. The third resistor 134 can perform a shunting function in the detection circuit 110, so that on one hand, power sharing between the first resistor 130 and the third resistor 134 is realized, and on the other hand, the heat dissipation efficiency is improved by increasing the number of heat sources, so as to solve the problems of performance reduction and loss of the device caused by over-high local temperature. Correspondingly, as a preferred embodiment, the signal detection device further includes a heat dissipation mechanism 160, and the heat dissipation mechanism 160 is adjacent to the first resistor 130 and the third resistor 134, so as to further improve the efficiency of heat dissipation.

Preferably, the switch circuit 120 may include a MOSFET (field effect transistor), a source and a drain of which are connected between the first terminal 112 and the second terminal 114, and a gate of which is correspondingly connected to the third terminal 116. Preferably, the change of the control signal between the first state and the second state is reflected in the transistor switch circuit, and may be represented by a voltage applied to the gate of the MOS transistor.

In a preferred embodiment, the transistor switch circuit may be a triode switch circuit. Preferably, as shown in fig. 10, the emitter of the transistor 122 corresponds to the first terminal 112, the collector corresponds to the second terminal 114, and the base corresponds to the third terminal 116. In the above scenario, when the control signal received by the base of the transistor 122 through the control terminal 106 is at a high level, the transistor 122 is not conducting, and the emitter and the collector of the transistor are in an off state, whereas when the control signal is at a low level, the transistor 122 is conducting, and the emitter and the collector of the transistor are in an on state, so as to switch the switching circuit 120 between the on and off states, and further realize the change of the resistance value between the first terminal 112 and the second terminal 114.

Preferably, as shown in fig. 10, the detection circuit 110 may further include a current limiting component 140. Preferably, the current limiting component 140 may be connected between the second terminal 114 and the signal transmitting terminal 104, and is used for limiting a current output through the signal transmitting terminal 104, so that a circuit or a device connected to the signal transmitting terminal 104 may be protected.

Preferably, as shown in fig. 10, the detection circuit 110 may further include a pull-up resistor 142. Preferably, one end of the pull-up resistor 142 may be connected between the second end 114 and the signal transmitting end 104, and the other end of the pull-up resistor 142 is connected to the power end 108, for providing additional driving for the signal detecting circuit 110 when the switch circuit 120 is turned off, i.e., the transistor 122 is in an off state, so as to maintain the stability of the voltage signal output by the signal transmitting end 104.

In the present embodiment, considering the shunting function of the pull-up resistor 142 in the circuit and the voltage dividing function of the current limiting component 140, a more accurate calculation formula of the resistance value to be measured is given below according to the equivalent circuit shown in fig. 11. In fig. 11, a power supply voltage may be represented as E, a voltage value of the second ground with respect to the first ground, i.e., a ground voltage difference may be represented as S, the voltage signal may be represented as V, and a resistance value of the parallel circuit of the first resistor 130 and the third resistor 134 may be represented as R₁The total current value through the parallel circuit can be represented as I₁The resistance value of the pull-up resistor 142 can be expressed as R₂The resistance value of the current limiting component 140 can be represented as R₃The value of the current through the series circuit of the pull-up resistor 142 and the current limiting component 140 may be represented as I₂The resistance to be measured may be represented as R, the voltage value applied to both ends of the equivalent resistor 136 of the resistance to be measured may be represented as U, the current value applied to the equivalent resistor 136 may be represented as I, and the positive directions of the voltage value U and the current value I are shown in fig. 11, wherein one end of the equivalent resistor 136 is connected to the second ground. According to the circuit principle, the current value I loaded on the equivalent resistor 136 can be regarded as the current value I without considering the load of the circuit or the device connected to the signal transmitting terminal 104₁And the above current value I₂The sum of (a) and (b).

When the control signal is in the first state and the second state, the resistance values R are respectively set₁、R₂、R₃R, the power voltage E and the ground voltage difference S are all regarded as unchanged, and the first voltage value can be V_{_on}Said second voltage value can be represented by V_{_off}The current values can be represented by I in the first state_{1_on}、I_{2_on}And I_{_on}Can be respectively represented by I in the second state_{1_off}、I_{2_off}And I_{_off}Coming watchIt is shown that the voltage value applied across the equivalent resistor 136 can be U in the first state_{_on}Can be represented by U in the second state_{_off}To indicate. And from the circuit configuration and circuit principle in fig. 11 it follows that:

\{\begin{matrix} U_{_on} = E - I_{2_on} * (R_{2} + R_{3}) - S \\ I_{_on} = I_{1_on} + I_{2_on} \end{matrix}

and

\{\begin{matrix} U_{_off} = E - I_{2_off} * (R_{2} + R_{3}) - S \\ I_{_off} = I_{2_off} \end{matrix}

wherein,

\{\begin{matrix} I_{2_on} = \frac{E - V_{_on}}{R_{2}} \\ I_{1_on} = I_{2_on} * \frac{R_{2} + R_{3}}{R_{1}} = (E - V_{_on}) \frac{R_{2} + R_{3}}{R_{1} R_{2}} \end{matrix}

and

I_{2_off} = \frac{E - V_{_off}}{R_{2}}

therefore, according to the relation between the voltage value and the current value loaded by the two groups of equivalent resistors, the ohm law and the linear characteristic of the resistance element, the following can be obtained:

and

Preferably, as shown in fig. 10, the detecting circuit 110 may further include a clamping circuit 150, one end of the clamping circuit 150 is connected between the second end 114 and the signal transmitting end 104, the other end of the clamping circuit 150 is connected to the first ground, and the other end of the clamping circuit 150 is connected to the power end for clamping the voltage signal within a stable voltage range. Preferably, the clamp circuit 150 may include two diodes connected in series between the first ground and the power supply terminal, and as shown in fig. 10, the two diodes may have a conduction direction from the first ground to the power supply terminal, and a common terminal between the two diodes may be connected between the second terminal 114 and the signal transmitting terminal 104 as one terminal of the clamp circuit 150, so that the voltage signal may be clamped between the power supply voltage and the voltage value of the first ground.

Preferably, as shown in fig. 10, the detection circuit 110 may further include a first capacitor 144, one end of the first capacitor 144 is connected between the second terminal 114 and the signal transmitting terminal 104, and the other end of the first capacitor 144 is connected to the first ground for removing a high-frequency noise component, such as a spike signal, from the voltage signal.

Preferably, as shown in fig. 10, the detection circuit 110 may further include a second capacitor 146, one end of the second capacitor 146 is connected between the signal receiving terminal 102 and the second terminal 114, and the other end of the second capacitor 146 is connected to the first ground. Preferably, as shown in fig. 10, the detection circuit 110 may further include a fourth resistor 148, one end of the fourth resistor 148 is connected between the signal receiving terminal 102 and the second terminal 114, and the other end of the fourth resistor 148 is connected to the first ground. The electromagnetic interference doped in the resistance signal received by the signal receiving terminal 102 can be attenuated by the parallel circuit of the second capacitor 146 and the fourth resistor 148, one end of which is grounded.

As can be seen from the above description, the present invention achieves the following technical effects:

1) by the first voltage value V_{_on}And the second voltage value V_{_off}The difference between the first and second ground can eliminate the voltage existing between the first and second groundThe influence of the difference S on the resistance signal;

2) the first voltage value, the second voltage value, the power voltage, the first resistance value and the second resistance value can be used for accurately detecting the resistance value to be detected.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A signal detection device, comprising: a power supply terminal (108), a signal receiving terminal (102), a signal transmitting terminal (104), a control terminal (106) and a detection circuit (110), wherein the detection circuit (110) comprises a first terminal (112), a second terminal (114) and a third terminal (116), wherein,

the first terminal (112) is connected to a power supply terminal (108), the power supply terminal (108) is used for connecting a power supply, and the voltage value between the power supply and a first ground is constant;

the second end (114) is connected between the signal receiving end (102) and the signal transmitting end (104), the signal receiving end (102) is used for receiving a resistance value signal, the resistance value signal is used for representing a resistance value to be measured between the signal receiving end (102) and a second ground, the signal transmitting end (104) is used for transmitting a voltage signal, the voltage signal is used for representing a voltage value between the signal transmitting end (104) and the first ground, and a voltage difference exists between the first ground and the second ground;

the third terminal (116) is connected to the control terminal (106), the control terminal (106) is configured to receive a control signal, when the control signal is in a first state, a resistance value between the first terminal (112) and the second terminal (114) is a first resistance value, and when the control signal is in a second state, a resistance value between the first terminal (112) and the second terminal (114) is a second resistance value, where the first resistance value is not equal to the second resistance value.

2. The signal detection device according to claim 1, further comprising:

and the input end of the processor (180) is connected with the signal sending end (104) and is used for obtaining the resistance value to be detected according to the first resistance value, the second resistance value, the first voltage value and the second voltage value, wherein the first voltage value is the voltage value of the voltage signal when the control signal is in the first state, and the second voltage value is the voltage value of the voltage signal when the control signal is in the second state.

3. The signal detection device according to claim 2, wherein an output of the processor (180) is connected to the control terminal (106) for sending the control signal to the control terminal (106).

4. The signal detection device according to any one of claims 1 to 3, wherein the detection circuit (110) comprises:

a switching circuit (120) and a first resistor (130), the switching circuit (120) and the first resistor (130) being connected in series or in parallel between the first terminal (112) and the second terminal (114), wherein a control input of the switching circuit (120) is connected to the third terminal (116), the switching circuit (120) being turned on when the control signal is in the first state and the switching circuit (120) being turned off when the control signal is in the second state.

5. The signal detection device of claim 4, wherein the detection circuit (110) further comprises:

a second resistor (132), the second resistor (132) being connected in parallel between the first end (112) and the second end (114) relative to a combination of the switch circuit (120) and the first resistor (130) when the switch circuit (120) and the first resistor (130) are connected in series between the first end (112) and the second end (114), the second resistor (132) being connected in series between the first end (112) and the second end (114) relative to a combination of the switch circuit (120) and the first resistor (130) when the switch circuit (120) and the first resistor (130) are connected in parallel between the first end (112) and the second end (114).

6. The signal detection device of claim 4, wherein the detection circuit (110) further comprises:

one or more third resistors (134) connected in parallel across the first resistor (130).

7. The signal detection device according to claim 6, comprising:

a heat dissipation mechanism (160) adjacent to the first resistor (130) and the third resistor (134).

8. The signal detection device of claim 4, wherein the switching circuit (120) comprises a transistor switching circuit.

9. The signal detection device according to any one of claims 1 to 3, wherein the detection circuit (110) further comprises at least one of:

a current limiting component (140) connected between the second end (114) and the signal transmitting end (104);

a pull-up resistor (142), wherein one end of the pull-up resistor (142) is connected between the second end (114) and the signal transmitting end (104), and the other end of the pull-up resistor (142) is connected with the power supply end (108);

a clamping circuit (150), wherein one end of the clamping circuit (150) is connected between the second end (114) and the signal transmitting end (104), the other end of the clamping circuit (150) is used for connecting the first ground, and the other end of the clamping circuit (150) is connected with the power supply end (108);

a first capacitor (144), one end of the first capacitor (144) is connected between the second terminal (114) and the signal transmitting terminal (104), and the other end of the first capacitor (144) is used for connecting the first ground;

a second capacitor (146), one end of the second capacitor (146) is connected between the signal receiving end (102) and the second end (114), and the other end of the second capacitor (146) is used for connecting the first ground;

a fourth resistor (148), one end of the fourth resistor (148) is connected between the signal receiving end (102) and the second end (114), and the other end of the fourth resistor (148) is used for connecting the first ground.