WO2015001412A1

WO2015001412A1 - Signal detection device

Info

Publication number: WO2015001412A1
Application number: PCT/IB2014/001249
Authority: WO
Inventors: 柯友恒; 胡卓敏; 秦峰
Original assignee: 大陆汽车有限公司
Priority date: 2013-07-02
Filing date: 2014-07-01
Publication date: 2015-01-08
Also published as: TWI652450B; TW201516380A; CN203489891U

Abstract

The present utility model discloses a signal detection device. The device comprises: a power terminal, a signal receiving terminal, a signal transmitting terminal, a control terminal, and a detection circuit; the detection circuit comprises a first terminal, a second terminal, and a third terminal, the first terminal connecting to the power terminal; the second terminal connects to the signal receiving terminal and the signal transmitting terminal and is provided in between; the third terminal connects to the control terminal; the control terminal is used to receive a control signal, and when the control signal is in a first state, the resistance between the first terminal and the second terminal is of a first resistance value, and when the control signal is in a second state, the resistance between the first terminal and the second terminal is of a second resistance value, the first resistance value being different from the second resistance value. The signal detection device solves the problem in the prior art that the resistance signal is affected by the ground voltage due to the grounds being separate, thereby enabling accurate detection of the resistance signal that represents the resistance value to be measured.

Description

Signal detecting device

Technical field

The utility model relates to the field of signal detection, in particular to a signal detecting device. Background technique

The vehicle sensor is an input device of the in-vehicle electronic control system for sensing various types of working condition information of the motor vehicle, such as the speed of the vehicle, the temperature of each medium, the operating conditions of the engine, etc., and converts the information into an electrical signal transmission. Go to the control system to keep the vehicle in optimal working condition. Among them, the working principle of the oil pressure sensor, the water temperature sensor and the air temperature sensor usually uses a resistive sensitive element such as a varistor or a thermistor to convert the corresponding value into a resistance signal and pass the output of the sensor. The terminal sends out, and the resistance signal is used to indicate the resistance value between the sensor output and the sensor ground. Therefore, accurately detecting the resistance value of the resistance signal sent by the resistance sensor is an important part of vehicle control. ::〕

In the prior art, the above resistance signal is usually directly collected by a data acquisition module such as a microprocessor. In this mode of operation, the premise that the resistance value to be measured represented by the resistance signal is accurately detected is that the transmitting device of the resistance signal is shared with the collecting device. For example, for vehicle control, each sensor and vehicle electronic control are required. The data acquisition modules in the system are common. However, in the case where the vehicle body is separated from the sensor ground, there is usually a voltage difference between each of the above sensors and the ground of the data set module. In this case, the resistance signal input to the processor is usually affected by the voltage difference between the above grounds, so that the resistance value to be measured cannot be accurately represented. In addition to the field of vehicle control, the above problems are still widespread in the field of signal detection.

In response to the above problems, no effective solution has been proposed yet. Utility model content

The embodiment of the present invention provides a signal detecting device to solve at least the problem that the resistance signal caused by the ground separation in the prior art is affected by the ground voltage difference.

In order to solve the above technical problem, the signal detecting apparatus of the present invention includes: a power terminal, a signal receiving end, a signal transmitting end, a control end, and a detecting circuit, wherein the detecting circuit includes a first end, a second end, and a third end, wherein The first end is connected to the power end, the power end is used for connecting a power source, and the voltage between the power source and the first ground is constant; the second end is connected between the signal receiving end and the signal sending end, and the signal is The receiving end is configured to receive a resistance value, wherein the resistance signal is used to indicate a resistance value to be measured between the signal receiving end and the second ground, and the signal transmitting end is configured to send a voltage signal, where the voltage signal is used to represent the signal a voltage value between the transmitting end and the first ground, wherein a voltage difference exists between the first ground and the second ground; the third end is connected to the control end, and the control end is configured to receive a control signal, when When the control signal is in the first state, the resistance value between the first end and the second end is the first value And a resistance value, when the control signal is in the second state, the resistance value between the first end and the second end is a second resistance value, wherein the first resistance value and the second resistance value are not equal.

Preferably, the signal detecting device further includes: a processor, wherein an input end of the processor is connected to the signal sending end, and configured to perform, according to the first resistance value, the second resistance value, the first voltage value, and the second voltage value And the resistance value of the voltage to be measured, wherein 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 signal when the control signal is in the second state Voltage value. Preferably, the processor is configured to obtain the resistance value to be tested according to the following formula: R = r - " ⁿ ~ ^V -" ^ff _rr , where R is used to represent the resistance value to be tested, and E is used to indicate that the power source is relatively The voltage value of the first ground mentioned above, V_. _{n is} used to represent the above first voltage value, V-. _{Ff is} used to represent the above second voltage value, Z_. _{n is} used to represent the above first resistance value, Z_. _{Ff is} used to indicate the above second resistance value.

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

Preferably, the detecting circuit includes: a switch circuit and a first resistor, wherein the switch circuit and the first resistor are connected in series or in parallel between the first end and the second end, wherein the switch circuit The control input terminal is connected to the third terminal, and when the control signal is in the first state, the switch circuit is turned on, and when the control signal is in the second state, the switch circuit is turned off.

Preferably, the detecting circuit further includes: a second resistor, wherein the second resistor is opposite to the second resistor when the switching circuit is connected in series with the first resistor between the first end and the second end The switch circuit and the combination of the first resistor are connected in parallel between the first end and the second end, and the switch circuit and the first resistor are connected in parallel to the first end and And between the second end, the second resistor is connected in series between the first end and the second end with respect to the combination of the switch circuit and the first resistor.

Preferably, the detecting circuit further comprises: one or more third resistors connected in parallel at opposite ends of the first resistor. Preferably, the signal detecting device comprises: a heat dissipating mechanism adjacent to the first resistor and the third resistor.

Preferably, the above switching circuit comprises a transistor switching circuit.

Preferably, the detecting circuit further comprises at least one of: a current limiting component connected between the second end and the signal transmitting end; a pull-up resistor, one end of the pull-up resistor connected to the second end and the signal Between the transmitting ends, the other end of the pull-up resistor is connected to the power terminal; a clamping circuit, one end of the clamping circuit is connected between the second end and the signal transmitting end, and the other end of the clamping circuit is used Connecting the first ground, the other end of the clamping circuit is connected to the power supply end; the first capacitor, one end of the first capacitor is connected between the second end and the signal transmitting end, and the first capacitor is further One end is for connecting the first ground; the second capacitor is connected to one end of the second capacitor between the signal receiving end and the second end, and the other end of the second capacitor is used for connecting the first And a fourth resistor, wherein one end of the fourth resistor is connected between the signal receiving end and the second end, and the other end of the fourth resistor is used to connect the first ground.

In the embodiment of the present invention, the voltage division between the equivalent resistance formed by the equivalent resistance formed by the detecting circuit and the resistance value corresponding to the resistance signal received by the detecting circuit is passed to the first state. Obtaining the resistance value of the equivalent resistance formed by the detecting circuit in the second state and the second state, and acquiring the voltage value across the equivalent resistance formed by the detecting circuit, thereby realizing the above-mentioned accurate detection of the resistance signal The technical effect of the resistance value to be tested further solves the technical problem that the resistance signal is affected by the voltage difference existing between the first ground and the second ground. DRAWINGS

The drawings are intended to provide a further understanding of the present invention, and are intended to be a part of the present invention, and the description of the present invention is not intended to limit the invention. In the drawing:

1 is a preferred circuit diagram of a signal detecting apparatus according to an embodiment of the present invention;

2 is a preferred schematic diagram of a signal detecting apparatus according to an embodiment of the present invention;

3 is another preferred schematic diagram of a signal detecting apparatus according to an embodiment of the present invention;

4 is an equivalent circuit diagram of a preferred connection manner between a signal detecting device and a transmitting device for a resistance value according to an embodiment of the present invention;

5 is a preferred circuit diagram of a detection circuit of a signal detecting device according to an embodiment of the present invention; FIG. 6 is another preferred circuit diagram of a detecting circuit of a signal detecting device according to an embodiment of the present invention; Another preferred circuit diagram of the detection circuit of the signal detecting device of the embodiment of the present invention; FIG. 8 is another preferred circuit diagram of the detecting circuit of the signal detecting device according to the embodiment of the present invention; FIG. 9 is an embodiment of the present invention. a preferred structural diagram of the signal detecting device;

FIG. 10 is another preferred circuit diagram of a signal detecting apparatus according to an embodiment of the present invention; FIG.

Figure 11 is an equivalent circuit diagram of another preferred connection between the signal detecting device and the transmitting device of the resistance value signal according to an embodiment of the present invention. detailed description

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings in conjunction with the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. The embodiment of the present invention provides a preferred signal detecting device. As shown in FIG. 1, the device includes a detecting circuit 110. The detecting circuit 110 includes the following connecting ends: a first end 112, a second end 114, and a third end. 116, wherein the first end 112 is connected to the power terminal 108, the second end 114 is connected between the signal receiving end 102 and the signal transmitting end 104, and the third end 116 is connected to the control end 106. As shown in Figure 2, the power terminal 108 is used to connect a power source. As a preferred embodiment, the power source may be a low-voltage DC power source of the vehicle, and the voltage value between the power source and the ground of the vehicle, that is, the first ground, is constant.

As shown in Fig. 2, the signal receiving terminal 102 is for receiving a resistance signal. Preferably, the signal receiving end 102 can be connected to the output of the resistive sensor, which can be, but is not limited to, a resistive oil pressure sensor, a water temperature sensor or an air temperature sensor. In the above scenario, the resistance signal is used to indicate the resistance value to be measured between the output end of the resistive sensor and the sensor ground, that is, the resistance value between the signal receiving end 102 and the second ground, wherein the There is a voltage difference between the two places and the first ground described above.

As shown in Fig. 2, the signal transmitting terminal 104 is for outputting a voltage signal. Preferably, as shown in FIG. 3, the signal transmitting end 104 can be connected to an input end of the processor 180. The processor 180 can be, but is not limited to, a vehicle-mounted microprocessor or an electronic control unit, etc., and the power terminal 108. The connected power supply is common ground. In the above scenario, the voltage signal is read by the processor 180 and used to indicate the voltage value between the input end of the processor 180 and the ground of the processor, that is, between the signal transmitting end 104 and the first ground. Voltage value.

As shown in Figure 2, control terminal 106 is operative to receive control signals. Preferably, as shown in FIG. 3, the control terminal 106 can be connected to the output end of the processor 180, that is, the processor 180 outputs the above control signal. Specifically, the control terminal may be a terminal or a contact. Preferably, the above control signal may be a periodic high and low level signal or a contact on/off signal or the like. The control signal may be an active signal or a passive signal, which is not limited by the present invention. ί

In this embodiment, when the control signal is in the first state, the resistance between the first end 112 and the second end 114 of the detecting circuit 110 is a first resistance value, when the control signal is in the second state. The resistance between the first end 112 and the second end 114 is a second resistance value, wherein the first resistance value is not equal to the second resistance value. In the above scenario, a voltage dividing effect is formed between the power source and the second ground due to a resistance value between the first end 112 and the second end 114 of the detecting circuit 110 and an equivalent resistance formed by the resistance value to be measured. When the resistance value of the detection circuit 110 changes, and the first resistance value changes to the second resistance value, the voltage signal also changes, and the first voltage value changes to the second voltage value. The influence of the voltage difference existing between the first ground and the second ground on the resistance signal received by the signal receiving end 102 can be eliminated by the difference between the first voltage value and the second voltage value.

The principle of eliminating the influence of the ground voltage difference on the above-mentioned resistance signal by the difference between the above first voltage value and the above second voltage value will be explained in detail below. In the equivalent circuit shown in FIG. 4, the power source voltage relative to the first ground voltage, that is, the power source voltage, may be represented as Ε, and the ground voltage difference of the second ground relative to the first ground may be expressed as S, the voltage signal of the signal transmitting end 104 relative to the first ground, that is, the voltage signal may be represented as V, and the resistance value between the first end 112 and the second end 114 of the detecting circuit 110 may be represented as Z, The value of the resistance to be tested can be expressed as R, and the voltage value applied across the equivalent resistance 136 of the resistance value to be tested can be expressed as U, and the current value loaded on the equivalent resistor 136 can be expressed as I, the voltage value U. And the positive direction of the current value I is as shown in FIG. 4, wherein one end of the equivalent resistor 136 is connected to the second ground. The current value passed between the first end 112 and the second end 114 can be regarded as the current loaded with the equivalent resistor 136 without considering the load of the circuit or device to which the signal transmitting end 104 is connected. The values are equal.

When the control signal is in the first state, the resistance value between the first end 112 and the second end 114, that is, the first resistance value may be Z. _n indicates that the voltage value indicated by the voltage signal, that is, the first voltage value, can be V. „To the table The voltage value loaded by the above equivalent resistor 136 can be expressed, and the current value can be I_. „To express. According to the circuit structure and circuit principle in Figure 4, we can get:

E - V

I

Z When the control signal is in the second state, the resistance value between the first end 112 and the second end 114, that is, the second resistance value may be Z_. _{In the case of ff} , the voltage value indicated by the voltage signal, that is, the first voltage value, may be V. _Ff , the voltage value of the above equivalent resistor 136 can be represented by U-^, and the current value can be expressed by I^. According to the circuit structure and circuit principle in Figure 4, it can be concluded that -

E - V ff

a uff

z ff

In the case where the above-mentioned resistance value to be measured is relatively stable in the above two states, the calculation formula of the resistance value to be measured can be obtained according to Ohm's law and the characteristics of the resistor as a linear element:

R

Ding _― M― >ff

Therefore, according to the relationship between the voltage value and the current value loaded by the above two sets of equivalent resistances, it can be obtained: off -s) = v V ff

AI = ff

z z off and

AU U -U

R = ff V - V ff

AI E - V _t E - V

— off off

Z„„ Z off

As can be seen from the above formula, in the present embodiment, the first voltage value V_ is passed. The difference between the second voltage value V- _.ff can eliminate the influence of the voltage difference S existing between the first ground and the second ground on the resistance signal.

Preferably, the processor 180 further includes an arithmetic unit configured to determine the resistance value to be measured according to the first voltage value, the second voltage value, the power voltage, the first resistance value, and the second resistance value. Thereby, the technical effect of accurately detecting the resistance value to be tested is further realized. Further, the measured value of the sensor represented by the resistance value to be tested may be displayed by a display device, and the display device may be an on-board display or a dashboard 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 above-mentioned resistance value to be measured can also be obtained by 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 may be implemented by the signal detecting device, wherein the oil pressure signal may be outputted by the resistance oil pressure sensor. Output, the oil pressure sensor can be installed separately from the other in-vehicle electronic device inside or outside the automobile or motorcycle for detecting the oil pressure of the vehicle, and the sensor ground of the oil pressure sensor and the in-vehicle electronic control unit ECU (Electronic) There is a systematic difference in the voltage of the 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 for transmitting the oil pressure signal to the signal detecting device; The terminal 104 can be connected to the input end of the processor 180 through a wire for transmitting the voltage signal output by the signal detecting device to the processor 180. The output end of the processor 180 can pass through the wire and the control end of the signal detecting device. The signal is connected to the signal detecting device. The processor 180 can be a microprocessor (MCU), and the output signal outputted by the output terminal can be a square wave signal with a period of ltns. Or pulse width modulation PWM (Pulse Width Modulation) signal. In the above 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 signal detecting device in the first state and the second state may be used. The resistance value between the first end 112 and the second end 114 of the detecting circuit 110, that is, the first resistance value and the second resistance value, respectively, is denoted as Z_. „ _和 ^. _ff , the voltage values of the voltage signals output from the signal transmitting end 104 of the signal detecting device in the first state and the second state, that is, the first voltage value and the second voltage value are respectively recorded as .. V- _n and V_ _ff, thereby accurately predict the value of the oil pressure signal is calculated according to the following formula:

Here, R is used to indicate the resistance value corresponding to the hydraulic pressure signal, and E is used to indicate the system voltage value of the power supply for the ECU on the vehicle. Further, the actual oil pressure value may be obtained according to a 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 can also be performed by the above MCU. Of course, the above is only a preferred embodiment of the present invention, and should not be construed as limiting the invention.

Preferably, the detecting circuit 110 includes a switching circuit 120 and a first resistor 130. The switching 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 Figure 5 and Figure 6, respectively. The control input end of the switch circuit 120 is connected to the third end 116 for receiving 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 where 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 first end 112 and the second end The resistance value between 114 is the resistance value of the first resistor 130. When the switch circuit 120 is turned off, the first end 112 and the second end 114 are disconnected, and the resistance value can be regarded as positive infinity. For the case where the switching circuit 120 is connected in parallel with the first resistor 130 between the first end 112 and the second end 114, when the switching circuit 120 is turned on, the resistance between the first end 112 and the second end U4 Zero, 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 composition of the above-mentioned detection circuit 110 described in the present embodiment is not unique. For example, the combination of the above-mentioned switch circuit 120 and the first resistor 130 may also be in the detection circuit 110. Part of the structure, or the detection circuit may include a variable resistor controlled by an electrical signal, and the like.

Preferably, as shown in FIGS. 7 and 8, the detecting 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 opposite to the switch circuit 120 and the first resistor. The combination of the devices 130 is connected in parallel between the first end 112 and the second end 114, as shown in FIG. In the above scenario, when the switch circuit 120 is turned on, the resistance between the first end 112 and the second 114 is the resistance value of the parallel circuit of the first resistor 130 and the second resistor 132. When the switch circuit 120 is turned off, the resistance value of the second resistor 132 is between the first end 112 and the second end 114.

As another preferred embodiment, for the case where the switch circuit 120 is connected in parallel with the first resistor 130 between the first end 112 and the second end 114, the second resistor 132 may be opposite to the switch circuit 120 and the first A combination of resistors 130 is connected in series between the first end 112 and the second end 114, as shown in FIG. 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 value of the second resistor 132. When the switch circuit 120 is turned off, the first Between one end 112 and the second end 114 is a resistance value of a series circuit of the first resistor 130 and the second resistor 132.

Preferably, as shown in FIG. 9, the above detection circuit further includes one or more third resistors 134, which are connected in parallel at both ends of the first resistor 130. The third resistor 134 can be shunted in the detecting circuit 110, and on the one hand, the power sharing between the first resistor 130 and the third resistor 134 is realized, and on the other hand, the number of heat sources is increased. The efficiency of heat dissipation to solve the problem of device performance degradation and loss caused by excessive local temperature. Correspondingly, as a preferred embodiment, the signal detecting device further includes a heat dissipating mechanism 160 adjacent to the first resistor 130 and the third resistor 134 for further improving the efficiency of heat dissipation.

Preferably, the switch circuit 120 may include a MOSFET (Field Effect Transistor) having a source and a drain connected between the first end 112 and the second end 114, and a gate correspondingly connected to the third end. 116. Preferably, the change of the control signal between the first state and the second state is reflected in the transistor switching circuit, and can represent the level of the voltage applied to the gate of the MOS transistor.

As a preferred embodiment, the transistor switching circuit may be a triode switching circuit. Preferably, as shown in FIG. 10, the emitter of the transistor 122 corresponds to the first end 112, the collector corresponds to the second end 114, and the base corresponds to the third end 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 turned on, and the emitter and the collector are equivalent to an off state, and vice versa. When the control signal is low level, the transistor 122 is turned on, and the emitter and the collector are equivalent to an on state, thereby switching between the on and off states of the switch circuit 120 to further realize the above. A change in resistance between the first end 112 and the second end 114 described above. '

Preferably, as shown in FIG. 10, the above detection circuit 110 may further include a current limiting component 140. Preferably, the current limiting component 140 can be connected between the second end 114 and the signal transmitting end 104 for limiting the current flowing through the signal transmitting end 104, thereby protecting the circuit connected to the signal transmitting end 104. Or equipment. Preferably, as shown in FIG. 10, the above detection circuit 110 may further include a pull-up resistor 142. Preferably, one end of the pull-up resistor 142 can 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 terminal 108 for closing the switch circuit 120. When the transistor 122 is in the off state, the signal detecting circuit 110 is additionally driven to maintain the stability of the voltage signal outputted by the signal transmitting terminal 104.

In the present embodiment, considering the shunting action of the pull-up resistor 142 in the circuit and the voltage dividing effect of the current limiting component 140, the resistance to be tested is given according to the equivalent circuit shown in FIG. A more accurate calculation of the value. In FIG. 11, the power supply voltage may be represented as E, the ground voltage difference of the second ground relative to the first ground may be represented as S, and the voltage signal may be represented as V, the first resistor 130 and the first resistor 130 The resistance value of the parallel circuit of the three resistors 134 can be expressed as R. The total current value through the parallel circuit can be expressed as I. The resistance value of the pull-up resistor 142 can be expressed as R ₂ , and the resistance value of the current limiting component 140 can be expressed. The current value of the series circuit through the pull-up resistor 142 and the current limiting component 140 can be expressed as 1 ₂ , and the resistance value to be tested can be expressed as R, and the equivalent resistance 136 of the resistance value to be tested is loaded at both ends. The voltage value can be expressed as U, and the current value loaded on the equivalent resistor 136 can be expressed as I, and the positive direction of the voltage value U and the current value I is as shown in FIG. 11, wherein one end of the equivalent resistor 136 is Connected to the second place. According to the circuit principle, the current value I loaded on the equivalent resistor 136 can be regarded as the sum of the current value ^ and the current value 1 ₂ without considering the load of the circuit or device to which the signal transmitting terminal 104 is connected. .

When the control signals are in the first state and the second state, respectively, the respective resistance values, R ₂ , R ₃ , R, the power supply voltage E, and the ground voltage difference S may be regarded as not changing, and the first The voltage value can be V. "To indicate the second voltage value V can be a." To represent the respective current values can be used in the first state -... _N, I _2, and I _n a _n a are represented, in the second The state can be represented by I _{1J) ff} , 1 ₂ __^ and 1 ^ ^ respectively. The voltage value of the above-mentioned loading across the equivalent resistor 136 can be expressed in the first state, and in the second state, U- can be used. "To show. And according to the circuit structure and circuit principle in Figure 11 can be:

as well as

U _off = E - I _{2 off} * (R _{2 +} R ₃ ) - S

—off a ¹ 2_off where,

Therefore, according to the relationship between the voltage value and the current value loaded by the above two sets of equivalent resistances, Ohm's law and the linear characteristics of the resistance element, it can be obtained:

as well as

AU U - U V .. - V

Ff _ off

R =

M I ., E - V V . ~ V

. ff ff

R,

As can be seen from the above formula, in the present embodiment, the first voltage value V ― is passed. The difference between the second voltage value V and _ff can eliminate the influence of the voltage difference s existing between the first ground and the second ground on the resistance signal.

Preferably, as shown in FIG. 10, the detecting circuit 110 further includes 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 clamping circuit 150 The other end is connected to the first ground, and the other end of the clamping circuit 150 is connected to the power terminal for clamping the voltage signal within a stable voltage value range. Preferably, the clamping circuit 150 may include two diodes connected in series between the first ground and the power terminal. As shown in FIG. 10, the conduction directions of the two diodes are the first ground to the power terminal. As one end of the clamp circuit 150, a common end between the two diodes is connected between the second end 114 and the signal transmitting end 104, thereby clamping the voltage signal to the power supply voltage and the first The effect between the ground voltage values.

Preferably, as shown in FIG. 10, the detecting circuit 110 may further include a first capacitor 144, one end of the first capacitor 144 is connected between the second end 114 and the signal transmitting end 104, and the first capacitor 144 is The other end is connected to the first ground to remove high frequency clutter portions, for example, sharp pulse signals, in the voltage signal.

Preferably, as shown in FIG. 10, the detecting circuit 110 may further include a second capacitor 146. One end of the second capacitor 146 is connected between the signal receiving end 102 and the second end 114. The second capacitor 146 is The other end is connected to the first ground described above. Preferably, as shown in FIG. 10, the detecting circuit 110 further includes a fourth resistor 148. One end of the fourth resistor 148 is connected between the signal receiving end 102 and the second end 114. The fourth resistor is connected. The other end of the 148 is connected to the first ground described above. A parallel circuit connected to one end of the second capacitor 146 and the fourth resistor 148 may attenuate the electromagnetic interference doped in the resistance signal received by the signal receiving end 102.

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

1) Passing the above first voltage value V-. _n and the above second voltage value V_. The difference between _ff can eliminate the influence of the voltage difference S existing between the first ground and the second ground on the resistance signal;

2) accurate detection of the resistance value to be measured can be realized by the first voltage value, the second voltage value, the power supply voltage, the first resistance value, and the second resistance value. The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention. For those skilled in the art, the present invention may be variously modified and changed. Any modifications, equivalent substitutions, improvements, etc. within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Request

A signal detecting device, comprising: a power terminal (108), a signal receiving end (102), a signal transmitting end (104), a control end (106), and a detecting circuit (110), wherein the detecting circuit (110) including a first end (112), a second end (114), and a third end (116), wherein

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

The second end (114) is connected between the signal receiving end (102) and the signal transmitting end (104), and the signal receiving end (102) is configured to receive a resistance value signal, the resistance value signal And used for indicating a resistance value to be measured between the signal receiving end (102) and the second ground, wherein the signal transmitting end (104) is configured to send a voltage signal, where the voltage signal is used to indicate the signal transmitting end ( 104) a voltage value between the first ground and the first ground, wherein a voltage difference exists between the first ground and the second ground;

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

2. The signal detecting apparatus according to claim 1, further comprising:

a processor (180), the input end of the processor (180) is connected to the signal transmitting end (104), and configured to be configured according to the first resistance value, the second resistance value, the first voltage value, and the The second voltage is worth the resistance value to be measured, wherein 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 the control signal a voltage value of the voltage signal when in the second state.

The signal detecting device according to claim 2, wherein the processor (180) is configured to obtain the resistance value to be tested according to the following formula:

Wherein R is used to represent the resistance value to be measured, and E is used to represent a voltage value of the power source relative to the first ground, V_. „ is used to indicate the first voltage value, V− _{ff is} used to represent the second voltage value, Z 。 is used to represent the first resistance value, Z. _{Ff is} used to indicate the second resistance value.

4. The signal detecting apparatus according to claim 2, wherein an output end of the processor (180) is connected to the control end (106) for transmitting the control signal to the control end (106).

The signal detecting device according to any one of claims 1 to 4, wherein the detecting circuit (110) comprises: a switching circuit (120) and a first resistor (130), the switching circuit (120) and the first resistor (130) are connected in series or in parallel at the first end (112) and the Between the second ends (114), wherein the control input of the switching circuit (120) is connected to the third end (116), and when the control signal is in the first state, the switch The circuit (120) is turned on, and when the control signal is in the second state, the switch circuit (120) is turned off.

The signal detecting device according to claim 5, wherein the detecting circuit (110) further comprises:

a second resistor (132), when the switching circuit (120) and the first resistor (130) are connected in series at the first end (112) and the second end (114) The second resistor (132) is connected in parallel with the switch circuit (120) and the first resistor (130) at the first end (112) and the Between the second ends (114), when the switching circuit (120) and the first resistor (130) are connected in parallel at the first end (112) and the second end (114) Between the second resistor (132) and the combination of the switch circuit (120) and the first resistor (130) are connected in series at the first end (U2) and Between the second ends (114).

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

The signal detecting device according to claim 7, comprising:

A heat dissipating mechanism (160) is adjacent to the first resistor (130) and the third resistor (134).

9. The signal detecting device according to claim 5, wherein the switching circuit (120) comprises a transistor switching circuit.

The signal detecting device according to any one of claims 1 to 4, wherein the detecting circuit (110) further comprises at least one of the following:

a current limiting component (140) connected between the second end (114) and the signal transmitting end (104); a pull-up resistor (142), one end of the pull-up resistor (142) is connected to the Between the second end (114) and the signal transmitting end (104), the other end of the pull-up resistor (142) is connected to the power terminal (108); a clamping circuit (150), the clamp One end of the circuit (150) is connected between the second end (114) and the signal transmitting end (104), and the other end of the clamping circuit (150) is used to connect the first ground, The other end of the clamp circuit (150) is connected to the power terminal (108):

a first capacitor (144), one end of the first capacitor (144) is connected between the second end and the signal transmitting end (104), and the other end of the first capacitor (144) is used for connection a first capacitor; a second capacitor (146), one end of the second capacitor (146) is connected between the signal receiving end (102) and the second end (114), the second capacitor The other end of the (146) is for connecting the first ground; the fourth resistor (148), one end of the fourth resistor (148) is connected to the signal receiving end (102) and the second end Between (114), the other end of the fourth resistor (148) is used to connect the first ground.