A two-wire TMR sensor, PCB board and control circuit thereof

Abstract

The invention discloses a two-wire TMR sensor, a PCB board and a control circuit thereof. The control circuit of the two-wire TMR sensor comprises a TMR sensor, a first charging and discharging unit and a second charging and discharging unit. A pin 1 of the TMR sensor and one end of the first charging and discharging unit are grounded, the other end of the first charging and discharging unit and one end of the second charging and discharging unit are respectively connected to a pin 2 of the TMR sensor, the other end of the second charging and discharging unit and a pin 3 of the TMR sensor are connected to an external mechanism, and the first charging and discharging unit and the second charging and discharging unit are used to supply power to the pin 2 of the TMR sensor. In the control circuit disclosed in the present application, the first charging and discharging unit and the second charging and discharging unit supply power to the pin 2 of the TMR sensor to ensure the normal operation of the TMR sensor. The TMR sensor can realize working control by only using a ground wire and a signal wire to connect to a client, and can directly replace a two-wire reed switch without replacing a mainboard interface, a control circuit and a control program of the client, thereby improving the applicability and use flexibility of the TMR sensor.

Description

Technical Field

[0001] The present invention relates to the technical field of TMR sensors, and in particular to a two-wire TMR sensor, a PCB board and a control circuit thereof. Background Art

[0002] The reed switch currently on the market is generally composed of a reed switch and a potted shell. For the normally open reed switch, when a magnet approaches, the two contacts of the reed switch will be attracted; for the normally closed reed switch, when a magnet approaches, the two contacts of the reed switch will be disconnected. By selecting different types of reed switches, work control in different situations can be achieved.

[0003] The shell of the existing reed switch is generally made of glass. If some reed switches fall from a height during production and transportation or are squeezed by external force during the potting process, the glass shell is prone to cracking, and even the contacts of the internal reed switches may be deformed, resulting in reduced detection accuracy of the reed switch or even detection failure. Therefore, the yield rate of reed switch in the production process is low. In addition, whether there are defects inside the reed switch cannot be observed by the human eye, and professional instruments need to be used for detection, which increases the difficulty of detecting product defects of the reed switch.

[0004] When the existing TMR sensor is connected to an external component, it is necessary to connect a power line, a ground line and a signal line. If a three-wire TMR sensor is used to replace a two-wire reed switch for detection, it is necessary to change the motherboard interface, adjust the control circuit and the detection program, etc., which is troublesome to operate.

[0005] It can be seen that the existing technology still needs to be improved and enhanced. Summary of the invention

[0006] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a control circuit for a two-wire TMR sensor. The TMR sensor can achieve working control by connecting to the client using a ground wire and a signal wire, and can directly replace a two-wire reed switch, thereby improving the applicability and flexibility of the TMR sensor.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A control circuit for a two-wire TMR sensor comprises a TMR sensor, a first charging and discharging unit and a second charging and discharging unit, wherein a pin 1 of the TMR sensor and one end of the first charging and discharging unit are grounded, the other end of the first charging and discharging unit and one end of the second charging and discharging unit are respectively connected to a pin 2 of the TMR sensor, the other end of the second charging and discharging unit and a pin 3 of the TMR sensor are connected to an external mechanism, and the first charging and discharging unit and the second charging and discharging unit are used to supply power to the pin 2 of the TMR sensor.

[0009] In the control circuit of the two-wire TMR sensor, the first charging and discharging part includes a first capacitor C1, the second charging and discharging part includes a first resistor R1, one end of the first capacitor C1 is grounded, the other end of the first capacitor C1 and one end of the first resistor R1 are connected to pin 2 of the TMR sensor, and the other end of the first resistor R1 is connected to an external mechanism.

[0010] In the control circuit of the two-wire TMR sensor, the external mechanism includes a pull-up unit and a power supply unit, one end of the pull-up unit is connected to the other end of the second charging and discharging unit and pin 3 of the TMR sensor, and the other end of the pull-up unit is connected to the power supply unit.

[0011] In the control circuit of the two-wire TMR sensor, the pull-up unit includes a second resistor R2, one end of the second resistor R2 is connected to the other end of the second charging and discharging unit and the pin 3 of the TMR sensor, and the other end of the second resistor R2 is connected to the power supply unit.

[0012] The present invention also provides a PCB board accordingly, on which the control circuit of any of the above-mentioned two-wire TMR sensors is printed.

[0013] The present invention also correspondingly provides a two-wire TMR sensor, including a housing, wherein the PCB board as described above is arranged in the housing, and two connecting ports are opened on the housing, and the PCB board is connected to an external mechanism through a signal line and the connecting ports.

[0014] In the two-wire TMR sensor, a plurality of positioning holes are provided on the shell, and the positioning holes are used to install and fix the two-wire TMR sensor.

[0015] Beneficial effects:

[0016] The invention provides a control circuit of a two-wire TMR sensor, comprising a first charging and discharging part and a second charging and discharging part, wherein the first charging and discharging part and the second charging and discharging part supply power to a pin 2 of the TMR sensor to ensure normal operation of the TMR sensor; the other end of the second charging and discharging part and a pin 3 of the TMR sensor are connected to an external mechanism through a signal line, that is, the TMR sensor only needs to be connected to a client through a ground line and a signal line to realize working control, and a two-wire reed switch can be directly replaced without replacing a mainboard interface, a control circuit and a control program of the client, thereby improving the applicability and use flexibility of the TMR sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A circuit structure diagram of a control circuit of a two-wire TMR sensor provided by the present invention;

[0018] Figure 2A circuit diagram of the external mechanism provided by the present invention;

[0019] Figure 3 This is a schematic structural diagram of the two-wire TMR sensor provided by the present invention.

[0020] Description of main component symbols: 1-housing, 11-positioning hole. DETAILED DESCRIPTION

[0021] The present invention provides a two-wire TMR sensor, a PCB board and a control circuit thereof. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below with reference to the accompanying drawings and examples.

[0022] In the description of the present invention, it should be understood that the terms "installation", "connection" and the like should be understood in a broad sense, and a person skilled in the art can understand the specific meanings of the above terms in the present invention according to specific circumstances.

[0023] See also Figure 1 and Figure 2 The present invention provides a control circuit of a two-wire TMR sensor, comprising a TMR sensor, a first charging and discharging unit and a second charging and discharging unit, wherein a pin 1 of the TMR sensor and one end of the first charging and discharging unit are grounded, the other end of the first charging and discharging unit and one end of the second charging and discharging unit are respectively connected to a pin 2 of the TMR sensor, the other end of the second charging and discharging unit and a pin 3 of the TMR sensor are connected to an external mechanism, and the first charging and discharging unit and the second charging and discharging unit are used to supply power to a pin 2 of the TMR sensor.

[0024] See also Figure 1 and Figure 2, let the connection point between pin 2 of the TMR sensor and the other end of the first charge-discharge part and one end of the second charge-discharge part be the VDD point, let the connection point between the other end of the second charge-discharge part and pin 3 of the TMR sensor and the external mechanism be the OUT point; when the TMR sensor is not subjected to magnetic induction, the TMR sensor is in a non-inductive state, at which time the voltage at point VDD is consistent with the voltage at point OUT, and the voltages at point VDD and OUT are both equal to VCC; when the TMR sensor is subjected to magnetic induction, the TMR sensor quickly pulls the voltage at point OUT down to 0V, which is equivalent to pulling it to ground; at this time, the first charge-discharge part and the second charge-discharge part are in a discharging state as a whole, and the voltage at point VDD slowly drops to the minimum voltage of the TMR sensor, which is also called the reset voltage. At this time, the TMR sensor enters a reset state, and the TMR sensor is insufficient to maintain the state of continuing to pull the voltage at point OUT down to 0V, and the first charge-discharge part and the second charge-discharge part are converted to a charging state as a whole. , the voltage at point VDD and the voltage at point OUT rise slowly; in the process of the voltage rising at point VDD, the change state of the voltage at point OUT is consistent with the change state of the voltage at point VDD; when the voltage at point VDD rises to the operating voltage, the voltage at point VDD of the TMR sensor meets the condition of pulling the voltage at point OUT down to 0V, the TMR sensor pulls the voltage at point OUT down to 0V again, the first charge-discharge section and the second charge-discharge section as a whole return to the discharge state, and the voltage at point VDD slowly drops to the minimum voltage; that is, in the process of the TMR sensor being magnetically induced, the first charge-discharge section and the second charge-discharge section as a whole continuously switch between the discharge state and the charging state, the voltage at point VDD continuously changes between the minimum voltage and the operating voltage, and the average voltage at point OUT is lower than VCC; when the TMR sensor eliminates the magnetic induction state, that is, when the TMR sensor does not sense the magnetic field, the voltage at point OUT and the voltage at point VDD return to being consistent with VCC.

[0025] In one embodiment, the voltage of the VCC may be 5V, the voltage of the minimum voltage may be 1.2V, and the voltage of the operating voltage may be 1.7V; the other end of the second charging and discharging unit and the pin 3 of the TMR sensor are connected to an external mechanism through a signal line, and the external mechanism may be a client; when the TMR sensor is in a non-sensing state, the voltage signal received by the external mechanism is a high level VCC, and when the TMR sensor is in a sensing state, the voltage signal received by the external mechanism is a low level, which satisfies the detection mechanism of the TMR sensor; the external mechanism performs corresponding control actions according to the level signal fed back by the TMR sensor.

[0026] The control circuit of the two-wire TMR sensor disclosed in the present application includes a first charging and discharging part and a second charging and discharging part. The first charging and discharging part and the second charging and discharging part supply power to pin 2 of the TMR sensor to ensure the normal operation of the TMR sensor. The other end of the second charging and discharging part and pin 3 of the TMR sensor are connected to an external mechanism through a signal line, that is, the TMR sensor only needs to be connected to the client using a ground line and a signal line to achieve working control. The two-wire reed switch can be directly replaced without replacing the client's mainboard interface, control circuit and control program, thereby improving the applicability and flexibility of use of the TMR sensor.

[0027] For further information, see Figure 1 The first charging and discharging part includes a first capacitor C1, and the second charging and discharging part includes a first resistor R1. One end of the first capacitor C1 is grounded, the other end of the first capacitor C1 and one end of the first resistor R1 are connected to pin 2 of the TMR sensor, and the other end of the first resistor R1 is connected to an external mechanism; the first capacitor C1 and the first resistor R1 together form an RC charging and discharging circuit, and the first capacitor C1 is used to realize the conversion of the charging and discharging state of the first charging and discharging part and the second charging and discharging part as a whole.

[0028] In one embodiment, the time required for the voltage at the VDD point to drop from VCC to the minimum voltage is approximately the multiplication of the first resistor R1 and the first capacitor C1; for example, assuming that the resistance of the first resistor R1 is 100 kilo-ohms and the capacitance of the first capacitor C1 is 10uf, the required time T is:

[0029] T = 0.00001*100000 = 1s.

[0030] In other embodiments, the first charging and discharging section may include a plurality of capacitors connected in series, and the second charging and discharging section may include a plurality of resistors connected in series. The user may select the number of capacitors included in the first charging and discharging section and the number of resistors included in the second charging and discharging section according to actual working conditions.

[0031] For further information, see Figure 2 The external mechanism includes a pull-up unit and a power supply unit, one end of the pull-up unit is connected to the other end of the second charging and discharging unit and pin 3 of the TMR sensor, and the other end of the pull-up unit is connected to the power supply unit; the power supply unit provides a voltage VCC for the OUT point and the VDD point.

[0032] For further information, see Figure 2, the pull-up unit includes a second resistor R2, one end of the second resistor R2 is connected to the other end of the second charging and discharging part and the pin 3 of the TMR sensor, and the other end of the second resistor R2 is connected to the power supply unit; in one embodiment, the external mechanism can be a client, the client includes a control chip, the power supply unit provides a stable operating voltage VCC for the control chip, the other end of the second charging and discharging part and the pin 3 of the TMR sensor are connected to the signal input pin of the control chip, the second resistor R2 can be a pull-up resistor arranged inside the control chip and corresponding to the signal input pin, and the second resistor R2 can also be used as a peripheral component of the signal input pin of the control chip to play a pull-up role.

[0033] The present invention also provides a PCB board accordingly, on which the control circuit of any of the above-mentioned two-wire TMR sensors is printed.

[0034] See also Figure 3 The present invention also provides a two-wire TMR sensor, including a housing 1, wherein the housing 1 is provided with the PCB board as described above, and the housing 1 is provided with two connection ports, wherein the PCB board uses a signal line and a ground line to pass through the connection ports to connect with an external mechanism.

[0035] For further information, see Figure 3 The housing 1 is also provided with a plurality of positioning holes 11, and the positioning holes 11 are used to realize the installation and fixation of the two-wire TMR sensor; in one embodiment, please refer to Figure 3 The housing 1 is provided with two positioning holes 11. In the actual installation process of the two-wire TMR sensor, screws can be passed through the positioning holes 11 to achieve the installation and fixation of the two-wire TMR sensor. The positioning holes 11 are threadedly connected with the screws.

[0036] It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of the present invention, and all these changes or substitutions should fall within the protection scope of the present invention.

Claims

1. A control circuit for a two-wire TMR sensor, characterized in that: It includes a TMR sensor, a first charging and discharging unit and a second charging and discharging unit, wherein a pin 1 of the TMR sensor and one end of the first charging and discharging unit are grounded, the other end of the first charging and discharging unit and one end of the second charging and discharging unit are respectively connected to a pin 2 of the TMR sensor, the other end of the second charging and discharging unit and a pin 3 of the TMR sensor are connected to an external mechanism, and the first charging and discharging unit and the second charging and discharging unit are used to supply power to the pin 2 of the TMR sensor; The first charging and discharging part includes a first capacitor C1, and the second charging and discharging part includes a first resistor R1. One end of the first capacitor C1 is grounded, the other end of the first capacitor C1 and one end of the first resistor R1 are connected to a pin 2 of the TMR sensor, and the other end of the first resistor R1 is connected to an external mechanism. The external mechanism includes a pull-up unit and a power supply unit, one end of the pull-up unit is connected to the other end of the second charging and discharging unit and the pin 3 of the TMR sensor, and the other end of the pull-up unit is connected to the power supply unit; The pull-up unit includes a second resistor R2, one end of the second resistor R2 is connected to the other end of the second charging and discharging unit and the pin 3 of the TMR sensor, and the other end of the second resistor R2 is connected to the power supply unit.

2. A PCB board, characterized in that: The control circuit of the two-wire TMR sensor as claimed in claim 1 is printed on the PCB board.

3. A two-wire TMR sensor, comprising a housing, characterized in that: The PCB board as claimed in claim 2 is arranged in the shell, and two connecting ports are provided on the shell. The PCB board is connected to an external mechanism through a signal line and the connecting ports.

4. A two-wire TMR sensor according to claim 3, characterized in that: The housing is also provided with a plurality of positioning holes, and the positioning holes are used to realize the installation and fixation of the two-wire TMR sensor.

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