Linear sensor conversion circuit with adjustable detection distance

Abstract

The utility model provides a linear sensor conversion circuit with an adjustable detection distance. The linear sensor conversion circuit comprises an input circuit, a signal amplification circuit, a signal processing circuit, an output circuit and a voltage stabilizing circuit, the input circuit comprises a magneto-dependent sensor IC1, the signal amplification circuit comprises a three-operational-amplifier instrumentation amplifier U1, and the signal processing circuit comprises a hysteresis comparator U2. According to the utility model, continuous signals output by the magneto-dependent sensor are converted into high and low level signals for output, so that the product has strong loading capacity; the power supply voltage range of the product is wide, and normal work under the power supply voltage of 8V to 58V can be realized; through the design of the temperature compensation resistor, the high-precision test of the detection distance in the temperature range from-55 DEG C to 85 DEG C is realized; within a certain magnetic induction intensity range, a high level conversion point and a low level conversion point are accurate and adjustable; the circuit can realize multi-group circuit triggering of the same magnetic induction intensity signal, the multi-group circuit triggering synchronism is high, the signals are physically isolated and do not interfere with each other, and multi-redundancy signal control is realized.

Description

Technical Field

[0001] The utility model relates to a linear sensor conversion circuit with adjustable detection distance. Background Art

[0002] There are many sensors developed using the Hall effect on the market. The output voltage signal changes linearly with the input magnetic induction intensity signal, and the linear output sensor; one converts the magnetic induction intensity signal into a high and low level signal for output; the power supply voltage of the linear sensor is generally 5V~10.5V, and the power supply voltage range is narrow. Exceeding the allowable power supply voltage may cause damage to the device, and there is no reverse connection protection at the power supply end and no short circuit protection at the output end. The same problem exists when using a switch-type Hall device. The power supply voltage range is narrow, there is no reverse connection protection at the power supply end, and there is no short circuit protection at the output end. Special attention should be paid to the application and assembly, otherwise the components will be destroyed. In addition, the magnetic induction parameters of the switch-type Hall device are fixed parameters. The magnetic induction parameters of the working point and the magnetic parameters of the release point have been determined and cannot be changed. Limit the application range of the product. The working point and release point can be customized to the manufacturer. If adjustment is required in actual application, it cannot be adjusted, which limits the application range. Utility Model Content

[0003] In order to solve the above technical problems, the utility model provides a linear sensor conversion circuit with adjustable detection distance.

[0004] The utility model is realized through the following technical solutions.

[0005] A detection distance adjustable linear sensor conversion circuit comprises an input circuit, a signal amplifying circuit, a signal processing circuit and an output circuit which are connected in sequence; the input circuit, the signal amplifying circuit, the signal processing circuit and the output circuit are also connected to a voltage stabilizing circuit; the voltage stabilizing circuit and the output circuit are also connected to a power supply; the output circuit is also connected to a load.

[0006] The input circuit is a magnetic sensor IC1.

[0007] The signal amplification circuit includes a three-op-amp instrumentation amplifier U1 and a sliding rheostat RP1; the -IN 1 pin and the +IN4 pin of the three-op-amp instrumentation amplifier are respectively connected to the V- pin and V+ of the magnetic sensor IC1, the RG 2 pin and the RG 3 pin are respectively connected to the two ends of the sliding rheostat RP1, the REF 6 pin is connected to the resistor R3, the resistor R10 and one end of the capacitor C4, the -VS 5 pin is connected to the other end of the resistor R10 and the capacitor C4, and the GND pin of the magnetic sensor IC1, and then connected to the power ground GND.

[0008] The signal processing circuit includes a hysteresis comparator U2 and a sliding rheostat RP2; the inverting input terminal of the hysteresis comparator U2 is connected to one end of a resistor R4, the non-inverting input terminal is connected to one end of the sliding rheostat RP2 and a resistor R8, the output terminal is connected to the other end of the sliding rheostat RP2, and the power supply voltage output terminal is connected to a power supply ground GND; the other end of the resistor R4 is connected to one end of a capacitor C3, a resistor R11 and a resistor R5, and the other end of the resistor R5 is connected to the OUT 7 pin of the three-op-amp instrumentation amplifier U1; the other end of the resistor R8 is connected to one end of a resistor R9, a capacitor C2 and a resistor R2, and the other end of the resistor R9 is connected to one end of a resistor R13 and a resistor R14 in parallel; the other ends of the capacitor C2, the capacitor C3 and the resistor R11, and the other end of the resistor R13 and the resistor R14 in parallel are connected to the power supply ground GND.

[0009] The output circuit includes a transistor Q1, a light emitting diode LED1, a resettable fuse 1B, and transient suppression diodes TVS1 and TVS2; the cathode of the light emitting diode LED1 is connected to the output end of the hysteresis comparator U2 through a resistor R7, and the anode is connected to the base of the transistor Q1 and one end of the resistor R1 through a resistor R6; the emitter of the transistor Q1 is connected to one end of the resettable fuse 1B, the collector is connected to the load end and one end of the resistor R12, and the other end of the resistor R12 is connected to the negative electrode of the power supply; the other end of the resettable fuse 1B and the resistor R1 is connected to the cathode of the diode D1, the anode of the diode D1 is connected to the negative electrode of the power supply through the transient suppression diode TVS1 and the capacitor C1, the anode of the diode D1 is also connected to the positive electrode of the power supply and one end of the transient suppression diode TVS2, and the other end of the transient suppression diode TVS2 is connected to the load end.

[0010] The voltage stabilizing circuit includes a transistor Q2, a voltage stabilizing diode ZD1, capacitors C5 and C6, and resistors R15 and R16; the base of the transistor Q2 is connected to the anode of the voltage stabilizing diode ZD1 and one end of the resistor R15, the collector is connected to the other end of the resistor R15 and one end of the resistor R16 and then connected to the power supply ground D_GND, the emitter is connected to one end of the capacitor C5 and the capacitor C6 and then connected to the power supply ground GND, and the other end of the resistor R16 is connected to the negative electrode of the power supply; the cathode of the voltage stabilizing diode ZD1 is connected to the other end of the capacitor C5 and the capacitor C6, the VCC pin of the magnetic sensor IC1, the +VS 8 pin of the three-op-amp instrumentation amplifier U1, the other end of the resistor R3, the other end of the resistor R2, and the power supply voltage input terminal of the hysteresis comparator U2.

[0011] The resistor R14 is a thermistor.

[0012] The beneficial effects of the utility model are:

[0013] The utility model converts a magnetic induction intensity signal into a continuous voltage signal output through a magnetic sensor IC1, amplifies the continuous voltage signal by adopting a three-op-amp instrument amplifier U1, and makes the gain of the three-op-amp instrument amplifier U1 adjustable through a sliding rheostat RP1, thereby realizing different electrical signal outputs under the same magnetic induction intensity and adjustable near working point of the sensor; the upper and lower threshold levels of the hysteresis comparator U2 are designed through resistance parameters, and the lower threshold level is adjusted by adjusting the sliding rheostat RP2, and the upper threshold level is changed by continuing to adjust the sliding rheostat RP1, and the two adjusting resistors are matched with each other to realize accurate control of the working point and the release point, and realize the purpose of making the detection distance adjustable; the utility model circuit can also realize the triggering of multiple groups of circuits by the same magnetic induction intensity signal, and the triggering synchronization of the multiple groups of circuits is high, and the signals are physically isolated and do not interfere with each other, thereby realizing redundant signal control. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural block diagram of the utility model;

[0015] Figure 2 This is a circuit schematic diagram of the utility model. DETAILED DESCRIPTION

[0016] The technical solution of the utility model is further described below in conjunction with the accompanying drawings and embodiments, but the scope of protection required is not limited to the description.

[0017] Example 1

[0018] like Figure 1 The structure block diagram of the utility model is shown; a detection distance adjustable linear sensor conversion circuit, including an input circuit, a signal amplifying circuit, a signal processing circuit and an output circuit connected in sequence; the input circuit, the signal amplifying circuit, the signal processing circuit and the output circuit are also connected to a voltage stabilizing circuit; the voltage stabilizing circuit and the output circuit are also connected to a power supply; the output circuit is also connected to a load.

[0019] like Figure 2 The figure shows the circuit principle diagram of the utility model; the input circuit is a magnetic sensor IC1;

[0020] Specifically, the magnetic sensor IC1 is a high-sensitivity linear sensor with a wide dynamic range, extremely low power consumption, and good temperature characteristics.

[0021] The signal amplification circuit includes a three-op-amp instrumentation amplifier U1 and a sliding rheostat RP1; the -IN 1 pin and the +IN 4 pin of the three-op-amp instrumentation amplifier are respectively connected to the V- pin and V+ of the magnetic sensor IC1, the RG 2 pin and the RG 3 pin are respectively connected to the two ends of the sliding rheostat RP1, the REF 6 pin is connected to the resistor R3, the resistor R10 and one end of the capacitor C4, the -VS 5 pin is connected to the other end of the resistor R10 and the capacitor C4, and the GND pin of the magnetic sensor IC1, and then connected to the power ground GND;

[0022] Specifically, a three-op-amp instrumentation amplifier U1 is selected for amplifying weak signals. The signal output by the magnetic sensor IC1 is a small differential signal with a large common-mode component. To amplify the signal, the amplifier needs to have a sufficiently large amplification factor, a higher input resistance and a higher common-mode rejection ratio. An amplifier composed of three op-amps is selected. The first two op-amps are both inverse proportional amplifier circuits with large input resistance. The back end is a differential amplifier that converts the differential input into a single-ended output and has the ability to suppress common-mode signals. The three-op-amp instrumentation amplifier U1 can set the gain through an external sliding rheostat RP1, change the input voltage of the back-end comparator, and the output voltage is divided from the power supply end to set the reference voltage through resistors R3 and R10.

[0023] The signal processing circuit includes a hysteresis comparator U2 and a sliding rheostat RP2; the inverting input terminal of the hysteresis comparator U2 is connected to one end of a resistor R4, the non-inverting input terminal is connected to one end of the sliding rheostat RP2 and a resistor R8, the output terminal is connected to the other end of the sliding rheostat RP2, and the power supply voltage output terminal is connected to the power supply ground GND; the other end of the resistor R4 is connected to one end of the capacitor C3, the resistor R11 and a resistor R5, and the other end of the resistor R5 is connected to the OUT 7 pin of the three-op-amp instrumentation amplifier U1; the other end of the resistor R8 is connected to one end of the resistor R9, the capacitor C2 and the resistor R2, and the other end of the resistor R9 is connected to one end of the resistor R13 and the resistor R14 in parallel; the other ends of the capacitor C2, the capacitor C3 and the resistor R11, and the other end of the resistor R13 and the resistor R14 in parallel are connected to the power supply ground GND;

[0024] Specifically, the hysteresis comparator U2 is a low-power operational amplifier that can realize track output, an external sliding rheostat RP2, resistors R4, R5, R2, R8, R9, R13, R14 and R7 set the upper and lower threshold levels, and capacitors C2 and C3 are filter capacitors to filter out interference. The sliding rheostat RP2 adjusts the sensor release point and converts the continuous signal into high and low level signals for output.

[0025] The output circuit includes a transistor Q1, a light emitting diode LED1, a resettable fuse 1B, and transient suppression diodes TVS1 and TVS2; the cathode of the light emitting diode LED1 is connected to the output end of the hysteresis comparator U2 through a resistor R7, and the anode is connected to the base of the transistor Q1 and one end of the resistor R1 through a resistor R6; the emitter of the transistor Q1 is connected to one end of the resettable fuse 1B, the collector is connected to the load end and one end of the resistor R12, and the other end of the resistor R12 is connected to the negative electrode of the power supply; the other end of the resettable fuse 1B and the resistor R1 is connected to the cathode of the diode D1, the anode of the diode D1 is connected to the negative electrode of the power supply through the transient suppression diode TVS1 and the capacitor C1, the anode of the diode D1 is also connected to the positive electrode of the power supply and one end of the transient suppression diode TVS2, and the other end of the transient suppression diode TVS2 is connected to the load end;

[0026] Specifically, the output signal of the output end of the hysteresis comparator U2 is combined with the resistor R6 and the resistor R7 to control the cut-off and conduction of the transistor Q1. The bias resistor R1 controls the transistor Q1 to be in the cut-off state when the high-level signal output by the hysteresis comparator U2 is not received; the diode D1 is used for reverse connection protection of the power supply end, and the magnetic sensor IC1 will not be damaged if the positive and negative poles of the power supply end of the magnetic sensor IC1 are reversed; whether the light-emitting diode is emitting light or not can directly determine the output state of the sensor; the self-resetting fuse 1B is used for short-circuit protection, and it is automatically disconnected when the output end is short-circuited, and the output transistor Q1 is not damaged; transient suppression diodes TVS1 and TVS2 act as voltage suppressors to play a role in surge protection and protect the back-end circuit of the magnetic sensor IC1.

[0027] The voltage stabilizing circuit includes a transistor Q2, a voltage stabilizing diode ZD1, capacitors C5 and C6, and resistors R15 and R16; the base of the transistor Q2 is connected to the anode of the voltage stabilizing diode ZD1 and one end of the resistor R15, the collector is connected to the other end of the resistor R15 and one end of the resistor R16 and then connected to the power supply ground D_GND, the emitter is connected to one end of the capacitor C5 and the capacitor C6 and then connected to the power supply ground GND, and the other end of the resistor R16 is connected to the negative electrode of the power supply; the cathode of the voltage stabilizing diode ZD1 is connected to the other end of the capacitor C5 and the capacitor C6, the VCC pin of the magnetic sensor IC1, the +VS 8 pin of the three-op-amp instrumentation amplifier U1, the other end of the resistor R3, the other end of the resistor R2, and the power supply voltage input terminal of the hysteresis comparator U2;

[0028] Specifically, the voltage stabilizing circuit can convert 8 to 58V voltage into 5V voltage for output, providing suitable power supply voltage and reference voltage for magnetic sensor IC1, three-op-amp instrumentation amplifier U1 and hysteresis comparator U2. The voltage stabilizing circuit composed of transistor Q2 has a strong load-carrying capacity. The loads are all connected to the collector stage, and the base current is amplified at the collector stage.

[0029] The resistor R14 is a thermistor;

[0030] Specifically, the resistor R14 is replaced by a thermistor to play a role in temperature compensation, and can achieve high-precision testing of the detection distance in the temperature range of -55°C to 85°C, with the temperature drift within 10%.

[0031] Example 2

[0032] The utility model adopts a linear magnetic sensor U1 to convert the magnetic induction intensity signal into a continuous voltage signal for output. Since the output signal is too small, it cannot be directly connected to a comparator for comparison. A three-op-amp instrument amplifier U1 is used as a precision amplifier to amplify the signal. The precision amplifier reference voltage is obtained by voltage division of power supply end resistors R3 and R10. The reference voltage adds a DC component to the output voltage to ensure that the input voltage of the hysteresis comparator U2 can cover the power supply voltage range. The input voltage can reach the upper and lower threshold levels and can trigger the high and low level outputs of the hysteresis comparator U2. The positive input end of the hysteresis comparator U2 adopts resistors R8, R9, R13, R14, and a sliding rheostat RP2 for parameter setting. According to the following formulas (1) and (2), if the power supply voltage is 28V, the upper and lower threshold levels are calculated and the resistance parameters are set.

[0033]

[0034] U T+ is the upper threshold level, U T— The lower threshold level is adjusted by adjusting the sliding rheostat RP2, and then the sensor release point is adjusted. When the lower threshold level is adjusted, the upper threshold level changes, that is, the working point changes. The external resistor sliding rheostat RP1 of the precision amplifier is adjusted to adjust the amplification factor. The gain of the precision amplifier can be adjusted to adjust the output voltage at the same point, and this setting will not change the upper and lower threshold levels of the hysteresis comparator U2. The sensor release point remains unchanged, and the upper and lower threshold levels of the hysteresis comparator U2 remain unchanged, but the output voltage increases under the same magnetic induction intensity, realizing the precise adjustment of the working point and the release point.

[0035] The beneficial effects of the utility model are as follows: the continuous signal output by the magnetic sensor IC1 is converted into high and low level signals for output, the product has strong load capacity, and according to the circuit parameter design, the maximum load current is 200mA; the product has a wide power supply voltage range, and according to the selection of the voltage stabilizing circuit and the transient suppression diode, it can achieve normal operation under the power supply voltage of 8V to 58V; the product is designed with overvoltage protection, reverse connection protection, and short circuit protection, and is designed with the temperature compensation resistor R14 to achieve high-precision testing of the detection distance in the temperature range of -55°C to 85°C, with the temperature drift within 10%; within a certain magnetic induction intensity range, the high-level conversion point and the low-level conversion point are accurately adjustable, and after the conversion point is determined, the repetition accuracy of the conversion of the conversion point reaches 0.05mm; the circuit of the utility model can also realize the triggering of multiple groups of circuits with the same magnetic induction intensity signal, the triggering synchronization of the multiple groups of circuits is high, and the signals are physically isolated and do not interfere with each other, thereby realizing redundant signal control.

Claims

1. A detection distance adjustable linear sensor conversion circuit, characterized in that: It includes an input circuit, a signal amplifying circuit, a signal processing circuit and an output circuit which are connected in sequence; the input circuit, the signal amplifying circuit, the signal processing circuit and the output circuit are also connected to a voltage stabilizing circuit; the voltage stabilizing circuit and the output circuit are also connected to a power supply; the output circuit is also connected to a load.

2. A detection distance adjustable linear sensor conversion circuit as claimed in claim 1, characterized in that: The input circuit is a magnetic sensor IC1.

3. The detection distance adjustable linear sensor conversion circuit as claimed in claim 1, characterized in that: The signal amplification circuit includes a three-op-amp instrumentation amplifier U1 and a sliding rheostat RP1; the -IN 1 pin and the +IN 4 pin of the three-op-amp instrumentation amplifier are respectively connected to the V- pin and V+ of the magnetic sensor IC1, the RG 2 pin and the RG 3 pin are respectively connected to the two ends of the sliding rheostat RP1, the REF 6 pin is connected to the resistor R3, the resistor R10 and one end of the capacitor C4, the -VS 5 pin is connected to the other end of the resistor R10 and the capacitor C4, and the GND pin of the magnetic sensor IC1, and then connected to the power ground GND.

4. The detection distance adjustable linear sensor conversion circuit as claimed in claim 1, characterized in that: The signal processing circuit includes a hysteresis comparator U2 and a sliding rheostat RP2; the inverting input terminal of the hysteresis comparator U2 is connected to one end of a resistor R4, the non-inverting input terminal is connected to one end of the sliding rheostat RP2 and a resistor R8, the output terminal is connected to the other end of the sliding rheostat RP2, and the power supply voltage output terminal is connected to a power supply ground GND; the other end of the resistor R4 is connected to one end of a capacitor C3, a resistor R11 and a resistor R5, and the other end of the resistor R5 is connected to the OUT 7 pin of the three-op-amp instrumentation amplifier U1; the other end of the resistor R8 is connected to one end of a resistor R9, a capacitor C2 and a resistor R2, and the other end of the resistor R9 is connected to one end of a resistor R13 and a resistor R14 in parallel; the other ends of the capacitor C2, the capacitor C3 and the resistor R11, and the other end of the resistor R13 and the resistor R14 in parallel are connected to the power supply ground GND.

5. The detection distance adjustable linear sensor conversion circuit as claimed in claim 1, characterized in that: The output circuit includes a transistor Q1, a light emitting diode LED1, a resettable fuse 1B, and transient suppression diodes TVS1 and TVS2; the cathode of the light emitting diode LED1 is connected to the output end of the hysteresis comparator U2 through a resistor R7, and the anode is connected to the base of the transistor Q1 and one end of the resistor R1 through a resistor R6; the emitter of the transistor Q1 is connected to one end of the resettable fuse 1B, the collector is connected to the load end and one end of the resistor R12, and the other end of the resistor R12 is connected to the negative electrode of the power supply; the other end of the resettable fuse 1B and the resistor R1 is connected to the cathode of the diode D1, the anode of the diode D1 is connected to the negative electrode of the power supply through the transient suppression diode TVS1 and the capacitor C1, the anode of the diode D1 is also connected to the positive electrode of the power supply and one end of the transient suppression diode TVS2, and the other end of the transient suppression diode TVS2 is connected to the load end.

6. The detection distance adjustable linear sensor conversion circuit as claimed in claim 1, characterized in that: The voltage stabilizing circuit includes a transistor Q2, a voltage stabilizing diode ZD1, capacitors C5 and C6, and resistors R15 and R16; the base of the transistor Q2 is connected to the anode of the voltage stabilizing diode ZD1 and one end of the resistor R15, the collector is connected to the other end of the resistor R15 and one end of the resistor R16 and then connected to the power supply ground D_GND, the emitter is connected to one end of the capacitor C5 and the capacitor C6 and then connected to the power supply ground GND, and the other end of the resistor R16 is connected to the negative electrode of the power supply; the cathode of the voltage stabilizing diode ZD1 is connected to the other end of the capacitor C5 and the capacitor C6, the VCC pin of the magnetic sensor IC1, the +VS 8 pin of the three-op-amp instrumentation amplifier U1, the other end of the resistor R3, the other end of the resistor R2, and the power supply voltage input terminal of the hysteresis comparator U2.

7. A detection distance adjustable linear sensor conversion circuit as claimed in claim 4, characterized in that: The resistor R14 is a thermistor.

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