CN115509287A - Adjusting circuit, pressure transmitter, adjusting chip and pressure transmitting chip - Google Patents

Abstract

The invention relates to the technical field of pressure transmission, in particular to an adjusting circuit, a pressure transmitter, an adjusting chip and a pressure transmitting chip. The adjusting circuit comprises a zero setting sub-circuit and a signal processing sub-circuit; the zero-adjusting sub-circuit mainly comprises an operational amplifier U1.2, a variable resistor P1 and 3 resistors R7, R8 and R9; the 4 capacitors C1, C2, C3 and C6 are used for carrying out noise filtering on weak signals of the sensor; the signal processing sub-circuit mainly comprises 3 operational amplifiers U1.1, U1.3 and U1.4, variable resistors P2,5 resistors R4, R5, R6, R10 and R11 and a PNP triode Q1, and a magnetic bead L2 and a capacitor C7 are used for enhancing the anti-electromagnetic interference of external connection. The invention solves the problem of zero drift caused by the backward flow current of the operational amplifier through the adjusting circuit; and when the sensor is connected with the diffused silicon sensor, the circuit balance of the diffused silicon sensor is not damaged.

Description

Adjusting circuit, pressure transmitter, adjusting chip and pressure transmitting chip

Technical Field

The invention relates to the technical field of pressure transmission, in particular to an adjusting circuit, a pressure transmitter based on the adjusting circuit, an adjusting chip and a pressure transmitting chip.

Background

A pressure transmitter is a device for converting pressure into pneumatic or electric signals for control and remote transmission, and the pressure transmitter usually uses a strain resistor as a sensor for detecting pressure. A diffused silicon pressure sensor is a strain resistor that operates using the principle of piezoresistive effect. Diffused silicon pressure sensors are typically fabricated using integrated process technology and include a wheatstone bridge of a plurality of base resistors. The pressure of the diffused silicon pressure sensor directly acts on a diaphragm of the sensor, so that the diaphragm generates micro displacement in direct proportion to the pressure of a medium, and the resistance value of the sensor changes. When the electronic circuit is designed to detect this change and convert it to output a standard measurement signal corresponding to this pressure, a pressure transmitter is obtained.

In the conventional pressure transmitter using the diffused silicon pressure sensor, in order to stabilize the signal of the sensor, a wheatstone bridge is subjected to a zeroing operation. In the currently widely used zeroing circuit, an adjusting resistor is connected in parallel to a bridge of a sensor itself, as shown in fig. 1, so that the circuit balance of the sensor itself is easily damaged, and the temperature coefficient and accuracy of a finally output signal are deteriorated. In addition, the existing diffused silicon pressure sensor usually adopts a single power supply device, when the sensor works by using a single power supply, because the sensor provides a differential signal, when the differential signal is processed, the zero drift problem caused by the backward flow current of an operational amplifier can occur. As shown in fig. 2, it can be seen that when the output signal is near zero, the current generated by V-via R2, R3 is poured into the output of the operational amplifier, thus generating zero drift.

Disclosure of Invention

In view of the above, it is necessary to provide an adjustment circuit, a pressure transmitter using the adjustment circuit, an adjustment chip, and a pressure transmitting chip, which solve the problems that the conventional zero adjustment circuit may damage the balance of the diffused silicon sensor itself and may easily cause zero point drift.

In order to achieve the purpose, the invention adopts the following technical scheme:

an adjustment circuit includes a nulling sub-circuit and a signal processing sub-circuit. The zero-adjusting sub-circuit mainly comprises an operational amplifier U1.2, a variable resistor P1 and 3 resistors R7, R8 and R9. The 4 capacitors C1, C2, C3 and C6 are used for carrying out noise filtering on weak signals of the sensor and increasing the anti-interference capacity. The signal processing sub-circuit mainly comprises 3 operational amplifiers U1.1, U1.3 and U1.4, variable resistors P2 and 5 resistors R4, R5, R6, R10 and R11 and a PNP triode Q1, and the magnetic bead L2 and the capacitor C7 enhance the anti-electromagnetic interference of external connection.

The specific connection mode of the adjusting circuit is as follows: the inverting input end and the output end of the operational amplifier U1.2 are connected with one end of the operational amplifier R9, the other end of the operational amplifier R9 is connected with the non-inverting input end of the operational amplifier U1.4, the non-inverting input end of the operational amplifier U1.3 is connected with one end of the operational amplifier C6 or the operational amplifier C3, and the moving plate pin of the variable resistor P1 is connected with the other end of the operational amplifier C6. The inverting input end and the output end of the operational amplifier U1.4 are connected with one end of the R4, and the other end of the R4 is connected with one of the stator pins of the variable resistor P2. The emitter of Q1 is connected with the other stator pin and the rotor pin of the variable resistor P2 and the inverting input end of the operational amplifier U1.3, the two ends of R10 are respectively connected with the base of Q1 and the output end of the operational amplifier U1.3, the collector of Q1 is connected with one end of R11, and the other end of R11 is grounded. The inverting input end and the output end of the operational amplifier U1.1 are respectively connected with two ends of the R6, the inverting input end of the operational amplifier U1.1 is further connected with one end of the R5, the other end of the R5 is grounded, the non-inverting input end of the operational amplifier U1.1 is connected with the collector of the Q1, the C7 is connected with the R11 in parallel, the output end of the operational amplifier U1.1 is connected with one end of the L2, the other end of the magnetic bead L2 is used as the voltage output end of the regulating circuit, the power supply input end of the operational amplifier U1.1 is used as the voltage input end of the regulating circuit, and the grounded end is grounded. One end of the R7 and one end of the C2 are connected and used as an input end + V of the adjusting circuit, the other end of the R7 is connected with one stator pin of the variable resistor P1, and the other stator pin of the variable resistor P1 is connected with one end of the R8. The other end of R8 is connected to the common ground of C1, C2 and C3 and serves as the input-V of the regulating circuit. One end of the C1 is connected to the non-inverting input of the operational amplifier U1.2 and serves as the input + S of the adjusting circuit. One end of the C3 is used as an input end-S of the adjusting circuit. The adjusting circuit can drive a signal of the sensor to pass through an input end + S, and the zero adjusting network formed by R7, R8, R9 and P1 is driven after impedance transformation is carried out on the signal by U1.2, and the original balance system of the sensor cannot be damaged. Meanwhile, a differential signal of the sensor can be converted into a single-end ground output signal through the input end + S and the input end-S, namely, a single-end voltage signal corresponding to the sensor is obtained in the resistor R11, and the problem that the traditional zero position of converting the differential signal into the single-end signal is not zero due to the offset step generated by the backward flow current is effectively avoided.

Furthermore, the signal processing sub-circuit further comprises a magnetic bead L2, and the magnetic bead L2 is connected with the output end of the operational amplifier U1.1.

Further, the operational amplifiers U1.3, U1.4, R4, P2, Q1, and R11 form a first stage amplification unit, and the amplification factor A1 of the first stage amplification unit is: a1= R11/(R4 + R) _P2 ) Wherein R is _P2 Is the resistance of the variable resistor P2.

Further, the operational amplifiers U1.1, R5, and R6 form a second stage amplification unit, and the amplification factor A2 of the second stage amplification unit is: a2=1+ R6/R5.

Further, the amplification factor a of the signal processing sub-circuit is: a = A1 × A2.

The invention also includes a pressure transmitter that includes a sensor, a power circuit, and a data processing circuit. The power circuit is used for providing required power. The sensor is used for generating corresponding detection signals in the detection process. The data processing circuit is used for converting the detection signal into a corresponding voltage signal, and the data processing circuit adopts the adjusting circuit.

Furthermore, the power supply circuit comprises a power supply input sub-circuit and a constant current and voltage stabilizing sub-circuit. The power input sub-circuit comprises 2 diodes D1 and D2 and 2 magnetic beads L1 and L3. The constant-current voltage-stabilizing sub-circuit comprises a linear voltage stabilizer U2 and 3 resistors R1, R2 and R3. And 2 capacitors C4, C5.

The specific connection mode of the power circuit is as follows: one end of each of the L1 and the L3 is used as an input end of the power supply circuit, the other end of the L1 is connected with the anode of the D1, the other end of the L3 is connected with the anode of the D2, the cathode of the D2 is connected with the anode of the D1, and the cathode of the D1 and a voltage input pin of the U2 are connected with one end of the C5. An adjustable pin of the U2 is connected with one ends of the R2 and the R3, and the other end of the R2 is used as a constant current output end of the power circuit. The other end of the R3 is connected with one end of the R1 and an output pin of the U2, the other end of the R1 is grounded, the output pin of the U2 is used as a constant voltage output end of the power circuit, the C4 is connected with the R1 in parallel, and the other end of the C5 is grounded with the R1. The constant current source output current provided for the sensor PT is: i =1.25V/R3. Here, 1.25V is a U2-specific reference voltage.

Furthermore, the sensor comprises a Wheatstone bridge consisting of four voltage variable resistors, and four bridge arms of the Wheatstone bridge are used as four terminals of the sensor and are respectively connected with the input ends + V, -V, + S and-S of the adjusting circuit.

The invention also comprises an adjusting chip which is formed by packaging the adjusting circuit. The pin of the adjusting chip comprises: the first pin is connected with the stator pin of the variable resistor P1 through a resistor R7. The second pin is connected to one end of the capacitors C1, C2, C3, which is common ground. The third pin is connected to the non-inverting input of the operational amplifier U1.2. The fourth pin is connected with the moving plate pin of the variable resistor P1 through a capacitor C6. The fifth pin is connected to the power input of operational amplifier U1.1. And the sixth pin is connected with the output end of the operational amplifier U1.1 through the magnetic bead L2.

The invention also comprises a pressure transmitter chip which is formed by packaging the data processing circuit and the power supply circuit of the pressure transmitter. The pin of the pressure transmitting chip comprises: the first pin is connected with the stator pin of the variable resistor P1 through a resistor R7. The second pin is connected to one end of the capacitors C1, C2, C3, which is grounded. The third pin is connected to the non-inverting input of operational amplifier U1.2. The fourth pin is connected with the moving plate pin of the variable resistor P1 through a capacitor C6. The fifth pin is connected with the anode of the diode D1 through the magnetic bead L1. And the sixth pin is connected with the anode of the diode D2 through the magnetic bead L3. And the seventh pin is connected with the output end of the operational amplifier U1.1 through the magnetic bead L2.

The technical scheme provided by the invention has the following beneficial effects:

1. the invention can solve the problem of zero drift caused by the backward flow current of the operational amplifier by arranging the adjusting circuit; and a zero adjustment unit consisting of U1.2, R7, R8, R9 and P1 is arranged on a circuit at the rear end of the operational amplifier, so that when the adjustment circuit is connected with the diffusion silicon sensor, the circuit balance of the diffusion silicon sensor is not damaged.

2. The pressure transmitter provided by the invention is universal, cheap and perfectly completes the conversion from the difference of the sensor to the voltage output of 0-5V standard, and the output voltage and the pressure sensed by the sensor are in a linear relation.

3. The power supply circuit provided by the invention not only has the function of circuit protection, but also can resist high-frequency electromagnetic interference; in addition, the LM317 chip is used for skillfully achieving two functions, namely providing a constant current source of 1.5mA for the sensor and providing a constant voltage source of 5V for the adjusting circuit.

4. The invention adopts a cheap general operational amplifier to complete the functions required by the pressure transmitter, and has the characteristics of low price and wide material supply range.

Drawings

FIG. 1 is a schematic diagram of a prior art nulling circuit coupled to a sensor;

FIG. 2 is a circuit diagram of a prior art differential signal to single-ended signal;

FIG. 3 is a circuit diagram of the adjusting circuit of the present invention;

FIG. 4 is a circuit diagram based on the zeroing sub-circuit of FIG. 3;

FIG. 5 is a circuit diagram based on the signal processing sub-circuit of FIG. 3;

fig. 6 is a circuit diagram of the pressure transmitter in embodiment 2;

FIG. 7 is a circuit diagram based on the power supply circuit of FIG. 5;

FIG. 8 is a circuit diagram based on the power input sub-circuit of FIG. 5;

fig. 9 is a circuit diagram based on the constant current regulator sub-circuit of fig. 5;

FIG. 10 is a signal flow diagram based on the pressure transmitter of FIG. 6;

FIG. 11 is a schematic diagram of the overall connection circuit of the pressure transmitter of FIG. 5;

FIG. 12 is a schematic structural diagram of a tuning chip according to embodiment 3;

fig. 13 is a schematic structural view of a pressure transmitting chip of embodiment 4.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.

Example 1

The adjusting circuit solves the problems that the circuit balance of the sensor is damaged when the diffused silicon sensor is adjusted to zero in the prior art, and the offset step problem caused by the backward flow current is caused when the traditional zero position is changed from a differential signal to a single-ended signal, namely the zero position is not zero. The invention places the zero adjusting unit composed of U1.2, R7, R8, R9 and P1 on the circuit at the rear end of the amplifier, thereby maintaining the compensation characteristic of the sensor; meanwhile, the problem of zero drift is solved by adopting a special current series negative feedback amplification unit, so that 0 bit output is normal.

As shown in fig. 3, the adjusting circuit includes a zeroing sub-circuit and a signal processing sub-circuit. The zero-adjusting sub-circuit mainly comprises an operational amplifier U1.2, a variable resistor P1 and 3 resistors R7, R8 and R9. The 4 capacitors C1, C2, C3 and C6 are used for carrying out noise filtering on weak signals of the pressure sensor and increasing the anti-interference capacity. The signal processing sub-circuit mainly comprises 3 operational amplifiers U1.1, U1.3 and U1.4, a variable resistor P2,5 resistors R4, R5, R6, R10 and R11 and a PNP triode Q1. The magnetic bead L2 and the capacitor C7 are used for enhancing the anti-electromagnetic interference of external connection.

The four operational amplifiers can be of the same type, can be LM2902 and LM324, are 14-pin packaged and internally comprise 4 independent operational amplifiers, and one operational amplifier can meet the requirements of the circuit (U1.1, U1.2, U1.3 and U1.4). Other operational amplifiers can be used instead as long as the performance of the operational amplifier meets the requirement of a single power supply circuit, the working power supply voltage is not less than 24V, all resistors meet the precision of 1%, and all capacitors meet the withstand voltage of 32V. An inexpensive LM2902 is preferred to accomplish the required functions of the pressure transmitter. Can completely replace precise and expensive inlet integrated circuits, so the method has the characteristics of low price and wide material supply range. For example, the LM2902DGR4 operational amplifier is a four-way operational amplifier, the range of a single power supply is 3-26V, and the range of a double power supply is +/-13V; LM2902 is operated by four independent, high gain, internal frequency compensation, which can be powered by a single power supply over a wide voltage range. A 14 pin DIP and SOP packaging process was used.

The capacitor in the adjusting circuit plays a role of filtering so as to eliminate noise and increase the anti-interference capability. C1, C2, C3, C6 and C7 may select 0.1 μ F patch capacitance.

The magnetic bead L2 in the adjusting circuit can eliminate high-frequency electromagnetic interference. For the selection of the resistor, the embodiment provides a specific scheme: selecting 510K omega resistors for R7 and R8; r9 selects a 2K omega resistor; r4 is a 100 omega resistor; r5 and R10 are resistors of 5.1K omega; r6 selects a 20K omega resistor; r11 is 1.5K omega resistance.

As shown in fig. 4, for the zeroing sub-circuit, the zeroing unit composed of U1.2, R7, R8, R9, and P1 is disposed on the circuit at the rear end of the amplifier, so that the compensation characteristic of the diffused silicon sensor itself is maintained, and the output signal is more accurate. And meanwhile, the large-scale migration can be carried out. The signal + S end of the sensor is subjected to impedance transformation by U1.2 and then drives a zero adjustment unit consisting of R7, R8, R9 and P1, so that the original balance system of the sensor (PT) cannot be damaged by the circuit. As shown in fig. 5, for the signal processing sub-circuit, the current series type negative feedback amplification unit formed by the operational amplifiers U1.3, U1.4, R4, P2, Q1 and R11, i.e. the first stage amplification unit, completes the conversion of the differential signal (+ S, -S) of the sensor into the single-ended ground output signal, i.e. the single-ended voltage signal corresponding to the sensor is obtained at the resistor R11, which effectively avoids the conventional zero position of converting the differential signal into the single-ended signal, and the problem that the zero position cannot reach zero due to the step of maladjustment caused by the backward flow current. And P2 may be used as a fullness adjustment.

The method for calculating the amplification factor of the current series type negative feedback amplification unit, namely the first-stage amplification unit, is as follows: and acquiring the resistance values of the resistor R4 and the adjustable resistor P2. The resistance values of the resistor R4 and the adjustable resistor P2 are added to obtain a total resistance value. And calculating the ratio of the resistance value of the resistor R11 to the total resistance value to obtain the required amplification factor. The calculation formula is as follows: magnification a = R11/(R4 + R) _P2 ) Wherein R is _P2 Is the resistance of the variable resistor P2.

The operational amplifiers U1.1, R5, R6 constitute a second stage amplification unit, and the method of calculating the amplification factor A2 of the second stage amplification unit is as follows: acquiring resistance values of a resistor R5 and a resistor R6; calculating the ratio of the resistor R6 to the resistor R5 to obtain a resistor ratio; and adding the resistance ratio to one time to calculate the required amplification factor A2. The calculation formula is as follows: a2=1+ R6/R5.

The formula for calculating the amplification factor a of the whole signal processing sub-circuit is as follows: a = A1 × A2.

The specific connection mode of the adjusting circuit is as follows: the inverting input end and the output end of the operational amplifier U1.2 are connected with one end of the operational amplifier R9, the other end of the operational amplifier R9 is connected with the non-inverting input end of the operational amplifier U1.4, the non-inverting input end of the operational amplifier U1.3 is connected with one end of the operational amplifier C6 and one end of the operational amplifier C3, and the moving plate pin of the variable resistor P1 is connected with the other end of the operational amplifier C6. The inverting input end and the output end of the operational amplifier U1.4 are connected with one end of the R4, and the other end of the R4 is connected with one of the fixed sheet pins of the variable resistor P2. The emitter of Q1 is connected with the other stator pin and the rotor pin of the variable resistor P2 and the inverting input end of the operational amplifier U1.3, the two ends of R10 are respectively connected with the base of Q1 and the output end of the operational amplifier U1.3, the collector of Q1 is connected with one end of R11, and the other end of R11 is grounded. The inverting input end and the output end of the operational amplifier U1.1 are respectively connected with two ends of the R6, the inverting input end of the operational amplifier U1.1 is further connected with one end of the R5, the other end of the R5 is grounded, the non-inverting input end of the operational amplifier U1.1 is connected with one end of the R11, the C7 is connected with the R11 in parallel, the output end of the operational amplifier U1.1 is connected with one end of the L2, the other end of the magnetic bead L2 is used as a voltage output end of the regulating circuit, the power supply input end of the operational amplifier U1.1 is used as a voltage input end of the regulating circuit, and the grounding end is grounded. One end of the R7 and one end of the C2 are connected and used as an input end + V of the adjusting circuit, the other end of the R7 is connected with one stator pin of the variable resistor P1, and the other stator pin of the variable resistor P1 is connected with one end of the R8. The other end of R8 is connected to the common ground of C1, C2 and C3 and serves as the input-V of the regulating circuit. One end of the C1 is connected to the non-inverting input of the operational amplifier U1.2 and serves as the input + S of the adjusting circuit. One end of the C3 is used as an input end-S of the adjusting circuit.

This embodiment realizes the voltage signal of output standard through four fortune of low price is amplified, can keep sensor self circuit balance when being connected with diffusion silicon sensor simultaneously, makes the signal of telecommunication precision of sensor transmission higher when zeroing diffusion silicon sensor, solves the problem that 0 bit that operational amplifier backward flow electric current arouses can not export 0 bit simultaneously when handling differential signal, keeps 0 bit output normal.

Example 2

As shown in fig. 6, the present embodiment describes a pressure transmitter including a sensor, a power circuit, and a data processing circuit. The power supply circuit is used for providing required power supply. The sensor is used for generating corresponding detection signals in the detection process. The data processing circuit is used for converting the detection signal into a corresponding voltage signal. For the data processing circuit, the adjusting circuit in embodiment 1 is employed.

The sensor comprises a Wheatstone bridge consisting of four voltage variable resistors, and four bridge arms of the Wheatstone bridge are used as four wiring terminals of the sensor and are respectively connected with the input ends + V, -V, + S and-S of the adjusting circuit.

As shown in fig. 7, the power supply circuit includes a power supply input sub-circuit and a constant current regulator sub-circuit. As shown in fig. 8, the power input sub-circuit includes 2 diodes D1, D2 and 2 magnetic beads L1, L3. As shown in fig. 9, the constant current regulator sub-circuit includes a linear regulator U2,3 resistors R1, R2, R3, and 2 capacitors C4, C5.

The diodes D1, D2 play a circuit protection role. D1 is to prevent the power line from being connected wrongly to cause damage. D2 is to prevent the power supply voltage from being abnormally high and causing damage (the protection voltage is 26V). The models of L1 and L3 can be consistent, and the MMZ1608Q601 is preferably selected, the working temperature of the MMZ1608Q601 can be between-20 ℃ and 90 ℃, and the high-frequency electromagnetic interference can be eliminated. The magnetic beads L1, L2, and L3 have a zero dc impedance and a certain inductance to high frequencies.

For the constant-current voltage-stabilizing sub-circuit, the linear voltage stabilizer U2 adopts an LDO (low dropout regulator) with adjustable three-terminal positive voltage and is composed of a three-terminal adjustable voltage-stabilizing integrated circuit LM 317. The sensor power supply device skillfully utilizes the special structure of the LM317 to simultaneously complete the power supply of the sensor by outputting 1.5mA current from the constant current source through the R2 and outputting 5V stabilized power supply operational amplifier to provide stable power supply. The specific model is LM317LBDR2G adjustable voltage stabilizer. It can provide a current of more than 1.5mA in the output voltage range of 1.2V to 37V. It is easy to use and only needs 2 external resistors to set the output voltage. In addition, it also employs internal current limiting, overheat shutdown and safe zone compensation, greatly reducing the possibility of damage. So that it is not substantially damaged. In addition, the selection of the capacitor and the resistor, this embodiment provides a specific scheme: c4 is 2.2 muF capacitance, C5 is 0.1 muF capacitance; r1 is a resistor of 5.1K omega, R2 is a resistor of 1.5K omega, and R3 is a resistor of 820 omega.

The specific connection mode of each electronic element in the power circuit is as follows: one end of the L1 and the L3 is used as the input end of the power supply circuit, the other end of the L1 is connected with the anode of the D1, the other end of the L3 is connected with the anode of the D2, the cathode of the D2 is connected with the anode of the D1, and the cathode of the D1 and the voltage input pin of the U2 are connected with one end of the C5. An adjustable pin of the U2 is connected with one ends of the R2 and the R3, and the other end of the R2 is used as a constant current output end of the power circuit. The other end of the R3 is connected with one end of the R1 and an output pin of the U2, the other end of the R1 is grounded, the output pin of the U2 is used as a constant voltage output end of the power circuit, the C4 is connected with the R1 in parallel, and the other end of the C5 is grounded with the R1.

The power supply circuit of the embodiment adopts the M317 voltage stabilizer, and the use of the M317 voltage stabilizer skillfully achieves two functions, namely, providing a 1.5mA constant current source for the sensor and providing a 5V constant voltage source for the adjusting circuit.

As shown in fig. 10, the power circuit may provide a constant current source of 1.5mA for the sensor, and provide a constant voltage source of 5V for the adjusting circuit, and as shown in fig. 11, specifically, provide a constant voltage source of 5V for the operational amplifier in the adjusting circuit, and the adjusting circuit collects the differential signal of the sensor and outputs a voltage signal for representing the pressure value, where the voltage signal is a standard voltage signal of 0-5V.

The pressure transmitter perfectly completes differential conversion from the sensor to 0-5V standard signal output by using a universal cheap four-operational amplifier. The output voltage is linear with the pressure sensed by the sensor.

Example 3

As shown in fig. 12, this embodiment describes a regulator chip packaged by the regulator circuit in embodiment 1. The specific pins are: the first pin is connected with the stator pin of the variable resistor P1 through a resistor R7. The second pin is connected to one end of the capacitors C1, C2, C3, which is grounded. The third pin is connected to the non-inverting input of the operational amplifier U1.2. The fourth pin is connected with the moving plate pin of the variable resistor P1 through a capacitor C6. The fifth pin is connected to the power input of operational amplifier U1.1. And the sixth pin is connected with the output end of the operational amplifier U1.1 through the magnetic bead L2.

The adjusting circuit is designed into a chip mode, so that the adjusting circuit is convenient to popularize in the market and is quickly used by a person skilled in the art.

Example 4

As shown in fig. 13, this embodiment describes a pressure transmitting chip packaged by the data processing circuit and the power supply circuit in embodiment 2. The pin of the pressure transmitting chip comprises: the first pin is connected with the stator pin of the variable resistor P1 through a resistor R7. The second pin is connected to one end of the capacitors C1, C2, C3, which is grounded. The third pin is connected to the non-inverting input of operational amplifier U1.2. The fourth pin is connected with the moving plate pin of the variable resistor P1 through a capacitor C6. The fifth pin is connected with the anode of the diode D1 through the magnetic bead L1. And the sixth pin is connected with the anode of the diode D2 through the magnetic bead L3. The seventh pin is connected with the output end of the operational amplifier U1.1 through the magnetic bead L2.

The circuit except the sensor in the pressure transmitter is set to be in a chip mode, the sensor and the chip are only required to be connected in actual use, the pressure transmitter is convenient to use quickly, and only the pressure transmitter needs to face a product specification to carry out line connection.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above examples only show some embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent should be subject to the appended claims.

Claims (10)

1. An adjusting circuit is used for collecting a detection signal of a sensor and generating a voltage signal corresponding to a detection amount according to the detection signal of the sensor, and is characterized by comprising a zero-adjusting sub-circuit and a signal processing sub-circuit; the zero setting sub-circuit comprises an operational amplifier U1.2,3 resistors R7, R8 and R9, a variable resistor P1 and 4 capacitors C1, C2, C3 and C6; the signal processing sub-circuit comprises 3 operational amplifiers U1.1, U1.3 and U1.4, a variable resistor P2,5 resistors R4, R5, R6, R10 and R11, a PNP triode Q1 and a capacitor C7;

the inverting input end and the output end of the operational amplifier U1.2 are connected with one end of the R9, the other end of the R9 is connected with the non-inverting input end of the operational amplifier U1.4, the non-inverting input end of the operational amplifier U1.3 is connected with one end of the C6 or the C3, and the moving plate pin of the variable resistor P1 is connected with the other end of the C6; the inverting input end and the inverting output end of the operational amplifier U1.4 are connected with one end of the R4, and the other end of the R4 is connected with one of the fixed sheet pins of the variable resistor P2; the emitter of the Q1 is connected with the other stator pin and the rotor pin of the variable resistor P2 and the inverting input end of the operational amplifier U1.3, the two ends of the R10 are respectively connected with the base of the Q1 and the output end of the operational amplifier U1.3, the collector of the Q1 is connected with one end of the R11, and the other end of the R11 is grounded; the inverting input end and the output end of the operational amplifier U1.1 are respectively connected with two ends of the R6, the inverting input end of the operational amplifier U1.1 is also connected with one end of the R5, the other end of the R5 is grounded, the non-inverting input end of the operational amplifier U1.1 is connected with the collector of the Q1, the C7 is connected with the R11 in parallel, the output end of the operational amplifier U1.1 is used as the voltage output end of the regulating circuit, the power supply input end of the operational amplifier U1.1 is used as the constant voltage input end of the regulating circuit, and the ground end is grounded; one end of the R7 and one end of the C2 are connected and used as an input end + V of the adjusting circuit, the other end of the R7 is connected with one stator pin of the variable resistor P1, and the other stator pin of the variable resistor P1 is connected with one end of the R8; the other end of R8 is connected with the ground of C1, C2 and C3 and is used as an input end-V of the adjusting circuit; one end of the C1 is connected with the non-inverting input end of the operational amplifier U1.2 and is used as the input end + S of the adjusting circuit; the other end of C3 is used as the input end-S of the adjusting circuit.

2. The adjusting circuit according to claim 1, characterized in that the signal processing sub-circuit further comprises a magnetic bead L2, wherein L2 is connected to the output of the operational amplifier U1.1.

3. The adjusting circuit of claim 1, wherein the operational amplifiers U1.3, U1.4, R4, P2, Q1, and R11 form a first stage amplifying unit, and the amplification factor A1 of the first stage amplifying unit is: a1= R11/(R4 + R) _P2 ) Wherein R is _P2 Is the resistance of the variable resistor P2.

4. The adjusting circuit of claim 3, wherein the operational amplifiers U1.1, R5, and R6 form a second stage amplifying unit, and the amplification factor A2 of the second stage amplifying unit is: a2=1+ R6/R5.

5. The adjustment circuit of claim 4, wherein the amplification factor A of the signal processing sub-circuit is: a = A1 × A2.

6. A pressure transmitter comprising a sensor, a power circuit and a data processing circuit; the power supply circuit is used for providing required power supply; the sensor is used for generating a corresponding detection signal in a detection process; the data processing circuit is used for converting the detection signal into a corresponding voltage signal; the method is characterized in that:

the data processing circuit employs an adjustment circuit as claimed in any one of claims 1-5.

7. The pressure transmitter of claim 6 wherein the power circuit includes a power input sub-circuit and a constant current regulator sub-circuit; the power input sub-circuit comprises 2 diodes D1 and D2 and 2 magnetic beads L1 and L3; the constant-current voltage stabilizing sub-circuit comprises a linear voltage stabilizer U2 and 3 resistors R1, R2 and R3; and 2 capacitors C4, C5;

one end of each of the L1 and the L3 is respectively used as an input end of a power circuit, the other end of the L1 is connected with the anode of the D1, the other end of the L3 is connected with the anode of the D2, the cathode of the D2 is connected with the anode of the D1, and the cathode of the D1 and a voltage input pin of the U2 are connected with one end of the C5; an adjustable pin of the U2 is connected with one end of the R2 and one end of the R3, and the other end of the R2 is used as a constant current output end of the power circuit; the other end of the R3 is connected with one end of the R1 and an output pin of the U2, the other end of the R1 is grounded, the output pin of the U2 is used as a constant voltage output end of the power circuit, the C4 is connected with the R1 in parallel, and the other end of the C5 is grounded with the R1.

8. The pressure transmitter of claim 7, wherein the sensor comprises a wheatstone bridge formed by four voltage-variable resistors, and four arms of the wheatstone bridge serve as four terminals of the sensor and are respectively connected to the input terminals + V, -V, + S, and-S of the regulating circuit.

9. A regulation chip, characterized in that it is packaged by a regulation circuit according to any one of claims 1 to 5; the pin of the adjusting chip comprises:

the first pin is connected with a stator pin of the variable resistor P1 through a resistor R7;

the second pin is connected with one end of the capacitors C1, C2 and C3 which are connected with the common ground;

a third pin connected to the non-inverting input of operational amplifier U1.2;

the fourth pin is connected with the moving plate pin of the variable resistor P1 through a capacitor C6;

a fifth pin connected to a power input of operational amplifier U1.1;

and the sixth pin is connected with the output end of the operational amplifier U1.1 through the magnetic bead L2.

10. A pressure transmitter chip, which is packaged by the data processing circuit and the power supply circuit of the pressure transmitter according to any one of claims 6 to 8; the pin of the pressure transmitting chip comprises:

the first pin is connected with a stator pin of the variable resistor P1 through a resistor R7;

the second pin is connected with one end of the capacitors C1, C2 and C3 which are grounded;

a third pin connected to the non-inverting input of operational amplifier U1.2;

the fourth pin is connected with the moving plate pin of the variable resistor P1 through a capacitor C6;

the fifth pin is connected with the anode of the diode D1 through the magnetic bead L1;

the sixth pin is connected with the anode of the diode D2 through the magnetic bead L3;

and the seventh pin is connected with the output end of the operational amplifier U1.1 through the magnetic bead L2.

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