Three-stage amplification type signal processing circuit

Abstract

The utility model discloses a three-stage amplification type signal processing circuit, which comprises an amplification module, an AD conversion module and a frequency output module, the input end of the amplification module is connected to the output end of a sensor to be processed, and the output end of the amplification module is connected to the signal input end of the AD conversion module. The frequency input end of the AD conversion module is connected to the output end of the frequency output module; the frequency output module comprises a transformer unit, a direction current limiting unit, a first reference voltage supply unit and a first comparison unit, the input end of the transformer unit is connected to commercial power alternating current 220v voltage, and the output end of the alternating current-direct current conversion unit is connected to the input end of the direction current limiting unit; the output end of the reverse current limiting unit is connected to the input end of the first comparison unit. The three-stage amplification type signal processing circuit solves the problem that in the prior art, output signals are affected due to the fact that the control frequency is inconsistent with the mains supply frequency.

Description

Technical Field

[0001] The utility model relates to a signal processing circuit, in particular to a three-stage amplification signal processing circuit. Background Art

[0002] In the prior art, the amplifying signal processing circuit includes: an amplifying module and an AD conversion module. The input end of the amplifying module is connected to the output end of the sensor to be processed, the output end of the amplifying module is connected to the input end of the AD conversion module, and the output end of the AD conversion module is the output end of the final amplifying signal processing circuit.

[0003] In the above-mentioned amplified signal processing circuit, the amplification module amplifies the signal, and the AD conversion module converts the analog signal into a digital signal. Although the analog-to-digital conversion processing can be performed after amplification, the amplified signal processing circuit still has the following disadvantages: the AD conversion module operates under the control frequency of the controller, and the controller is connected to the AC 220V mains power. The frequency of the AC 220V mains power is the mains frequency, and the control frequency is different from the mains frequency. As a result, the mains frequency will interfere with the sampling frequency of the AD conversion module (the sampling frequency is theoretically the same as the control frequency), resulting in the sampling frequency being different from the control frequency, thereby affecting the output signal. Utility Model Content

[0004] The utility model provides a three-stage amplification signal processing circuit to solve the problem in the prior art that the output signal is affected due to the inconsistency between the control frequency and the mains frequency.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] The utility model discloses a three-stage amplification signal processing circuit, comprising: an amplification module, an AD conversion module and a frequency output module, wherein the input end of the amplification module is connected to the output end of a sensor to be processed, the output end of the amplification module is connected to the signal input end of the AD conversion module, and the frequency input end of the AD conversion module is connected to the output end of the frequency output module; the frequency output module comprises: a transformer unit, a direction current limiting unit, a first reference voltage supply unit and a first comparison unit, the input end of the transformer unit is connected to a 220V AC mains voltage, the output end of the AC / DC conversion unit is connected to the input end of the direction current limiting unit, the output end of the reverse current limiting unit is connected to the input end of the first comparison unit, the reference voltage end of the first comparison unit is connected to the output end of the first reference voltage supply unit, and the output end of the first comparison unit is the output end of the frequency output module.

[0007] Preferably, the amplification module includes: amplifier U2, amplifier U3 and amplifier U4, the input end of amplifier U2 is the input end of the amplification module, the output end of amplifier U2 is connected to the input end of amplifier U3, the output end of amplifier U3 is connected to the input end of amplifier U4, and the output end of amplifier U4 is the output end of the amplification module.

[0008] Preferably, the amplification module also includes: a first feedforward stage U5 and a second feedforward stage U6, the input end of the first feedforward stage U5 is connected to the input end of the amplifier U2, and the output end of the first feedforward stage U5 is connected to the output end of the amplifier U3; the input end of the second feedforward stage U6 is connected to the input end of the amplifier U3, and the output end of the second feedforward stage U6 is connected to the output end of the amplifier U4.

[0009] Preferably, the positive electrode of the capacitor C4 is connected to the output terminal of the amplifier U2, and the negative electrode of the capacitor C4 is connected to the output terminal of the amplifier U4.

[0010] Preferably, the three-stage amplification signal processing circuit further includes: a VEF voltage supply module, wherein the output end of the VEF voltage supply module is connected to the reference voltage input end of the AD conversion module.

[0011] Preferably, the VEF voltage supply module includes: a digital-to-analog voltage conversion unit, a voltage boosting unit, a second reference voltage supply unit and a second comparison unit, the input end of the analog-to-digital voltage conversion unit is connected to the output end of the external controller, the output end of the analog-to-digital voltage conversion unit and the output end of the voltage boosting unit are both connected to the input end of the second comparison unit, the reference voltage end of the second comparison unit is connected to the output end of the second reference voltage supply unit, and the output end of the second comparison unit is the output end of the VEF voltage supply module.

[0012] Preferably, the transformer unit includes: a transformer TR1, the two ends of the first coil of the transformer TR1 are respectively connected to the A phase and B phase of the AC 220V mains power, one end of the second coil of the transformer TR1 is grounded, and the other end of the second coil of the transformer TR1 is the output end of the transformer unit.

[0013] Preferably, the directional current limiting unit includes: a resistor R1 and a diode D1, the anode of the diode D1 is the input end of the directional current limiting unit, the cathode of the diode D1 is connected to one end of the resistor R1, and the other end of the resistor R1 is the output end of the directional current limiting unit.

[0014] Preferably, the first reference voltage supply unit includes: a resistor R2 and a resistor R3, one end of the resistor R2 is connected to an external DC power supply VCC, and the other end of the resistor R2 is grounded through the resistor R3, and the connection point between the resistor R2 and the resistor R3 is the output end of the first reference voltage supply unit or the output end of the second reference voltage supply unit.

[0015] Preferably, the voltage raising unit includes: resistor R4, resistor R5, resistor R6 and resistor R7, one end of resistor R4 is connected to the external DC power supply VCC, the other end of resistor R4 is grounded through resistor R5, the connection point between resistor R4 and resistor R5 is connected to one end of resistor R6, the other end of resistor R6 is grounded through resistor R7, and the connection point between resistor R6 and resistor R7 is the output end of the voltage raising unit.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] In the present application, the frequency output module is set to output the mains frequency converted from the mains AC 220V voltage. Since the mains AC 220V voltage cannot directly provide the mains frequency, the frequency output module is used. In the frequency output module, the transformer unit outputs the mains AC 220V voltage after stepping down the voltage, and then passes through the direction current limiting unit. The direction current limiting unit limits the current to flow only from the transformer unit to the first comparison unit to avoid the current flowing in the opposite direction and causing damage to the transformer unit. After that, the first comparison unit compares the AC output of the transformer unit with the voltage output by the first reference voltage unit, thereby converting the AC output of the transformer unit into a signal with the mains frequency, outputting a high voltage when it is greater than the voltage output by the first reference voltage unit, and outputting a low voltage when it is greater than the voltage output by the first reference voltage unit, so that after the frequency input end of the AD conversion module is connected, the AD conversion module can identify it, thereby controlling the AD conversion module to work at the mains frequency, avoiding interference caused by the mains frequency and the frequency input end input frequency of the AD conversion module being inconsistent, ensuring that the output signal of the AD conversion module is not interfered with, and improving the output signal accuracy of the AD conversion module.

[0018] Other advantages, objectives and features of the present invention will be reflected in part through the following description, and in part will be understood by those skilled in the art through research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the circuit diagram of the frequency output module in the three-stage amplification signal processing circuit.

[0020] Figure 2 This is the circuit diagram of the amplification module in the three-stage amplification signal processing circuit.

[0021] Figure 3 This is a circuit diagram of the VEF voltage supply module in a three-stage amplification signal processing circuit. DETAILED DESCRIPTION

[0022] In order to make the technical means, creative features, objectives and functions of the present invention clearer and easier to understand, the present invention is further described below with reference to the accompanying drawings and specific embodiments:

[0023] like Figures 1 to 3 As shown, the utility model discloses a three-stage amplification signal processing circuit, including: an amplification module, an AD conversion module and a frequency output module, the input end of the amplification module is connected to the output end of the sensor to be processed, the output end of the amplification module is connected to the signal input end of the AD conversion module, and the frequency input end of the AD conversion module is connected to the output end of the frequency output module; the frequency output module includes: a transformer unit, a direction current limiting unit, a first reference voltage supply unit and a first comparison unit, the input end of the transformer unit is connected to the AC 220V mains voltage, the output end of the AC-DC conversion unit is connected to the input end of the direction current limiting unit, the output end of the reverse current limiting unit is connected to the input end of the first comparison unit, the reference voltage end of the first comparison unit is connected to the output end of the first reference voltage supply unit, and the output end of the first comparison unit is the output end of the frequency output module.

[0024] The amplification module includes amplifiers U2, U3, and U4. The input of amplifier U2 serves as the input of the amplification module, the output of amplifier U2 is connected to the input of amplifier U3, the output of amplifier U3 is connected to the input of amplifier U4, and the output of amplifier U4 serves as the output of the amplification module. Amplifiers U2, U3, and U4 implement three-stage amplification.

[0025] The amplification module also includes a first feedforward stage U5 and a second feedforward stage U6. The input of the first feedforward stage U5 is connected to the input of the amplifier U2, and the output of the first feedforward stage U5 is connected to the output of the amplifier U3. The input of the second feedforward stage U6 is connected to the input of the amplifier U3, and the output of the second feedforward stage U6 is connected to the output of the amplifier U4. The first feedforward stage U5 and the second feedforward stage U6 implement circuit biasing.

[0026] The positive electrode of capacitor C4 is connected to the output of amplifier U2, and the negative electrode of capacitor C4 is connected to the output of amplifier U4. Capacitor C4 stabilizes the amplifier.

[0027] The three-stage amplification signal processing circuit further includes a VEF voltage supply module, wherein the output end of the VEF voltage supply module is connected to the reference voltage input end of the AD conversion module, providing a reference voltage for the operation of the AD conversion module.

[0028] The VEF voltage supply module includes a digital-to-analog voltage conversion unit, a voltage boost unit, a second reference voltage supply unit, and a second comparison unit. The input DIN of the analog-to-digital voltage conversion unit is connected to the output of the external controller. The output OUT of the analog-to-digital voltage conversion unit and the output of the voltage boost unit are both connected to the input of the second comparison unit. The reference voltage terminal of the second comparison unit is connected to the output of the second reference voltage supply unit. The output of the second comparison unit serves as the output of the VEF voltage supply module. The digital-to-analog voltage conversion unit (using the TLC5615C(L)D model) converts the discrete voltage signal output by the external controller into an analog voltage signal, thereby enabling the AD conversion module to operate under the control of the external controller. Since the voltage output by the digital-to-analog voltage conversion unit is within the 5V range and is difficult to stabilize at 5V, a voltage boosting unit, a second reference voltage supply unit and a second comparison unit are designed. The output voltage of the voltage boosting unit and the output voltage of the digital-to-analog voltage conversion unit are simultaneously added to the input end of the second comparison unit, so that the input end voltage of the second comparison unit is higher than 5V. The second reference voltage supply unit provides a second reference voltage for comparison, so that the second comparison unit can output a constant 5V voltage, ensuring that the reference voltage input end of the AD conversion module has sufficient 5V voltage.

[0029] The transformer unit includes a transformer TR1. The two ends of the first coil of the transformer TR1 are connected to the A-phase and B-phase of the 220V AC mains power, respectively. One end of the second coil of the transformer TR1 is grounded, and the other end of the second coil of the transformer TR1 serves as the output end of the transformer unit, thereby achieving voltage reduction.

[0030] The directional current limiting unit includes a resistor R1 and a diode D1. The anode of the diode D1 is the input terminal of the directional current limiting unit, and the cathode of the diode D1 is connected to one end of the resistor R1. The other end of the resistor R1 is the output terminal of the directional current limiting unit. The diode D1 has a current limiting function.

[0031] The first reference voltage supply unit includes: a resistor R2 and a resistor R3. One end of the resistor R2 is connected to the external DC power supply VCC, and the other end of the resistor R2 is grounded through the resistor R3. The connection point between the resistor R2 and the resistor R3 is the output end of the first reference voltage supply unit or the output end of the second reference voltage supply unit.

[0032] The voltage boost unit includes resistors R4, R5, R6, and R7. One end of resistor R4 is connected to the external DC power supply VCC, and the other end of resistor R4 is grounded via resistor R5. The connection point between resistors R4 and R5 is connected to one end of resistor R6, and the other end of resistor R6 is grounded via resistor R7. The connection point between resistors R6 and R7 forms the output of the voltage boost unit. Resistors R4, R5, R6, and R7 all act as voltage dividers, dividing the external DC power supply VCC and outputting a voltage of approximately 0.7V.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model and are not limiting. Although the utility model is described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A three-stage amplification signal processing circuit, characterized in that: include: An amplification module, an AD conversion module, and a frequency output module, wherein the input end of the amplification module is connected to the output end of the sensor to be processed, the output end of the amplification module is connected to the signal input end of the AD conversion module, and the frequency input end of the AD conversion module is connected to the output end of the frequency output module; The frequency output module includes: a transformer unit, a directional current limiting unit, a first reference voltage supply unit and a first comparison unit. The input end of the transformer unit is connected to the AC 220V mains voltage, the output end of the AC-DC conversion unit is connected to the input end of the directional current limiting unit, the output end of the reverse current limiting unit is connected to the input end of the first comparison unit, the reference voltage end of the first comparison unit is connected to the output end of the first reference voltage supply unit, and the output end of the first comparison unit is the output end of the frequency output module.

2. The three-stage amplification signal processing circuit according to claim 1, characterized in that: The amplification module includes: amplifier U2, amplifier U3 and amplifier U4. The input end of amplifier U2 is the input end of the amplification module, the output end of amplifier U2 is connected to the input end of amplifier U3, the output end of amplifier U3 is connected to the input end of amplifier U4, and the output end of amplifier U4 is the output end of the amplification module.

3. The three-stage amplification signal processing circuit according to claim 2, characterized in that: The amplification module also includes: a first feedforward stage U5 and a second feedforward stage U6, the input end of the first feedforward stage U5 is connected to the input end of the amplifier U2, and the output end of the first feedforward stage U5 is connected to the output end of the amplifier U3; the input end of the second feedforward stage U6 is connected to the input end of the amplifier U3, and the output end of the second feedforward stage U6 is connected to the output end of the amplifier U4.

4. The three-stage amplification signal processing circuit according to claim 3, characterized in that: The positive electrode of capacitor C4 is connected to the output terminal of amplifier U2, and the negative electrode of capacitor C4 is connected to the output terminal of amplifier U4.

5. The three-stage amplification signal processing circuit according to claim 1, characterized in that: Also includes: A VEF voltage supply module, wherein the output end of the VEF voltage supply module is connected to the reference voltage input end of the AD conversion module.

6. The three-stage amplification signal processing circuit according to claim 5, characterized in that: The VEF voltage supply module includes: a digital-to-analog voltage conversion unit, a voltage boosting unit, a second reference voltage supply unit and a second comparison unit. The input end of the analog-to-digital voltage conversion unit is connected to the output end of the external controller, the output end of the analog-to-digital voltage conversion unit and the output end of the voltage boosting unit are both connected to the input end of the second comparison unit, the reference voltage end of the second comparison unit is connected to the output end of the second reference voltage supply unit, and the output end of the second comparison unit is the output end of the VEF voltage supply module.

7. The three-stage amplification signal processing circuit according to claim 6, characterized in that: The transformer unit includes: a transformer TR1, the two ends of the first coil of the transformer TR1 are respectively connected to the A phase and B phase of the AC 220V mains power, one end of the second coil of the transformer TR1 is grounded, and the other end of the second coil of the transformer TR1 is the output end of the transformer unit.

8. The three-stage amplification signal processing circuit according to claim 7, characterized in that: The directional current limiting unit includes: a resistor R1 and a diode D1. The anode of the diode D1 is the input end of the directional current limiting unit, the cathode of the diode D1 is connected to one end of the resistor R1, and the other end of the resistor R1 is the output end of the directional current limiting unit.

9. The three-stage amplification signal processing circuit according to claim 8, characterized in that: The first reference voltage supply unit includes: a resistor R2 and a resistor R3. One end of the resistor R2 is connected to the external DC power supply VCC, and the other end of the resistor R2 is grounded through the resistor R3. The connection point between the resistor R2 and the resistor R3 is the output end of the first reference voltage supply unit or the output end of the second reference voltage supply unit.

10. The three-stage amplification signal processing circuit according to claim 9, characterized in that: The voltage boosting unit includes: resistor R4, resistor R5, resistor R6 and resistor R7. One end of resistor R4 is connected to the external DC power supply VCC, and the other end of resistor R4 is grounded through resistor R5. The connection point between resistor R4 and resistor R5 is connected to one end of resistor R6, and the other end of resistor R6 is grounded through resistor R7. The connection point between resistor R6 and resistor R7 is the output end of the voltage boosting unit.

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