AC detection circuit based on integrated operational amplifier
By combining integrated operational amplifiers and discrete components, synchronous detection of voltage, frequency, and zero-crossing parameters of AC signals is achieved, solving the problems of complex design and high cost in existing technologies and providing an economical and efficient power control solution.
Patent Information
- Application Number
- CN202423311834.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2026-02-03
- Estimated Expiration
- 2034-12-31
AI Technical Summary
Existing AC current detection methods require two independent circuits, which are complex and costly to design. They are also difficult to accurately detect the voltage, frequency, and zero-crossing parameters of AC signals and suffer from energy loss.
An AC detection circuit based on integrated operational amplifiers is adopted. Using discrete components such as resistors, operational amplifiers and transistors, the voltage, frequency and zero-crossing parameters of AC signals are synchronously detected through voltage attenuation and synthesis circuits.
It achieves low-cost, simple and reliable AC signal detection, and is suitable for fields such as uninterruptible power supplies, emergency power supplies, high-frequency rectifiers and inverters, providing precise power control.
Smart Images
Figure CN223870737U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to signal conversion circuit technical field especially relates to an alternating current detection circuit based on integrated operational amplifier. BACKGROUND
[0002] In order to ensure the stable power supply of medical place equipment, usually equipped with emergency power supply system, to realize uninterrupted power supply, prevent the accident caused by sudden power failure. At present, uninterruptible power supply, emergency power supply, high frequency rectifier and inverter fields all need to detect alternating current signal to obtain voltage size, frequency and zero crossing point and other key parameters, so as to realize the accurate control of power supply. The existing method usually reduces the voltage through the transformer, then rectifies and divides, and the voltage signal is collected by single-chip microcomputer to obtain voltage detection data, and the zero crossing point parameter is obtained through a separate zero crossing detection circuit. However, this method needs to design two sets of circuits for voltage detection and zero crossing detection respectively, and relies on complex devices such as transformer, which leads to complicated design and high cost. In addition, due to the nonlinear characteristics of alternating current signal, the voltage, frequency and zero crossing point and other parameters may fluctuate, and the existing method is difficult to accurately detect these actual values. In addition, the method also needs to increase additional dividing resistor and comparator and other elements, which not only further increases the complexity of the circuit, but also may cause additional energy loss.
[0003] Therefore, there is an urgent need for an improved alternating current voltage detection circuit, which can detect the voltage, frequency and zero crossing point parameters of alternating current signal at the same time by using simple discrete components and common integrated operational amplifier devices, so as to overcome the defects of high cost, instability and difficulty in implementation of the existing method. UTILITY MODEL CONTENT
[0004] The utility model aims at providing an alternating current detection circuit based on integrated operational amplifier to solve the technical problems of high cost, instability and difficulty in implementation.
[0005] To achieve the above-mentioned purpose, the specific technical scheme of the utility model of an alternating current detection circuit based on integrated operational amplifier is as follows:
[0006] An AC detection circuit based on integrated operational amplifier, characterized in that it comprises an operational amplifier U1, an operational amplifier U3 and an NPN triode Q1, the non-inverting input terminal of the operational amplifier U3 is connected with one end of an AC power source through a resistor R2 and a resistor R1 in sequence, the inverting input terminal of the operational amplifier U3 is connected with the other end of the AC power source through a resistor R4 and a resistor R3 in sequence, the non-inverting input terminal of the operational amplifier U1 is connected with a DC power source VDD through a resistor R9 and a resistor R6 in sequence, the inverting input terminal of the operational amplifier U1 is connected with the DC power source VDD through a resistor R10 and a resistor R5 in sequence, the middle junction of the resistor R1 and the resistor R2 is connected with the middle junction of the resistor R5 and the resistor R10 to form a node A, the middle junction of the resistor R3 and the resistor R4 is connected with the middle junction of the resistor R6 and the resistor R9 to form a node B; the output terminal of the operational amplifier U3 is connected with one end of a series resistor circuit, the output terminal of the operational amplifier U1 is connected with the other end of the series resistor circuit, the output terminal of the operational amplifier U1 is connected with the base of the triode Q1 through a current-limiting resistor R17, the emitter of the triode Q1 is grounded, the collector of the triode Q1 is connected with the DC power source VDD through a pull-up resistor, and the collector of the triode Q1 is used for outputting a voltage signal Vz.
[0007] Further, the series resistor circuit is composed of a resistor R15 and a resistor R16 in series, the non-inverting input terminal of the operational amplifier U3 is grounded through a resistor R7, and the non-inverting input terminal of the operational amplifier U1 is grounded through a resistor R11.
[0008] Further, the output terminal of the operational amplifier U3 is connected with the inverting input terminal thereof through a feedback resistor R8, and the output terminal of the operational amplifier U1 is connected with the inverting input terminal thereof through a feedback resistor R12.
[0009] Further, the base of the triode Q1 is grounded through a capacitor C1 and a resistor R18 respectively.
[0010] The AC detection circuit based on integrated operational amplifier has the following advantages:
[0011] The resistance R1, the resistance R3, the resistance R5 and the resistance R6 constitute a voltage attenuation circuit, respectively attenuating an AC power supply and a DC power supply, the resistance R2, the resistance R4 and the operational amplifier U3 constitute a first voltage synthesis circuit, the resistance R9, the resistance R10 and the operational amplifier U1 constitute a second voltage synthesis circuit, respectively outputting voltage signals VAO and VBO for AC voltage signal synthesis at the output terminals of the operational amplifier U3 and the operational amplifier U1, any one of the two operational amplifier output signals can be used as the input of the zero-crossing and frequency detection circuit, the voltage signals VAO and VBO are connected together through a series resistance circuit to form an output signal VO, and the output signal VO can be directly connected to a single-chip microcomputer or a DSP for subsequent operation and control processing. The resistance R17, the resistance R19 and the triode Q1 form a frequency detection circuit, and the voltage signal Vz is output through the collector of the triode Q1. The whole circuit converts an AC signal with a high voltage into a weak signal for detection by a control chip.
[0012] The circuit of the application is composed of simple discrete resistors, integrated operational amplifiers and triodes, and has the advantages of low cost. The voltage, voltage frequency and zero-crossing point parameters of an AC signal are simultaneously detected by using simple discrete components and common integrated operational amplifier components, and an AC detection circuit with low cost, simplicity, reliability and easy implementation is provided for the fields of uninterrupted power supply, emergency power supply, high-frequency rectifier and inverter. BRIEF DESCRIPTION OF DRAWINGS
[0013] Figure 1 A circuit structure diagram is provided for the application. DETAILED DESCRIPTION
[0014] In order to make the purpose, technical scheme and advantages of the application more clear and understandable, the application will be further described in detail below with reference to the drawings and examples. It should be understood that the specific examples described herein are only used to explain the application and do not limit the application.
[0015] Referring to Figure 1The application discloses an AC detection circuit based on integrated operational amplifier, which comprises a voltage attenuation circuit, a voltage synthesis circuit and a frequency detection circuit. The voltage attenuation circuit comprises a DC bias voltage and resistors R1, R3, R5 and R6. The voltage synthesis circuit is divided into two paths, one of which is connected with the resistor R1 and the resistor R3, and the other of which is connected with the resistor R5 and the resistor R6. The resistor R1 and the resistor R5 form a node A, and the resistor R3 and the resistor R6 form a node B. A weak voltage signal of the millivolt level is obtained at the nodes A and B. The voltage synthesis circuit is provided with two voltage signals VAO and VBO for AC voltage signal synthesis. Any one of the two paths of operational amplifier output signals can be used as the input of the zero-crossing and frequency detection circuit. The voltage signals VAO and VBO are connected together through two resistors to form an output signal VO. The frequency detection circuit is provided with a voltage signal Vz. The two paths of the voltage synthesis circuit are connected with the base of a triode Q1. The base and the emitter of the triode Q1 are connected with a capacitor C1. The collector of the triode Q1 is connected with the voltage signal Vz.
[0016] The AC detection is realized through a weak current control chip. The 220V AC needs to be subjected to voltage attenuation treatment first, and then be converted into a smaller voltage signal. Then, the signal is amplified and synthesized through the integrated operational amplifier circuit, so that the signal is adapted to the input requirement of the control chip such as the single-chip microcomputer, and the whole system is reliably controlled.
[0017] The voltage attenuation circuit is composed of R1, R3, R5, R6 and a DC bias voltage source, and a millivolt-level weak voltage signal is generated at nodes A and B after AC power V1 is divided by the four resistors, and the signal is input into the integrated operational amplifier for proportional amplification. In order to simplify the power supply design and reduce the number of required power supplies, the integrated operational amplifier is powered by a single power supply, and in this case, only the positive half cycle voltage of the AC signal can be output by one operational amplifier circuit. In order to restore the complete AC signal, another integrated operational amplifier is needed to reverse the polarity of the input signal and convert the negative half cycle voltage into a positive voltage output. Finally, the output signals VAO and VBO of the two operational amplifier circuits are combined through two resistors to form a complete AC voltage signal VO. The combined signal VO can be directly connected to a single-chip microcomputer or a DSP controller for subsequent data processing and system control. Either of the two operational amplifier output signals of the voltage combination circuit can be used as the input of the zero-crossing and frequency detection circuit. In this application, the negative voltage output is used as the input of the zero-crossing and frequency detection circuit, and the positive half cycle of the AC voltage is output as zero voltage, so that the switching triode Q1 is not conductive, and the Vz output is high. When the positive half cycle of the AC voltage decreases to zero and the negative voltage begins to increase, the operational amplifier output voltage begins to increase, triggering the switching triode Q1 to conduct, and the Vz output is low. When the AC voltage continuously changes, the Vz is a high-low pulse signal, and the high-low pulse edge is the zero-crossing point, and the period of the pulse signal is the period of the AC signal. Therefore, the zero-crossing point and frequency parameters of the AC signal can be obtained by capturing the Vz signal through a single-chip microcomputer or a DSP and through calculation and processing.
[0018] The application detects the amplitude, frequency and zero-crossing point of the AC voltage, inputs the obtained signals into a processor for calculation and analysis, and thus realizes accurate control of the power supply system.
[0019] The AC detection circuit based on the integrated operational amplifier has the following advantages.
[0020] The circuit of the application is designed by using common discrete resistors, integrated operational amplifiers and triodes, and has the characteristics of low cost. Through the combination of these devices, synchronous detection of the voltage, frequency and zero-crossing point of the AC signal is successfully realized. The circuit provides an economical and efficient, simple and reliable AC signal detection scheme for the fields of uninterruptible power supplies, emergency power supplies, high-frequency rectifiers and inverters, and has good implementability and promotional value.
[0021] The above merely describes preferred embodiments of the utility model and is not intended to limit the utility model, and any modification, equivalent replacement and improvement made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.
Claims
1. An AC detection circuit based on an integrated operational amplifier, characterized in that, This configuration includes operational amplifiers U1 and U3, and an NPN transistor Q1. The non-inverting input of operational amplifier U3 is connected to one end of an AC power supply via resistors R2 and R1, and the inverting input is connected to the other end of the AC power supply via resistors R4 and R3. The non-inverting input of operational amplifier U1 is connected to a DC power supply VDD via resistors R9 and R6, and the inverting input is connected to a DC power supply VDD via resistors R10 and R5. The midpoint between resistors R1 and R2 is connected to resistor R5... The middle nodes of resistor R10 are connected to form node A. The middle nodes of resistors R3 and R4 are connected to the middle nodes of resistors R6 and R9 to form node B. The output terminal of operational amplifier U3 is connected to one end of the series resistor circuit, and the output terminal of operational amplifier U1 is connected to the other end of the series resistor circuit. The output terminal of operational amplifier U1 is connected to the base of transistor Q1 through current-limiting resistor R17. The emitter of transistor Q1 is grounded, and the collector of transistor Q1 is connected to the DC power supply VDD through a pull-up resistor. The collector of transistor Q1 is used to output the voltage signal Vz.
2. The AC detection circuit based on an integrated operational amplifier according to claim 1, characterized in that, The series resistor circuit consists of resistors R15 and R16 connected in series. The non-inverting input terminal of operational amplifier U3 is grounded through resistor R7, and the non-inverting input terminal of operational amplifier U1 is grounded through resistor R11.
3. The AC detection circuit based on an integrated operational amplifier according to claim 1, characterized in that, The output of op-amp U3 is connected to its inverting input via feedback resistor R8, and the output of op-amp U1 is connected to its inverting input via feedback resistor R12.
4. The AC detection circuit based on an integrated operational amplifier according to claim 1, characterized in that, The base of transistor Q1 is grounded through capacitor C1 and resistor R18.