Overload limiting circuit

Abstract

The utility model discloses an overload limiting circuit which comprises a gain amplification module, a sampling amplification holding module, a voltage-regulator tube adjusting module and an optocoupler adjusting module. The gain amplification module is respectively connected with an external signal source and the sampling amplification holding module; the sampling, amplifying and holding module is connected with the optocoupler adjusting module through the voltage-regulator tube adjusting module; the optocoupler adjusting module is coupled with an external load through the gain amplification module. According to the utility model, the operational amplifier is used for sampling, holding and amplifying, the volt-ampere characteristic of the voltage-regulator tube is matched with the photoelectric coupler to linearly adjust the output power, overload caused by peak signals is effectively limited, and meanwhile, the low distortion level is achieved.

Description

Technical Field

[0001] The utility model relates to the field of electronic regulation, in particular to an overload limiting circuit. Background Art

[0002] In the field of electronic control, non-steady-state spike signals can easily cause excessive output power, resulting in overcurrent overload and damage to electronic equipment, such as audio amplifiers. Due to burst signals, excessively strong signals can cause the audio power amplifier to output excessive power, leading to amplifier overload and speaker burnout.

[0003] The conventional solution is to directly control the output gain of the system to drop sharply to a preset value when the audio output power reaches a certain threshold. Although this method is direct and efficient, it also causes severe signal level clipping. The greater the signal exceeds the threshold, the more severe the clipping. In this case, although the output power is suppressed, the distortion is severe. Utility Model Content

[0004] The purpose of the utility model is to solve at least one of the technical problems existing in the prior art. To this end, the utility model provides an overload limiting circuit.

[0005] The technical solution provided by the utility model is: an overload limiting circuit, comprising: a gain amplification module, a sampling amplification and holding module, a voltage regulator adjustment module and an optical coupling adjustment module;

[0006] Preferably, the gain amplifier module is connected to the external signal source and the sampling amplifier holding module respectively; the sampling amplifier holding module is connected to the optocoupler adjustment module via the voltage regulator adjustment module; the optocoupler adjustment module is coupled to the external load via the gain amplifier module.

[0007] Preferably, the gain amplification module includes: a capacitor C6, a resistor R4, an operational amplifier U2, a capacitor C1, a capacitor C2 and a capacitor C3; one end of the capacitor C6 is connected to an external signal source, and the other end is connected to the third connection end of the operational amplifier U2 via the resistor R4; the second connection end of the operational amplifier U2 is connected to an external load via the capacitor C1; the second connection end of the operational amplifier U2 is also respectively connected to the sampling, amplification and holding module and the first connection end of the operational amplifier U2; the fourth connection end and the third connection end of the operational amplifier U2 are respectively connected to the positive and negative ends of the power supply network;

[0008] Preferably, the sampling, amplifying and holding module includes: a resistor R1, a resistor R2, an operational amplifier U3, a diode D1, a diode D3 and a capacitor C4; one end of the resistor R2 is connected to the second connection end of the operational amplifier U2, and the other end is respectively connected to the second connection end of the operational amplifier U3, one end of the resistor R1 and the positive electrode of the diode D1; the cathode of the diode D1 is respectively connected to the first connection end of the operational amplifier U3 and the positive electrode of the diode D3; the other end of the resistor R1 is grounded via the capacitor C4; the other end of the resistor R1 is also respectively connected to the negative electrode of the diode D3 and the voltage regulator adjustment module; the third connection end of the operational amplifier U3 is grounded; the fourth connection end and the fifth connection end of the operational amplifier U3 are respectively connected to the positive and negative ends of the power supply network.

[0009] Preferably, the voltage regulator regulation module includes: a voltage regulator ZD1 and a diode D2; the anode of the diode D2 is connected to the cathode of the diode D3, and the cathode of the diode D2 is connected to one end of the voltage regulator ZD1; the other end of the voltage regulator ZD1 is connected to the optocoupler regulation module.

[0010] Preferably, the optocoupler adjustment module includes: a photoelectric coupler U1, a capacitor C5, a capacitor C7, a resistor R3 and a resistor R5; one end of the capacitor C5 is respectively connected to the other end of the voltage regulator tube ZD1 and one end of the resistor R3, and the other end is grounded; the other end of the resistor R3 is connected to the first connection end of the photoelectric coupler U1; the second connection end of the photoelectric coupler U1 is grounded; the third connection end of the photoelectric coupler U1 is respectively connected to the fourth connection end of the photoelectric coupler U1 via the capacitor C7 and the resistor R5; the fourth connection end of the photoelectric coupler U1 is grounded.

[0011] Preferably, the photocoupler U1 is provided with a light emitting diode and a photoresistor; the positive electrode of the light emitting diode serves as the first connection end of the photocoupler U1; the negative electrode of the light emitting diode serves as the second connection end of the photocoupler U1; and the two ends of the photoresistor serve as the third connection end and the fourth connection end of the photocoupler U1 respectively;

[0012] Preferably, the power supply network uses a voltage of 15V.

[0013] The beneficial effects of the utility model are as follows: the utility model adopts an operational amplifier to sample, hold and amplify, and utilizes the volt-ampere characteristic of a voltage regulator tube in conjunction with a photoelectric coupler to linearly adjust the output power, effectively limiting overload caused by spike signals while also having a low distortion level. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0015] Figure 1 It is a schematic diagram of the module structure of the utility model;

[0016] Figure 2 This is a circuit structure diagram of an overload limiting circuit of the utility model;

[0017] Figure 3 It is a schematic diagram of the volt-ampere characteristic curve of the voltage regulator tube ZD1 of the utility model;

[0018] In the figure: INPUT - signal source, OUTPUT - load. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the utility model clearer, the following will refer to the drawings in the embodiments of the utility model to clearly and completely describe the technical solution of the utility model through the implementation method. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0020] Reference Figures 1 to 3 , the preferred embodiment of the utility model provides an overload limiting circuit, including: a gain amplification module, a sampling amplification and holding module, a voltage regulator adjustment module and an optical coupler adjustment module;

[0021] In a preferred embodiment, the gain amplifier module is connected to the external signal source and the sampling amplifier holding module respectively; the sampling amplifier holding module is connected to the optical coupling adjustment module via the voltage regulator adjustment module; the optical coupling adjustment module is coupled to the external load via the gain amplifier module. The gain amplifier module is used to amplify and output the input signal from the signal source; the sampling amplifier holding module is used to amplify, peak sample and hold the input signal from the signal source. Peak hold can keep the circuit amplification factor in a relatively stable state, and the distortion will be relatively small.

[0022] In a preferred embodiment, the gain amplification module includes: a capacitor C6, a resistor R4, an operational amplifier U2, a capacitor C1, a capacitor C2 and a capacitor C3; one end of the capacitor C6 is connected to an external signal source, and the other end is connected to the third connection end of the operational amplifier U2 via the resistor R4; the second connection end of the operational amplifier U2 is connected to an external load via the capacitor C1; the second connection end of the operational amplifier U2 is also respectively connected to the sampling, amplification and holding module and the first connection end of the operational amplifier U2; the fourth connection end and the third connection end of the operational amplifier U2 are respectively connected to the positive and negative ends of the power supply network;

[0023] In a preferred embodiment, the sampling, amplifying and holding module includes: a resistor R1, a resistor R2, an operational amplifier U3, a diode D1, a diode D3 and a capacitor C4; one end of the resistor R2 is connected to the second connection end of the operational amplifier U2, and the other end is respectively connected to the second connection end of the operational amplifier U3, one end of the resistor R1 and the positive electrode of the diode D1; the negative electrode of the diode D1 is respectively connected to the first connection end of the operational amplifier U3 and the positive electrode of the diode D3; the other end of the resistor R1 is grounded through the capacitor C4; the other end of the resistor R1 is also respectively connected to the negative electrode of the diode D3 and the voltage regulator adjustment module; the third connection end of the operational amplifier U3 is grounded; the fourth connection end and the fifth connection end of the operational amplifier U3 are respectively connected to the positive and negative ends of the power supply network. After the input signal from the signal source is amplified and sampled, a relatively stable voltage value will be obtained at the capacitor C4, and this voltage value will change with the change of the peak value of the input signal. The voltage value of the capacitor C4 is set by the resistance value of the resistor R1 and the resistor R2, and the capacitance value of the capacitor C4 sets the voltage holding time and the driving capability for the subsequent stage.

[0024] In a preferred embodiment, the voltage regulator regulation module includes: a voltage regulator ZD1 and a diode D2; the anode of the diode D2 is connected to the cathode of the diode D3, and the cathode of the diode D2 is connected to one end of the voltage regulator ZD1; the other end of the voltage regulator ZD1 is connected to the optocoupler regulation module. The diode D2 is used to prevent the electric energy of the capacitor C5 from flowing back.

[0025] like Figure 3The volt-ampere characteristic curve shown: the voltage regulator ZD1 is an electronic device whose output current changes linearly with the input voltage; before reaching the rated voltage, the output current increases very steadily with the input voltage, and when the voltage value exceeds the rated voltage value, the current increases rapidly. Using this characteristic, when the input signal is too large, the output power changes linearly like the characteristic curve of the voltage regulator ZD1. Before reaching the rated voltage, the suppression of the output power is slow and stable, rather than sudden and sudden reduction, thereby reducing the distortion rate; setting the rated voltage of the voltage regulator ZD1 through the specification parameters is equivalent to setting the output power threshold of overload and overcurrent. When the rated voltage is reached, the output power will be suppressed faster, thereby ensuring the stability and reliability of its limiting function. The volt-ampere characteristic curves of different voltage regulators are different, and can be selected according to actual needs.

[0026] In a preferred embodiment, the optocoupler adjustment module includes: a photocoupler U1, a capacitor C5, a capacitor C7, a resistor R3 and a resistor R5; one end of the capacitor C5 is connected to the other end of the voltage regulator tube ZD1 and one end of the resistor R3 respectively, and the other end is grounded; the other end of the resistor R3 is connected to the first connection end of the photocoupler U1; the second connection end of the photocoupler U1 is grounded; the third connection end of the photocoupler U1 is connected to the fourth connection end of the photocoupler U1 through the capacitor C7 and the resistor R5 respectively; the fourth connection end of the photocoupler U1 is grounded. Capacitor C5 is used for filtering and energy storage; the output resistance of U1 will decrease as the input current increases, and is inversely proportional to the input current. The output end of the photocoupler U1 is connected in parallel with the voltage divider resistor of the system amplification part, which is used to adjust the amplification factor, thereby adjusting the output power to the load. The amplification factor decreases when the output resistance of the photocoupler U1 decreases.

[0027] In a preferred embodiment, the photocoupler U1 is provided with a light emitting diode and a photoresistor; the positive electrode of the light emitting diode serves as the first connection terminal of the photocoupler U1; the negative electrode of the light emitting diode serves as the second connection terminal of the photocoupler U1; the two ends of the photoresistor are respectively the third connection terminal and the fourth connection terminal of the photocoupler U1; the luminous intensity of the light emitting diode is positively correlated with the input current; and the output resistance of the photoresistor is negatively correlated with the luminous intensity of the light emitting diode.

[0028] In a preferred embodiment, the power supply network uses a 15V voltage.

[0029] The main working process of the overload limiting circuit of the utility model is:

[0030] As the input signal gradually increases and reaches the preset value, the voltage at the capacitor C4 increases, the output current of the voltage regulator ZD1 increases slowly, the output resistance of the photocoupler U1 decreases slowly, the power amplification factor decreases slowly, and the distortion is small.

[0031] When the input signal reaches the preset value, the output current of the voltage regulator ZD1 increases rapidly, the output resistance of the optocoupler U1 decreases rapidly, and the power amplification factor decreases rapidly, achieving efficient suppression.

[0032] If the signal continues to exceed the preset value, the voltage on capacitors C4 and C5 is relatively stable, so that the output power will be maintained at the set voltage limit value, and the output power will be effectively suppressed.

[0033] The utility model adopts an operational amplifier to sample, hold and amplify, and uses the volt-ampere characteristic of a voltage regulator tube in conjunction with a photoelectric coupler to linearly adjust the output power, effectively limiting overload caused by peak signals and excessive signals while also having a low distortion level.

[0034] In the description of the present utility model, "several" means more than one, "many" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used to distinguish the technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0035] In the description of the present utility model, unless otherwise clearly defined, words such as "setting" should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meaning of the words in the present utility model in combination with the specific content of the technical solution.

[0036] In the description of the utility model, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the terms does not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0037] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An overload limiting circuit, characterized in that: include: Gain amplifier module, sampling amplifier and holding module, voltage regulator adjustment module and optocoupler adjustment module; The gain amplification module is connected to the external signal source and the sampling amplification and holding module respectively; The sampling, amplifying and holding module is connected to the optical coupling adjustment module via the voltage regulator adjustment module; The optical coupling adjustment module is coupled to an external load via the gain amplification module.

2. An overload limiting circuit according to claim 1, characterized in that: The gain amplification module includes: capacitor C6, resistor R4, operational amplifier U2, capacitor C1, capacitor C2 and capacitor C3; One end of the capacitor C6 is connected to an external signal source, and the other end is connected to the third connection end of the operational amplifier U2 via the resistor R4; The second connection end of the operational amplifier U2 is connected to the external load via the capacitor C1; The second connection end of the operational amplifier U2 is also connected to the sampling, amplifying and holding module and the first connection end of the operational amplifier U2 respectively; The fourth connection terminal and the fifth connection terminal of the operational amplifier U2 are connected to the positive and negative terminals of the power supply network respectively.

3. An overload limiting circuit according to claim 2, characterized in that: The sampling, amplifying and holding module includes: a resistor R1, a resistor R2, an operational amplifier U3, a diode D1, a diode D3 and a capacitor C4; One end of the resistor R2 is connected to the second connection end of the operational amplifier U2, and the other end is respectively connected to the second connection end of the operational amplifier U3, one end of the resistor R1 and the positive electrode of the diode D1; The cathode of the diode D1 is connected to the first connection terminal of the operational amplifier U3 and the anode of the diode D3 respectively; The other end of the resistor R1 is grounded via the capacitor C4; The other end of the resistor R1 is also connected to the cathode of the diode D3 and the voltage regulator adjustment module respectively; The third connection terminal of the operational amplifier U3 is grounded; The fourth connection terminal and the fifth connection terminal of the operational amplifier U3 are connected to the positive and negative terminals of the power supply network respectively.

4. An overload limiting circuit according to claim 3, characterized in that: The voltage regulator adjustment module includes: a voltage regulator ZD1 and a diode D2; The anode of the diode D2 is connected to the cathode of the diode D3, and the cathode of the diode D2 is connected to one end of the voltage regulator tube ZD1; The other end of the voltage regulator tube ZD1 is connected to the optical coupling adjustment module.

5. An overload limiting circuit according to claim 4, characterized in that: The optical coupling adjustment module includes: a photoelectric coupler U1, a capacitor C5, a capacitor C7, a resistor R3 and a resistor R5; One end of the capacitor C5 is connected to the other end of the voltage regulator tube ZD1 and one end of the resistor R3 respectively, and the other end is grounded; The other end of the resistor R3 is connected to the first connection end of the photoelectric coupler U1; The second connection end of the photoelectric coupler U1 is grounded; The third connection terminal of the photoelectric coupler U1 is connected to the fourth connection terminal of the photoelectric coupler U1 via the capacitor C7 and the resistor R5 respectively; The fourth connection terminal of the photoelectric coupler U1 is grounded.

6. An overload limiting circuit according to claim 5, characterized in that: The photoelectric coupler U1 is provided with a light emitting diode and a photoresistor; The positive electrode of the light emitting diode serves as the first connection terminal of the photoelectric coupler U1; The cathode of the light emitting diode serves as the second connection terminal of the photoelectric coupler U1; Two ends of the photoresistor are respectively the third connection end and the fourth connection end of the photocoupler U1 .

7. An overload limiting circuit according to claim 6, characterized in that: The power supply network adopts 15V voltage.

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