Current detection based limiter and power amplifier system

Abstract

The application provides an amplitude limiter based on current detection and a power amplifier system, and relates to the technical field of current detection.The amplitude limiter comprises a current detection circuit, which is used for a to-be-detected circuit provided with a control circuit and a signal amplification circuit, the control circuit is connected with the signal amplification circuit, a sampling end of the current detection circuit is connected with an output end of the to-be-detected circuit, and an output end of the current detection circuit is connected with the control circuit; the current detection circuit is used for outputting an amplitude limiting signal to the control circuit to make the control circuit reduce the signal amplitude and limit the signal amplitude in a certain threshold range when the output end current of the to-be-detected circuit exceeds a predetermined threshold value.The application embodiment can detect whether the output power of the to-be-detected circuit exceeds the predetermined threshold value by using the current detection circuit, so that the control circuit can effectively realize the signal amplitude limiting action according to the output power, the safety of the circuit is improved, and the risk of component damage is reduced.

Description

Technical Field

[0001] This application relates to the field of current detection technology, and more specifically, to a current detection-based limiter and power amplifier system. Background Technology

[0002] Audio amplifiers are used in complex scenarios and have high output power. In actual installation and use, there is a risk that excessive output power may lead to signal distortion or even burnout of load components such as speakers due to excessive signal input, excessive amplification factor, or abnormal load.

[0003] The existing limiting logic works as follows: the power amplifier system's control circuit digitally modulates signals exceeding a threshold based on the amplitude of the received signal voltage, limiting them to a reasonable range. This method can achieve precise detection, regulation, and dynamic limiting protection of audio signals. However, because the power amplifier system's control circuit has a limited voltage tolerance, it can generally only be controlled at the pre-amplifier stage (i.e., before the signal amplification circuit). In this case, the control circuit cannot detect whether the signal output from the post-amplifier stage exceeds the threshold, therefore it cannot effectively perform limiting based on output power, and there is still a certain risk of component damage. Utility Model Content

[0004] This application provides a current-sensing-based limiter and power amplifier system, which can solve the problem that existing limiting methods cannot perform limiting actions according to the output power, and there is a certain risk of component damage.

[0005] To achieve this objective, the embodiments of this application provide the following solutions.

[0006] According to one aspect of the embodiments of this application, a current-detection-based limiter is provided. The limiter includes a current detection circuit, which is used for a circuit under test that includes a control circuit and a signal amplification circuit. The control circuit is connected to the signal amplification circuit, the sampling terminal of the current detection circuit is connected to the output terminal of the circuit under test, and the output terminal of the current detection circuit is connected to the control circuit.

[0007] The current detection circuit is used to output a limiting signal to the control circuit when the current at the output terminal of the circuit under test exceeds a predetermined threshold, so that the control circuit reduces the amplification factor of the signal amplification circuit.

[0008] In one possible implementation, the current detection circuit includes a Hall sensor, the sampling terminal of which is connected in series with the output terminal of the circuit under test. The Hall sensor is used to convert the output current of the circuit under test into an AC voltage signal and output the AC voltage signal through the signal output terminal.

[0009] In one possible implementation, the control circuit includes a controller with signal sampling function, and the current detection circuit includes a third capacitor, the first terminal of which is connected to the signal output terminal of the Hall sensor for outputting an AC voltage signal, and the second terminal of which is connected to the signal sampling terminal of the controller.

[0010] In one possible implementation, the circuit to be detected includes a load, and the sampling terminal of the Hall sensor includes a positive power input terminal and a negative power output terminal. The positive power input terminal is connected to the output terminal of the signal amplification circuit, the negative power output terminal is connected to a first terminal of the load, and the second terminal of the load is grounded.

[0011] In one possible implementation, the current detection circuit further includes an operational amplifier and a rectifier circuit. The inverting input of the operational amplifier is connected to a reference voltage source, the non-inverting input of the operational amplifier is connected to the signal output of the Hall sensor, the output of the operational amplifier is connected to the input of the rectifier circuit, and the output of the rectifier circuit is connected to the control circuit.

[0012] In one possible implementation, the current detection circuit includes a first resistor and a second resistor, with a first terminal of the first resistor grounded and a second terminal connected to the inverting input terminal of the operational amplifier and the second terminal of the second resistor.

[0013] The first end of the second resistor is connected to the reference voltage source.

[0014] In one possible implementation, the current detection circuit includes a potentiometer, with a first terminal grounded, an adjustment terminal connected to the inverting input of the operational amplifier, and a second terminal connected to the reference voltage source.

[0015] In one possible implementation, the rectifier circuit includes a first diode and a second capacitor. The anode of the first diode is connected to the output terminal of the operational amplifier, the cathode is connected to the first terminal of the second capacitor, and the second terminal of the second capacitor is grounded.

[0016] In one possible implementation, the current detection circuit further includes a third resistor and a fourth resistor. The first end of the third resistor is connected to the cathode of the first diode, the second end of the third resistor is connected to the first end of the fourth resistor and the sampling point of the control circuit, and the second end of the fourth resistor is grounded.

[0017] According to one aspect of the embodiments of this application, a power amplifier system is provided, the power amplifier system including a circuit under test and a current detection-based limiter as described above, the circuit under test being connected to the limiter, the circuit under test being used to amplify a received signal.

[0018] The beneficial effects of the technical solutions provided in this application are:

[0019] This application provides a current-detection-based limiter. The limiter includes a current detection circuit for a circuit under test, which is equipped with a control circuit and a signal amplification circuit. The output terminal of the signal amplification circuit is connected to the output terminal of the circuit under test, and the control circuit is connected to the signal amplification circuit. The sampling terminal of the current detection circuit is connected to the output terminal of the circuit under test, and the output terminal of the current detection circuit is connected to the control circuit. When the output current of the circuit under test exceeds a predetermined threshold, the current detection circuit outputs a limiting signal to the control circuit, causing the control circuit to reduce the amplification factor of the signal amplification circuit. This embodiment of the application can utilize the current detection circuit to detect whether the output power of the circuit under test exceeds a predetermined threshold, thereby facilitating the control circuit to effectively implement signal limiting based on the output power, improving circuit safety and reducing the risk of component damage. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments of this application will be briefly introduced below.

[0021] Figure 1 A circuit diagram of a current detection circuit provided in an embodiment of this application;

[0022] Figure 2 A schematic diagram showing the connection between the circuit to be detected and the current detection circuit provided in an embodiment of this application;

[0023] Figure 3 Another circuit diagram of the current detection circuit provided in the embodiments of this application;

[0024] Figure 4 Another circuit diagram of the current detection circuit provided in the embodiments of this application;

[0025] Figure 5 This is a structural diagram of the power amplifier system provided in an embodiment of this application.

[0026] Label Explanation:

[0027] U1, Hall sensor; R1, first resistor; R2, second resistor; C1, first capacitor; D1, first diode; C2, second capacitor; R3, third resistor; R4, fourth resistor; VRT1, potentiometer; C3, third capacitor; C4, fourth capacitor; U2A, operational amplifier. Detailed Implementation

[0028] The embodiments of this application are described below with reference to the accompanying drawings. It should be understood that the embodiments described below with reference to the accompanying drawings are exemplary descriptions for explaining the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions of the embodiments of this application.

[0029] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the terms “comprising” and “including” as used in embodiments of this application mean that the corresponding feature can be implemented as the presented feature, information, data, step, operation, element, and / or component, but do not exclude implementation as other features, information, data, step, operation, element, component, and / or combinations thereof supported by the art. It should be understood that when we say that an element is “connected” or “coupled” to another element, the one element can be directly connected or coupled to the other element, or it can mean that the one element and the other element establish a connection relationship through an intermediate element. Furthermore, “connected” or “coupled” as used herein can include wireless connection or wireless coupling. The term “and / or” as used herein indicates at least one of the items defined by the term; for example, “A and / or B” indicates implementation as “A,” or implementation as “A,” or implementation as “A and B.”

[0030] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0031] The technical solutions of this utility model and their effects are described below through several exemplary embodiments. It should be noted that the following embodiments can be referenced, borrowed from, or combined with each other. Identical terms, similar features, and similar implementation steps in different embodiments will not be repeated.

[0032] The current-sensing-based limiter and power amplifier system provided in this application aim to solve at least one technical problem existing in the prior art.

[0033] This application provides a current-sensing-based limiter, such as... Figures 1-4As shown, the limiter includes a current detection circuit. This current detection circuit is used with a circuit under test that includes a control circuit and a signal amplification circuit. The output of the signal amplification circuit is connected to the output of the circuit under test, and the control circuit is connected to the signal amplification circuit. The sampling terminal of the current detection circuit is connected to the output of the circuit under test, and the output of the current detection circuit is connected to the control circuit. When the output current of the circuit under test exceeds a predetermined threshold, the current detection circuit outputs a limiting signal to the control circuit, causing the control circuit to reduce the signal amplitude and limit it within a certain threshold range. Specifically, the detection of the output current of the signal amplification circuit by the current detection circuit can largely reflect whether the output power at the output terminal meets the normal value. Based on the signal current detection at the output terminal, the current detection circuit can convert the detected value into a DC voltage that can be acquired by the control circuit. The control circuit then systematically limits or regulates the signal, thereby achieving a more comprehensive signal limiting function.

[0034] Optionally, the circuit to be tested may further include a signal receiving circuit and a signal transmitting circuit. The input terminal of the signal receiving circuit can receive the signal to be amplified, and its output terminal can be connected to the signal amplification circuit. The output terminal of the signal amplification circuit can be connected to the output terminal of the signal transmitting circuit, and the amplified signal is output through the signal transmitting circuit.

[0035] Optionally, the signal transmitting circuit can be connected to the speaker and other devices or circuits, and the current detection circuit can be connected to the signal transmitting circuit (such as to the output of the signal transmitting circuit) or to the output of the signal amplification circuit.

[0036] Optionally, the control circuit can be connected to the input terminal of the signal amplification circuit. The control circuit can sample the signal of the input signal amplification circuit and control the signal amplification circuit to amplify the signal according to the sampling result to avoid the output signal being too large. It can also further adjust the amplification factor of the signal amplification circuit according to the signal output by the current detection circuit, thereby fully realizing the signal limiting function.

[0037] Optionally, the current detection circuit includes a Hall sensor U1, the sampling terminal of which is connected in series with the output terminal of the circuit under test. The Hall sensor U1 is used to convert the output current of the circuit under test into an AC voltage signal and output the AC voltage signal through the signal output terminal.

[0038] In one embodiment, the Hall sensor U1 can be of model RXA628P8-30A (SOP-8). The magnitude of the AC voltage signal output by the Hall sensor U1 corresponds to the magnitude of the output current it detects, and the output voltage is used to detect whether it exceeds a predetermined threshold.

[0039] Optionally, the current detection circuit may also include a voltage divider circuit or a step-down circuit, which may be connected in parallel with the output terminal of the signal amplification circuit or the signal output circuit, and the output power is detected by the signal output through the voltage divider circuit or the step-down circuit.

[0040] Optionally, the control circuit includes a controller with signal sampling function, and the current detection circuit includes a third capacitor C3. The first terminal of the third capacitor C3 is connected to the signal output terminal of the Hall sensor U1 for outputting an AC voltage signal, and the second terminal is connected to the signal sampling terminal of the controller. The third capacitor C3 is used to isolate the DC signal output by the Hall sensor U1 to prevent the output signal from exceeding the controller's withstand voltage.

[0041] Optionally, the sampling frequency of the controller can be much higher than the frequency of the output signal to obtain more accurate sampling values. By obtaining the sampling values, the controller can determine the current output current level and, when it exceeds the set threshold, promptly perform amplitude limiting protection on the circuit under test.

[0042] Optionally, such as Figure 4 As shown, the Hall sensor U1 can operate at 5V. The current detection circuit may also include a fourth capacitor C4, with one end of C4 grounded and the other end connected to the ground terminal and the FILTER terminal of the Hall sensor U1. Specifically, when the controller is a microcontroller, the second end of the third capacitor C3 can be connected to the I-LEVEL terminal of the microcontroller.

[0043] Optionally, the circuit under test may include a load. The sampling terminals of the Hall sensor U1 include a positive power input terminal and a negative power output terminal. The positive power input terminal is connected to the output terminal of the signal amplification circuit, and the negative power output terminal is connected to the first terminal of the load, while the second terminal of the load is grounded. The Hall sensor U1 is connected in series with the output terminal of the circuit under test through its positive power input terminal and negative power output terminal.

[0044] In one embodiment, the load can be a resistor with a resistance value of 4Ω or other values. The size and type of the load can be determined based on parameters such as the sampling current requirements and sampling current characteristics of the Hall sensor U1.

[0045] Optionally, the current detection circuit also includes an operational amplifier U2A and a rectifier circuit. The inverting input of the operational amplifier U2A is connected to a reference voltage source, the non-inverting input of the operational amplifier U2A is connected to the signal output of the Hall sensor U1, the output of the operational amplifier U2A is connected to the input of the rectifier circuit, and the output of the rectifier circuit is connected to the control circuit. The operational amplifier U2A rectifies the AC voltage output from the Hall sensor U1 and compares it with a set voltage threshold to determine whether it exceeds the threshold. Based on the determination result, a signal indicating the determination result is output.

[0046] In one embodiment, the positive power input terminal of the operational amplifier U2A can be connected to a +15V voltage source, and the negative power input terminal can be connected to a -15V voltage source.

[0047] Optionally, the current detection circuit includes a first resistor R1 and a second resistor R2. The first end of the first resistor R1 is grounded, and the second end is connected to the inverting input terminal of the operational amplifier U2A and the second end of the second resistor R2. The first end of the second resistor R2 is connected to a reference voltage source. The first resistor R1 and the second resistor R2 form a voltage divider circuit, which is used to adjust the reference voltage of the operational amplifier U2A.

[0048] Optionally, the operational amplifier U2A and the Hall sensor U1 can share a common reference voltage source. Specifically, the first terminal of the second resistor R2 can be connected to the voltage input terminal of the Hall sensor U1.

[0049] Optionally, the current detection circuit may further include a first capacitor C1, one end of which is grounded and the other end is connected to the ground terminal and the FILTER terminal of the Hall sensor U1.

[0050] In one embodiment, the voltage value of the reference voltage source can be 5V, and the resistance values ​​of the first resistor R1 and the second resistor R2 can be determined according to the magnitude of the reference voltage.

[0051] Alternatively, an adjustable potentiometer VRT1 can be used to replace the voltage divider circuit formed by the first resistor R1 and the second resistor R2. The current detection circuit includes potentiometer VRT1, with its first terminal grounded, its adjustment terminal connected to the inverting input of operational amplifier U2A, and its second terminal connected to a reference voltage source. By changing the resistance of potentiometer VRT1, the voltage input to the inverting input of operational amplifier U2A is adjusted, thereby regulating the reference voltage.

[0052] When the operational amplifier U2A and the Hall sensor U1 share the same reference voltage source, the second terminal of the potentiometer VRT1 can be connected to the voltage input terminal of the Hall sensor U1.

[0053] Optionally, the rectifier circuit includes a first diode D1 and a second capacitor C2. The anode of the first diode D1 is connected to the output terminal of the operational amplifier U2A, and the cathode is connected to the first terminal of the second capacitor C2. The second terminal of the second capacitor C2 is grounded. The square wave signal output by the operational amplifier U2A is converted into a DC signal through the first diode D1 and the second capacitor C2. Specifically, the first diode D1 rectifies the square wave signal, and the second capacitor C2 makes the output a relatively stable DC signal.

[0054] Optionally, the current detection circuit further includes a third resistor R3 and a fourth resistor R4. The first end of the third resistor R3 is connected to the cathode of the first diode D1, and the second end is connected to the first end of the fourth resistor R4 and the sampling point of the control circuit. The second end of the fourth resistor R4 is grounded. The signal transmitted by the current detection circuit is divided by the third resistor R3 and the fourth resistor R4, so that the signal input to the sampling point of the control circuit is within the withstand voltage range of the controller in the control circuit.

[0055] In one embodiment, such as Figure 1 As shown, the current detection circuit is connected to the controller in the control circuit. The Hall sensor U1 can be an RXA628P8-30A chip with an output voltage / input current conversion ratio of 0.066V / A, and a 2.6V DC level is superimposed. Taking a load resistance of 4Ω and a power of 150W as an example, when the output current (the current sensed by the Hall sensor U1 through the sampling terminal) is approximately 6A or higher, the limiting function is activated. That is, when the Hall sensor U1 outputs 2.6V DC superimposed with 0.4V AC, the limiting function of the control circuit is activated. The resistance of the first resistor R1 is set to 3K, and the resistance of the second resistor R2 is set to 2K. At this time, the reference voltage V-COMP of the operational amplifier U2A is 3V. When the output current exceeds 6A, the VIOUT pin of the Hall sensor outputs a voltage of 2.6VDC + 0.4VAC or higher. After comparison by operational amplifier U2A, when the output voltage of the VIOUT pin is higher than the reference voltage V-COMP, operational amplifier U2A outputs a high level +15V, and when the output voltage is lower than the reference voltage V-COMP, operational amplifier U2A outputs a low level -15V. After comparison by operational amplifier U2A, the output is a square wave signal of ±15V. This signal is rectified into a DC signal by the first diode D1 and the second capacitor C2, and then divided by the third resistor R3 and the fourth resistor R4 to output a DC level signal that can be acquired within the voltage range of the microcontroller (taking 3V as an example).

[0056] The current-sensing-based limiter provided in this application has the following advantages:

[0057] 1. The controller adjusts the output power based on the detection results of the current sensing circuit. In actual use of the signal amplifier, whether or not a load is connected to the output, and whether the connected load is the rated load, will not affect the signal voltage amplitude. Voltage-sensing limiters can only judge and limit the output power based on the amplified signal amplitude, and the actual output power may be abnormal due to current overload or other reasons. Adding a limiter based on output current voltage limiting, by detecting the magnitude of the current signal and feeding it back to the preceding stage to regulate the voltage, allows for output limiting in both current and voltage dimensions, greatly improving circuit safety.

[0058] 2. The output current is converted into a voltage signal that can be acquired by the controller (such as a microcontroller) of the control circuit, and the hardware and software work together to regulate it. The microcontroller usually acquires a low-level DC signal, converts the large AC current signal into a small DC voltage signal, acquires the signal, and then performs unified voltage regulation. This can achieve a limiting effect from both the current and voltage perspectives, thereby protecting the power amplifier and other load components such as speakers.

[0059] 3. Feedback from the output stage to the preamplifier stage enables overall control and protection of the power amplifier system. After the microcontroller acquires the signal at the output terminal, it adjusts the signal amplitude at the input terminal until the output current returns to the normal range. This method avoids the inability to eliminate abnormalities in other parts of the system when only input or output limiting is performed, thus completing signal limiting and protecting the overall circuit.

[0060] Based on the same inventive concept, this application also proposes a power amplifier system, such as... Figure 5 As shown, the power amplifier system includes a circuit under test and a current-sensing-based limiter as described in the above embodiment. The circuit under test is connected to the limiter and is used to amplify the received signal.

[0061] The terms "first," "second," "third," "fourth," "1," "2," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in a sequence other than that shown in the illustrations or text descriptions.

[0062] It should be understood that although arrows indicate various operation steps in the flowcharts of this application's embodiments, the order in which these steps are implemented is not limited to the order indicated by the arrows. Unless explicitly stated herein, in some implementation scenarios of this application's embodiments, the implementation steps in each flowchart can be executed in other orders as required. Furthermore, some or all steps in each flowchart, based on the actual implementation scenario, may include multiple sub-steps or multiple stages. Some or all of these sub-steps or stages can be executed at the same time, and each sub-step or stage can also be executed at different times. In scenarios where execution times differ, the execution order of these sub-steps or stages can be flexibly configured according to requirements, and this application's embodiments do not limit this.

[0063] The above description is only an optional implementation method for some implementation scenarios of this application. It should be noted that for those skilled in the art, other similar implementation methods based on the technical concept of this application without departing from the technical concept of this application also fall within the protection scope of the embodiments of this application.

Claims

1. A current detection based limiter, characterized by, The limiter comprises a current detection circuit, which is configured to be provided with a to-be-detected circuit provided with a control circuit and a signal amplification circuit, the control circuit is connected with the signal amplification circuit, a sampling end of the current detection circuit is connected with an output end of the to-be-detected circuit, and an output end of the current detection circuit is connected with the control circuit. The current detection circuit is configured to output a limiting signal to the control circuit to reduce an amplification multiple of the signal amplification circuit when an output current of the to-be-detected circuit exceeds a predetermined threshold.

2. The current detection based limiter of claim 1, wherein, The current detection circuit comprises a Hall sensor, a sampling end of the Hall sensor is connected in series with the output end of the to-be-detected circuit, and the Hall sensor is configured to convert the output current of the to-be-detected circuit into a voltage signal and output the voltage signal through a signal output end.

3. The current sense based limiter of claim 2, wherein, The control circuit comprises a controller with a signal sampling function, the current detection circuit comprises a third capacitor, a first end of the third capacitor is connected with a signal output end of the Hall sensor for outputting an alternating voltage signal, and a second end of the third capacitor is connected with a signal sampling end of the controller.

4. The current sense based limiter of claim 2, wherein, The to-be-detected circuit comprises a load, the sampling end of the Hall sensor comprises a positive power input end and a negative power output end, the positive power input end is connected with an output end of the signal amplification circuit, the negative power output end is connected with a first end of the load, and a second end of the load is grounded.

5. The current sense based limiter of claim 2, wherein, The current detection circuit further comprises an operational amplifier and a rectifier circuit, a non-inverting input end of the operational amplifier is connected with a reference voltage source, an inverting input end of the operational amplifier is connected with a signal output end of the Hall sensor, an output end of the operational amplifier is connected with an input end of the rectifier circuit, and an output end of the rectifier circuit is connected with the control circuit.

6. The current sense based limiter of claim 5, wherein, The current detection circuit comprises a first resistor and a second resistor, a first end of the first resistor is grounded, a second end of the first resistor is connected with the non-inverting input end of the operational amplifier and a second end of the second resistor, and a first end of the second resistor is connected with the reference voltage source. The current detection circuit comprises a first resistor and a second resistor, a first end of the first resistor is grounded, a second end of the first resistor is connected with the non-inverting input end of the operational amplifier and a second end of the second resistor, and a first end of the second resistor is connected with the reference voltage source.

7. The current sense based limiter of claim 5, wherein, The current detection circuit comprises a first resistor and a second resistor.

8. The current sense based limiter of claim 5, wherein, The current detection circuit further comprises a third resistor and a fourth resistor, a first end of the third resistor is connected with a cathode of the first diode, a second end of the third resistor is connected with a first end of the fourth resistor and a sampling point of the control circuit, and a second end of the fourth resistor is grounded.

9. The current sense based limiter of claim 8, wherein, The power amplifier system comprises a to-be-detected circuit and the current detection-based limiter according to any one of claims 1-9, the to-be-detected circuit is connected with the limiter, and the to-be-detected circuit is configured to amplify a received signal.

10. A power amplifier system, characterized by, ​

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