CN219145579U - Voltage limiting circuit, PCBA and microphone - Google Patents

Abstract

The utility model discloses a voltage limiting circuit, a PCBA and a microphone, wherein the voltage limiting circuit is used for limiting the signal level of a microphone pickup and comprises a first voltage limiting module, an operational amplification module, a second voltage limiting module and an output module; the first voltage limiting module is connected with the operational amplification module; the operational amplification module is connected with the second voltage limiting module; the second pressure limiting module is connected with the output module; the first voltage limiting module is used for reducing the voltage input into the operational amplification module; the second voltage limiting module is used for reducing the voltage input into the output module; the voltage limiting circuit can reduce the distortion of the signal level and realize the wider range of sound signal pickup. The utility model can be widely applied to the technical field of circuits.

Description

Voltage limiting circuit, PCBA and microphone

Technical Field

The utility model relates to the technical field of circuits, in particular to a voltage limiting circuit, a PCBA and a microphone.

Background

The sound of a person is used as a sound source, and although the sound pressure is limited, a very important factor is that the level of a signal detected by a conference microphone changes very strongly, and the closer the microphone is to the mouth of the person, the stronger the signal is. Such variations can sometimes occur far beyond the limits of the operational amplifier, where clipping distortion is likely to occur, where the dynamic range is also narrowed, and where too high signal levels are likely to damage the speaker. It is difficult for most people to control this distance, so excessive distortion due to too close a distance is often heard.

Disclosure of Invention

The present utility model aims to solve at least one of the technical problems existing in the related art to a certain extent.

It is therefore an object of embodiments of the present utility model to provide a voltage limiting circuit, a PCBA and a microphone, which can reduce distortion of signal level.

In order to achieve the technical purpose, the technical scheme adopted by the embodiment of the utility model comprises the following steps:

a voltage limiting circuit is used for limiting the signal level of a microphone pickup and comprises a first voltage limiting module, an operational amplification module, a second voltage limiting module and an output module; the first voltage limiting module is connected with the operational amplification module; the operational amplification module is connected with the second voltage limiting module; the second pressure limiting module is connected with the output module; the first voltage limiting module is used for reducing the voltage input into the operational amplification module; the second voltage limiting module is used for reducing the voltage input into the output module.

In addition, a voltage limiting circuit according to the above embodiment of the present utility model may further have the following additional technical features:

optionally, in one embodiment of the present utility model, the operational amplification module includes an operational amplifier.

Optionally, in one embodiment of the present utility model, the operational amplifier includes a first operational amplifier and a second operational amplifier; the reverse input end of the first operational amplifier is connected with the first voltage limiting module; the output end of the first operational amplifier is connected with the reverse input end of the second operational amplifier; and the output end of the second operational amplifier is connected to the second voltage limiting module.

Optionally, in an embodiment of the present utility model, the first voltage limiting module and the second voltage limiting module include an audio clipping chip.

Optionally, in an embodiment of the present utility model, the audio clip chip includes a NJM2762 chip.

Optionally, in an embodiment of the present utility model, the operational amplifier includes a NE5532 chip.

Optionally, in an embodiment of the present utility model, the output module includes a NE5532 chip.

In addition, the application also provides a PCBA, which comprises the voltage limiting circuit in any one of the embodiments.

Optionally, in one embodiment of the present utility model, the microphone further comprises a microphone interface; the microphone core interface is used for connecting a microphone core.

In addition, the application also provides a microphone comprising the PCBA according to any one of the above embodiments.

The advantages and benefits of the utility model will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the utility model.

The voltage limiting circuit in the embodiment of the utility model can limit the voltage of the signal level of the microphone by the two voltage limiting modules, can reduce the distortion of the signal level by the operational amplification module, and can realize the wider range of sound signal pickup.

Drawings

Fig. 1 is a schematic diagram of a voltage limiting circuit according to an embodiment of the utility model;

fig. 2 is a schematic circuit diagram of a voltage limiting circuit according to an embodiment of the utility model.

Detailed Description

Embodiments of the present utility model are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the utility model.

In the description of the present utility model, it should be understood that the directions or positional relationships indicated by the terms "distance", "upper", "lower", "left", "right", "front", "rear", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present utility model. Furthermore, features defining "first", "second" may include one or more such features, either explicitly or implicitly. In the description of the present utility model, unless otherwise indicated, the meaning of "a plurality" is two or more.

In the description of the present utility model, it should be noted that, unless explicitly stated and limited otherwise, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

Referring to fig. 1, a voltage limiting circuit is provided in an embodiment of the present application, which is used for limiting a signal level picked up by a microphone, and may include a first voltage limiting module 1, an operational amplification module 2, a second voltage limiting module 3, and an output module 4; the first voltage limiting module 1 can be connected with the operational amplification module 2; the operational amplification module 2 can be connected with the second voltage limiting module 3; the second pressure limiting module 3 can be connected with the output module 4; the first voltage limiting module 1 is used for reducing the voltage input into the operational amplification module 2; the second voltage limiting module 3 may reduce the voltage of the input-output module 4.

Further, in some embodiments of the present utility model, the operational amplification module may include an operational amplifier; the number of operational amplifiers may be set to two or more.

Further, in some embodiments of the present utility model, the operational amplifier may include a first operational amplifier and a second operational amplifier; the reverse input end of the first operational amplifier can be connected with the first voltage limiting module; the output end of the first operational amplifier can be connected with the reverse input end of the second operational amplifier; the output end of the second operational amplifier can be connected with a second voltage limiting module.

Further, in some embodiments of the present utility model, the first clipping module may include an audio clipping chip; the second wire pressing module can comprise an audio amplitude limiting chip; the audio amplitude limiting chip can be selected from various types of chips, and can limit the signal level picked up by the microphone.

Further, in some embodiments of the present utility model, the audio clip chip may include a NJM2762 chip; NJM2762 is a 2ch input audio slicer. The output level of one channel of the output of each channel is attenuated if the output level exceeds the slice level. The slice level may be set with an external number. The chip can be suitable for oversized input protection of a loudspeaker and the like, is not only used for PC (personal computer) and portable sound equipment, but also suitable for all audio equipment.

Further, in some embodiments of the utility model, the operational amplifier may comprise a NE5532 chip.

Further, in some embodiments of the utility model, the output module may comprise a NE5532 chip; NE5532 is a high-performance low-noise dual operational amplifier similar to many standard operational amplifiers, but has the characteristics of better noise performance, excellent output driving capability, quite high small signal bandwidth, large power supply voltage range and the like. Therefore, the amplifier is very suitable for being applied to high-quality and professional audio equipment, instruments, control circuits and telephone channel amplifiers.

In addition, the embodiment of the application also provides a PCBA. The PCBA integrates the voltage limiting circuit described in any one of the embodiments; the contents of the above-mentioned voltage limiting circuit embodiments are applicable to the system embodiment, and the functions specifically implemented by the system embodiment are the same as those of the method embodiment, and the beneficial effects achieved by the method embodiment are the same as those achieved by the method embodiment.

Further, in some embodiments of the utility model, the PCBA further comprises a microphone interface; the core interface may be attached to the PCBA, and the core may be attached to the interface.

In addition, the embodiment of the application also provides a microphone, which comprises the PCBA in any one of the embodiments; the content in the PCBA embodiment is applicable to the system embodiment, the functions of the system embodiment are the same as those of the method embodiment, and the beneficial effects achieved by the method embodiment are the same as those achieved by the method embodiment.

The following describes the use principle of the voltage limiting circuit of the present utility model:

in this embodiment, the audio clipping chip is of the type nmm 2762, and the first operational amplifier and the second operational amplifier are NE5532 chips.

Referring to fig. 2, the specific circuit can be referred to as a filtering process for the capacitor C116 after the microphone connected to the circuit picks up the voice signal of 30 mV. The 30mV is input to the 3 rd pin and the 8 th pin of the audio amplitude limiting chip U15 for chip internal processing, and the R117 resistor is used for adjusting voltage limiting signal setting. Assuming that the set voltage limit of the U15 is 100mV, if the input end is 30mV, the set voltage limit threshold is not reached, the pins 2 and 9 of the U15 directly output 50mV to the capacitor C120 for filtering to the first operational amplifier IC1A. At this time, pins 4 and 5 of the U15 do not act, and the whole chip is in a straight-through state. Assuming that the input end is 120mV, the voltage limiting function of the audio frequency limiting chip U15 is started, the output voltage is directly pressed to 100mV and output to the capacitor C120 for filtering and then is supplied to the first operational amplifier IC1A, the capacitor C121 is the voltage limiting starting time of the voltage limiting chip U15, the capacitor C121 can be generally set to 154pF in a conference place, the voltage limiter can act within tens of milliseconds, the chip starting voltage limiter, after receiving the first voltage limiting, the voltage of the input end of the audio frequency limiting chip U17 of the second voltage limiting module is still larger than the preset voltage value, the second voltage limiting can be carried out through the audio frequency limiting chip U17 to obtain a value meeting the preset threshold, and finally, the signal is amplified to the circuit of the next stage through the operational amplifier IC2B of the output module. Because the circuit is pressed by adopting one-stage voltage limiting circuit more than the traditional circuit, the circuit can obtain wider dynamic range.

In addition, the circuit can also realize the following functions:

1) And (3) adjusting a threshold value of a circuit: the threshold value of the voltage limit can be adjusted by adjusting the resistance values of R171, R193 in the voltage limit circuit, and its maximum output level is kept constant to be output to the operational amplifier IC1A regardless of an increase in the front-end input level.

2) Circuit start time: when the signal level exceeds the threshold value set by us, the voltage limiter starts to work within a certain period of time, and the starting time of the first voltage limiting chip U15 of the first voltage limiting module and the starting time of the second voltage limiting chip U17 of the first voltage limiting module can be determined by adjusting capacitance values of the C121 and the C144.

3) Circuit recovery time: the specific setting is also reasonably adjusted by referring to the starting time, and can be realized by adjusting capacitance values of the C122 and the C145.

In the description of the present utility model, it should be noted that, unless explicitly specified and defined otherwise, the term "switching" should be interpreted broadly, and for example, it may be a transformation or a conversion; the specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

In the description of the present specification, reference to the description of terms means that a particular structure or feature described in connection with an embodiment or example is included in at least one embodiment or example of the utility model. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present utility model have been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and variations may be made to the embodiments without departing from the spirit and principles of the utility model, the scope of which is defined by the claims and their equivalents.

Claims (10)

1. The voltage limiting circuit is characterized by comprising a first voltage limiting module, an operational amplification module, a second voltage limiting module and an output module, wherein the voltage limiting module is used for limiting the signal level of a microphone;

the first voltage limiting module is connected with the operational amplification module; the operational amplification module is connected with the second voltage limiting module; the second pressure limiting module is connected with the output module; the first voltage limiting module is used for reducing the voltage input into the operational amplification module; the second voltage limiting module is used for reducing the voltage input into the output module.

2. The voltage limiting circuit of claim 1 wherein the operational amplifier module comprises an operational amplifier.

3. The voltage limiting circuit of claim 2 wherein the operational amplifier comprises a first operational amplifier and a second operational amplifier; the reverse input end of the first operational amplifier is connected with the first voltage limiting module; the output end of the first operational amplifier is connected with the reverse input end of the second operational amplifier; and the output end of the second operational amplifier is connected to the second voltage limiting module.

4. The voltage limiting circuit of claim 1, wherein the first voltage limiting module and the second voltage limiting module comprise audio limiting chips.

5. The voltage limiting circuit of claim 4 wherein the audio clip chip comprises a NJM2762 chip.

6. A voltage limiting circuit according to claim 2, wherein the operational amplifier comprises a NE5532 chip.

7. The voltage limiting circuit of claim 1, wherein the output module comprises a NE5532 chip.

8. A PCBA comprising a voltage limiting circuit as claimed in any one of claims 1 to 7.

9. A PCBA according to claim 8, further comprising a core interface; the microphone core interface is used for connecting a microphone core.

10. A microphone comprising a PCBA according to any of claims 8-9.

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