CN212518933U - Circuit capable of realizing differential PWM audio signal - Google Patents
Circuit capable of realizing differential PWM audio signal Download PDFInfo
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- CN212518933U CN212518933U CN202021351470.XU CN202021351470U CN212518933U CN 212518933 U CN212518933 U CN 212518933U CN 202021351470 U CN202021351470 U CN 202021351470U CN 212518933 U CN212518933 U CN 212518933U
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Abstract
The utility model discloses a can realize difference PWM audio signal's circuit, including resistance R1, resistance R2, resistance R3, electric capacity C1, electric capacity C2, electric capacity C3 and electric capacity C4, PWM + signal end is connected to resistance R1 one end, and the resistance R1 other end is connecting resistance R2, electric capacity C1 and electric capacity C2 respectively, and electric capacity C2 other end is connected electric capacity C4 and ground connection, and the electric capacity C4 other end is the connecting resistance R2 other end respectively, resistance R3 and electric capacity C3, and PWM-signal end is connected to the resistance R3 other end, the electric capacity C1 other end is output VIP, the electric capacity C3 other end is output VIN. The utility model discloses the circuit adopts resistance-capacitance element to design, does not adopt any inductance element, has avoided adopting the easy interference problem that causes of inductance element, and circuit structure is simple, and is with low costs, need not design extra anti jamming unit, and the range of application is wide.
Description
Technical Field
The utility model relates to an audio circuit specifically is a circuit that can realize difference PWM audio signal.
Background
When a PWM audio signal based on a differential driving mode output by a digital voice chip is processed, a high-frequency PWM signal of a switching power level of the PWM audio signal contains the audio signal, the PWM frequency is hundreds of kHz and is much larger than the bandwidth of the audio signal, namely 20 Hz-20 kHz, a lot of noise can be obtained by directly amplifying the audio signal, and in order to recover the audio signal from the PWM switching signal, a low-pass filter circuit is usually adopted and then connected to a digital power amplifier for amplification.
Most of existing low-pass filter circuits are designed by adopting LRC circuits, but the circuits designed by using inductors are easily interfered by external circuits, certain isolation processing is needed, and the cost and the size of a design object are increased.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a can realize difference PWM audio signal's circuit to solve the problem that proposes among the above-mentioned background art.
In order to achieve the above object, the utility model provides a following technical scheme:
a circuit capable of realizing differential PWM audio signals comprises a resistor R1, a resistor R2, a resistor R3, a capacitor C1, a capacitor C2, a capacitor C3 and a capacitor C4, wherein one end of the resistor R1 is connected with a PWM + signal end, the other end of the resistor R1 is respectively connected with a resistor R2, a capacitor C1 and a capacitor C2, the other end of the capacitor C2 is connected with a capacitor C4 and is grounded, the other end of the capacitor C4 is respectively connected with the other end of the resistor R2, the resistor R3 and the capacitor C3, the other end of the resistor R3 is connected with a PWM-signal end, the other end of the capacitor C1 is an output end VIP, and the other end of the capacitor.
As a still further preferred aspect of the present invention, the PWM +, PWM-is a pair of differential driven PWM signals.
As a still further preferred aspect of the present invention, the PWM signal carrier frequency is 800 kHZ.
As a still further preferred embodiment of the present invention, the resistor R1, the capacitor C2, the resistor R3, and the capacitor C4 respectively constitute an RC low-pass filter, and perform low-pass filtering on the PWM + signal and the PWM-signal, and the cutoff frequency is fc =1/2 pi RC.
Compared with the prior art, the beneficial effects of the utility model are that: the utility model discloses the circuit adopts resistance-capacitance element to design, does not adopt any inductance element, has avoided adopting the easy interference problem that causes of inductance element, and circuit structure is simple, and is with low costs, need not design extra anti jamming unit, and the range of application is wide.
Drawings
Fig. 1 is a schematic circuit diagram of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
Referring to fig. 1, in an embodiment of the present invention, a circuit capable of implementing differential PWM audio signals includes a resistor R1, a resistor R2, a resistor R3, a capacitor C1, a capacitor C2, a capacitor C3, and a capacitor C4, where one end of the resistor R1 is connected to a PWM + signal terminal, the other end of the resistor R1 is connected to a resistor R2, a capacitor C1, and a capacitor C68692, the other end of the capacitor C8 is connected to a capacitor C4 and grounded, the other end of the capacitor C4 is connected to the other end of the resistor R2, the other end of the resistor R3, and the other end of the capacitor C3, the other end of the resistor R3 is connected to a PWM-signal terminal, the other end of the capacitor C1 is an output.
The PWM + signal and the WM signal are a pair of differential driving PWM signals, the carrier frequency is 800kHZ, the audio signal transmission is realized by periodically modulating the pulse width, and if the pulse width of each period is the same, only a direct current waveform can be obtained after passing through a low-pass filter; if the pulse width of each period is changed according to the sine wave rule, the sine wave can be obtained after passing through a low-pass filter, and the audio signal is recovered.
The resistor R1, the capacitor C2, the resistor R3 and the capacitor C4 respectively form an RC low-pass filter for performing low-pass filtering on PWM + and PWM-, and the cut-off frequency is fc =1/2 pi RC; r2 is used for matching of differential mode signals to ensure signal stability and eliminate differential mode interference; c1 and C3 are blocking capacitors, which block the DC component in the signal and make the AC component smoothly transmit to the post-stage circuit, and the calculation formula of capacitive reactance is: xc =1/2 pi f. When the duty ratio of the PWM signal is fixed and unchanged, the PWM signal passes through the low-pass filter to obtain a direct current waveform and cannot pass through the blocking capacitor, when the duty ratio of the PWM signal is changed according to the sine wave rule, the PWM signal passes through the low-pass filter to obtain a sine waveform, and the audio signal can be obtained through the blocking capacitor.
The output end VIP and the output end VIN can be connected to a digital power amplifier.
To sum up, the utility model discloses the circuit adopts resistance-capacitance element to design, does not adopt any inductance element, has avoided adopting the easy interference problem that causes of inductance element, and circuit structure is simple, and is with low costs, need not design extra anti jamming unit, and the range of application is wide.
It is obvious to a person skilled in the art that the invention is not restricted to details of the above-described exemplary embodiments, but that it can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.
Claims (4)
1. A circuit capable of realizing differential PWM audio signals is characterized by comprising a resistor R1, a resistor R2, a resistor R3, a capacitor C1, a capacitor C2, a capacitor C3 and a capacitor C4, wherein one end of the resistor R1 is connected with a PWM + signal end, the other end of the resistor R1 is respectively connected with a resistor R2, a capacitor C1 and a capacitor C2, the other end of the capacitor C2 is connected with a capacitor C4 and grounded, the other end of the capacitor C4 is respectively connected with the other end of a resistor R2, a resistor R3 and a capacitor C3, the other end of the resistor R3 is connected with a PWM-signal end, the other end of the capacitor C1 is an output end VIP, and the other end of the capacitor C3.
2. The circuit capable of implementing differential PWM audio signals according to claim 1, wherein the PWM +, PWM-is a pair of differential driving PWM signals.
3. The circuit capable of implementing differential PWM audio signals according to claim 2, wherein the PWM signal carrier frequency is 800 kHZ.
4. The circuit capable of implementing differential PWM audio signal according to claim 3, wherein the resistor R1, the capacitor C2, the resistor R3 and the capacitor C4 respectively form an RC low pass filter for low pass filtering the PWM + signal and the PWM-signal, and the cut-off frequency is fc =1/2 pi RC.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021351470.XU CN212518933U (en) | 2020-07-10 | 2020-07-10 | Circuit capable of realizing differential PWM audio signal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021351470.XU CN212518933U (en) | 2020-07-10 | 2020-07-10 | Circuit capable of realizing differential PWM audio signal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN212518933U true CN212518933U (en) | 2021-02-09 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202021351470.XU Active CN212518933U (en) | 2020-07-10 | 2020-07-10 | Circuit capable of realizing differential PWM audio signal |
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| CN (1) | CN212518933U (en) |
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2020
- 2020-07-10 CN CN202021351470.XU patent/CN212518933U/en active Active
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