Dynamic amplitude limiting circuit of power amplifier and power amplifier

Abstract

The utility model relates to a dynamic amplitude limiting circuit of a power amplifier and the power amplifier, and the circuit comprises a protection circuit which accesses a sound electric signal and transmits the sound electric signal to a signal conditioning circuit; the signal adjusting circuit receives the sound electric signal transmitted by the protection circuit and adjusts the size; the filter circuit filters the sound electric signal and then transmits the sound electric signal to the amplitude limiting circuit and the power amplifier circuit; the amplitude limiting circuit is used for dividing voltage to limit the voltage of the power amplifier; and the power amplifier circuit converts the sound electric signal into a sound signal. The input point voltage of the amplitude limiting circuit is compared with the VDD output voltage and the VSS output voltage, different triodes are driven to drive a thirteenth triode to be conducted, and an optical coupler is driven to change the resistance value of an output resistor of the optical coupler to carry out voltage division so as to reduce an input voltage signal of the power amplifier circuit. Amplitude limiting is carried out through dynamic detection of VDD voltage and VSS voltage, power supply fluctuation is prevented from influencing transmission of electric signals, adverse effects caused by power supply fluctuation are eliminated, and the power amplifier works more stably.

Description

Technical Field

[0001] The utility model relates to the field of sound amplifiers, in particular to a dynamic amplitude limiting circuit of a power amplifier and the power amplifier. Background Art

[0002] The storage of digital audio computer data is accessed in the form of 0 and 1, so digital audio is to first convert the audio file, then convert these level signals into binary data for storage, and then convert these data into analog level signals and send them to the speakers for broadcast when playing. Digital sound is essentially different from the sound in general tapes, radio, and television in terms of storage and playback methods; in comparison, it has the characteristics of convenient storage, low storage cost, no sound distortion during storage and transmission, and very convenient editing and processing. In order to increase the power of audio playback, an audio amplifier will be installed in the audio player so that the power of audio playback can be adjusted. However, after the audio signal is amplified by the power amplifier, the audio signal will be accompanied by a large noise after output, so the audio effect played by the audio player is poor, affecting the quality of audio output. In addition, the current of the power amplifier under light load and full load is very different. The power supply voltages VDD and VSS of amplifiers with different configurations may fluctuate with the output power, which is easy to cause clipping distortion, which is easy to have adverse effects on the power amplifier and listening experience. Utility Model Content

[0003] The technical problem to be solved by the utility model is that the current of the power supply of the power amplifier under light load and full load is very different. The power supply voltages VDD and VSS of power amplifiers with different configurations may fluctuate with the output power, which may easily cause clipping distortion and adversely affect the power amplifier and listening experience. In view of the above defects of the prior art, a dynamic limiting circuit of a power amplifier and a power amplifier are provided.

[0004] In order to solve the above technical problems, the technical solution adopted by the utility model is:

[0005] A dynamic limiting circuit of a power amplifier is constructed, including a protection circuit, a signal conditioning circuit, a filtering circuit, and a power amplifier circuit. The circuit also includes a limiting circuit.

[0006] A protection circuit, used for receiving the sound electrical signal and transmitting the sound electrical signal to the signal conditioning circuit;

[0007] A signal adjustment circuit, used for receiving the sound electrical signal transmitted by the protection circuit and adjusting the size of the sound electrical signal;

[0008] A filter circuit is used for filtering the regulated sound electrical signal and transmitting it to the limiting circuit and the power amplifier circuit;

[0009] A limiting circuit is used to divide the voltage to limit the voltage of the power amplifier;

[0010] The power amplifier circuit is used to amplify the sound electrical signal and convert it into a sound signal through a speaker.

[0011] Preferably, the limiting circuit outputs a VDD voltage and a VSS voltage, and is respectively connected to the VDD pole and the VSS pole of the power amplifier circuit, the limiting circuit input voltage outputs the VDD voltage through the fourteenth and twenty-ninth transistors, and the limiting circuit input voltage outputs the VSS voltage through the thirty-third and thirty-first transistors.

[0012] Preferably, the filter circuit inputs a limiting circuit through point C, outputs a VDD voltage through point A, and outputs a VSS voltage through point B. Points A and B are connected to the VDD pole and VSS pole of the power amplifier circuit after resistors are connected in series. Points A and B also include resistors connected to a power supply to divide the voltage and then output the VDD voltage and VSS voltage.

[0013] Preferably, the c-pole of the fourteenth transistor is connected to the thirteenth transistor, the c-pole of the thirty-third transistor is connected to the thirty-second transistor, the c-pole of the thirty-second transistor is connected to the b-pole of the thirteenth transistor, the c-pole of the thirteenth transistor is connected to the input end of the optocoupler, and the output end of the optocoupler is connected to the voltage input point of the limiting circuit. When the voltage at point C is higher than the voltage at point A, the thirty-third transistor drives the thirty-second transistor to drive the thirteenth transistor to turn on, and when the voltage at point C is lower than point B, the fourteenth transistor drives the thirteenth transistor to turn on, and the output resistance of the optocoupler driven by the thirteenth transistor is changed to perform voltage division.

[0014] Preferably, the circuit further comprises a voltage limiting circuit arranged between the protection circuit and the signal regulating circuit, and the voltage limiting circuit is a bidirectional TVS transient voltage diode arranged in the circuit.

[0015] Preferably, the filtering circuit includes at least one group of high-pass filters and one group of low-pass filters, the high-pass filters are connected to the signal conditioning circuit, and the low-pass filters are connected to the limiting circuit and the power amplifier circuit.

[0016] Preferably, the high-pass filter and the low-pass filter both include a comparator, and a voltage and a resistor connecting the first pin and the third pin of the comparator, and the first pin and the second pin of the comparator are connected.

[0017] Preferably, a 112th resistor is connected in series between the filter circuit and the limiting circuit, one end of the 112th resistor is connected to the output end of the filter circuit, and the other end is connected to the input end of the limiting circuit and the power amplifier circuit.

[0018] Preferably, the one-hundred-twelfth resistor may also have one end connected to the input point of the limiting circuit and the output end of the filtering circuit, and the other end connected to the power amplifier circuit.

[0019] A power amplifier is constructed, wherein the power amplifier contains the above-mentioned dynamic amplitude limiting circuit of the power amplifier for voltage limiting.

[0020] The beneficial effect of the utility model is that by comparing the input point voltage of the limiting circuit with the VDD output voltage and the VSS output voltage, the thirteenth transistor is driven to conduct by driving different transistors, and the optical coupler is driven to change the resistance value of its output resistor, so as to divide the voltage to reduce the input voltage signal of the power amplifier circuit, and the VDD voltage and VSS voltage of the power amplifier are dynamically detected to limit the amplitude, so as to avoid the power supply fluctuation from affecting the transmission of the electric signal and avoid clipping distortion. The circuit input electric signal plays a protective role when the protection circuit is convenient for detection, and the voltage limiting circuit is set to avoid the input electric signal from being too large to affect subsequent use. The signal adjustment circuit in the circuit adjusts the signal value to change the output signal size to adjust the sound size, eliminate the adverse effects caused by power supply fluctuations, and the power amplifier works more stably, and the listening experience is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the utility model will be further described below in conjunction with the accompanying drawings and embodiments. The drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work:

[0022] Figure 1 This is a schematic block diagram of a dynamic amplitude circuit according to a preferred embodiment 1 of the present utility model;

[0023] Figure 2 This is a schematic diagram of the specific structure of the dynamic amplitude circuit of the first preferred embodiment of the utility model;

[0024] Figure 3 This is an amplifying circuit diagram of the protection circuit of the dynamic amplitude circuit of the preferred embodiment 1 of the utility model;

[0025] Figure 4 This is an amplifying circuit diagram of a high-pass filter circuit of a dynamic amplitude circuit of a preferred embodiment 1 of the utility model;

[0026] Figure 5 This is an amplifying circuit diagram of the amplitude limiting circuit of the dynamic amplitude circuit of the preferred embodiment 1 of the utility model;

[0027] Figure 6 This is a schematic block diagram of a dynamic amplitude circuit according to a second preferred embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the utility model clearer, the following will be described clearly and completely in combination with the technical solution in the embodiments of the utility model. Obviously, the described embodiments are partial embodiments of the utility model, not all 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 protection scope of the utility model.

[0029] A dynamic limiting circuit of a power amplifier in a preferred embodiment of the utility model; Figure 1 As shown, it includes a protection circuit for receiving input sound electrical signals, a voltage limiting circuit connected to the protection circuit, a signal adjustment circuit connected to the voltage limiting circuit to adjust the size of the electrical signal, a filter circuit for filtering the adjusted electrical signal, and a limiter circuit connected to the filter circuit, the limiter circuit outputs VDD voltage and VSS voltage. The dynamic limiter circuit also includes a power amplifier circuit connected to the filter circuit, the power amplifier circuit is also connected to the VDD voltage and VSS voltage output by the limiter circuit, and the output electrical signal is converted into a sound signal through a speaker for playback, thereby realizing the reception and playback of the sound signal and adjusting the size of the sound after playback.

[0030] Specifically, Figure 2-3 As shown, the protection circuit includes a first socket JP1 for connecting the sound electrical signal, the first socket includes two groups of jacks, one or two groups of jacks are connected to the second fuse F2, and the middle of the two groups of jacks is grounded, the other end of the second fuse F2 is connected to the thirty-ninth bidirectional TVS transient voltage diode D39 and the one hundred and second resistor R102, the other ends of the thirty-ninth bidirectional TVS transient voltage diode D39 and the one hundred and second resistor R102 are grounded, and the other end of the second fuse F2 is connected to the sixty-sixth capacitor C66 and then connected to the ninety-ninth resistor R99 before output. By setting the fuse to connect the electrical signal, the circuit is protected, and the circuit is also protected during the certification test, so that the test results are not affected by too many external signals or too large signals during the test, thereby ensuring the test of the circuit.

[0031] Furthermore, if Figure 2 The voltage limiting circuit shown includes a thirty-eighth bidirectional trigger diode D38 connected to the other end of the ninety-ninth resistor R99, and the other end of the thirty-eighth bidirectional trigger diode D38 is grounded. The thirty-eighth bidirectional trigger diode D38 limits the voltage, which has a soft limiting effect, and the input signal is too large to affect the subsequent circuit.

[0032] Furthermore, if Figure 2As shown, the signal conditioning circuit includes a sixteenth chip U16, which uses 8 groups of pins, wherein the first pin and the eighth pin are connected to the ninety-ninth resistor R99 through the sixty-fourth capacitor C64, the sixty-fifth capacitor C65 and the seventy-sixth resistor R76 arranged in series to input the electrical signal. The sixty-fourth capacitor C64 is connected to the one hundredth resistor R100 in parallel at both ends, and the one hundredth resistor R100 is connected to the 6th and 7th pins of the second B comparator U2B respectively, and the fifth and sixth pins of the second B comparator U2B are connected through the seventy-third capacitor C73, and the fifth pin of the second B comparator U2B is connected to the ground through the one hundred fifth resistor R105 and the seventy-fourth capacitor C74 connected in parallel, and is connected to the other end of the thirty-eighth bidirectional trigger diode D38. The fourth pin of the sixteenth chip U16 is grounded through the one hundred and forty-fifth capacitor C145, and is connected to other control chips through the two hundred and fifty-fifth resistor R252, and the fifth pin of the sixteenth chip U16 is grounded through the one hundred and forty-sixth capacitor C146, and is connected to other control chips through the two hundred and fifty-third capacitor R253. The seventh pin of the sixteenth chip U16 is connected to the volume adjustment button XS3 through the one hundred and thirtieth resistor R130 and the sixty-third capacitor C63 arranged in series to adjust the size of the output signal and thus adjust the output volume. The sixth pin of the sixteenth chip U16 is connected to the power supply through the seventh inductor L7 to power the signal conditioning circuit. The third pin of the sixteenth chip U16 is grounded and connected to the sixth pin through the seventy-first capacitor C71 and the seventy-second capacitor C72 arranged in parallel. The two hundred and thirty-fourth resistor R234 is connected between the second pin and the seventh pin of the sixteenth chip U16, and the electrical signal is output to the filter circuit through the second pin.

[0033] Furthermore, if Figure 2 and Figure 4As shown, the filter circuit includes three groups of filters arranged in series, including two groups of high-pass filters and one group of low-pass filters. The high-pass filter includes a second A comparator U2A, and the output end of the signal conditioning circuit is connected to the first group of high-pass filters through the sixty-ninth capacitor C69. The other end of the sixty-ninth capacitor C69 is connected to the third pin of the second A comparator U2A through the seventy-first capacitor C70, and the third pin of the second A comparator U2A is grounded through the one hundred and fourth resistor R104. The other end of the sixty-ninth capacitor C69 is connected to the first pin of the second A comparator U2A through the ninety-eighth resistor R98, and the first pin and the second pin of the second A comparator U2A are connected, and output to the second high-pass filter through the first pin. The second high-pass filter has the same electronic component position as the first high-pass filter, and will not be repeated here. The difference is that the parameters of some electronic components are different. The output of the second high-pass filter is further filtered through a low-pass filter. The electronic components in the low-pass filter are opposite to those of the high-pass filter. The inductor in the high-pass filter is replaced by a capacitor, and the capacitor is replaced by an inductor, and their parameters are changed. The specific connection relationship refers to the high-pass filter, and no repeated explanation is given here.

[0034] Furthermore, if Figure 2 and Figure 5As shown, the output electric signal of the filter circuit is connected to the power amplifier and the limiter circuit through the 112th resistor R112. The input current point C of the limiter circuit (for the convenience of subsequent description, it is expressed as point C) is connected to the e-pole of the 14th transistor Q14, and the b-pole and c-pole of the 14th transistor Q14 are connected through the 139th resistor R139, the 131st resistor R131 and the 212th resistor R212 arranged in series, and the other end of the 212th resistor R212 is connected to the b-pole of the 13th transistor Q13, and the other end of the 131st resistor R131 is connected to the e-pole of the 13th transistor Q3 and connected to the positive terminal of the 12V power supply, and the c-pole of the 13th transistor Q13 is grounded through the 113th resistor R113 and the 108th capacitor C108 arranged in series. The b-pole of the fourteenth transistor Q14 is connected to the e-pole of the twenty-ninth transistor Q29, the c-pole of the twenty-ninth transistor Q29 is connected to the negative terminal of the 12V power supply, and the b-pole of the twenty-ninth transistor Q29 outputs the current at point B (for the convenience of description, it is expressed as point B), point B is grounded through the one hundred and eighty-eighth resistor R188, and is connected to the negative terminal of the 12V power supply through the twenty-twenty-third resistor R223, and the VSS voltage output through the twenty-thirteenth resistor R213 and the twenty-fourteenth resistor R214 arranged in series is the VSS input of the power amplifier. Point C is connected to the e-pole of the thirty-third transistor Q30, and is connected to the thirty-first transistor Q31 through the b-pole of the thirty-third transistor Q30, and outputs the current at point A (for the convenience of description, it is expressed as point A) through the b-pole of the thirty-first transistor Q31, and then is connected to the VDD input terminal of the power amplifier in the same connection method as the fourteenth transistor, and no repeated description is made here. The difference is that the connecting section of the twenty-twentieth resistor R220 and the twenty-twenty-fourth resistor R224 is connected to the b-pole of the thirty-second transistor Q32, the e-pole of the thirty-second transistor Q32 is connected to the twenty-fourth resistor R224, and the c-pole of the thirty-second transistor Q32 is connected to the b-pole of the thirteenth transistor Q13 through the twenty-twenty resistor R220. The c-pole of the thirteenth transistor Q13 is also grounded through a twenty-sixth resistor R216, a twenty-nineteenth resistor R219 and a seventy-sixth capacitor C76 which are arranged in series. The connecting end of the twenty-sixth resistor R216 and the twenty-nineteenth resistor R219 is connected to a first pin of the optocoupler, the second pin of the optocoupler is grounded and connected to the other end of the seventy-sixth capacitor C76, the third pin of the optocoupler is grounded, and the fourth pin is connected to point C.

[0035] The power amplifier VDD divides the voltage of point A through the 215th resistor R215, the 218th resistor R218 and the 222nd resistor R222, and the VSS divides the voltage of point B through the 188th resistor R188, the 213th resistor R213 and the 214th resistor R214. When the signal is input to the power amplifier circuit through the 112th resistor R112, the voltages of point A, point B and point C can be detected and compared through the 33rd transistor Q30 and the 31st transistor Q31 and the 14th transistor Q14 and the 29th transistor Q29. When the voltage at point C is higher than the voltage at point A, the 33rd transistor Q30 is turned on to clamp the voltage at point C, and the 32nd transistor Q32 is driven to drive the 13th transistor Q13 to turn on. When the voltage at point C is lower than the voltage at point B, the 14th transistor Q14 is turned on to clamp the voltage at point C, and the 32nd transistor Q32 is driven to turn on by driving the 13th transistor Q13. At the same time, the thirteenth transistor Q13 is turned on to drive the 1st and 2nd pins of the photocoupler to be turned on through the 216th resistor R216, and the resistance values ​​of the 3rd and 4th pins are changed to divide the voltage with the 112th resistor R112 to reduce the voltage input to the power amplifier circuit. The limiter circuit can also be placed before the 112th resistor R112.

[0036] A dynamic limiting circuit of a power amplifier in a preferred embodiment 2 of the present utility model; Figure 6 As shown, the difference from the first embodiment is that no voltage limiting circuit is provided, and the other parts are the same as the first embodiment, which will not be repeated here.

[0037] A power amplifier in a preferred embodiment of the utility model comprises a dynamic amplitude limiting circuit of the power amplifier mentioned above. The specific structure of the dynamic amplitude limiting circuit is the same as that mentioned above and will not be repeated here.

[0038] It should be understood that the present invention is described by some embodiments, and those skilled in the art are aware that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the scope protected by the present invention.

Claims

1. A dynamic limiting circuit of a power amplifier, comprising a protection circuit, a signal conditioning circuit, a filtering circuit, and a power amplifier circuit, characterized in that: The circuit also includes a limiting circuit. A protection circuit, used for receiving the sound electrical signal and transmitting the sound electrical signal to the signal conditioning circuit; A signal adjustment circuit, used for receiving the sound electrical signal transmitted by the protection circuit and adjusting the size of the sound electrical signal; A filter circuit is used for filtering the regulated sound electrical signal and transmitting it to the limiting circuit and the power amplifier circuit; A limiting circuit is used to divide the voltage to limit the voltage of the power amplifier; The power amplifier circuit is used to amplify the sound electrical signal and convert it into a sound signal through a speaker.

2. The circuit according to claim 1, characterized in that: The limiting circuit outputs a VDD voltage and a VSS voltage, and is respectively connected to the VDD pole and the VSS pole of the power amplifier circuit; the limiting circuit inputs a VDD voltage through the fourteenth transistor and the twenty-ninth transistor; the limiting circuit inputs a VSS voltage through the thirty-third transistor and the thirty-first transistor.

3. The circuit according to claim 2, characterized in that: The filter circuit inputs the limiting circuit through point C, outputs the VDD voltage through point A, and outputs the VSS voltage through point B. Point A and point B are connected to the VDD pole and VSS pole of the power amplifier circuit after being connected in series with resistors. Point A and point B also include resistors connected to the power supply to divide the voltage and then output the VDD voltage and VSS voltage.

4. The circuit according to claim 3, characterized in that: The c-pole of the fourteenth transistor is connected to the thirteenth transistor, the c-pole of the thirty-third transistor is connected to the thirty-second transistor, the c-pole of the thirty-second transistor is connected to the b-pole of the thirteenth transistor, the c-pole of the thirteenth transistor is connected to the input end of the optical coupler, and the output end of the optical coupler is connected to the voltage input point of the limiting circuit. When the voltage at point C is higher than the voltage at point A, the thirty-third transistor drives the thirty-second transistor to drive the thirteenth transistor to turn on. When the voltage at point C is lower than the voltage at point B, the fourteenth transistor drives the thirteenth transistor to turn on, and the output resistance of the optical coupler driven by the thirteenth transistor is changed to perform voltage division.

5. The circuit according to any one of claims 1 to 4, characterized in that: The circuit also includes a voltage limiting circuit arranged between the protection circuit and the signal conditioning circuit. The voltage limiting circuit is a bidirectional TVS transient voltage diode arranged in the circuit.

6. The circuit according to claim 5, characterized in that: The filtering circuit includes at least one group of high-pass filters and one group of low-pass filters, wherein the high-pass filters are connected to the signal conditioning circuit, and the low-pass filters are connected to the limiting circuit and the power amplifier circuit.

7. The circuit according to claim 6, characterized in that: The high-pass filter and the low-pass filter both include a comparator, and a voltage and a resistor connecting the first pin and the third pin of the comparator, and the first pin and the second pin of the comparator are connected.

8. The circuit according to claim 1, characterized in that: A 112th resistor is connected in series between the filter circuit and the limiter circuit, one end of the 112th resistor is connected to the output end of the filter circuit, and the other end is connected to the input end of the limiter circuit and the power amplifier circuit.

9. The circuit according to claim 8, characterized in that: The 112th resistor may also have one end connected to the input point of the limiting circuit and the output end of the filtering circuit, and the other end connected to the power amplifier circuit.

10. A power amplifier, characterized in that: The power amplifier contains a dynamic limiting circuit of a power amplifier as described in any one of claims 1 to 9 for voltage limiting.

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