Automobile power amplifier system and vehicle

Abstract

The utility model provides an automobile power amplifier system and a vehicle, and relates to the technical field of automobile power amplifiers, the automobile power amplifier system comprises a processing chip, a filter circuit and a loudspeaker which are connected in sequence, a vibrating diaphragm of the loudspeaker is provided with a force sensor, and the force sensor is connected with the processing chip. The second modulation signal is fed back to the processing chip through the filter circuit to form a first-stage negative feedback, and the amplitude of the vibrating diaphragm of the loudspeaker is fed back to the processing chip through the force sensor to form a second-stage negative feedback, so that the system distortion caused by the circuit and the loudspeaker can be greatly reduced, and the stability, the reliability and the fidelity of the automobile power amplifier system are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of automotive power amplifiers, and particularly relates to an automotive power amplifier system and a vehicle. Background Technique

[0002] An automotive power amplifier, namely an automotive power amplifier, is used to amplify the power of an automotive audio system. Its task is to amplify the audio signal from the car radio to drive the speaker to emit sound, achieving an ideal in-vehicle effect. Existing automotive power amplifiers usually adopt class-D amplifiers. As shown in Figure 1 , the class-D amplifier includes a pulse width modulator 11, an amplifier 12, two transistors (MOSFETs) connected in sequence, and a low-pass filter for restoring the amplified audio signal.

[0003] Figure 1 , the two transistors are a p-channel transistor 13 and an n-channel transistor 14 respectively, which are used as current steering switches. The output node of the class-D amplifier is alternately connected to the power supply VDD and the ground through the two transistors. When the gates of the two transistors are connected to a high level, the output node of the two transistors is connected to the ground. When the gates of the two transistors are connected to a low level, the output node of the two transistors is connected to the power supply VDD. Figure 1 In which V O (t) is the real-time voltage of the output node of the class-D amplifier.

[0004] Since the two transistors cause the output node of the class-D amplifier to switch between the power supply VDD or the ground, the final output of the class-D amplifier is a high-frequency square wave signal. The switching frequency (fSW) of most class-D amplifiers is usually between 250 kHz and 1.5 MHz. Through the audio signal V AUDIO , the square wave signal output by the class-D amplifier can be pulse width modulated (PWM). Through the pulse width modulator, the audio signal V AUDIO generated by the car radio is compared with the triangular wave or sawtooth wave generated by the oscillator 15 inside the car radio, and a pulse width modulation signal can be obtained. This modulation method is usually called "natural sampling", and the oscillator serves as the sampling clock. The duty cycle of the output square wave signal is proportional to the level of the audio signal V AUDIO .

[0005] When there is no audio signal V AUDIO , the duty cycle of the output square wave signal is 50%. In order to extract the amplified audio signal from the square wave signal, the square wave signal output by the class-D amplifier needs to be sent to a low-pass filter. Figure 1 The low-pass filter in F consists of an inductor L FComposed, the low-pass filter acts as a passive integrator, and its output is equal to the average value of the square-wave signal. The two ends of the capacitor C F are used to connect to the load R L , the load R L is connected to one end of the capacitor C through the load capacitor C OUT and the other end of the capacitor C F is grounded. F

[0006] However, in a class D amplifier, the non-linearity of the pulse-width modulator, two transistors, and the deviation of the in-vehicle power supply voltage will inevitably introduce in-band noise, which will further cause distortion in the automotive power amplifier system. Summary of the Invention

[0007] The present invention provides an automotive power amplifier system and a vehicle to solve the defects existing in the related art.

[0008] The present invention provides an automotive power amplifier system, including: a processing chip, a filtering circuit, and a speaker connected in sequence. A force sensor is installed on the diaphragm of the speaker, and the force sensor is connected to the processing chip;

[0009] The processing chip is configured to receive an initial audio signal sent by the in-vehicle unit, and perform pulse-width modulation and amplification on the initial audio signal to obtain a first modulation signal;

[0010] The filtering circuit is configured to perform waveform conversion on the first modulation signal to obtain a second modulation signal, feedback the second modulation signal to the processing chip, and filter the second modulation signal to obtain an output signal;

[0011] The speaker is configured to receive the output signal and work;

[0012] The force sensor is configured to monitor the amplitude of the diaphragm and feedback the amplitude to the processing chip.

[0013] According to an automotive power amplifier system provided by the present invention, the force sensor is a capacitive flexible force sensor.

[0014] According to an automotive power amplifier system provided by the present invention, the dielectric layer of the force sensor is a nano-oxide layer on the aluminum surface.

[0015] According to an automotive power amplifier system provided by the present invention, the filtering circuit includes a first buffer, a low-pass filter, and a second buffer;

[0016] The first buffer and the low-pass filter are respectively connected to the processing chip, and the low-pass filter and the second buffer are connected; ​

[0017] The first buffer is configured to eliminate overshoot of the first modulation signal to obtain a filtered signal;

[0018] The low-pass filter is configured to perform waveform conversion on the filtered signal to obtain a second modulation signal;

[0019] The second buffer is configured to eliminate spikes of the second modulation signal to obtain the output signal.

[0020] According to an automotive power amplifier system provided by the present invention, the buffer includes a first capacitor, a first resistor, a second capacitor, and a second resistor;

[0021] One end of the first capacitor is connected to the processing chip, and the other end of the first capacitor is grounded after being connected in series with the first resistor;

[0022] One end of the second capacitor is connected to the processing chip, and the other end of the second capacitor is grounded after being connected in series with the second resistor.

[0023] According to an automotive power amplifier system provided by the present invention, the low-pass filter includes a first inductor, a second inductor, a third capacitor, and a fourth capacitor;

[0024] One end of the first inductor is connected to the processing chip, and the other end of the first inductor is grounded through the third capacitor and is connected to the processing chip;

[0025] One end of the second inductor is connected to the processing chip, and the other end of the second inductor is grounded through the fourth capacitor and is connected to the processing chip.

[0026] According to an automotive power amplifier system provided by the present invention, the second buffer includes a fifth capacitor, a third resistor, a sixth capacitor, and a fourth resistor;

[0027] One end of the fifth capacitor is connected to the other end of the first inductor, and the other end of the fifth capacitor is grounded after being connected in series with the third resistor;

[0028] One end of the sixth capacitor is connected to the other end of the second inductor, and the other end of the sixth capacitor is grounded after being connected in series with the fourth resistor.

[0029] According to an automotive power amplifier system provided by the present invention, the processing chip is further configured to:

[0030] Receive the amplitude and determine the working state of the speaker according to the magnitude of the amplitude.

[0031] According to an automotive power amplifier system provided by the present invention, the force sensor is adhered to the diaphragm.

[0032] The present utility model also provides a vehicle, including the above-mentioned automotive power amplifier system.

[0033] The automotive power amplifier system and the vehicle provided by the present utility model, the automotive power amplifier system includes: a processing chip, a filtering circuit and a speaker connected in sequence, a force sensor is installed on the diaphragm of the speaker, and the force sensor is connected to the processing chip. The second modulation signal is fed back to the processing chip through the filtering circuit to form a first-stage negative feedback, and the amplitude of the diaphragm of the speaker is fed back to the processing chip through the force sensor to form a second-stage negative feedback, which can greatly reduce the system distortion caused by the circuit and the speaker, and improve the stability, reliability and fidelity of the automotive power amplifier system. Description of the Drawings

[0034] In order to more clearly illustrate the technical solutions in the present utility model or related technologies, the following will briefly introduce the drawings required for use in the embodiments or related technology descriptions. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0035] Figure 1 It is a schematic structural diagram of an existing Class D amplifier.

[0036] Figure 2 It is one of the schematic structural diagrams of the automotive power amplifier system provided by the present utility model.

[0037] Figure 3 It is a schematic structural diagram of the processing chip in the automotive power amplifier system provided by the present utility model.

[0038] Figure 4 It is another schematic structural diagram of the automotive power amplifier system provided by the present utility model.

[0039] Figure 5 It is a comparison diagram of the fidelity and efficiency of various power amplifiers.

[0040] Figure 6 It is a schematic structural diagram of the vehicle provided by the present utility model. Detailed Embodiments

[0041] To make the purpose, technical solutions and advantages of the present utility model clearer, the following will clearly and completely describe the technical solutions in the present utility model in conjunction with the drawings in the present utility model. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model. Based on the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present utility model.

[0042] Figure 2 The following is a schematic structural diagram of an automotive power amplifier system provided in an embodiment of the present invention. As Figure 2 shown, the automotive power amplifier system includes: a processing chip 21, a filter circuit 22, and a speaker 23 that are connected in sequence. A force sensor 24 is installed on the diaphragm of the speaker 23, and the force sensor 24 is connected to the processing chip 21;

[0043] The processing chip 21 is configured to receive an initial audio signal sent by the vehicle head unit, perform pulse width modulation and amplification on the initial audio signal to obtain a first modulation signal;

[0044] The filter circuit 22 is configured to perform waveform conversion on the first modulation signal to obtain a second modulation signal, feedback the second modulation signal to the processing chip 21, and filter the second modulation signal to obtain an output signal;

[0045] The speaker 23 is configured to receive the output signal and operate;

[0046] The force sensor 24 is configured to monitor the amplitude of the diaphragm of the speaker 23 and feedback the amplitude of the speaker 23 to the processing chip 21.

[0047] Specifically, for the automotive power amplifier system provided in an embodiment of the present invention, the processing chip 21 used therein can be a class-D amplifier chip, for example, it can be an FDA801 chip.

[0048] As Figure 3 shown, the processing chip 21 may include a control unit 211, a driver stage unit 212, and a power stage unit 213 that are connected in sequence. The control unit 211 can be connected to the vehicle head unit to receive the initial audio signal sent by the vehicle head unit. The driver stage unit 212 includes a pulse width modulator and an amplifier that are connected in sequence. The pulse width modulator can be the same as the pulse width modulator 11 in Figure 1 , and the amplifier can be the same as the amplifier 12 in Figure 1 . The power stage unit 213 includes a p-channel transistor and an n-channel transistor. The gates of the p-channel transistor and the n-channel transistor are both connected to the output of the driver stage unit 212. The source of the p-channel transistor and the drain of the n-channel transistor are connected together as the output node of the power stage unit 213. The drain of the p-channel transistor is connected to the power supply, and the source of the n-channel transistor is grounded.

[0049] The processing chip 21 can be configured to receive the initial audio signal sent by the vehicle head unit through the control unit 211, perform pulse width modulation on the initial audio signal through the driver stage unit 212, and amplify the result of the pulse width modulation through the power stage unit 213 to obtain a first modulation signal.

[0050] The first modulation signal may be a square wave signal, and the filtering circuit 22 may be configured to perform waveform conversion on the first modulation signal to obtain a second modulation signal, which may be a sine wave signal.

[0051] The second modulation signal is fed back to the processing chip 21 to form a first-stage negative feedback. After receiving the second modulation signal, the processing chip 21 can use the second modulation signal to shape the noise in the circuit and reduce the in-band noise introduced by the non-linearity of the driver stage unit 212, power stage unit 213, and power supply voltage deviation in the processing chip 21.

[0052] The filtering circuit 22 can also be configured to filter the second modulation signal, filter out the high-frequency spikes in the second modulation signal to obtain an output signal, and send the output signal to the speaker 23.

[0053] The speaker 23 is configured to receive the output signal to work and play the output signal.

[0054] Since the speaker 23 is a non-linear element, it will introduce signals such as harmonics and noise, resulting in system distortion. Therefore, the amplitude of the diaphragm of the speaker 23 is monitored in real time by the force sensor 24 installed on the diaphragm of the speaker 23, and the amplitude of the speaker 23 is fed back to the processing chip 21 to form a second-stage negative feedback. The processing chip 21 can be configured to receive the amplitude in real time and shape the harmonics and noise introduced by the speaker 23 according to the magnitude of the amplitude, reducing the possibility of system distortion caused by the speaker. Moreover, it can be understood that due to the introduction of the second-stage negative feedback, not only can the possibility of system distortion caused by the speaker be reduced, but also the instability problems of under-compensation or over-compensation brought by the first-stage negative feedback can be solved.

[0055] The automotive power amplifier system provided in the embodiment of the present invention includes: a processing chip, a filtering circuit, and a speaker connected in sequence. A force sensor is installed on the diaphragm of the speaker, and the force sensor is connected to the processing chip. The second modulation signal is fed back to the processing chip through the filtering circuit to form a first-stage negative feedback, and the amplitude of the diaphragm of the speaker is fed back to the processing chip through the force sensor to form a second-stage negative feedback, which can greatly reduce the system distortion caused by the circuit and the speaker, and improve the stability, reliability, and fidelity of the automotive power amplifier system.

[0056] Based on the above embodiment, the force sensor is a capacitive flexible force sensor.

[0057] Specifically, the capacitive flexible force sensor has a relatively thin thickness and is relatively soft, and can be attached to the diaphragm of the speaker for installation to reduce the impact on the operation of the speaker.

[0058] Based on the above embodiments, the dielectric layer of the force sensor is a nano-oxide layer on the aluminum surface.

[0059] Specifically, since a nano-oxide layer can be naturally formed on the aluminum surface, it is used as the dielectric layer of the force sensor. At the same time, by utilizing the Schottky effect of the semiconductor-metal contact to block the tunneling current on the dielectric layer, pressure sensing at the nF signal level can be achieved, with very good frequency stability and environmental stability. In the frequency range of 20 - 100 kHz, the fluctuation of the permittivity is less than 8.1%, and it will not be damaged even when soaked in water for one day. In addition to the improvement of anti-interference ability, the force sensor also has good environmental and mechanical stability and can be assembled in-situ on the surface of the speaker.

[0060] As Figure 4 shown, based on the above embodiments, the filter circuit 22 includes a first buffer 221, a low-pass filter (LPF), and a second buffer 222;

[0061] The first buffer 221 and the low-pass filter LPF are respectively connected to the processing chip 21, and the low-pass filter LPF and the second buffer 222 are connected;

[0062] The first buffer 221 is configured to eliminate overshoot of the first modulation signal to obtain a filtered signal;

[0063] The low-pass filter LPF is configured to perform waveform conversion on the filtered signal, convert the square wave signal into a sine wave signal, and obtain a second modulation signal;

[0064] The second buffer 222 is configured to eliminate spikes of the second modulation signal to obtain an output signal to make the speaker 23 work.

[0065] By introducing the filter circuit, not only can the first-stage negative feedback be achieved by providing the second modulation information to the processing chip 21, but also the interference in the circuit can be filtered out and waveform conversion can be achieved.

[0066] Figure 4 In, the processing chip 21 may include a power supply interface VCC2, an output port OUT2, a first feedback interface FB2, a second feedback interface FB, and a ground interface GND2. The power supply interface VCC2 is used to access the power supply signal VCC. The output port OUT2 is used to be respectively connected to the first buffer 221 and the low-pass filter LPF. The first feedback interface FB2 is used to be connected to the output port of the low-pass filter LPF. The second feedback interface FB is used to be connected to the force sensor 24. The ground interface GND2 is used to ground.

[0067] As Figure 4As shown, on the basis of the above embodiments, the buffer 221 includes a first capacitor C1, a first resistor R1, a second capacitor C2, and a second resistor R2;

[0068] One end of the first capacitor C1 is connected to the processing chip 21, and the other end of the first capacitor C1 is grounded after being connected in series with the first resistor R1;

[0069] One end of the second capacitor C2 is connected to the processing chip 21, and the other end of the second capacitor C2 is grounded after being connected in series with the second resistor R2.

[0070] By grounding the first capacitor in series with the first resistor and grounding the second capacitor in series with the second resistor, the overshoot phenomenon of the first modulation signal can be eliminated.

[0071] As Figure 4 shown, on the basis of the above embodiments, the low-pass filter LPF includes a first inductor L1, a second inductor L2, a third capacitor C3, and a fourth capacitor C4;

[0072] One end of the first inductor L1 is connected to the processing chip 21, and the other end of the first inductor L1 is grounded through the third capacitor C3 and is also connected to the processing chip 21;

[0073] One end of the second inductor L2 is connected to the processing chip 21, and the other end of the second inductor L2 is grounded through the fourth capacitor C4 and is also connected to the processing chip 21.

[0074] The low-pass filter formed by combining the first inductor L1 and the third capacitor C3, and the second inductor L2 and the fourth capacitor C4 can make the output second modulation signal become a smoother sine wave signal, thereby further improving the sound effect.

[0075] As Figure 4 shown, on the basis of the above embodiments, the second buffer 222 includes a fifth capacitor C5, a third resistor R3, a sixth capacitor C6, and a fourth resistor R4;

[0076] One end of the fifth capacitor C5 is connected to the other end of the first inductor L1, and the other end of the fifth capacitor C5 is grounded after being connected in series with the third resistor R3;

[0077] One end of the sixth capacitor C6 is connected to the other end of the second inductor L2, and the other end of the sixth capacitor C6 is grounded after being connected in series with the fourth resistor R4.

[0078] By grounding the fifth capacitor C5 in series with the third resistor R3 and grounding the sixth capacitor C6 in series with the fourth resistor R4, the high-frequency spikes of the second modulation signal can be eliminated.

[0079] On the basis of the above embodiments, the processing chip is further configured to:

[0080] Receive the amplitude and determine the operating state of the speaker according to the magnitude of the amplitude.

[0081] Specifically, the processing chip 21 can receive the amplitude and determine the operating state of the speaker 23 according to the magnitude of the amplitude. For example, if no amplitude is received, that is, the magnitude of the amplitude is 0, it is considered that the speaker 23 is not working. If an amplitude is received, that is, the magnitude of the amplitude is not 0, it is considered that the speaker 23 is in an operating state. Further, in the case of receiving an amplitude, if the amplitude is large, it indicates that the speaker 23 plays a louder sound, and if the amplitude is small, it indicates that the speaker 23 plays a softer sound.

[0082] By detecting the amplitude of the diaphragm of the speaker to judge the state of the speaker, the design of the speaker can be optimized, and more flexible sound effect adjustment and speaker design can be realized.

[0083] Figure 5 For the comparison intention of the fidelity and efficiency of various power amplifiers, such as Figure 5 shown, traditional class A power amplifiers and class AB power amplifiers have high fidelity but too low efficiency and are not suitable for automotive applications. The traditional class D power amplifier is an open-loop class D power amplifier, which has higher efficiency but lower fidelity. The single-feedback class D power amplifier with the first-stage negative feedback in the embodiment of the present invention has a great improvement in fidelity compared with the open-loop class D power amplifier; the double-feedback class D power amplifier with the first-stage negative feedback and the second-stage negative feedback has great improvements in both fidelity and efficiency.

[0084] Such as Figure 6 shown, on the basis of the above embodiments, the embodiment of the present invention further provides a vehicle 61, and the vehicle 61 includes an automotive power amplifier system 62. By introducing the automotive power amplifier system and applying the two-stage negative feedback in the automotive power amplifier system, the system distortion caused by the circuit and the speaker is reduced, and the stability, reliability and fidelity of the automotive power amplifier system are improved, and the performance of the vehicle and the user experience and satisfaction are improved.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An automotive power amplifier system, characterized in that, Comprising: A processing chip, a filtering circuit and a speaker connected in sequence. A force sensor is mounted on the diaphragm of the speaker, and the force sensor is connected to the processing chip; The processing chip is configured to receive an initial audio signal sent by a car radio, and perform pulse width modulation and amplification on the initial audio signal to obtain a first modulation signal; The filtering circuit is configured to perform waveform conversion on the first modulation signal to obtain a second modulation signal, feedback the second modulation signal to the processing chip, and filter the second modulation signal to obtain an output signal; The speaker is configured to receive the output signal and work; The force sensor is configured to monitor the amplitude of the diaphragm and feedback the amplitude to the processing chip.

2. The automotive power amplifier system according to claim 1, characterized in that The force sensor is a capacitive flexible force sensor.

3. The automotive power amplifier system according to claim 2, characterized in that The dielectric layer of the force sensor is a nano-oxide layer on the aluminum surface.

4. The automotive power amplifier system according to claim 1, wherein The filtering circuit includes a first buffer, a low-pass filter and a second buffer; The first buffer and the low-pass filter are respectively connected to the processing chip, and the low-pass filter and the second buffer are connected; The first buffer is configured to eliminate overshoot of the first modulation signal to obtain a filtered signal; The low-pass filter is configured to perform waveform conversion on the filtered signal to obtain a second modulation signal; The second buffer is configured to eliminate spikes of the second modulation signal to obtain the output signal.

5. The automotive power amplifier system according to claim 4, wherein The buffer includes a first capacitor, a first resistor, a second capacitor and a second resistor; One end of the first capacitor is connected to the processing chip, and the other end of the first capacitor is grounded in series with the first resistor; One end of the second capacitor is connected to the processing chip, and the other end of the second capacitor is grounded in series with the second resistor.

6. The automotive power amplifier system according to claim 4, wherein The low-pass filter includes a first inductor, a second inductor, a third capacitor and a fourth capacitor; One end of the first inductor is connected to the processing chip, and the other end of the first inductor is grounded through the third capacitor and is connected to the processing chip; One end of the second inductor is connected to the processing chip, and the other end of the second inductor is grounded through the fourth capacitor and is connected to the processing chip.

7. The automotive power amplifier system according to claim 6, wherein The second buffer includes a fifth capacitor, a third resistor, a sixth capacitor and a fourth resistor; One end of the fifth capacitor is connected to the other end of the first inductor, and the other end of the fifth capacitor is grounded in series with the third resistor; One end of the sixth capacitor is connected to the other end of the second inductor, and the other end of the sixth capacitor is grounded in series with the fourth resistor.

8. The automotive power amplifier system according to any one of claims 1-7, characterized in that, The processing chip is further configured to: Receive the amplitude, and determine the working state of the speaker according to the magnitude of the amplitude.

9. The automotive power amplifier system according to any one of claims 1-7, characterized in that, The force sensor is adhered to the diaphragm.

10. A vehicle, characterized in that, Comprising: The automotive power amplifier system according to any one of claims 1-9.

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