Audio amplifier chip controlled through analog input and audio amplifier

Abstract

The audio amplifier chip comprises an input port, a control mechanism algorithm library, a voltage generation circuit, a positive voltage power supply, a grid driving unit and a half-bridge circuit, the control mechanism algorithm library comprises a negative voltage control mechanism algorithm, and the voltage generation circuit comprises a negative voltage control mechanism algorithm. The voltage generation circuit comprises a negative voltage generation circuit, and the half-bridge circuit is formed by connecting two switching tubes in series; wherein the input port is used for receiving an analog input audio signal; the negative voltage generation circuit is used for generating negative voltage according to a negative voltage control mechanism algorithm and an analog input audio signal; the gate driving unit is used for generating a PWM signal according to an analog input audio signal; the duty ratio of the pulse width modulation signal is determined according to the voltage output by the positive voltage power supply, the negative voltage and the output signal of the audio amplifier chip; and applying a pulse width modulation signal with a duty ratio to the grid electrode of the switching tube. The embodiment of the invention can reduce the device cost and improve the performance of the audio amplifier.

Description

Technical Field

[0001] This invention relates to the field of amplifier technology, and more particularly to an audio amplifier chip and an audio amplifier controlled by analog input. Background Technology

[0002] An audio amplifier is an electronic device or circuit whose main function is to amplify weak audio signals (such as those from microphones, mobile phones, music players, etc.) to a sufficiently strong level to drive speakers, headphones, or other audio output devices, thereby producing audible sound.

[0003] Audio amplifiers are widely used in car audio systems, and multi-channel designs can enhance sound quality and immersion. For example, economy cars typically use four-channel or six-channel systems, with each channel driving one or two speakers to meet basic listening needs. Some mid-range models add a center speaker or subwoofer, often using six-channel or eight-channel systems to support richer sound effects and surround sound. High-end models are equipped with multi-channel systems, such as those from brands like Bose and Harman Kardon, supporting advanced sound effects like 7.1.4 Dolby Atmos, providing an immersive listening experience. Luxury flagship models use multi-channel systems with more than 20 speakers, supporting complex channel layouts to create an ultimate surround sound field. With the development of car audio technology and consumers' increasing demands for sound quality, from economy cars to luxury flagship models, there is a growing pursuit of more and more speakers. If traditional audio amplifiers are used, it will lead to a significant increase in component costs and a significant decrease in performance. Summary of the Invention

[0004] This application provides an audio amplifier chip and an audio amplifier controlled by analog input, which can reduce device cost and improve audio amplifier performance.

[0005] The first aspect of this application provides an audio amplifier chip controlled by analog input. The audio amplifier chip includes an input port, a control mechanism algorithm library, a voltage generation circuit, a positive voltage power supply, a gate drive unit, and a half-bridge circuit. The control mechanism algorithm library includes a negative voltage control mechanism algorithm, the voltage generation circuit includes a negative voltage generation circuit, and the half-bridge circuit consists of two connected switching transistors. The input port is used to receive analog input audio signals; The positive voltage power supply is connected to the input terminal of one of the switching transistors, and the negative voltage generating circuit is connected to the output terminal of the other switching transistor. The negative voltage generating circuit is used to generate negative voltage according to the negative voltage control mechanism algorithm and the analog input audio signal. The gate driving unit is used to generate a pulse width modulation signal based on the analog input audio signal; determine the duty cycle of the pulse width modulation signal based on the voltage output by the positive voltage power supply, the negative voltage, and the output signal of the audio amplifier chip; and apply the pulse width modulation signal with the duty cycle to the gate of the switching transistor.

[0006] Optionally, the negative voltage generating circuit is used to generate negative voltage according to the negative voltage control mechanism algorithm and the analog input audio signal, including: The negative pressure generating circuit is used to determine the amplitude of the envelope after taking the absolute value of the input audio signal as the envelope amplitude; to determine the candidate negative pressure according to the product of the envelope amplitude, the preset compensation coefficient and the power amplifier gain; and to determine the minimum value between the candidate negative pressure and the preset fixed negative pressure as the negative pressure.

[0007] Optionally, the preset fixed negative voltage is obtained by converting the output voltage of the positive voltage power supply through a DC-to-DC circuit.

[0008] Optionally, the control mechanism algorithm library also includes a positive voltage control mechanism algorithm, the voltage generation circuit includes a positive voltage boost circuit, the positive voltage power supply is connected to the input terminal of one of the switching transistors through the positive voltage boost circuit, and the positive voltage boost circuit is used to generate positive voltage according to the positive voltage control mechanism algorithm and the analog input audio signal; The step of determining the duty cycle of the pulse width modulation signal based on the positive voltage output from the positive voltage power supply, the negative voltage, and the voltage corresponding to the output signal of the audio amplifier chip includes: The duty cycle of the pulse width modulation signal is determined based on the voltage corresponding to the positive voltage, the negative voltage, and the output signal of the audio amplifier chip.

[0009] Optionally, the positive voltage boost circuit is used to generate a positive voltage according to the positive voltage control mechanism algorithm and the analog input audio signal, including: The positive voltage boost circuit is used to determine a candidate positive voltage based on the envelope amplitude, a preset compensation coefficient, and the product of the power amplifier gain; and to determine the maximum value between the candidate positive voltage and the voltage output by the positive voltage power supply as the positive voltage.

[0010] Optionally, the audio amplifier chip controlled by analog input further includes a configurable delay module. The input port is connected to the gate driving unit through the configurable delay module. The configurable delay module is used to compensate for the delay of the control mechanism algorithm library and the delay of the voltage generation circuit.

[0011] Optionally, the audio amplifier chip controlled by analog input further includes an output sampling circuit, which is used to acquire the output signal of the audio amplifier chip, and the analog input audio signal is a signal determined based on the output signal of the audio amplifier chip.

[0012] A second aspect of this application provides an audio amplifier, which includes an audio amplifier chip, a filter, and a load as described in the first aspect, all controlled by analog input. The audio amplifier chip is connected to a first terminal of the filter via an output port, a second terminal of the filter is grounded, a third terminal of the filter is connected to one end of the load, and the other end of the load is grounded.

[0013] Optionally, each output port corresponds to one half-bridge circuit, and the output port is connected to the output terminal of one of the switching transistors and the input terminal of the other switching transistor.

[0014] Optionally, the output signal of the audio amplifier chip includes the input signal of the filter and / or the output signal of the filter.

[0015] The embodiments of this application have at least the following technical effects: Traditional audio amplifiers typically use a single power supply (e.g., positive voltage only), which limits the output signal to oscillating between 0 and VDD, restricting the maximum undistorted output amplitude. This solution introduces a negative voltage generation circuit, working in conjunction with a positive voltage power supply to form a bipolar power supply (positive and negative power supply). This allows the half-bridge output to oscillate between positive and negative voltages, significantly expanding the output dynamic range and thus improving the peak output capability and overall fidelity of the audio signal, especially at high volumes or in the low-frequency range. Second, the gate drive unit generates a pulse width modulation signal based on the analog input audio signal. The duty cycle depends not only on the input signal but also dynamically on the positive and negative voltages and the current output feedback. This control strategy effectively suppresses nonlinear distortion caused by power supply fluctuations and load changes, improving total harmonic distortion performance. Specifically, with small-amplitude signals, the negative voltage amplitude is much smaller than the positive voltage amplitude, and under negative feedback, the duty cycle remains at a low value. This results in reduced circuit power consumption and improved circuit efficiency. Third, the negative voltage generation circuit, control algorithm library, gate drive, half-bridge switch, etc. are integrated into a single chip, eliminating the need for an external negative power supply or complex charge pump, thus reducing BOM cost and PCB area. Internal co-design optimizes signal path matching and timing control, reduces EMI interference and parasitic effects, and improves overall system reliability. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This invention provides a schematic diagram of the structure of an audio amplifier controlled by analog input according to an embodiment of the present application. Figure 2 A schematic diagram of the structure of an audio amplifier controlled by analog input is shown in another embodiment of this application; Figure 3 This illustration shows a schematic diagram of the structure of an audio amplifier controlled by analog input according to yet another embodiment of this application; Figure 4 This illustration shows a schematic diagram of the structure of a single-channel audio amplifier controlled by analog input according to yet another embodiment of this application; Figure 5 This illustration shows a schematic diagram of a two-channel audio amplifier controlled by analog input according to yet another embodiment of this application; Figure 6 The diagram illustrates the amplitude variation of the inductor current when the PWM duty cycle is 12.5% ​​and 50% according to the embodiments of this application. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0019] Please refer to Figure 1 This document illustrates a schematic diagram of an audio amplifier controlled by analog input according to an embodiment of this application. The audio amplifier includes an audio amplifier chip, which comprises an input port 1, a control mechanism algorithm library 2, a voltage generation circuit 3, a positive voltage power supply 4, a gate drive unit 5, and a half-bridge circuit 6. The control mechanism algorithm library 2 includes a negative voltage control mechanism algorithm 2b, the voltage generation circuit 3 includes a negative voltage generation circuit 3b, and the half-bridge circuit 6 is composed of two switching transistors Q1 and Q2 connected in series. The input port 1 is used to receive analog input audio signals; The positive voltage power supply 4 is connected to the input terminal of one of the switching transistors Q1, and the negative voltage generating circuit 3b is connected to the output terminal of the other switching transistor Q2. The negative voltage generating circuit 3b is used to generate negative voltage according to the negative voltage control mechanism algorithm 2b and the analog input audio signal. The gate driving unit 5 is used to generate a pulse width modulation signal according to the analog input audio signal; determine the duty cycle of the pulse width modulation signal according to the voltage output by the positive voltage power supply 4, the negative voltage and the output signal of the audio amplifier chip; and apply the pulse width modulation signal with the duty cycle to the gate of the switching transistor.

[0020] Please refer to Figure 2 This illustration shows a schematic diagram of an audio amplifier controlled by analog input according to another embodiment of this application. The audio amplifier includes an audio amplifier chip, which comprises an input port 1, a control mechanism algorithm library 2, a voltage generation circuit 3, a positive voltage power supply 4, a gate drive unit 5, and a half-bridge circuit 6. The control mechanism algorithm library 2 includes a positive voltage control mechanism algorithm 2a and a negative voltage control mechanism algorithm 2b. The voltage generation circuit 3 includes a positive voltage boost circuit 3a and a negative voltage generation circuit 3b. The half-bridge circuit 6 is composed of two switching transistors Q1 and Q2 connected in series. The input port 1 is used to receive analog input audio signals; The positive voltage power supply 4 is connected to the input terminal of one of the switching transistors Q1 through the positive voltage boost circuit 3a. The positive voltage boost circuit 3a is used to generate positive voltage according to the positive voltage control mechanism algorithm 2a and the analog input audio signal. The negative voltage generation circuit 3b is connected to the output terminal of the other switching transistor Q2. The negative voltage generation circuit 3b is used to generate negative voltage according to the negative voltage control mechanism algorithm 2b and the analog input audio signal. The gate driving unit 5 is used to generate a pulse width modulation signal according to the analog input audio signal; determine the duty cycle of the pulse width modulation signal according to the voltage corresponding to the positive voltage, the negative voltage and the output signal of the audio amplifier chip; and apply the pulse width modulation signal with the duty cycle to the gate of the switching transistor.

[0021] Please refer to Figure 3This illustration shows a schematic diagram of an audio amplifier controlled by analog input according to another embodiment of this application. The audio amplifier includes an audio amplifier chip, which comprises an input port 1, a control mechanism algorithm library 2, a voltage generation circuit 3, a positive voltage power supply 4, a gate drive unit 5, a half-bridge circuit 6, and an output sampling circuit 8. The control mechanism algorithm library 2 includes a positive voltage control mechanism algorithm 2a and a negative voltage control mechanism algorithm 2b. The voltage generation circuit 3 includes a positive voltage boost circuit 3a and a negative voltage generation circuit 3b. The half-bridge circuit 6 is composed of two switching transistors Q1 and Q2 connected in series. The input port 1 is used to receive analog input audio signals; The positive voltage power supply 4 is connected to the input terminal of one of the switching transistors Q1 through the positive voltage boost circuit 3a. The positive voltage boost circuit 3a is used to generate positive voltage according to the positive voltage control mechanism algorithm 2a and the analog input audio signal. The negative voltage generation circuit 3b is connected to the output terminal of the other switching transistor Q2. The negative voltage generation circuit 3b is used to generate negative voltage according to the negative voltage control mechanism algorithm 2b and the analog input audio signal. The gate driving unit 5 is used to generate a pulse width modulation signal according to the analog input audio signal; determine the duty cycle of the pulse width modulation signal according to the voltage corresponding to the positive voltage, the negative voltage and the output signal of the audio amplifier chip; and apply the pulse width modulation signal with the duty cycle to the gate of the switching transistor. The output sampling circuit 8 is used to acquire the output signal of the audio amplifier chip, and the analog input audio signal is a signal determined based on the output signal of the audio amplifier chip.

[0022] like Figures 1 to 3 As shown, the audio amplifier chip controlled by analog input also includes a configurable delay module 7. The input port 1 is connected to the gate drive unit 5 through the configurable delay module 7. The configurable delay module 7 is used to compensate for the delay of the control mechanism algorithm library and the delay of the voltage generation circuit.

[0023] Without this delay, one consequence is that when the audio signal suddenly increases, the power supply voltage does not have time to change, resulting in clipping of the audio signal. Therefore, adding a configurable delay module can suppress the generation of audio signal clipping.

[0024] The gate drive unit 5 determines the duty cycle of the pulse width modulation signal based on the positive voltage, negative voltage, and the voltage corresponding to the output signal of the audio amplifier chip. The positive and negative voltages are generated based on the analog input audio signal. Due to the inherent propagation delay of the power output stage (i.e., the half-bridge circuit and filter in this application), if the output signal of the audio amplifier chip is one beat slower than the analog input audio signal, it will cause phase lag, disrupting loop stability and even causing oscillation or high-frequency distortion. Therefore, adding a configurable delay module 7 before the gate drive unit 5 allows the input audio signal and the output signal of the audio amplifier chip to be aligned.

[0025] In addition, this application may include multiple channels, i.e., multiple one-to-one corresponding gate drive units 5 and half-bridge circuits 6, and the configurable delay module 7 can also align signals from different channels. The two switches in the half-bridge circuit 6 may not be turned on simultaneously, thus requiring the insertion of a dead time to prevent shoot-through current. However, the dead time introduces nonlinear distortion, especially near the zero-crossing point. Therefore, the inserted configurable delay module 7 can also pre-delay the input audio signal to cooperate with predictive control or feedforward compensation, thereby compensating for waveform distortion caused by the dead time.

[0026] Furthermore, the audio amplifier includes the audio amplifier chip controlled by analog input, the filter, and the load; the audio amplifier chip is connected to the first end of the filter through an output port, the second end of the filter is grounded, the third end of the filter is connected to one end of the load, and the other end of the load is grounded.

[0027] The audio amplifier can be single-channel or multi-channel; for a single-channel embodiment, please refer to [link to example]. Figure 4 For multi-channel implementation examples, please refer to [link to example]. Figure 5 .

[0028] Please refer to Figure 4 This illustration shows a schematic diagram of a single-channel audio amplifier controlled by analog input according to another embodiment of this application. The audio amplifier includes an audio amplifier chip, a filter, and a load; the audio amplifier chip is connected to a first terminal of the filter through an output port, the second terminal of the filter is grounded, the third terminal of the filter is connected to one end of the load, and the other end of the load is grounded.

[0029] The first filter includes an inductor. and capacitor .

[0030] It should be noted that the filter can have other structures. The above is the simplest case, including only one inductor and one capacitor. For example, it can also include multiple capacitors and inductors, or other components such as resistors; this is not limited here. When the filter includes only one inductor and one capacitor, the first terminal of the filter is... One end of the filter, the second end is At the other end, the third end of the filter is The other end and One end.

[0031] For example, the audio amplifier chip connects to the single-channel output port OUT A. One end is connected, The other end is respectively with Connected to one end of the first load. The other end of the load is grounded, and the other end of the first load is grounded.

[0032] The audio amplifier may also include at least two filters and at least two loads; the audio amplifier chip is connected to the first end of one of the filters through two output ports, the second ends of the two filters are connected and then grounded, the third end of each filter is connected to one end of one of the loads, and the other ends of the two loads are connected and then grounded.

[0033] Please refer to Figure 5 This illustration shows a schematic diagram of a two-channel audio amplifier controlled by analog input according to another embodiment of this application. The two filters are a first filter and a second filter; exemplarily, the first filter includes an inductor. and capacitor The second filter includes an inductor. and capacitor It should be noted that the filter can have other structures; the above is the simplest case, including only one inductor and one capacitor. For example, it can also include multiple capacitors and inductors, or other components such as resistors; this is not limited here. When the filter includes only one inductor and one capacitor, the first terminal of the filter is... One end of the filter, the second end of the filter is At the other end, the third end of the filter is The other end and One end.

[0034] For example, the audio amplifier chip connects to the output port OUT A of one of its channels. One end is connected, The other end is respectively with Connect to one end of the first load; The audio amplifier chip connects to the output port OUT B of another channel. One end is connected, The other end is respectively with One end of the load is connected to one end of the second load; The other end and The other end of the first load is connected to the ground, and the other end of the first load is connected to the other end of the second load and then grounded.

[0035] Figure 1 and Figure 2 This is an audio amplifier chip controlled via open-loop analog input, compared to... Figure 2 The audio amplifier in Figure 1 The audio amplifier in the middle directly supplies power to the half-bridge circuit with a positive voltage power supply, eliminating the need for... Figure 2 The positive voltage boost circuit in the circuit can save on bill of materials costs. Figure 1 Suitable for audio amplifiers with low output power requirements. If a higher voltage is desired to power the half-bridge circuit to obtain greater output power, then... Figure 2 The audio amplifier in the circuit can be equipped with a positive voltage boost circuit. For example, an output power threshold can be set, and when the output power is exceeded, a voltage boosting circuit can be used. Figure 2 The audio amplifier in the system, when not exceeding this output power threshold, uses... Figure 1 The audio amplifier in the middle.

[0036] Figure 3 This is an audio amplifier chip controlled by analog input closed-loop, compared to... Figure 1 and Figure 2 An audio amplifier chip controlled by open-loop analog input. Figure 3 The analog input audio signal is determined based on the output signal of the audio amplifier chip. The output signal of the audio amplifier chip includes the input signal of the filter and / or the output signal of the filter. The dynamically adjusted analog input audio signal can be determined based on the product of the original analog input audio signal and the ratio of the forward gain to the closed-loop gain. Figure 1 and Figure 2 The analog input audio signal of an audio amplifier chip controlled by analog input open loop has no feedback term and will not be corrected according to the output deviation.

[0037] In a specific embodiment provided in this application, the negative voltage generating circuit is used to generate negative voltage according to the negative voltage control mechanism algorithm and the analog input audio signal, including: The negative pressure generating circuit is used to determine the amplitude of the envelope after taking the absolute value of the input audio signal as the envelope amplitude; to determine the candidate negative pressure according to the product of the envelope amplitude, the preset compensation coefficient and the power amplifier gain; and to determine the minimum value between the candidate negative pressure and the preset fixed negative pressure as the negative pressure.

[0038] For example, negative pressure is: V_negative pressure = min(V_offset, - envelope amplitude × compensation coefficient × Gain), Here, Voffset is a preset fixed negative voltage, such as -1V, -2V, -3V, etc., with no specific value limited. When the audio envelope amplitude is close to 0V, a fixed small-amplitude negative voltage is output, forcing the audio amplifier to have a small duty cycle PWM output. If Voffset is too close to 0V, the PWM pulse output by the audio amplifier will be too narrow, causing the pulse to fall back to Voffset before fully rising to a high voltage. This will increase total harmonic distortion and prevent the bootstrap capacitor in the bootstrap circuit from fully charging, resulting in the high-side switch of the half-bridge circuit not being fully turned on. If the Voffset amplitude is too high, it will increase the PWM duty cycle, leading to increased power consumption of the audio amplifier.

[0039] The compensation factor is a number greater than or close to 1, such as 1.05, 1.1, or 1.15. Its purpose is to increase the voltage drop across parasitic parameters such as PCB traces and the on-resistance of the switching transistor when the audio amplifier outputs power. For the audio amplifier to output a certain voltage amplitude, the negative voltage generation circuit needs to provide a higher voltage amplitude to the switching transistor.

[0040] Gain represents the power amplifier gain, for example, Gain = 20dB (10 times); Voffset = -2V; compensation coefficient = 1.1. When the envelope amplitude is 0V, the output of the negative voltage generating circuit is min(-2V, 0V) = -2V. When the envelope amplitude is 0.1V, the output of the negative voltage generating circuit is min(-2V, -0.1V × 1.1 × 10) = (-2V, -1.1V) = -2V. When the envelope amplitude is 1V, the output voltage of the negative voltage generating circuit is min(-2V, –1V × 1.1 × 10) = -11V.

[0041] In a specific embodiment provided in this application, the positive voltage boost circuit is used to generate a positive voltage according to the positive voltage control mechanism algorithm and the analog input audio signal, including: The positive voltage boost circuit is used to determine a candidate positive voltage based on the envelope amplitude, a preset compensation coefficient, and the product of the power amplifier gain; and to determine the maximum value between the candidate positive voltage and the voltage output by the positive voltage power supply as the positive voltage.

[0042] For example, positive pressure is: V positive pressure = max(battery voltage, envelope amplitude × compensation coefficient × Gain). The battery voltage is the output voltage of the positive voltage power supply, for example, 14.4V, with a compensation factor of 1.1 and a power amplifier gain of 10. When the envelope amplitude is 0V, the output of the positive voltage boost circuit is max(14.4V, 0V) = 14.4V. The audio amplifier is powered by the positive voltage power supply. If the positive voltage boost circuit is not working, the positive voltage power supply directly powers the half-bridge circuit. When the envelope amplitude is 1V, the output of the positive voltage boost circuit is max(14.4V, 1V × 1.1 × 10) = 14.4V. The audio amplifier is powered by the positive voltage power supply. When the envelope amplitude is 2V, the output voltage of the positive voltage boost circuit is max(14.4V, 2V × 1.1 × 10) = 22V. The audio amplifier is powered by the boosted voltage.

[0043] Both the negative voltage generating circuit and the positive voltage boosting circuit can be DC-DC converters.

[0044] Furthermore, the preset fixed negative voltage is obtained by converting the output voltage of the positive voltage power supply through a DC-to-DC circuit.

[0045] In this embodiment, a preset fixed negative voltage is obtained by converting the output voltage of the positive voltage power supply through a DC-DC converter circuit, instead of being set separately. Structurally, this eliminates the need for additional power interfaces, transformers, or a second input, resulting in a more compact PCB layout, simplifying the system and saving space. Economically, it eliminates the need for a separate negative power supply module, connectors, and cables, significantly reducing the bill of materials cost. Simultaneously, the negative voltage automatically adjusts with the positive power supply, ensuring dual-power supply symmetry and improving the common-mode rejection performance of circuits such as operational amplifiers. Regarding the conversion method, a highly integrated DC-DC circuit is selected, requiring only a few external components to achieve a stable negative voltage output.

[0046] Specifically, the gate driving unit can be used to convert the analog input audio signal into an amplified signal, and then compare the amplified signal with a preset modulation signal to output a pulse width modulation (PWM) signal. The PWM signal is used to alternately drive the gates of the two switching transistors so that current flows through the load. The gate driving unit can be, for example, a comparator, and the preset modulation signal can employ various modulation schemes, such as a half-swing modulation scheme.

[0047] Specifically, determining the duty cycle of the pulse width modulation signal based on the positive voltage, the negative voltage, and the output signal of the audio amplifier chip includes: substituting the positive voltage, the negative voltage, and the output signal of the audio amplifier chip into the duty cycle determination formula to calculate the duty cycle of the pulse width modulation signal. The duty cycle determination formula is as follows: , in, For PWM duty cycle, It is positive pressure. It is negative pressure. This refers to the voltage corresponding to the output signal of the audio amplifier chip.

[0048] The output signal of the audio amplifier chip can be the output signal of the half-bridge circuit, the output signal of the filter, or both, without limitation.

[0049] For most of the time, audio power amplifiers require a relatively small output signal amplitude. Correspondingly, for most of the time, the negative power supply of the amplifier requires a relatively small voltage amplitude. Taking an output amplitude of 0V as an example, when the audio power amplifier requires an output amplitude of 0V, with a positive voltage of, for example, 14V and a negative voltage of, for example -2V, to achieve an output voltage of 0, the duty cycle required by the half-bridge circuit is calculated using the duty cycle determination formula mentioned above: .

[0050] In existing technologies, to ensure that the positive and negative swings of the waveform are the same, the amplitudes of the positive and negative power supplies of the audio amplifier are set to the same value, such as + / -15V. This means that when there is no audio signal or the audio signal amplitude is small, the PWM duty cycle of the H half-bridge output needs to be close to 50%. However, in this application, the power amplifier output signal amplitude is small for most of the time, and the PWM output duty cycle is a relatively small value.

[0051] Please refer to Figure 6 This diagram illustrates the amplitude variation of the inductor current when the PWM duty cycle is 12.5% ​​and 50% according to an embodiment of this application. During the high PWM voltage period, the voltage at one end of the inductor in the filter is the positive power supply voltage, while the other end is close to 0V. The current in the inductor increases with a slope equal to the ratio of the positive power supply voltage to the inductance. As the PWM duty cycle decreases, the time maintained at the positive power supply voltage shortens, and the peak current in the inductor decreases proportionally. When the inductor current flows through the inductor and the switching transistor, a voltage drop and power loss occur due to the DC resistance of the inductor and the on-resistance of the switching transistor, the value of which is... , This is the total resistance value, including DC resistance and on-resistance.

[0052] In summary, compared with existing audio amplifiers, the audio amplifier provided in this application has a smaller PWM duty cycle in static state, which reduces the current flowing through the inductor and the switching transistor, thereby reducing static power loss.

[0053] The embodiments of this application have at least the following technical effects: Traditional audio amplifiers typically use a single power supply (e.g., positive voltage only), which limits the output signal to oscillating between 0 and VDD, restricting the maximum undistorted output amplitude. This solution introduces a negative voltage generation circuit, working in conjunction with a positive voltage power supply to form a bipolar power supply (positive and negative power supply). This allows the half-bridge output to oscillate between positive and negative voltages, significantly expanding the output dynamic range and thus improving the peak output capability and overall fidelity of the audio signal, especially at high volumes or in the low-frequency range. Second, the gate drive unit generates a pulse width modulation signal based on the analog input audio signal. The duty cycle depends not only on the input signal but also dynamically on the positive and negative voltages and the current output feedback. This control strategy effectively suppresses nonlinear distortion caused by power supply fluctuations and load changes, improving total harmonic distortion performance. Specifically, with small-amplitude signals, the negative voltage amplitude is much smaller than the positive voltage amplitude, and under negative feedback, the duty cycle remains at a low value. This results in reduced circuit power consumption and improved circuit efficiency. Third, the negative voltage generation circuit, control algorithm library, gate drive, half-bridge switch, etc. are integrated into a single chip, eliminating the need for an external negative power supply or complex charge pump, thus reducing BOM cost and PCB area. Internal co-design optimizes signal path matching and timing control, reduces EMI interference and parasitic effects, and improves overall system reliability.

[0054] It is understood that the specific examples in this application are only intended to help those skilled in the art better understand the implementation methods of this application, and are not intended to limit the scope of the invention.

[0055] It is understood that the various implementation methods described in this application can be implemented individually or in combination, and the implementation methods in this application are not limited in this respect.

[0056] Unless otherwise stated, all technical and scientific terms used in the embodiments of this application have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "and / or" as used in this application includes any and all combinations of one or more of the associated listed items. The singular forms "a," "the," and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0057] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0058] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0059] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0060] The above are merely specific embodiments of this application, but the scope of protection of this invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this invention should be determined by the scope of the claims.

Claims

1. An audio amplifier chip controlled by analog input, characterized in that, The audio amplifier chip controlled by analog input includes an input port, a control mechanism algorithm library, a voltage generation circuit, a positive voltage power supply, a gate drive unit, and a half-bridge circuit. The control mechanism algorithm library includes a negative voltage control mechanism algorithm, the voltage generation circuit includes a negative voltage generation circuit, and the half-bridge circuit consists of two switching transistors connected in series. The input port is used to receive analog input audio signals; The positive voltage power supply is connected to the input terminal of one of the switching transistors, and the negative voltage generating circuit is connected to the output terminal of the other switching transistor. The negative voltage generating circuit is used to generate negative voltage according to the negative voltage control mechanism algorithm and the analog input audio signal. The gate driving unit is used to generate a pulse width modulation signal based on the analog input audio signal; determine the duty cycle of the pulse width modulation signal based on the voltage output by the positive voltage power supply, the negative voltage, and the output signal of the audio amplifier chip; and apply the pulse width modulation signal with the duty cycle to the gate of the switching transistor.

2. The audio amplifier chip controlled by analog input according to claim 1, characterized in that, The negative voltage generating circuit is used to generate negative voltage according to the negative voltage control mechanism algorithm and the analog input audio signal, including: The negative pressure generating circuit is used to determine the amplitude of the envelope after taking the absolute value of the input audio signal as the envelope amplitude; to determine the candidate negative pressure according to the product of the envelope amplitude, the preset compensation coefficient and the power amplifier gain; and to determine the minimum value between the candidate negative pressure and the preset fixed negative pressure as the negative pressure.

3. The audio amplifier chip controlled by analog input according to claim 2, characterized in that, The preset fixed negative voltage is obtained by converting the output voltage of the positive voltage power supply through a DC-to-DC circuit.

4. The audio amplifier chip controlled by analog input according to claim 2 or 3, characterized in that, The control mechanism algorithm library also includes a positive voltage control mechanism algorithm. The voltage generation circuit includes a positive voltage boost circuit. The positive voltage power supply is connected to the input terminal of one of the switching transistors through the positive voltage boost circuit. The positive voltage boost circuit is used to generate positive voltage according to the positive voltage control mechanism algorithm and the analog input audio signal. The step of determining the duty cycle of the pulse width modulation signal based on the positive voltage output from the positive voltage power supply, the negative voltage, and the voltage corresponding to the output signal of the audio amplifier chip includes: The duty cycle of the pulse width modulation signal is determined based on the voltage corresponding to the positive voltage, the negative voltage, and the output signal of the audio amplifier chip.

5. The audio amplifier chip controlled by analog input according to claim 4, characterized in that, The positive voltage boost circuit is used to generate a positive voltage according to the positive voltage control mechanism algorithm and the analog input audio signal, including: The positive voltage boost circuit is used to determine a candidate positive voltage based on the envelope amplitude, a preset compensation coefficient, and the product of the power amplifier gain; and to determine the maximum value between the candidate positive voltage and the voltage output by the positive voltage power supply as the positive voltage.

6. The audio amplifier chip controlled by analog input according to claim 5, characterized in that, The audio amplifier chip controlled by analog input also includes a configurable delay module. The input port is connected to the gate driving unit through the configurable delay module. The configurable delay module is used to compensate for the delay of the control mechanism algorithm library and the delay of the voltage generation circuit.

7. The audio amplifier chip controlled by analog input according to claim 6, characterized in that, The audio amplifier chip controlled by analog input also includes an output sampling circuit, which is used to acquire the output signal of the audio amplifier chip, and the analog input audio signal is a signal determined based on the output signal of the audio amplifier chip.

8. An audio amplifier, characterized in that, The audio amplifier includes an audio amplifier chip, a filter, and a load controlled by analog input as described in any one of claims 1-7; the audio amplifier chip is connected to a first end of the filter via an output port, the second end of the filter is grounded, the third end of the filter is connected to one end of the load, and the other end of the load is grounded.

9. The audio amplifier according to claim 8, characterized in that, Each output port corresponds to one half-bridge circuit, and the output port is connected to the output terminal of one of the switching transistors and the input terminal of the other switching transistor.

10. The audio amplifier according to claim 9, characterized in that, The output signal of the audio amplifier chip includes the input signal of the filter and / or the output signal of the filter.

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