Circuit for replacing 24V system analog power amplifier with 12V system vehicle-mounted digital power amplifier

Abstract

The invention provides a circuit for replacing a 24V system analog power amplifier with a 12V system vehicle-mounted digital power amplifier. The circuit comprises a dual-mode intelligent power supply system, a digital power amplifier main circuit and an enhanced short-circuit protection system. The dual-mode power supply system reduces the voltage of a 24V power supply to a 12V power supply through the DCDC voltage reduction conversion circuit, and intelligently adjusts the voltage of the power supply in combination with the dynamic voltage monitoring circuit and the dynamic MOS switching module. The digital power amplifier main circuit adopts a digital switch amplification (Class D) technology, and is matched with high-frequency PWM (Pulse Width Modulation) modulation and full-bridge MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) topology, so that the conversion efficiency is greatly improved to more than 90%, and the heat loss and heat dissipation requirements are reduced. The enhanced short-circuit protection system can respond to a power supply short-circuit fault in time and protect the power amplifier from being damaged. Compared with a traditional analog power amplifier, the digital power amplifier replaces analog amplification, dynamic voltage adaptation and DSP dynamic compensation, the problems of high loss, low compatibility, complex maintenance and the like are solved, an efficient, stable and low-power-consumption vehicle-mounted audio solution is provided, and the requirements of new energy vehicles are met.

Description

Technical Field

[0001] The present invention relates to the field of audio engineering, and in particular to a circuit for replacing a 24V system analog power amplifier with a 12V system vehicle-mounted digital power amplifier. Background Art

[0002] Traditional analog power amplifiers use linear amplification circuits (such as BJT or Class AB amplifiers), with efficiencies generally below 50%. A large amount of electrical energy is converted into heat energy, requiring reliance on large heat sinks or forced air cooling systems, resulting in high vehicle space occupancy and increased costs.

[0003] The existing 24V system requires independent development of analog power amplifier circuits and cannot reuse the 12V system design, resulting in repeated hardware development (such as independent power modules and filter circuits). In addition, when directly connected to a 12V power amplifier, the device is easily damaged by transient voltage shocks from the 24V system and short power supply experiments. Summary of the Invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art and propose a circuit in which a 12V system vehicle-mounted digital power amplifier replaces a 24V system analog power amplifier.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a circuit for a 12V system on-board digital power amplifier to replace a 24V system analog power amplifier, characterized in that it includes a dual-mode intelligent power system, a digital power amplifier main circuit, and an enhanced short-circuit protection system; the dual-mode intelligent power system is equipped with a DCDC buck conversion circuit, a dynamic voltage detection circuit, and a dynamic MOS switching 12V module; the dynamic voltage detection circuit is electrically connected to the DCDC buck conversion circuit and the dynamic MOS switching 12V module, respectively; the DCDC buck conversion circuit and the dynamic MOS switching 12V module are both electrically connected to the digital power amplifier main circuit; the digital power amplifier main circuit is electrically connected to the enhanced short-circuit protection system; the enhanced short-circuit protection system quickly responds to a power short circuit fault to protect the audio output end of the digital power amplifier main circuit from damage caused by overvoltage and short circuit.

[0006] Preferably, the DCDC step-down converter circuit includes a DCDC controller U3105, a first capacitor C3149, a second capacitor C3150, a third capacitor C3147, a fourth capacitor C3148, a fifth capacitor C3151, a sixth capacitor C3144, a seventh capacitor C3154, an eighth capacitor C3137, a first resistor R3131, a second resistor R3132, a third resistor R3130, a fourth resistor 3151, a fifth resistor R3145, an upper transistor Q3104, a lower transistor Q3105, and an inductor L3104; one end of the upper transistor Q3104 is electrically connected to BATT; the other end of the upper transistor Q3104 is electrically connected to the DCDC controller U3105. The SW output terminal of the DCDC controller U3105 is electrically connected to the SW output terminal of the DCDC controller U3105; one end of the lower transistor Q3105 is also electrically connected to the SW output terminal of the DCDC controller U3105; one end of the first capacitor C3149 is electrically connected to the SW output terminal of the DCDC controller U3105, and the other end is grounded; one end of the second capacitor C3150 is electrically connected to the SW output terminal of the DCDC controller U3105, and the other end is connected to the electrical connection node of the first capacitor C3149; one end of the third capacitor C3147 is electrically connected to the SW output terminal of the DCDC controller U3105, and the other end is connected to the electrical connection node of the second capacitor C3150; one end of the fourth capacitor C3148 is electrically connected to the DCDC controller U3105. The SW output terminal of the CDC controller U3105 is connected to the electrical connection node of the three capacitors C3147 at the other end; one end of the fifth capacitor C3151 is electrically connected to the SW output terminal of the DCDC controller U3105, and the other end is connected to the electrical connection node of the fourth capacitor C3148; one end of the sixth capacitor C3144 is electrically connected to the SW output terminal of the DCDC controller U3105, and the other end is connected to the electrical connection node of the fifth capacitor C3151; one end of the first resistor R3131 is connected to the EN output terminal of the DCDC controller U3105, and the other end is electrically connected to M_+12V_EN; one end of the second resistor R3132 is electrically connected to the The first resistor R3131 is electrically connected to a node, and the other end is grounded; one end of the third resistor R3130 is electrically connected to the FB output terminal of the DCDC controller U3105, and the other end is electrically connected to a +12V DC voltage source; one end of the fourth resistor 3151 is electrically connected to the electrical connection node of the third resistor R3130, and the other end is grounded; one end of the fifth resistor R3145 is electrically connected to the SW output terminal of the DCDC controller U3105, and the other end is electrically connected to one end of the seventh capacitor C3154, and the other end of the seventh capacitor C3154 is grounded; one end of the eighth capacitor C3137 is electrically connected to the SS output terminal of the DCDC controller U3105, and the other end is grounded;One end of the inductor L3104 is connected to the electrical connection node of the fifth resistor R3145, and the other end is connected to the electrical connection node of the first capacitor C3149.

[0007] Preferably, the dynamic voltage monitoring circuit includes a sixth resistor R3102, a seventh resistor R3215, a first NMOS transistor Q3102, a first diode D3107, a first transistor Q3103, an eighth resistor R3104, a ninth resistor R3114, a tenth resistor R3108, an eleventh resistor R3109, a twelfth resistor R3105, a thirteenth resistor R3119, a second transistor T3101, a ninth capacitor C3120, and a first voltage stabilizing diode D3108; one end of the sixth resistor R3102 is electrically connected to the power input terminal BATT, and the other end is electrically connected to the No. 3 interface of the first NMOS transistor Q3102. , port 2 of the first NMOS transistor Q3102 is electrically connected to the seventh resistor R3215, and the other end of the seventh resistor R3215 is electrically connected to BAT_MCU_AD; port 2 of the first diode D3107 is electrically connected to the electrical connection node of the sixth resistor R3102, and port 1 of the first diode D3107 is electrically connected to port 2 of the first transistor Q3103; port 3 of the first transistor Q3103 is electrically connected to the tenth resistor R3108; the other end of the tenth resistor R3108 is electrically connected to the eleventh resistor R3109 and port 1 of the first NMOS transistor Q3102. The other end of the eleventh resistor R3109 is grounded; the No. 1 interface of the first transistor Q3103 is electrically connected to the ninth resistor R3114; the other end of the ninth resistor R3114 is electrically connected to the No. 3 interface of the second transistor T3101; one end of the eighth resistor R3104 is electrically connected to the No. 1 interface of the first diode D3107 and the No. 2 interface of the first transistor Q3103; the other end is connected to the electrical connection node of the ninth resistor R3114 and the No. 3 interface of the second transistor T3101; the No. 2 interface of the second transistor T3101 is grounded; One end of the thirteenth resistor R3119 is electrically connected to MCU_MON_EN, and the other end is electrically connected to interface No. 1 of the second transistor T3101; one end of the ninth capacitor 3120 is electrically connected to interface No. 1 of the second transistor T3101 and the electrical connection node of the thirteenth resistor R3119, and the other end is grounded; the first voltage-stabilizing diode D3108 is arranged in parallel in the circuit of the tenth resistor R3108 and the eleventh resistor R3109; one end of the twelfth resistor R3105 is grounded, and the other end is electrically connected to interface No. 2 of the first transistor Q3103 and the electrical connection node of the seventh resistor R3215.

[0008] Preferably, the dynamic MOS switching 12V module circuit includes a first TVS protection tube D3102, a second TVS protection tube D3106, a first large current freewheeling diode D3103, a second large current freewheeling diode D3105, a second NMOS tube Q3101, an ideal diode U3101, a tenth capacitor C3101, an eleventh capacitor C3118, a twelfth capacitor C3102, a twelfth capacitor C3104, a fourteenth resistor R3111, a fifteenth resistor R3115 and a second diode D3 101; the first TVS protection tube D3102 and the second TVS protection tube D3106 are arranged in parallel on the power input terminal BATT, and are arranged in the positive and negative directions; the first large current freewheeling diode D3103 and the second large current freewheeling diode D3105 are arranged in parallel beside the parallel pipe of the first TVS protection tube D3102 and the second TVS protection tube D3106; one end of the second NMOS tube Q3101 is electrically connected to the power input terminal BATT, and the other end is electrically connected to the ideal two The GATE terminal on the diode U3101; one end of the tenth capacitor C3101 is electrically connected to the electrical connection node of the power input terminal BATT, and the other end is grounded; one end of the fourteenth resistor R3111 is electrically connected to MCU_DIOOU_EN, and the other end is electrically connected to the EN terminal on the ideal diode U3101; one end of the fifteenth resistor R3115 is electrically connected to the electrical connection node of the fourteenth resistor R3111, and the other end is grounded; the eleventh capacitor C3118 is arranged in parallel with the fifteenth resistor R 3115; the GND terminal on the ideal diode U3101 is grounded; one end of the twelfth capacitor C3104 is electrically connected to the electrical connection node of the power input terminal BATT, and the other end is electrically connected to the VCP terminal on the ideal diode U3101; one end of the twelfth capacitor C3102 is electrically connected to the electrical connection node of the power input terminal BATT, and the other end is grounded; port 2 of the second diode D3101 is electrically connected to the power input terminal BATT, and port 1 is electrically connected to a 12V DC voltage source.

[0009] Preferably, the digital power amplifier main circuit includes a core power amplifier chip U15, a low-pass filter L25, a first main circuit capacitor C432, a first main circuit resistor R299, a second main circuit resistor R300, a third main circuit resistor R322, a fourth main circuit resistor R304, a fifth main circuit resistor R275, and a sixth main circuit resistor R298; the low-pass filter L25 and the first main circuit capacitor C432 are combined to realize a low-pass filter to filter the audio source signal output by the power amplifier; pin 18 of the core power amplifier chip U15 is electrically connected to the first main circuit resistor R299 and the second main circuit resistor R300 respectively; the other end of the first main circuit resistor R299 is electrically connected to the 3.3V VSW terminal; The second main circuit resistor R300 is electrically connected to the AMP_FAULT terminal; the 17th pin of the core power amplifier chip U15 is electrically connected to the third main circuit resistor R322 and the fourth main circuit resistor R304 respectively; the other end of the fourth main circuit resistor R304 is grounded; the other end of the fourth main circuit resistor R304 is electrically connected to the AMP_STB terminal; the 15th pin of the core power amplifier chip U15 is electrically connected to the fifth main circuit resistor R275, and the other end of the fifth main circuit resistor R275 is electrically connected to the MCU_SCL terminal; the 15th pin of the core power amplifier chip U16 is electrically connected to the sixth main circuit resistor R298, and the other end of the sixth main circuit resistor R298 is electrically connected to the MCU_SDA terminal.

[0010] Preferably, the enhanced short-circuit protection system includes a first current limiting resistor R12, a protection system NMOS transistor X2, a second current limiting resistor R10, a third current limiting resistor R11, a protection system diode D2, a protection system first PMOS transistor M1, a protection system second PMOS transistor M3 and a protection system transistor Q1; one end of the first current limiting resistor R12 is electrically connected to the current output end, and the other end is electrically connected to the protection system NMOS transistor X2; the other end of the protection system NMOS transistor X2 is grounded, and the remaining end is electrically connected to the third current limiting resistor R11; the other end of the third current limiting resistor R11 is electrically connected to the second current limiting resistor R10; one end of the protection system diode D2 is electrically connected to the electrical connection node of the third current limiting resistor R11, and the other end is electrically connected to the protection system first PMOS transistor M1; the other end of the protection system first PMOS transistor M1 is electrically connected to the protection system transistor Q1.

[0011] Preferably, the dual-mode intelligent power supply system serves as the entrance to the entire power supply system, is responsible for receiving and introducing external power supply signals, and providing an initial source of power for the vehicle amplifier; the DCDC step-down conversion circuit steps down the introduced 24V power supply signal and converts it into a 12V system, outputting a voltage that meets the working requirements of the digital power amplifier module; the dynamic voltage monitoring circuit monitors the external power input signal in real time, and adjusts the power supply scheme in real time according to the power supply voltage, switching the power supply path; the dynamic MOS switching 12V module is used to realize the function of switching the 12V system to power the digital power amplifier; the digital power amplifier main circuit performs digital amplification processing of the audio signal, and provides high-fidelity audio output for the vehicle amplifier; the enhanced short-circuit protection system responds quickly to a power short-circuit fault, protecting the audio output end of the digital power amplifier main circuit from damage caused by overvoltage and short circuit.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention adopts a digital power amplifier switching amplifier circuit (Class D), replaces analog linear amplification with high-frequency PWM modulation (>500kHz), and combines the full-bridge MOSFET power tube topology to reduce the loss of the transistor in the linear region. The power conversion efficiency is increased from 40%-50% of the traditional analog power amplifier to more than 90%, the heat loss is reduced by 60%, and the heat dissipation demand is reduced (no large heat sink is required). The static current is reduced from the 100mA level of the analog power amplifier to the 10mA level, which adapts to the low power consumption requirements of new energy vehicles and indirectly improves the cruising range. The integrated dynamic voltage identification module (12V / 24V adaptive) and the digital power amplifier circuit design replace the traditional discrete power supply, amplification and filtering circuits. Differential signal transmission + four-layer PCB shielding design: isolates high-frequency switching noise from the audio signal path; DSP dynamic compensation algorithm: the main core processes audio decoding, and the auxiliary core monitors the load impedance in real time and adjusts the PWM parameters. This invention achieves breakthroughs in energy efficiency, sound quality, reliability and cost control by replacing analog power amplifiers with digital power amplifiers, integrating DSP dynamic compensation and intelligent voltage compatibility design. It solves the core pain points of traditional solutions such as high loss, low compatibility and complex maintenance, and provides a cost-effective and highly stable industrial solution for in-vehicle audio systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Flowchart for designing a 12V system digital amplifier to replace a 24V system analog amplifier.

[0014] Figure 2 This is the DCDC step-down conversion circuit diagram of the vehicle digital power amplifier system;

[0015] Figure 3 This is the circuit diagram of dynamic voltage monitoring;

[0016] Figure 4 This is the circuit diagram of the dynamic MOS switching 12V module;

[0017] Figure 5a This is the schematic diagram of the main circuit of the digital power amplifier①;

[0018] Figure 5b This is the schematic diagram of the main circuit of the digital power amplifier;

[0019] Figure 6 This is the circuit diagram of the enhanced short-circuit protection system;

[0020] Figure 101 - Dual-mode intelligent power system; 102 - DCDC step-down converter circuit; 103 - Dynamic voltage detection circuit; 104 - Dynamic MOS switching 12V module; 105 - Digital power amplifier main circuit; 106 - Enhanced short-circuit protection system DETAILED DESCRIPTION

[0021] In order to provide a further understanding of the purpose, structure, features, and functions of the present invention, the present invention is described in detail below with reference to the embodiments.

[0022] Please refer to Figure 1 The present invention provides a circuit for replacing a 24V analog power amplifier with a 12V system on-board digital power amplifier, characterized in that it includes a dual-mode intelligent power system 101, a digital power amplifier main circuit 105, and an enhanced short-circuit protection system 106; the dual-mode intelligent power system 101 is equipped with a DC-DC buck converter circuit 102, a dynamic voltage detection circuit 103, and a dynamic MOS switching 12V module 104; the dynamic voltage detection circuit 103 is electrically connected to the DC-DC buck converter circuit 102 and the dynamic MOS switching 12V module 104, respectively; the DC-DC buck converter circuit 102 and the dynamic MOS switching 12V module 104 are both electrically connected to the digital power amplifier main circuit 105; the digital power amplifier main circuit 105 is electrically connected to the enhanced short-circuit protection system 106; the enhanced short-circuit protection system 106 quickly responds to a power short-circuit fault to protect the audio output terminal of the digital power amplifier main circuit from damage caused by overvoltage and short circuit.

[0023] This invention effectively replaces a 24V analog power amplifier with a 12V system by combining a dual-mode intelligent power supply system, a digital power amplifier main circuit, and an enhanced short-circuit protection system. The dual-mode intelligent power supply system utilizes a DC-DC step-down converter circuit and a dynamic voltage detection circuit to achieve stable voltage regulation and switching, ensuring the normal operation of the power amplifier system with a 12V input. Furthermore, the enhanced short-circuit protection system rapidly responds to power short-circuit faults, preventing damage to the digital power amplifier main circuit from overvoltage short-circuits. This improves system safety and reliability, and extends the service life of the device.

[0024] Preferably, the DCDC step-down converter circuit 102 includes a DCDC controller U3105, a first capacitor C3149, a second capacitor C3150, a third capacitor C3147, a fourth capacitor C3148, a fifth capacitor C3151, a sixth capacitor C3144, a seventh capacitor C3154, an eighth capacitor C3137, a first resistor R3131, a second resistor R3132, a third resistor R3130, a fourth resistor 3151, a fifth resistor R3145, an upper transistor Q3104, a lower transistor Q3105, and an inductor L3104; one end of the upper transistor Q3104 is electrically connected to BATT; the other end of the upper transistor Q3104 is electrically connected to the DCDC Controller U3105 SW output terminal; one end of the lower transistor Q3105 is also electrically connected to the SW output terminal of the DCDC controller U3105; one end of the first capacitor C3149 is electrically connected to the SW output terminal of the DCDC controller U3105, and the other end is grounded; one end of the second capacitor C3150 is electrically connected to the SW output terminal of the DCDC controller U3105, and the other end is connected to the electrical connection node of the first capacitor C3149; one end of the third capacitor C3147 is electrically connected to the SW output terminal of the DCDC controller U3105, and the other end is connected to the electrical connection node of the second capacitor C3150; one end of the fourth capacitor C3148 is electrically connected The SW output terminal of the DCDC controller U3105 is connected to the SW output terminal, and the other end is connected to the electrical connection node of the three capacitors C3147; one end of the fifth capacitor C3151 is electrically connected to the SW output terminal of the DCDC controller U3105, and the other end is connected to the electrical connection node of the fourth capacitor C3148; one end of the sixth capacitor C3144 is electrically connected to the SW output terminal of the DCDC controller U3105, and the other end is connected to the electrical connection node of the fifth capacitor C3151; one end of the first resistor R3131 is connected to the EN output terminal of the DCDC controller U3105, and the other end is electrically connected to M_+12V_EN; one end of the second resistor R3132 is electrically connected to the The first resistor R3131 is electrically connected to a node, and the other end is grounded. One end of the third resistor R3130 is electrically connected to the FB output terminal of the DCDC controller U3105, and the other end is electrically connected to a +12V DC voltage source. One end of the fourth resistor 3151 is electrically connected to the electrical connection node of the third resistor R3130, and the other end is grounded. One end of the fifth resistor R3145 is electrically connected to the SW output terminal of the DCDC controller U3105, and the other end is electrically connected to one end of a seventh capacitor C3154. The other end of the seventh capacitor C3154 is grounded. One end of the eighth capacitor C3137 is electrically connected to the SS output terminal of the DCDC controller U3105, and the other end is grounded.One end of the inductor L3104 is connected to the electrical connection node of the fifth resistor R3145, and the other end is connected to the electrical connection node of the first capacitor C3149.

[0025] The combined design of multiple capacitors and resistors ensures smooth current transmission and effective noise suppression, while also optimizing power supply filtering and reducing system power consumption and heat generation. The rational combination of upper and lower transistors improves switching efficiency, ensuring stable operation of the 12V system under varying load conditions. Furthermore, the combination of inductors and capacitors helps achieve higher current conversion efficiency, thereby improving the reliability and response speed of the entire circuit, ensuring that the system maintains high efficiency and stability during the voltage conversion process. This overall design improves the performance of the power supply system, enhances anti-interference capabilities, and further ensures the safety and reliability of the digital power amplifier circuit.

[0026] The core of the DC-DC step-down circuit is the JWQ6346QFNAC#TR DCDC controller U3105, which is responsible for stepping down the 24V input voltage to ensure a stable 12V DC output. This design ensures that the in-vehicle digital power amplifier system receives a stable power supply in various voltage environments, thus ensuring normal operation and optimal performance.

[0027] Capacitors such as C3149, C3150, C3147 (all 22uF, 10%, 1210), C3148 (100nF, 50V, 10%, 0603), C3151 (1nF, 50V, 0603), and C3144 (100uF, 50V, 20%) provide a short-term energy buffer during load fluctuations, ensuring a stable power supply even under transient demands. The energy storage and filtering functions of these capacitors are crucial to improving the stability and reliability of the power supply.

[0028] This circuit design utilizes a two-NMOS switch design at the power supply output: the Q3104 top tube and the Q3105 bottom tube. Under MCU control, this switch combination allows flexible power delivery to downstream loads. Simultaneously, R3155 limits the output current, ensuring power supply safety and stability. Furthermore, R3131 (10K) and R3132 (47K) combine to provide voltage division and current limiting, while R3130 (93.1K) and R3151 (6.2K) precisely control the output voltage to 12V via feedback calculation from U3105's FB pin 5.

[0029] Furthermore, R3145 (51R) and C3154 (33pF) form a wave-absorbing circuit that suppresses power supply overpulses, effectively protecting other components in the circuit. L3104 (4.7uH, 20%, 10A), an output power inductor, significantly suppresses power supply ripple, further enhancing the stability and reliability of the power supply.

[0030] In addition, C3137 (33nF, 50V, 0603) is connected to pin 3 of U3105. Its main function is to soft-start the power supply. It allows the power supply to rise and fall more smoothly during startup, thus avoiding damage to the circuit caused by sudden high current surges.

[0031] In summary, this 24V to 12V DC-DC buck converter circuit, through efficient design and control, provides a stable and reliable 12V power supply for the in-vehicle digital amplifier system. This not only meets the stable power requirements of in-vehicle equipment but also enhances system stability and safety through innovative circuit design.

[0032] Preferably, the dynamic voltage monitoring circuit 103 includes a sixth resistor R3102, a seventh resistor R3215, a first NMOS transistor Q3102, a first diode D3107, a first transistor Q3103, an eighth resistor R3104, a ninth resistor R3114, a tenth resistor R3108, an eleventh resistor R3109, a twelfth resistor R3105, a thirteenth resistor R3119, a second transistor T3101, a ninth capacitor C3120, and a first voltage stabilizing diode D3108; one end of the sixth resistor R3102 is electrically connected to the power input terminal BATT, and the other end is electrically connected to the 3rd terminal of the first NMOS transistor Q3102. Interface, interface No. 2 of the first NMOS tube Q3102 is electrically connected to the seventh resistor R3215, and the other end of the seventh resistor R3215 is electrically connected to BAT_MCU_AD; interface No. 2 of the first diode D3107 is electrically connected to the electrical connection node of the sixth resistor R3102, and interface No. 1 of the first diode D3107 is electrically connected to interface No. 2 of the first transistor Q3103; interface No. 3 of the first transistor Q3103 is electrically connected to the tenth resistor R3108; the other end of the tenth resistor R3108 is electrically connected to the eleventh resistor R3109 and interface No. 1 of the first NMOS tube Q3102. The electrical connection node of the interface; the other end of the eleventh resistor R3109 is grounded; the No. 1 interface of the first transistor Q3103 is electrically connected to the ninth resistor R3114; the other end of the ninth resistor R3114 is electrically connected to the No. 3 interface of the second transistor T3101; one end of the eighth resistor R3104 is electrically connected to the No. 1 interface of the first diode D3107 and the No. 2 interface of the first transistor Q3103; the other end is connected to the electrical connection node of the ninth resistor R3114 and the No. 3 interface of the second transistor T3101; the No. 2 interface of the second transistor T3101 is grounded; One end of the thirteenth resistor R3119 is electrically connected to MCU_MON_EN, and the other end is electrically connected to interface No. 1 of the second transistor T3101; one end of the ninth capacitor 3120 is electrically connected to interface No. 1 of the second transistor T3101 and the electrical connection node of the thirteenth resistor R3119, and the other end is grounded; the first voltage-stabilizing diode D3108 is arranged in parallel in the circuit of the tenth resistor R3108 and the eleventh resistor R3109; one end of the twelfth resistor R3105 is grounded, and the other end is electrically connected to interface No. 2 of the first transistor Q3103 and the electrical connection node of the seventh resistor R3215.

[0033] The design of the dynamic voltage monitoring circuit in the present invention can monitor the voltage changes of the power input terminal BATT in real time through the combination of precise resistors, capacitors, diodes and transistors, and ensure the stability and safety of the circuit through accurate current and voltage feedback mechanisms. The cooperation of the first NMOS tube and the multi-stage transistor can achieve a rapid response to voltage fluctuations and ensure timely protection of the power supply system in overvoltage or undervoltage conditions. The parallel setting of the voltage-stabilizing diode improves the anti-interference ability of the circuit, so that the system can still work stably in a complex electrical environment. In addition, the use of capacitors effectively smoothes voltage fluctuations, improves the noise suppression ability of the system, and ensures the accuracy and reliability of monitoring. Overall, this design improves the response speed, accuracy and system stability of voltage monitoring, and has strong application value.

[0034] Among them, BATT serves as the power input terminal, providing initial power for the entire circuit.

[0035] The D3107 (TRB751W-40) diode is connected in series between the power input and the circuit. Its main function is to prevent voltage backflow, thereby protecting other components in the circuit from damage.

[0036] D3108 (BZX84C16) is a voltage stabilizing diode connected in parallel in the circuit with a voltage stabilization value of 16 V. It is used to limit the maximum voltage on the gate of Q3102 to prevent damage to the NMOS tube due to excessive gate voltage.

[0037] Resistors R3104 (47K, 5%) and R3114 (10K, 5%) are connected in series and then grounded to form a voltage divider circuit. This voltage divider circuit is used to adjust the voltage applied to the base of transistor Q3103, ensuring that Q3103 can be turned on or off under appropriate conditions.

[0038] The base of transistor Q3103 (MMBT3906) is connected to the aforementioned voltage divider circuit, and the emitter is grounded. When the MCU pin MCU_MON_EN turns on transistor T3101 (DDTC114YCAQ-7-F), the base potential of Q3103 is lower than the emitter potential, turning on Q3103.

[0039] Q3102 (BSS138WQ-7-F) is an NMOS transistor. Its gate is connected to the power supply through two resistors, R3102 (56K, 0.5%) and R3105 (5.6K, 0.5%), which divide the voltage. When Q3103 turns on, the gate-source voltage VGS of Q3102 meets the turn-on condition, turning on Q3102.

[0040] When Q3102 is turned on, the voltage difference between its drain and source will be monitored and input to the MCU end (BAT_MCU_AD) after AD conversion, so that the MCU can monitor the power supply voltage in real time.

[0041] Under normal circumstances, the MCU controls the conduction state of transistor T3101 through the MCU_MON_EN pin, which in turn controls the base potential of transistor Q3103. When Q3103 is turned on, the NMOS transistor Q3102 is also turned on, and the divided value of the power supply voltage is input to the MCU for monitoring.

[0042] When the power supply voltage is abnormal (such as falling below the set threshold), the MCU will take corresponding measures, such as switching to the backup power supply, to ensure stable operation of the system.

[0043] Preferably, the dynamic MOS switching 12V module circuit 104 includes a first TVS protection tube D3102, a second TVS protection tube D3106, a first large current freewheeling diode D3103, a second large current freewheeling diode D3105, a second NMOS tube Q3101, an ideal diode U3101, a tenth capacitor C3101, an eleventh capacitor C3118, a twelfth capacitor C3102, a twelfth capacitor C3104, a fourteenth resistor R3111, a fifteenth resistor R3115 and a second diode The first TVS protection tube D3102 and the second TVS protection tube D3106 are arranged in parallel on the power input terminal BATT, and are arranged in the positive and negative directions; the first large current freewheeling diode D3103 and the second large current freewheeling diode D3105 are arranged in parallel beside the parallel pipe of the first TVS protection tube D3102 and the second TVS protection tube D3106; one end of the second NMOS tube Q3101 is electrically connected to the power input terminal BATT, and the other end is electrically connected to the power input terminal BATT. The GATE terminal on the ideal diode U3101; one end of the tenth capacitor C3101 is electrically connected to the electrical connection node of the power input terminal BATT, and the other end is grounded; one end of the fourteenth resistor R3111 is electrically connected to MCU_DIOOU_EN, and the other end is electrically connected to the EN terminal on the ideal diode U3101; one end of the fifteenth resistor R3115 is electrically connected to the electrical connection node of the fourteenth resistor R3111, and the other end is grounded; the eleventh capacitor C3118 is arranged in parallel with the fifteenth resistor The GND terminal on the ideal diode U3101 is grounded; one end of the twelfth capacitor C3104 is electrically connected to the electrical connection node of the power input terminal BATT, and the other end is electrically connected to the VCP terminal on the ideal diode U3101; one end of the twelfth capacitor C3102 is electrically connected to the electrical connection node of the power input terminal BATT, and the other end is grounded; the 2nd port of the second diode D3101 is electrically connected to the power input terminal BATT, and the 1st port is electrically connected to the 12V DC voltage source.

[0044] This dynamic MOS switching 12V module circuit utilizes carefully designed protection and filtering measures to effectively enhance circuit stability and anti-interference capabilities. The parallel configuration of the first and second TVS protection diodes at the power input quickly suppresses voltage spikes, protecting the circuit from overvoltage damage. The parallel configuration of high-current freewheeling diodes enhances the freewheeling capability, ensuring stable operation under high loads. The coordinated operation of the ideal diode and NMOS transistor effectively controls the switching of the power supply and the flow of current, improving power supply efficiency and response speed. Furthermore, the coordinated design of multiple capacitors and resistors optimizes the circuit's filtering and voltage regulation capabilities, ensuring smooth power output, reducing electromagnetic interference and noise, and enhancing the module's overall reliability and service life.

[0045] The dynamic MOS switching 12V module circuit primarily implements intelligent power switching and transient protection for the vehicle's 12V system, ensuring the stability and safety of the digital amplifier's power supply. The core circuit consists of a TVS transient protection module, a dynamic MOS switching module, and filtering and anti-reverse protection modules.

[0046] D3106 (ASC36CA) and D3102 (SMBJ28AQ-13-F): Serving as forward and reverse TVS protection diodes, connected in parallel at the BATT power input, they clamp transient pulse voltages to safe levels (e.g., 28V). For example, during a vehicle cold start or load dump, the TVS diode absorbs transient energy through a fast response (nanoseconds), preventing the high-voltage pulse from damaging subsequent circuits.

[0047] D3103 and D3105 (MBRS3200T3G): Acting as high-current freewheeling diodes, they are connected in parallel to bypass the TVS diode. When transient pulse currents exceed the TVS diode's withstand capability, the diodes provide a low-impedance path, diverting most of the current, preventing damage to the TVS diode due to overcurrent and reducing the risk of circuit overheating.

[0048] The Q3101 (NVMFS5C673NLT1G NMOS) and U3101 (AP74700QW6-7 ideal diode) form the dynamic switching core. When the MCU detects a 12V system connection, the following logic is used to achieve seamless switching.

[0049] M_+12V_EN pin: Sends a signal to shut down the U3105 DCDC buck converter chip, cutting off the original power supply path.

[0050] MCU_DIODE_EN pin: enables the U3101 ideal diode and drives the Q3101NMOS to turn on.

[0051] After being turned on, Q3101 directly transmits the BATT power supply to the digital power amplifier module, replacing the DCDC conversion path, reducing energy loss and improving response speed.

[0052] R3111 (1kΩ, 5%) and R3115 (100kΩ, 5%): Precisely control the enable threshold of the U3101 ideal diode through the voltage divider network to ensure the stability of the switching logic.

[0053] C3101 and C3102 (100nF, 100V, 0805): Serving as high-frequency filter capacitors, they suppress power supply ripple, smooth input voltage fluctuations, and ensure that the high-fidelity audio signal of the digital power amplifier is not interfered with.

[0054] D3101 (SBR1U200P1Q-7): connected in series at the output end of the DCDC step-down converter circuit, using its low forward voltage drop (0.5V) to prevent the output voltage from flowing back to the Q3101 NMOS and U3101 ideal diode, thereby avoiding reverse conduction damage to the components.

[0055] Among them, when the 12V system is connected, the MCU quickly shuts down the DCDC converter through logic control and turns on the dynamic MOS path, achieving seamless switching of the power supply path and avoiding audio distortion or system downtime caused by power interruption in the digital amplifier.

[0056] The TVS tube and freewheeling diode work together to suppress transient overvoltage, the NMOS and ideal diode combination reduces conduction loss, and the anti-reverse diode and filter capacitor ensure power supply cleanliness, comprehensively improving system reliability.

[0057] Preferably, the digital power amplifier main circuit 105 includes a core power amplifier chip U15, a low-pass filter L25, a first main circuit capacitor C432, a first main circuit resistor R299, a second main circuit resistor R300, a third main circuit resistor R322, a fourth main circuit resistor R304, a fifth main circuit resistor R275, and a sixth main circuit resistor R298; the low-pass filter L25 and the first main circuit capacitor C432 are combined to realize a low-pass filter to filter the audio source signal output by the power amplifier; the 18th pin of the core power amplifier chip U15 is electrically connected to the first main circuit resistor R299 and the second main circuit resistor R300 respectively; the other end of the first main circuit resistor R299 is electrically connected to the 3.3V VSW end; the second main circuit resistor R300 is electrically connected to the AMP_FAULT end; the 17th pin of the core power amplifier chip U15 is electrically connected to the third main circuit resistor R322 and the fourth main circuit resistor R304 respectively; the other end of the fourth main circuit resistor R304 is grounded; the other end of the fourth main circuit resistor R304 is electrically connected to the AMP_STB end; the 15th pin of the core power amplifier chip U15 is electrically connected to the fifth main circuit resistor R275, and the other end of the fifth main circuit resistor R275 is electrically connected to the MCU_SCL end; the 15th pin of the core power amplifier chip U16 is electrically connected to the sixth main circuit resistor R298, and the other end of the sixth main circuit resistor R298 is electrically connected to the MCU_SDA end.

[0058] This digital amplifier main circuit design optimizes the performance of the power amplifier chip U15 by precisely configuring the various resistors, capacitors, and filters. The combination of low-pass filter L25 and the first main circuit capacitor C432 effectively filters the audio signal output by the power amplifier, reducing high-frequency noise and improving sound quality. The precise selection and reasonable connection of resistors (such as R299, R300, R322, R304, etc.) ensure the voltage stability and protection functions of the chip's various functional ports, such as fault detection at the AMP_FAULT terminal and startup control at the AMP_STB terminal. In addition, the connection between the MCU_SCL and MCU_SDA terminals ensures stable communication with the microcontroller through the fifth and sixth resistors R275 and R298, facilitating system control and debugging. The overall design optimizes the operating stability of the power amplifier circuit, audio quality, and system reliability, thereby improving product performance.

[0059] The main circuit of the digital amplifier uses TI's TPA6304QDDVRQ1 as the core amplifier chip. This is a CLASSD digital amplifier that supports four-channel analog audio source input and four-channel audio source output, and can meet the processing requirements of the car audio system for multi-channel audio signals.

[0060] The input power supply voltage of the TPA6304QDDVRQ1 power amplifier chip is 12V, which is suitable for the low-voltage power supply environment of the vehicle system.

[0061] The output end uses a low-pass filter through an LC component combination (L25 3.3UH, 5.2A and C4321uF, 50V, 1206, 10%) to filter the audio signal output by the power amplifier.

[0062] This filter can effectively suppress high-frequency interference and improve sound quality indicators such as total harmonic distortion plus noise (THD+N) and signal-to-noise ratio (SNR), making the sound quality of the car audio system purer and clearer.

[0063] When the system detects a bus fault, it will report the fault via R299 and 300 (97k, 0402) through pin 18 of U15.

[0064] Furthermore, the power amplifier is designed with a bus fault recognition function. Once a fault is triggered, the system will quickly decide to shut down the power amplifier circuit to protect the power amplifier and audio system from damage.

[0065] The power amplifier status can be controlled through the AMP_STB pin of the MCU through the voltage divider circuit of R322 (0Ω, 0402) and R30 (47k, 0402).

[0066] When needed, the amplifier can be put into sleep mode to reduce power consumption and extend service life.

[0067] The power amplifier chip communicates with external slave devices via the I2C bus through R275 and R298 (0Ω) to achieve analysis and control of the power amplifier status.

[0068] This enables the amplifier to work in conjunction with other car audio system components to achieve more complex audio processing and control functions.

[0069] The design also includes multiple heat dissipation components (such as thermistors and heat sinks) to ensure that the power amplifier maintains a stable temperature during operation to avoid performance degradation or damage due to overheating.

[0070] The TPA6304QDDVRQ1 power amplifier chip is known for its high efficiency and can provide high-fidelity audio output at low power consumption, meeting the dual requirements of car audio systems for sound quality and energy efficiency.

[0071] In summary, the design of the digital amplifier main circuit fully considers the particularity of the in-vehicle environment and the sound quality requirements. Through efficient CLASSD digital amplifier chips, low-pass filters, bus fault identification, amplifier status control, and I2C communication modules, it replaces the 24V analog amplifier and improves the sound quality, efficiency, stability, and reliability.

[0072] Preferably, the enhanced short-circuit protection system 106 includes a first current limiting resistor R12, a protection system NMOS transistor X2, a second current limiting resistor R10, a third current limiting resistor R11, a protection system diode D2, a protection system first PMOS transistor M1, a protection system second PMOS transistor M3 and a protection system transistor Q1; one end of the first current limiting resistor R12 is electrically connected to the current output end, and the other end is electrically connected to the protection system NMOS transistor X2; the other end of the protection system NMOS transistor X2 is grounded, and the remaining end is electrically connected to the third current limiting resistor R11; the other end of the third current limiting resistor R11 is electrically connected to the second current limiting resistor R10; one end of the protection system diode D2 is electrically connected to the electrical connection node of the third current limiting resistor R11, and the other end is electrically connected to the protection system first PMOS transistor M1; the other end of the protection system first PMOS transistor M1 is electrically connected to the protection system transistor Q1.

[0073] The enhanced short-circuit protection system provides effective short-circuit protection through precise current-limiting resistor and transistor configuration. The first current-limiting resistor R12 and the second and third current-limiting resistors R10 and R11 jointly limit the current to prevent overload current from damaging the circuit. The combination of the protection system NMOS transistor X2 and the current-limiting resistor helps to quickly respond to current overloads and trigger the protection mechanism. At the same time, the linkage between the protection system diode D2 and the PMOS transistor M1 ensures that the current path can be quickly cut off when a short circuit occurs, protecting subsequent circuit components from damage. The design of the PMOS transistor M1 and the triode Q1 further enhances the response speed and stability of the protection circuit, improves the reliability and short-circuit resistance of the system, and effectively prevents power supply damage and equipment failure.

[0074] When a 12V system digital amplifier is in operation, current first flows through the 1K current-limiting resistor R12, connecting to the terminals of NMOS transistor X2. X2 is then turned on and connected to ground. The current is then divided by resistors R10 (200K) and R11 (20K). This divided voltage passes through diode D2, causing the gate of PMOS transistor M1 to reach a low potential. Because M1's drain is connected to 12V, the high voltage is transmitted to the MOS transistor's source through the body diode. The resulting voltage difference with the gate is greater than M1's VGS turn-on voltage, turning M1 on. M1's internal resistance RDS(on) is extremely low, less than 0.005Ω. This ensures that the output voltage is very close to the input source voltage, resulting in an extremely low voltage drop. This effectively reduces sound source loss and ensures output sound quality.

[0075] The situation changes when a 32V short circuit is applied to the output. The additional voltage flows through the combination of transistor Q1 and PMOS transistor M3, causing the shorted power supply to flow directly to the gate of M1. At this point, the VGS voltage drop across M1 is lower than its turn-on voltage, causing M1 to rapidly shut down. The reverse-blocking characteristics of the PMOS diode cut off the shorted power supply, preventing it from flowing to the amplifier's audio output. This protection mechanism, with a response time of less than 1ns, quickly prevents damage to the amplifier caused by a short circuit.

[0076] When the short circuit disappears, the M1 tube is turned on again and the system can quickly resume normal audio output. This design ensures that the power amplifier can protect itself when facing abnormal conditions such as short circuits, and can quickly resume normal operation after the abnormality is eliminated.

[0077] In summary, this enhanced short-circuit protection system effectively protects the 12V system digital amplifier from damage caused by abnormal conditions such as short circuits through a carefully designed circuit layout and a fast response mechanism, while ensuring the amplifier's efficient, stable operation and sound quality under normal working conditions.

[0078] Preferably, the dual-mode intelligent power supply system serves as the entrance to the entire power supply system, responsible for receiving and introducing external power signals to provide an initial source of power for the vehicle amplifier; the DCDC step-down conversion circuit 102 steps down the introduced 24V power supply signal to a 12V system, and outputs a voltage that meets the working requirements of the digital amplifier module; the dynamic voltage monitoring circuit 103 monitors the external power input signal in real time, and adjusts the power supply scheme in real time according to the power supply voltage, switching the power supply path; the dynamic MOS switching 12V module 104 is used to realize the function of switching the 12V system to power the digital amplifier; the digital amplifier main circuit 105 performs digital amplification processing of the audio signal to provide high-fidelity audio output for the vehicle amplifier; the enhanced short-circuit protection system 106 responds quickly to a power short-circuit fault, protecting the audio output end of the digital amplifier main circuit from damage caused by overvoltage and short circuit.

[0079] Furthermore, in the DCDC step-down conversion module: a synchronous Buck circuit (JWQ6346QFNAC) is used, the input voltage range covers 6V to 75V, the output constant voltage is 12V, and the efficiency is ≥93% (under peak load).

[0080] Dynamic MOS switching module: A low-resistance N-channel MOS transistor (such as NVMFS5C673NLT1G, RDS(on) = 9.2Ω) is configured in parallel, and the power supply type is determined in real time through a voltage detection circuit:

[0081] When the power supply is 24V: the DCDC step-down circuit works, the MOS tube is turned off, and the output is stable at 12V;

[0082] When powered by 12V: the DCDC circuit is turned off and the MOS tube is turned on instantaneously (switching delay <10ms) to reduce power loss.

[0083] Furthermore, in the main circuit of the digital power amplifier: a Class D power amplifier architecture (such as TAS6424QDDVRQ1) is used, supporting 4×50W output, an operating frequency of 500kHz, and an LC filter (L=3.3μH, C=1μF) to suppress high-frequency noise;

[0084] The input stage integrates differential signal conditioning circuitry and is compatible with analog / digital audio inputs.

[0085] Furthermore, in the enhanced short-circuit protection system, the MOS switch protection array: a low-resistance PMOS tube is connected in series at the output of the power amplifier. Under normal operation, the on-resistance is less than 2mΩ and the signal distortion rate is less than 0.05%;

[0086] Voltage monitoring and fast shutdown:

[0087] The output voltage is sampled in real time, and the conduction and shutdown of the transistor are controlled by the resistor divider at the lower end. The chain reaction triggers the protection, and the gate voltage of the MOS tube is increased to the short-circuit power supply voltage. The external high voltage is blocked from reversely flowing into the power amplifier chip by utilizing the turn-on condition lower than VGS and the reverse cut-off characteristics of the body diode (reverse withstand voltage ≥40V).

[0088] Example 1:

[0089] Traditional analog power amplifiers have low energy efficiency and insufficient thermal management:

[0090] Technical issues:

[0091] Traditional analog power amplifiers use linear amplification circuits (such as BJT or Class AB amplifiers), with efficiencies generally below 50%. A large amount of electrical energy is converted into heat energy, requiring reliance on large heat sinks or forced air cooling systems, resulting in high vehicle space occupancy and increased costs.

[0092] Corresponding solutions:

[0093] The present invention adopts digital power amplifier technology (Class D switching amplification) to convert audio signals into high-frequency pulses through PWM modulation. The power MOS tube amplifies in switching mode, increasing efficiency to over 90% and reducing heat loss by 50%. It does not require a complex heat dissipation structure and is suitable for the compact space in the vehicle.

[0094] Example 2:

[0095] Poor voltage compatibility and hardware redundancy:

[0096] Technical issues:

[0097] The existing 24V system requires independent development of analog power amplifier circuits and cannot reuse the 12V system design, resulting in repeated hardware development (such as independent power modules and filter circuits). In addition, when directly connected to a 12V power amplifier, the device is easily damaged by transient voltage shocks from the 24V system and short power supply experiments.

[0098] Corresponding solutions:

[0099] Dynamic voltage monitoring + DC-DC dynamic voltage reduction supports 12V / 24V dual-mode automatic switching. The wide voltage input design (9-36V) is compatible with different vehicle models, avoiding independent circuit development, deploying hardware-level fast shutdown, and adding short-power protection circuit to resist amplifier damage caused by the short-power test standard of the 24V system.

[0100] Example 3:

[0101] Size and cost limitations:

[0102] Technical issues:

[0103] Analog power amplifiers require large LC filter circuits and heat sinks, which take up a lot of space.

[0104] Corresponding solutions:

[0105] Through modular design (power supply, DSP, digital power amplifier), the number of discrete components is reduced, the overall volume is reduced by 50%, and the cost is reduced by 50% compared to traditional analog power amplifiers.

[0106] Example 4:

[0107] Electromagnetic Interference (EMI) and Sound Quality Degradation

[0108] Technical issues:

[0109] Analog power amplifiers are prone to electromagnetic noise (such as conducted interference affecting the vehicle's CAN bus) due to the wide bandwidth of their linear amplification circuits, and the analog filter circuit design is complex. Although digital power amplifiers suppress low-frequency noise through PWM modulation, the insufficient precision of early DSP processing leads to harmonic distortion (THD>0.1%).

[0110] Corresponding solutions:

[0111] The DSP architecture (for processing audio signals) is combined with differential transmission and a four-layer PCB shielding design to increase the signal-to-noise ratio (SNR) to >100dB and reduce THD to <0.05%. High-frequency modulation (>500kHz) is also used to avoid conflicts with vehicle communication bands.

[0112] Embodiment 5:

[0113] Protection mechanism response delay and irreversible damage:

[0114] Technical issues:

[0115] Traditional overvoltage protection relies on fuses (response time > 1ms) or varistors, which cannot quickly suppress transient pulses and short power supply experiments, and require manual replacement after the fuse is blown; the digital power amplifier software protection algorithm has difficulty capturing high-frequency fault signals due to its low sampling rate (<50kHz).

[0116] Corresponding solutions:

[0117] Deploy hardware-level fast shutdown (intelligent MOS tube control) to achieve multi-level transient protection (overvoltage, short circuit), support fault self-recovery, and improve device reliability by 60%.

[0118] Example 6:

[0119] System working principle:

[0120] S1: Power compatibility implementation process:

[0121] Input voltage detection: The voltage monitoring circuit continuously samples the supply voltage (VIN):

[0122] When VIN>15V, it is determined to be a 24V system, the DCDC step-down module is started, and the MOS tube remains turned off;

[0123] When VIN≤15V, it is determined to be a 12V system, the DCDC module is turned off, the MOS tube is turned on, and the 12V power supply is directly transmitted.

[0124] Seamless switching mechanism: To prevent voltage drops, a 3ms overlap period is set between the DCDC module and the MOS tube switching, and a smooth transition is achieved through a soft-start circuit (RC time constant τ = 5ms).

[0125] S2: Short circuit protection working process:

[0126] Normal output state: MOS switch is turned on, and the amplifier output signal is transmitted to the speaker through a low-impedance path;

[0127] Short circuit event trigger: When the output terminal is accidentally shorted to the 32V external power supply:

[0128] The differential sampling circuit detects an abnormal voltage at the output terminal;

[0129] The comparator outputs a trigger signal to the drive circuit within 1μs;

[0130] The MOS tube gate voltage is raised to the short-circuit power supply voltage, and the channel is turned off;

[0131] The external high voltage is reversely cut off through the MOS tube body diode, and the power amplifier chip is electrically isolated from the short-circuit point;

[0132] The fault is locked until the system is reset.

[0133] The present invention has been described with reference to the above embodiments. However, the above embodiments are merely exemplary embodiments of the present invention. It should be noted that the disclosed embodiments do not limit the scope of the present invention. On the contrary, modifications and improvements that do not depart from the spirit and scope of the present invention are intended to be protected by the present invention.

Claims

1. A circuit for replacing a 24V system analog power amplifier with a 12V system vehicle-mounted digital power amplifier, characterized by: The invention comprises a dual-mode intelligent power supply system (101), a digital power amplifier main circuit (105) and an enhanced short-circuit protection system (106); the dual-mode intelligent power supply system (101) is provided with a DCDC buck conversion circuit (102), a dynamic voltage detection circuit (103) and a dynamic MOS switching 12V module (104); the dynamic voltage detection circuit (103) is electrically connected to the DCDC buck conversion circuit (102) and the dynamic MOS switching 12V module (104) respectively; the DCDC buck conversion circuit (102) and the dynamic MOS switching 12V module (104) are both electrically connected to the digital power amplifier main circuit (105); the digital power amplifier main circuit (105) is electrically connected to the enhanced short-circuit protection system (106); the enhanced short-circuit protection system (106) quickly responds to a power short-circuit fault to protect the audio output end of the digital power amplifier main circuit from damage caused by overvoltage short circuit.

2. The circuit for replacing a 24V system analog power amplifier with a 12V system vehicle-mounted digital power amplifier as claimed in claim 1, characterized in that: The DCDC step-down converter circuit (102) includes a DCDC controller U3105, a first capacitor C3149, a second capacitor C3150, a third capacitor C3147, a fourth capacitor C3148, a fifth capacitor C3151, a sixth capacitor C3144, a seventh capacitor C3154, an eighth capacitor C3137, a first resistor R3131, a second resistor R3132, a third resistor R3130, a fourth resistor 3151, a fifth resistor R3145, an upper transistor Q3104, a lower transistor Q3105, and an inductor L3104; one end of the upper transistor Q3104 is electrically connected to BATT; the other end of the upper transistor Q3104 is electrically connected to the DCDC controller U3105. The SW output terminal of the DCDC controller U3105 is electrically connected to the SW output terminal of the DCDC controller U3105; one end of the lower transistor Q3105 is also electrically connected to the SW output terminal of the DCDC controller U3105; one end of the first capacitor C3149 is electrically connected to the SW output terminal of the DCDC controller U3105, and the other end is grounded; one end of the second capacitor C3150 is electrically connected to the SW output terminal of the DCDC controller U3105, and the other end is connected to the electrical connection node of the first capacitor C3149; one end of the third capacitor C3147 is electrically connected to the SW output terminal of the DCDC controller U3105, and the other end is connected to the electrical connection node of the second capacitor C3150; one end of the fourth capacitor C3148 is electrically connected to the DCDC controller U3105. The SW output terminal of the CDC controller U3105 is connected to the electrical connection node of the three capacitors C3147 at the other end; one end of the fifth capacitor C3151 is electrically connected to the SW output terminal of the DCDC controller U3105, and the other end is connected to the electrical connection node of the fourth capacitor C3148; one end of the sixth capacitor C3144 is electrically connected to the SW output terminal of the DCDC controller U3105, and the other end is connected to the electrical connection node of the fifth capacitor C3151; one end of the first resistor R3131 is connected to the EN output terminal of the DCDC controller U3105, and the other end is electrically connected to M_+12V_EN; one end of the second resistor R3132 is electrically connected to the The first resistor R3131 is electrically connected to a node, and the other end is grounded; one end of the third resistor R3130 is electrically connected to the FB output terminal of the DCDC controller U3105, and the other end is electrically connected to a +12V DC voltage source; one end of the fourth resistor 3151 is electrically connected to the electrical connection node of the third resistor R3130, and the other end is grounded; one end of the fifth resistor R3145 is electrically connected to the SW output terminal of the DCDC controller U3105, and the other end is electrically connected to one end of the seventh capacitor C3154, and the other end of the seventh capacitor C3154 is grounded; one end of the eighth capacitor C3137 is electrically connected to the SS output terminal of the DCDC controller U3105, and the other end is grounded;One end of the inductor L3104 is connected to the electrical connection node of the fifth resistor R3145, and the other end is connected to the electrical connection node of the first capacitor C3149.

3. The circuit for replacing a 24V system analog power amplifier with a 12V system vehicle-mounted digital power amplifier as claimed in claim 1, characterized in that: The dynamic voltage monitoring circuit includes a sixth resistor R3102, a seventh resistor R3215, a first NMOS transistor Q3102, a first diode D3107, a first transistor Q3103, an eighth resistor R3104, a ninth resistor R3114, a tenth resistor R3108, an eleventh resistor R3109, a twelfth resistor R3105, a thirteenth resistor R3119, a second transistor T3101, a ninth capacitor C3120, and a first voltage stabilizing diode D3108. One end of the sixth resistor R3102 is electrically connected to the power input terminal BATT, and the other end is electrically connected to the No. 3 interface of the first NMOS transistor Q3102. The No. 2 interface of the first NMOS transistor Q3102 is electrically connected to the seventh resistor R3215. The other end of the seventh resistor R3215 is electrically connected to BAT_MCU_AD. Interface 2 of the first diode D3107 is electrically connected to the electrical connection node of the sixth resistor R3102, interface 1 of the first diode D3107 is electrically connected to interface 2 of the first transistor Q3103; interface 3 of the first transistor Q3103 is electrically connected to the tenth resistor R3108; the other end of the tenth resistor R3108 is electrically connected to the electrical connection node between the eleventh resistor R3109 and interface 1 of the first NMOS transistor Q3102; the other end of the eleventh resistor R3109 is grounded; interface 1 of the first transistor Q3103 is electrically connected to the ninth resistor R3114; the other end of the ninth resistor R3114 is electrically connected to interface 3 of the second transistor T3101; one end of the eighth resistor R3104 is electrically connected to interface 1 of the first diode D3107 and the first transistor Q3102. 03; the other end is connected to the electrical connection node of the ninth resistor R3114 and the electrical connection node of the No. 3 interface of the second transistor T3101; the No. 2 interface of the second transistor T3101 is grounded; one end of the thirteenth resistor R3119 is electrically connected to MCU_MON_EN, and the other end is electrically connected to the No. 1 interface of the second transistor T3101; one end of the ninth capacitor 3120 is electrically connected to the No. 1 interface of the second transistor T3101 and the electrical connection node of the thirteenth resistor R3119, and the other end is grounded; the first voltage-stabilizing diode D3108 is arranged in parallel in the circuit of the tenth resistor R3108 and the eleventh resistor R3109; one end of the twelfth resistor R3105 is grounded, and the other end is electrically connected to the No. 2 interface of the first transistor Q3103 and the electrical connection node of the seventh resistor R3215.

4. The circuit for replacing a 24V system analog power amplifier with a 12V system vehicle-mounted digital power amplifier as claimed in claim 1, characterized in that: The dynamic MOS switching 12V module circuit includes a first TVS protection tube D3102, a second TVS protection tube D3106, a first large current freewheeling diode D3103, a second large current freewheeling diode D3105, a second NMOS tube Q3101, an ideal diode U3101, a tenth capacitor C3101, an eleventh capacitor C3118, a twelfth capacitor C3102, a twelfth capacitor C3104, a fourteenth resistor R3111, a fifteenth resistor R3115, and a second diode D3101. The first TVS protection tube D3102 and the second TVS protection tube D3106 are arranged in parallel at the power input terminal BATT, and are arranged in the forward and reverse directions. The first large current freewheeling diode D3103 and the second large current freewheeling diode D3105 are arranged in parallel next to the parallel connection of the first TVS protection tube D3102 and the second TVS protection tube D3106. One end of the second NMOS tube Q3101 is electrically connected to the power input terminal BATT, and the other end is electrically connected to the ideal diode. The GATE terminal on U3101; one end of the tenth capacitor C3101 is electrically connected to the electrical connection node of the power input terminal BATT, and the other end is grounded; one end of the fourteenth resistor R3111 is electrically connected to MCU_DIOOU_EN, and the other end is electrically connected to the EN terminal on the ideal diode ‌U3101; one end of the fifteenth resistor R3115 is electrically connected to the electrical connection node of the fourteenth resistor R3111, and the other end is grounded; the eleventh capacitor C3118 is arranged in parallel with the fifteenth resistor R3 115; the GND terminal on the ideal diode U3101 is grounded; one end of the twelfth capacitor C3104 is electrically connected to the electrical connection node of the power input terminal BATT, and the other end is electrically connected to the VCP terminal on the ideal diode U3101; one end of the twelfth capacitor C3102 is electrically connected to the electrical connection node of the power input terminal BATT, and the other end is grounded; the 2nd port of the second diode D3101 is electrically connected to the power input terminal BATT, and the 1st port is electrically connected to the 12V DC voltage source.

5. The circuit for replacing a 24V system analog power amplifier with a 12V system vehicle-mounted digital power amplifier as claimed in claim 1, characterized in that: The digital power amplifier main circuit includes a core power amplifier chip U15, a low-pass filter L25, a first main circuit capacitor C432, a first main circuit resistor R299, a second main circuit resistor R300, a third main circuit resistor R322, a fourth main circuit resistor R304, a fifth main circuit resistor R275 and a sixth main circuit resistor R298; the low-pass filter L25 and the first main circuit capacitor C432 are combined to realize a low-pass filter to filter the audio source signal output by the power amplifier; the 18th pin of the core power amplifier chip U15 is electrically connected to the first main circuit resistor R299 and the second main circuit resistor R300 respectively; the other end of the first main circuit resistor R299 is electrically connected to the 3.3V VSW end; the The second main circuit resistor R300 is electrically connected to the AMP_FAULT terminal; the 17th pin of the core power amplifier chip U15 is electrically connected to the third main circuit resistor R322 and the fourth main circuit resistor R304 respectively; the other end of the fourth main circuit resistor R304 is grounded; the other end of the fourth main circuit resistor R304 is electrically connected to the AMP_STB terminal; the 15th pin of the core power amplifier chip U15 is electrically connected to the fifth main circuit resistor R275, and the other end of the fifth main circuit resistor R275 is electrically connected to the MCU_SCL terminal; the 15th pin of the core power amplifier chip U16 is electrically connected to the sixth main circuit resistor R298, and the other end of the sixth main circuit resistor R298 is electrically connected to the MCU_SDA terminal.

6. The circuit for replacing a 24V system analog power amplifier with a 12V system vehicle-mounted digital power amplifier as claimed in claim 1, characterized in that: The enhanced short-circuit protection system includes a first current limiting resistor R12, a protection system NMOS transistor X2, a second current limiting resistor R10, a third current limiting resistor R11, a protection system diode D2, a protection system first PMOS transistor M1, a protection system second PMOS transistor M3 and a protection system transistor Q1; one end of the first current limiting resistor R12 is electrically connected to the current output end, and the other end is electrically connected to the protection system NMOS transistor X2; the other end of the protection system NMOS transistor X2 is grounded, and the remaining end is electrically connected to the third current limiting resistor R11; the other end of the third current limiting resistor R11 is electrically connected to the second current limiting resistor R10; one end of the protection system diode D2 is electrically connected to the electrical connection node of the third current limiting resistor R11, and the other end is electrically connected to the protection system first PMOS transistor M1; the other end of the protection system first PMOS transistor M1 is electrically connected to the protection system transistor Q1.

7. The circuit for replacing a 24V system analog power amplifier with a 12V system vehicle-mounted digital power amplifier as claimed in claim 1, characterized in that: The dual-mode intelligent power supply system serves as the entrance to the entire power supply system and is responsible for receiving and introducing external power supply signals to provide an initial power source for the vehicle-mounted power amplifier; the DCDC step-down conversion circuit (102) steps down the introduced 24V power supply signal to a 12V system and outputs a voltage that meets the working requirements of the digital power amplifier module; the dynamic voltage monitoring circuit (103) monitors the external power supply input signal in real time and adjusts the power supply scheme in real time according to the power supply voltage to switch the power supply path; the dynamic MOS switching 12V module (104) is used to realize the function of switching the 12V system to supply power to the digital power amplifier; the digital power amplifier main circuit (105) performs digital amplification processing of the audio signal to provide high-fidelity audio output for the vehicle-mounted power amplifier; When a power short circuit fault occurs, the enhanced short circuit protection system (106) quickly responds to protect the audio output end of the main circuit of the digital power amplifier from damage caused by overvoltage short circuit.

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