A Bluetooth sound box

Abstract

A Bluetooth speaker includes a BOOST boost module, a power amplifier, and a charging module for charging a battery (BAT). The output voltage of the BOOST boost module supplies the power amplifier, which drives the speaker. The BOOST boost module includes a synchronous boost controller U8, and an inverter U9 is provided between the power amplifier and the synchronous boost controller. The power amplifier detects the audio input in real time and outputs a power supply voltage adjustment signal BOOST_PWM at pin 5 according to the desired signal swing. The synchronous boost controller U8 dynamically adjusts the output voltage at pin 18 based on the received voltage adjustment signal BOOST_PWM and the detected feedback voltage. The charging module includes a waterproof protection circuit for a Type-C interface, which uses an unused pin of the Type-C interface as a sensor, without occupying normal function pins or affecting the original performance of the interface.

Description

Technical Field

[0001] This invention relates to the field of audio technology, and in particular to a Bluetooth speaker employing dynamic voltage regulation. Background Technology

[0002] Many Bluetooth speakers on the market currently use boost circuits to increase battery voltage in order to boost power. When the battery voltage hasn't reached low-voltage protection, the boost circuit maintains a fixed output voltage. Some are even software-controlled, reducing the boost circuit's output voltage to a certain level when the battery voltage drops below a certain threshold. These designs cannot flexibly adjust the boost output voltage in real-time according to the amplifier's volume. Since the amplifier's efficiency decreases as the supply voltage increases, the boost circuit's efficiency also decreases with increasing output voltage, thus reducing battery efficiency.

[0003] In addition, many Bluetooth speakers on the market now use Type-C interfaces, supporting PD fast charging, USB playback, and external charging. However, most Type-C interfaces lack waterproof detection circuitry. The current solution is to use custom-developed chips, but this is costly, and in practice, it has been found that the comparators are susceptible to temperature and voltage variations, making them prone to malfunctions and unreliable. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a Bluetooth speaker that can flexibly adjust the boost voltage in real time, save power, and extend battery life; the Type-C interface waterproof protection circuit improves charging reliability.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is: a Bluetooth speaker, including a BOOST boost module, a power amplifier, and a charging module for charging a battery BAT, wherein the output voltage of the BOOST boost module supplies the power amplifier, and the power amplifier drives the speaker;

[0006] The BOOST boost module includes a synchronous boost controller U8. An inverter U9 is provided between the power amplifier and the synchronous boost controller. The power amplifier detects the audio input in real time. According to the desired signal swing, the power amplifier outputs a power supply voltage adjustment signal BOOST_PWM at pin 5. The synchronous boost controller U8 dynamically adjusts the output voltage at pin 18 based on the received voltage adjustment signal BOOST_PWM and the detected feedback voltage.

[0007] The charging module includes a waterproof protection circuit for a Type-C interface. This circuit includes transistors Q23 and Q24. The emitter of transistor Q23 is connected to a +3.3V power supply, and the collector of transistor Q23 is connected to the AD detection pin of the MCU via the KEY pin. The emitter of transistor Q24 is connected to both the base of transistor Q23 and the +3.3V power supply. The collector of transistor Q24 is connected to the collector of transistor Q23. The base of transistor Q24 is connected to both the +3.3V power supply and pin A8 of the Type-C interface. Pin B8 of the Type-C interface is grounded.

[0008] As an improvement, the synchronous boost controller U8 is model LM5123-Q1, and the inverter U9 is model 74HC1G14.

[0009] As an improvement, pin 2 of inverter U9 is connected to pin 5 of power amplifier, and pin 4 of inverter U9 is connected to pin 18 of synchronous boost controller U8.

[0010] As an improvement, the positive terminal of the battery BAT outputs voltage through the MOSFET Q7, and pin 5 of the synchronous boost controller U8 is connected to the gate of the MOSFET Q7.

[0011] As an improvement, the +3.3V power supply is connected to pin A8 via resistors R128 and R131. A grounded capacitor C154 and a transient suppression diode D13 are located between resistors R128 and R131. A grounded transient suppression diode D14 is directly connected between resistor R131 and pin A8. A resistor R129 is located between the emitter and base of transistor Q23. The collectors of transistors Q23 and Q24 are connected to pin KEY via resistor R125. A grounded resistor R127 is located between resistor R125 and pin KEY. Pin B8 of the Type-C interface is grounded via resistor R135.

[0012] The beneficial effects of this invention compared to the prior art are:

[0013] 1. By dynamically tracking the audio signal to adjust the power amplifier supply voltage, the power amplifier always operates at near-optimal efficiency, greatly reducing power loss at medium and low volumes, thereby significantly extending the battery's single-charge usage time.

[0014] 2. Due to the improved efficiency, the heat generated by the power amplifier and power supply circuit is significantly reduced, which improves the reliability and lifespan of the product, while also enhancing the user experience;

[0015] 3. At high volumes or with large dynamic range signals, the system can quickly boost the voltage to ensure that the power amplifier has sufficient voltage margin, avoid clipping distortion, and guarantee the quality of audio output;

[0016] 4. Complex functions can be achieved by using the PWM signal generated by the power amplifier itself and a standard boost controller and inverter, without the need for additional dedicated dynamic voltage regulation chips. The circuit implementation is simple and the cost is controllable.

[0017] 5. It can monitor whether water has entered the Type-C interface in real time, and immediately notify the MCU to take protective measures such as power-off when liquid is detected to prevent further damage;

[0018] 6. The core circuit for waterproof protection of the Type-C interface consists only of general-purpose transistors and resistors, eliminating the need for dedicated liquid sensors or complex sealing structures, thus significantly reducing costs;

[0019] 7. Utilize the unused pins of the Type-C interface as sensors, without occupying normal function pins or affecting the original performance of the interface;

[0020] 8. Based on transistor switching circuits, state switching occurs in the microsecond range, enabling rapid response. Attached Figure Description

[0021] Figure 1 This is the circuit diagram for the BOOST boost module.

[0022] Figure 2 This is the circuit diagram for the power amplifier.

[0023] Figure 3 Circuit diagram for waterproof protection of Type-C interface.

[0024] Figure 4 This is the circuit diagram for the charging module. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings.

[0026] A Bluetooth speaker includes a BOOST boost module, a power amplifier, and a charging module for charging a battery (BAT). The output voltage of the BOOST boost module supplies the power amplifier, which drives the speaker.

[0027] like Figure 1 , 2As shown, the BOOST boost module includes a synchronous boost controller U8, model LM5123-Q1. To improve stability, an inverter U9 is provided between the power amplifier and the synchronous boost controller to adjust the timing; the inverter U9 is model 74HC1G14, pin 2 of which is connected to pin 5 of the power amplifier, and pin 4 of which is connected to pin 18 of the synchronous boost controller U8. Power amplifiers U2 and U3 detect the audio input in real time, and output a supply voltage adjustment signal BOOST_PWM at pin 5 according to the desired signal swing. The positive terminal of the battery BAT outputs voltage through MOSFET Q7, and pin 5 of the synchronous boost controller U8 is connected to the gate of MOSFET Q7. The synchronous boost controller U8 dynamically adjusts the output voltage at pin 18 based on the received voltage adjustment signal BOOST_PWM and the detected feedback voltage. Because audio signals typically have a high peak factor, the average power is only 40% or less of the peak power. BOOST_PWM enables dynamic tracking of the BOOST output voltage to the audio output amplitude, keeping the BOOST output (i.e., the power amplifier supply voltage) at just the right voltage. This avoids clipping distortion due to insufficient boost output voltage and prevents reduced system efficiency due to excessive boost output voltage, ensuring that the entire audio system always operates at its optimal efficiency.

[0028] like Figure 3 , 4As shown, the charging module includes a Type-C interface waterproof protection circuit. The Type-C interface waterproof protection circuit includes transistors Q23 and Q24. The emitter of transistor Q23 is connected to the +3.3V power supply, and the collector of transistor Q23 is connected to the AD detection pin of the MCU through the KEY pin. The emitter of transistor Q24 is connected to the base of transistor Q23 and the +3.3V power supply, and the collector of transistor Q24 is connected to the collector of transistor Q23. The base of transistor Q24 is connected to the +3.3V power supply and pin A8 of the Type-C interface, and pin B8 of the Type-C interface is grounded. The +3.3V power supply is connected to pin A8 via resistors R128 and R131. A grounded capacitor C154 and a transient voltage suppressor diode D13 are located between resistors R128 and R131. A grounded transient voltage suppressor diode D14 is directly connected between resistor R131 and pin A8. A resistor R129 is located between the emitter and base of transistor Q23. The collectors of transistors Q23 and Q24 are connected to pin KEY via resistor R125. A grounded resistor R127 is located between resistor R125 and pin KEY. Pin B8 of the Type-C interface is grounded via resistor R135. The system primarily utilizes the unused pins A8 and B8 on the Type-C interface. Pin A8 is on the front of the Type-C interface, and pin B8 is on the back. Pins A8 and B8 function as a water sensor. When water enters the Type-C interface, pins A8 and B8 are connected, the base of transistor Q24 is low, and transistor Q23 is connected, outputting +3.3V to the MCU AD detection pin through the KEY pin, controlling the machine to stop working and issuing a warning. When water does not enter the Type-C interface, pins A8 and B8 are not connected, the base of transistor Q24 is high, and transistor Q23 is cut off. The KEY pin outputs 0V to the MCU AD detection pin, and the machine works normally.

Claims

1. A Bluetooth speaker, comprising a BOOST boost module, a power amplifier, and a charging module for charging a battery (BAT), wherein the output voltage of the BOOST boost module supplies the power amplifier, and the power amplifier drives a speaker; characterized in that: The BOOST boost module includes a synchronous boost controller U8. An inverter U9 is provided between the power amplifier and the synchronous boost controller. The power amplifier detects the audio input in real time. According to the desired signal swing, the power amplifier outputs a power supply voltage adjustment signal BOOST_PWM at pin 5. The synchronous boost controller U8 dynamically adjusts the output voltage at pin 18 based on the received voltage adjustment signal BOOST_PWM and the detected feedback voltage. The charging module includes a waterproof protection circuit for a Type-C interface. This circuit includes transistors Q23 and Q24. The emitter of transistor Q23 is connected to a +3.3V power supply, and the collector of transistor Q23 is connected to the AD detection pin of the MCU via the KEY pin. The emitter of transistor Q24 is connected to both the base of transistor Q23 and the +3.3V power supply. The collector of transistor Q24 is connected to the collector of transistor Q23. The base of transistor Q24 is connected to both the +3.3V power supply and pin A8 of the Type-C interface. Pin B8 of the Type-C interface is grounded. The synchronous boost controller U8 is model LM5123-Q1, and the inverter U9 is model 74HC1G14; Pin 2 of the inverter U9 is connected to pin 5 of the power amplifier, and pin 4 of the inverter U9 is connected to pin 18 of the synchronous boost controller U8. The positive terminal of the battery BAT outputs voltage through the MOSFET Q7, and pin 5 of the synchronous boost controller U8 is connected to the gate of the MOSFET Q7; The +3.3V power supply is connected to pin A8 via resistors R128 and R131. A grounded capacitor C154 and a transient suppression diode D13 are located between resistors R128 and R131. A grounded transient suppression diode D14 is directly connected between resistor R131 and pin A8. A resistor R129 is located between the emitter and base of transistor Q23. The collectors of transistors Q23 and Q24 are connected to pin KEY via resistor R125. A grounded resistor R127 is located between resistor R125 and pin KEY. Pin B8 of the Type-C interface is grounded via resistor R135.

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