Conversion circuit for converting standard USB signal into sound signal

Abstract

The utility model discloses a conversion circuit for converting a standard USB (Universal Serial Bus) signal into a sound signal, which comprises a USB interface circuit, a power conversion circuit, a voltage isolation circuit, a USB signal conversion circuit, a crystal oscillator circuit, an audio amplification circuit and an audio output circuit, the USB signal conversion circuit is respectively connected with the USB interface circuit, the voltage isolation circuit, the crystal oscillator circuit and the audio amplification circuit, and the audio amplification circuit is respectively connected with the USB signal conversion circuit and the audio output circuit. The conversion circuit for converting the USB signals into the sound signals is miniaturized, localized and low in cost, so that clients can normally play the sound signals in some special scenes requiring localization.

Description

Technical Field

[0001] The utility model belongs to the technical field of circuits, in particular to a conversion circuit for converting a standard USB signal into a sound signal. Background Art

[0002] The conversion process of USB signals into sound signals involves the conversion of digital signals to analog signals (Digital-to-Analog Conversion, DAC), which is mainly used in various occasions where digital audio data needs to be played as audible sound. For example, computer audio output, professional audio equipment, car audio system, USB audio adapter. In these application scenarios, the core of the conversion circuit is usually a DAC chip, which is responsible for converting the digital audio data transmitted by USB into a continuous analog voltage signal, which in turn drives the speaker or headphones to produce sound.

[0003] However, the procurement of imported electronic components such as DAC chips has become increasingly difficult. At this stage, it has become normal to use domestic electronic components to complete some circuit designs. Especially in certain specific occasions, such as the shortwave business field, many customers require that all domestic electronic components must be used when designing products. At present, there are many main control modules based on domestic electronic components on the market, but each customer has inconsistent requirements for the peripherals of the main control modules, which greatly limits the application of audio scenarios. Therefore, it is necessary to provide a conversion circuit that can meet specific requirements for sound. Utility Model Content

[0004] In order to overcome the above technical defects, the utility model provides a conversion circuit for converting a standard USB signal into a sound signal to solve the problems involved in the background technology.

[0005] The utility model provides a conversion circuit for converting a standard USB signal into a sound signal, comprising: a USB interface circuit, a power conversion circuit, a voltage isolation circuit, a USB signal conversion circuit, a crystal oscillator circuit, an audio amplifier circuit and an audio output circuit; wherein two ends of the power conversion circuit are respectively connected to the USB interface circuit and the voltage isolation circuit, the USB signal conversion circuit is respectively connected to the USB interface circuit, the voltage isolation circuit, the crystal oscillator circuit and the audio amplifier circuit, and the audio amplifier circuit is respectively connected to the USB signal conversion circuit and the audio output circuit.

[0006] Preferably or optionally, the USB interface circuit includes a USB interface, a current limiting circuit and an anti-static protection circuit electrically connected to the USB interface.

[0007] Preferably or optionally, the current limiting circuit includes an integrated chip U1, a resistor R1, a capacitor C1, a capacitor C2, and a capacitor C3; a power pin of the USB interface is connected to the integrated chip U1, both ends of the resistor R1 are connected to the integrated chip U1, one end of the capacitor C1 is connected to the integrated chip U1 and the other end is grounded, and the capacitors C2 and C3 are connected in parallel with one end connected to the integrated chip U1 and the other end is grounded;

[0008] The integrated chip U1 adopts a current limiting chip model SGM2581A;

[0009] TVS tubes D1 and D2, both of which are model ESDA05CP, are connected in series to the differential signal pins of the USB interface.

[0010] Preferably or optionally, the power conversion circuit includes a power conversion chip U2, a resistor R2, a resistor R3, a resistor R4, a capacitor C4, a capacitor C5, a capacitor C6 and an inductor L1; both ends of the resistor R2 are connected to the conversion chip U2, one end of the capacitor C4 is connected to the conversion chip U2 and the other end is grounded, one end of the inductor L1 is connected to the conversion chip U2 and the other end is connected to the resistor R3, the capacitor C5 and the capacitor C6, the other end of the resistor R3 is connected to the conversion chip U1 and the resistor R4, the other end of the resistor R4 is grounded, the other end of the capacitor C5 is connected to the conversion chip U2 and the resistor R4, and the other end of the capacitor C6 is grounded;

[0011] The conversion chip U2 is a conversion chip of model RY3420.

[0012] Preferably or optionally, the voltage isolation circuit includes a magnetic bead FB1, a magnetic bead FB2, a resistor R5, a resistor R6, a capacitor C7, and a capacitor C8; one end of the magnetic bead FB1 is connected to the power conversion circuit, and the other end is connected to the USB signal conversion circuit and one end of the resistor R5 and the resistor R6, the other end of the resistor R5 is connected to the USB signal conversion circuit and the capacitor C7, the other end of the resistor R6 is connected to the USB signal conversion circuit and the capacitor C8, the other end of the capacitor C7 is connected to the ground, the other end of the capacitor C8 is connected to the ground, and one end of the magnetic bead FB2 is connected to the ground and the other end is connected to the USB conversion circuit.

[0013] Preferably or optionally, the USB signal conversion circuit includes a filtering circuit, a chip conversion circuit and a chip configuration circuit.

[0014] Preferably or optionally, the filtering circuit comprises a capacitor C9, a capacitor C10, a capacitor C11, and a capacitor C12; the capacitors C9 and C10 are connected in parallel with one end connected to the chip conversion circuit and the other end connected to the ground; the capacitors C11 and C12 are connected in parallel with one end connected to the chip conversion circuit and the other end connected to the ground;

[0015] The chip conversion circuit adopts a conversion chip U3 of model CJC6811A;

[0016] The chip configuration circuit includes resistors R7, R8, R10 and capacitor C19; both ends of the resistors R7 and R8 are connected to the chip conversion circuit, one end of the resistor R10 is connected to the power isolation circuit and the other end is connected to the chip conversion circuit, and one end of the capacitor C19 is connected to the chip conversion circuit and the other end is connected to the ground.

[0017] Preferably or optionally, the crystal oscillator circuit includes a crystal oscillator Y1 and a capacitor C20; one end of the crystal oscillator Y1 is connected to the power conversion circuit and the other end is connected to the USB signal conversion circuit, and one end of the capacitor C20 is connected to the crystal oscillator Y1 and the other end is connected to the ground.

[0018] Preferably or optionally, the audio amplifier circuit uses a chip model of NS4251;

[0019] The power input pin of the NS4251 chip is connected to the USB interface circuit, the signal input pin of the NS4251 chip enters the chip after passing through capacitor C208 and resistor R202, capacitor C209 and resistor R203 respectively, the configuration pin of the NS4251 chip is grounded through resistor R207, resistor R209, resistor R210 and resistor R211 respectively, and the output pin of the NS4251 chip is connected to the audio output circuit.

[0020] Preferably or optionally, the audio output circuit transmits and processes the output signal of the audio amplifier circuit after isolation through a voltage isolation circuit, and performs signal filtering on each output signal through a filtering circuit.

[0021] Preferably or optionally, the audio output circuit transmits and processes the output signal of the audio amplifier circuit after isolation through a voltage isolation circuit, and performs signal filtering on each output signal through a filtering circuit.

[0022] The utility model relates to a conversion circuit for converting a standard USB signal into a sound signal. Compared with the prior art, the utility model has the following beneficial effects:

[0023] (1) The utility model converts the input voltage into the voltage required by the circuit through the power conversion circuit, supplies power to the USB signal conversion circuit and the optical fiber signal conversion circuit, converts the USB signal into an Ethernet signal through the USB signal conversion circuit, filters and isolates the Ethernet signal through the isolation filter circuit, and then inputs it into the optical fiber signal conversion circuit, and then exchanges data with the filtered Ethernet signal through the optical fiber signal conversion circuit to provide a differential signal that meets the requirements of the optical fiber module, and finally converts the differential signal into an optical fiber signal through the optical fiber module, and directly transmits it through the optical fiber, thereby realizing a miniaturized and low-cost conversion circuit that converts USB signal transmission into optical fiber signal transmission, so that customers can transmit data faster and more reliably over long distances and with large capacity. It adopts the standard USB definition and can be directly connected to an ordinary USB interface without the need to install a driver, and is plug-and-play.

[0024] (2) The USB interface circuit of the utility model adds a current limiting circuit and an anti-static protection circuit, which can effectively ensure that the host will not be damaged due to damage to the subsequent circuit, thereby increasing the reliability of the device.

[0025] (3) The utility model has its own audio amplifier circuit, and the resistance value of the resistor in the audio amplifier circuit can be adjusted to change the amplification effect and adapt to different speakers.

[0026] (4) All electronic components used in the conversion circuit of the utility model are domestically produced electronic components and are currently mainstream products in China, further enhancing the ability of independent control. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a circuit structure diagram of the utility model;

[0028] Figure 2 This is the USB interface circuit diagram of the utility model;

[0029] Figure 3 The circuit diagram of the power conversion circuit of the utility model;

[0030] Figure 4 This is a voltage isolation circuit diagram of the utility model;

[0031] Figure 5 This is a circuit diagram of a USB signal conversion circuit of the utility model;

[0032] Figure 6 This is a circuit diagram of a crystal oscillator circuit of the utility model;

[0033] Figure 7 This is a circuit diagram of the audio amplifier circuit of the utility model;

[0034] Figure 8 This is a circuit diagram of the audio output circuit of the utility model. DETAILED DESCRIPTION

[0035] In the following description, a large number of specific details are given to provide a more thorough understanding of the utility model. However, it is obvious to those skilled in the art that the utility model can be implemented without one or more of these details. In other examples, in order to avoid confusion with the utility model, some technical features known in the art are not described.

[0036] See attached Figures 1 to 8 , a conversion circuit for converting a standard USB signal into a sound signal, including: a USB interface circuit, a power conversion circuit, a voltage isolation circuit, a USB signal conversion circuit, a crystal oscillator circuit, an audio amplifier circuit and an audio output circuit. Among them, the power conversion circuit converts and isolates the voltage on the USB interface power supply to power the USB signal conversion circuit, and the USB signal conversion circuit converts the USB differential signal on the USB interface circuit into an audio signal, and connects with the audio amplifier circuit to amplify the audio signal so that it can drive the subsequent audio output circuit. A miniaturized, low-cost, and domestically produced conversion circuit for converting USB signal transmission into audio signal transmission is realized, so that customers can directly use the circuit to realize the signal conversion function in certain specific occasions. It adopts the standard USB definition and can be directly connected to an ordinary USB interface. There is no need to install a driver, and it is plug-and-play.

[0037] See attached Figure 2, the USB interface circuit includes a USB interface, a current limiting circuit and an anti-static protection circuit. The USB interface uses a connector plug socket with model number JL29-04ZJB. The current limiting circuit includes an integrated chip U1, a resistor R1, a capacitor C1, a capacitor C2, and a capacitor C3; the power pin of the USB interface is connected to the integrated chip U1, both ends of the resistor R1 are connected to the integrated chip U1, one end of the capacitor C1 is connected to the integrated chip U1 and the other end is grounded, and the capacitors C2 and C3 are connected in parallel with one end connected to the integrated chip U1 and the other end is grounded; the integrated chip U1 uses a current limiting chip with model number SGM2581A; the differential signal pins of the USB interface are connected in series with TVS tubes D1 and D2 with model numbers ESDA05CP. The integrated chip U1 uses a current limiting chip of model SGM2581A to limit the input 5V voltage and current to 1.1A to prevent the subsequent circuit of the peripheral from short-circuiting and thus causing damage to the host, and TVS tubes D1 and D2 of model ESDA05CP are connected in series on the USB differential signal to further protect the host. Pin 3 of the integrated chip U1 is connected to a high level through resistor R1 to keep the integrated chip U1 in a working state, pin 1 of the integrated chip U1 is connected to the 5V power supply of the USB signal and a 47uf power supply is connected in parallel to the ground for filtering, and pin 5 of the integrated chip U1 is connected in parallel with a 47uf capacitor C2 and a 100nf capacitor C3 and then connected to the ground for output voltage filtering.

[0038] See attached Figure 3 The power conversion circuit includes a power conversion chip U2, a resistor R2, a resistor R3, a resistor R4, a capacitor C4, a capacitor C5, a capacitor C6 and an inductor L1; both ends of the resistor R2 are connected to the conversion chip U2, one end of the capacitor C4 is connected to the conversion chip U2 and the other end is grounded, one end of the inductor L1 is connected to the conversion chip U2 and the other end is connected to the resistor R3, the capacitor C5 and the capacitor C6, the other end of the resistor R3 is connected to the conversion chip U1 and the resistor R4, the other end of the resistor R4 is grounded, the other end of the capacitor C5 is connected to the conversion chip U2 and the resistor R4, and the other end of the capacitor C6 is grounded; the conversion chip U2 adopts a conversion chip with model RY3420. Pin 1 of the conversion chip U2 is connected to the input power supply No. 4 through resistor R2, so that the chip is always in working state. Pin 4 of the conversion chip U2 is connected to the ground in parallel through capacitor C4 for voltage input filtering. Pin 5 of the conversion chip U2 is the feedback voltage pin fixed at 0.6V, and the output is 3.3V required by the subsequent circuit through the resistance value adjustment of resistors R3 and R4. Pin 3 of the chip is connected to the ground in parallel with capacitor C6 after passing through the large current inductor L1, and directly outputs 3.3V.

[0039] See attached Figure 4, the voltage isolation circuit includes magnetic beads FB1, magnetic beads FB2, resistors R5, resistors R6, capacitors C7, and capacitors C8; one end of the magnetic bead FB1 is connected to the power conversion circuit, and the other end is connected to the USB signal conversion circuit and one end of the resistor R5 and resistor R6, the other end of the resistor R5 is connected to the USB signal conversion circuit and capacitor C7, the other end of the resistor R6 is connected to the USB signal conversion circuit and capacitor C8, the other end of the capacitor C7 is connected to the ground, the other end of the capacitor C8 is connected to the ground, and one end of the magnetic bead FB2 is connected to the ground and the other end is connected to the USB conversion circuit. The voltage isolation circuit is mainly used to isolate the converted 3.3V. The sound signal is an analog audio signal, and the related voltage and ground signals used need to be isolated and separated from the digital signal. The 3.3V voltage and ground are isolated by magnetic beads FB1 and FB2 respectively before entering the USB signal conversion circuit. The isolated 3.3V is filtered by 0 ohm resistors R5, R6 and capacitors C7, C8 respectively and enters the USB signal conversion circuit.

[0040] See attached Figure 5 , the USB signal conversion circuit includes a filter circuit, a chip conversion circuit and a chip configuration circuit. The filter circuit includes capacitors C9, C10, C11 and C12; the capacitors C9 and C10 are connected in parallel, one end of which is connected to the chip conversion circuit and the other end is connected to the ground; the capacitors C11 and C12 are connected in parallel, one end of which is connected to the chip conversion circuit and the other end is connected to the ground; the chip conversion circuit uses a conversion chip U3 of model CJC6811A; the chip configuration circuit includes resistors R7, R8, R10 and capacitor C19; both ends of the resistors R7 and R8 are connected to the chip conversion circuit, one end of the resistor R10 is connected to the power isolation circuit and the other end is connected to the chip conversion circuit, and one end of the capacitor C19 is connected to the chip conversion circuit and the other end is connected to the ground. The chip conversion circuit adopts a conversion chip U3 of model CJC6811A. Pins 9, 16, 32, and 12 of the conversion chip U3 are power input pins connected to the voltage isolation circuit. Pins 30 and 31 of the conversion chip U3 are signal input pins connected to the USB interface circuit. Pin 13 of the conversion chip U3 is a chip configuration pin connected to the chip power supply voltage through a resistor R9. Pins 2 and 8 of the conversion chip U3 are connected together through a resistor R7. Pins 3 and 5 of the conversion chip U3 are connected together through a resistor R8. Pin 13 of the conversion chip U3 is a chip reset pin, which is automatically reset when powered on through a resistor R10 and a capacitor C19. Pins 25 and 27 of the conversion chip U3 are audio signal output pins connected to a subsequent audio amplifier circuit.

[0041] See attached Figure 6The crystal oscillator circuit includes a crystal oscillator Y1 and a capacitor C20; one end of the crystal oscillator Y1 is connected to the power conversion circuit and the other end is connected to the USB signal conversion circuit, and one end of the capacitor C20 is connected to the crystal oscillator Y1 and the other end is connected to the ground. The crystal oscillator circuit uses a 12M active crystal to provide a stable frequency for the chip U3.

[0042] See attached Figure 7 The audio amplifier circuit uses a chip model NS4521. Pins 6 and 15 of the chip are power input pins connected to the USB interface circuit. Pins 8 and 13 of the chip are signal input pins, which enter the chip after passing through capacitor C208 and resistor R202, capacitor C209 and resistor R203 respectively. Pins 2, 3, 10, and 12 of the chip are configuration pins of the chip, which are connected to the USB interface circuit through resistors R207, R209, R210, and R211 respectively. Pins 1 and 14 of the chip are output pins connected to the subsequent audio output circuit.

[0043] See attached Figure 8 The audio output circuit transmits and processes the output signal of the audio amplifier circuit after being isolated by the voltage isolation circuit, and performs signal filtering on each output signal through the filter circuit. The audio output circuit transmits and processes the output signal of the audio amplifier circuit after being isolated by the magnetic beads FB204 and FB205, and performs signal filtering on each output signal through the ground input C219 and C220.

[0044] In order to facilitate understanding of the technical solution of the conversion circuit that converts standard USB signals into sound signals, a brief description of its working principle is given: This embodiment uses a power conversion circuit to convert and isolate the voltage on the USB interface power supply to power the USB signal conversion circuit. The USB signal conversion circuit converts the USB differential signal on the USB interface circuit into an audio signal, and connects it to the audio amplifier circuit to amplify the audio signal so that it can drive the subsequent audio output circuit. A miniaturized, low-cost, and domestically produced conversion circuit that converts USB signal transmission into audio signal transmission is realized, so that customers can directly use the circuit to realize the signal conversion function in certain specific occasions. It adopts standard USB definitions and can be directly connected to an ordinary USB interface without installing a driver, and is plug-and-play.

[0045] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

Claims

1. A conversion circuit for converting a standard USB signal into a sound signal, characterized in that: include: USB interface circuit, power conversion circuit, voltage isolation circuit, USB signal conversion circuit, crystal oscillator circuit, audio amplifier circuit and audio output circuit; wherein, the two ends of the power conversion circuit are respectively connected to the USB interface circuit and the voltage isolation circuit, the USB signal conversion circuit is respectively connected to the USB interface circuit, the voltage isolation circuit, the crystal oscillator circuit and the audio amplifier circuit, and the audio amplifier circuit is respectively connected to the USB signal conversion circuit and the audio output circuit.

2. The conversion circuit for converting a standard USB signal into a sound signal according to claim 1, characterized in that: The USB interface circuit includes a USB interface, a current limiting circuit electrically connected to the USB interface, and an anti-static protection circuit.

3. The conversion circuit for converting a standard USB signal into a sound signal according to claim 2, characterized in that: The current limiting circuit includes an integrated chip U1, a resistor R1, a capacitor C1, a capacitor C2, and a capacitor C3; the power pin of the USB interface is connected to the integrated chip U1, both ends of the resistor R1 are connected to the integrated chip U1, one end of the capacitor C1 is connected to the integrated chip U1 and the other end is grounded, and the capacitors C2 and C3 are connected in parallel with one end connected to the integrated chip U1 and the other end is grounded; The integrated chip U1 adopts a current limiting chip model SGM2581A; TVS tubes D1 and D2, both of which are model ESDA05CP, are connected in series to the differential signal pins of the USB interface.

4. The conversion circuit for converting a standard USB signal into a sound signal according to claim 1, characterized in that: The power conversion circuit includes a power conversion chip U2, a resistor R2, a resistor R3, a resistor R4, a capacitor C4, a capacitor C5, a capacitor C6 and an inductor L1; both ends of the resistor R2 are connected to the conversion chip U2, one end of the capacitor C4 is connected to the conversion chip U2 and the other end is grounded, one end of the inductor L1 is connected to the conversion chip U2 and the other end is connected to the resistor R3, the capacitor C5 and the capacitor C6, the other end of the resistor R3 is connected to the conversion chip U1 and the resistor R4, the other end of the resistor R4 is grounded, the other end of the capacitor C5 is connected to the conversion chip U2 and the resistor R4, and the other end of the capacitor C6 is grounded; The conversion chip U2 is a conversion chip of model RY3420.

5. The conversion circuit for converting a standard USB signal into a sound signal according to claim 1, characterized in that: The voltage isolation circuit includes a magnetic bead FB1, a magnetic bead FB2, a resistor R5, a resistor R6, a capacitor C7, and a capacitor C8; one end of the magnetic bead FB1 is connected to the power conversion circuit, and the other end is connected to the USB signal conversion circuit and one end of the resistor R5 and the resistor R6, the other end of the resistor R5 is connected to the USB signal conversion circuit and the capacitor C7, the other end of the resistor R6 is connected to the USB signal conversion circuit and the capacitor C8, the other end of the capacitor C7 is connected to the ground, the other end of the capacitor C8 is connected to the ground, and one end of the magnetic bead FB2 is connected to the ground and the other end is connected to the USB conversion circuit.

6. The conversion circuit for converting a standard USB signal into a sound signal according to claim 1, characterized in that: The USB signal conversion circuit includes a filter circuit, a chip conversion circuit and a chip configuration circuit.

7. The conversion circuit for converting a standard USB signal into a sound signal according to claim 6, characterized in that: The filter circuit includes capacitor C9, capacitor C10, capacitor C11, and capacitor C12; the capacitors C9 and C10 are connected in parallel with one end connected to the chip conversion circuit and the other end connected to the ground; the capacitors C11 and C12 are connected in parallel with one end connected to the chip conversion circuit and the other end connected to the ground; The chip conversion circuit adopts a conversion chip U3 of model CJC6811A; The chip configuration circuit includes resistors R7, R8, R10 and capacitor C19; both ends of the resistors R7 and R8 are connected to the chip conversion circuit, one end of the resistor R10 is connected to the power isolation circuit and the other end is connected to the chip conversion circuit, and one end of the capacitor C19 is connected to the chip conversion circuit and the other end is connected to the ground.

8. The conversion circuit for converting a standard USB signal into a sound signal according to claim 1, characterized in that: The crystal oscillator circuit includes a crystal oscillator Y1 and a capacitor C20; one end of the crystal oscillator Y1 is connected to the power conversion circuit and the other end is connected to the USB signal conversion circuit; one end of the capacitor C20 is connected to the crystal oscillator Y1 and the other end is connected to the ground.

9. The conversion circuit for converting a standard USB signal into a sound signal according to claim 1, characterized in that: The audio amplifier circuit uses a chip model of NS4251; The power input pin of the NS4251 chip is connected to the USB interface circuit, the signal input pin of the NS4251 chip enters the chip after passing through capacitor C208 and resistor R202, capacitor C209 and resistor R203 respectively, the configuration pin of the NS4251 chip is grounded through resistor R207, resistor R209, resistor R210 and resistor R211 respectively, and the output pin of the NS4251 chip is connected to the audio output circuit.

10. The conversion circuit for converting a standard USB signal into a sound signal according to claim 1, characterized in that: The audio output circuit transmits and processes the output signal of the audio amplifier circuit after isolation through the voltage isolation circuit, and performs signal filtering on each output signal through the filtering circuit.

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