Wireless receiver and wireless audio system

Abstract

The utility model relates to the technical field of audio equipment, in particular to a wireless receiver and a wireless audio system. The wireless receiver comprises a wireless receiving chip, an audio transmission circuit and an isolation voltage stabilizing circuit; a first end of the isolation voltage stabilizing circuit is connected with a bus of a system power supply, a second end of the isolation voltage stabilizing circuit is connected with a first end of the audio transmission circuit, a third end of the isolation voltage stabilizing circuit is connected with a system ground of the wireless audio system, and a fourth end of the isolation voltage stabilizing circuit is connected with an analog audio ground of the wireless receiver. The second end of the audio transmission circuit is connected with the wireless receiving chip, and the third end of the audio transmission circuit is connected with audio equipment; the isolation voltage stabilizing circuit is arranged to isolate and filter interference signals of the power supply signals output by the system power supply between the system ground and the analog audio ground, so that the audio transmission circuit can transmit audio differential signals of the wireless receiving chip to the audio equipment by using the power supply signals after the interference signals are filtered, and the problem that noise is generated in power supply is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of audio equipment, in particular to a wireless receiver and a wireless audio system. Background Art

[0002] With the popularization and application of Bluetooth technology, Bluetooth function has basically become a standard feature of electronic audio equipment. Users can use Bluetooth to connect TWS headphones and Bluetooth speakers wirelessly to play music. However, traditional speakers do not have Bluetooth function, so there are many Bluetooth audio receivers on the market. This Bluetooth audio receiver can convert wireless Bluetooth audio into analog audio output, so that traditional speakers can achieve the effect of wireless Bluetooth playback.

[0003] At present, when the Bluetooth audio receivers on the market are powered by USB, their input also comes from traditional speakers. The audio ground loop is equivalent to connecting an interference source of the system ground in series, thus generating noise. In particular, in recent years, a floor-standing integrated speaker with a microphone loop with ultra-high amplification has appeared on the market. The noise signal generated by the interference source is even louder than the human voice, affecting the user experience.

[0004] The above contents are only used to assist in understanding the technical solution of the present utility model and do not constitute an admission that the above contents are prior art. Utility Model Content

[0005] The main purpose of the utility model is to provide a wireless receiver and a wireless audio system, aiming to solve the technical problem in the prior art that when the wireless audio receiver is powered by USB, the system ground line generates interference noise that affects normal use.

[0006] To achieve the above object, the utility model provides a wireless receiver including: a wireless receiving chip, an audio transmission circuit and an isolation voltage stabilization circuit;

[0007] The first end of the isolation voltage stabilizing circuit is connected to the bus of the system power supply, the second end of the isolation voltage stabilizing circuit is connected to the first end of the audio transmission circuit, the third end of the isolation voltage stabilizing circuit is connected to the system ground of the wireless audio system, the fourth end of the isolation voltage stabilizing circuit is connected to the analog audio ground of the wireless receiver, the second end of the audio transmission circuit is connected to the wireless receiving chip, and the third end of the audio transmission circuit is connected to the audio device;

[0008] The isolation voltage stabilization circuit is used to isolate and filter out interference signals between the system ground and the analog audio ground of the power signal output by the system power supply, and transmit the power signal after the interference signal is filtered out to the audio transmission circuit;

[0009] The audio transmission circuit is used to transmit the audio differential signal received by the wireless receiving chip to the audio device when receiving the power signal after the interference signal is filtered out.

[0010] Optionally, the isolation voltage stabilization circuit includes: a first resistor;

[0011] The first resistor is arranged between the system ground and the analog audio ground.

[0012] Optionally, the isolation voltage stabilization circuit further includes: a ripple filtering unit;

[0013] The first end of the ripple filtering unit is connected to the bus of the system power supply, the second end of the ripple filtering unit is connected to the first end of the audio transmission circuit, and the third end of the ripple filtering unit is simultaneously connected to one end of the first resistor and the analog audio ground;

[0014] The ripple filtering unit is used to filter out ripples in the power supply signal and transmit the power supply signal after the ripple is filtered out to the audio transmission circuit.

[0015] Optionally, the ripple filtering unit includes: a first capacitor, a second capacitor and an LDO chip;

[0016] The first end of the LDO chip is connected to the bus of the system power supply and the first end of the first capacitor at the same time, the second end of the LDO chip is connected to the first end of the second capacitor and the first end of the audio transmission circuit at the same time, and the second end of the first capacitor is connected to the analog audio ground, the second end of the second capacitor and the third end of the LDO chip at the same time.

[0017] Optionally, the audio transmission circuit includes: second to fifth resistors, third to fifth capacitors and an operational amplifier;

[0018] The in-phase input terminal of the operational amplifier is simultaneously connected to the first end of the second resistor, the first end of the third resistor and the first end of the third capacitor, the inverting input terminal of the operational amplifier is simultaneously connected to the first end of the fourth resistor, the first end of the fifth resistor and the first end of the fourth capacitor, the output terminal of the operational amplifier is simultaneously connected to the second end of the fifth resistor and the second end of the fourth capacitor, the second end of the second resistor is connected to the differential positive signal line of the wireless receiving chip, the second end of the third resistor is connected to the second end of the third capacitor and receives the biased AC ground signal; the second end of the fourth resistor is connected to the differential negative signal line of the wireless receiving chip, the power supply terminal of the operational amplifier is connected to the first end of the fifth capacitor and the second end of the isolation voltage stabilizing circuit, the second end of the fifth resistor is connected to the analog audio ground, and the common terminal of the operational amplifier is connected to the analog audio ground.

[0019] Optionally, the audio transmission circuit further includes: a sixth capacitor and a seventh capacitor;

[0020] The first end of the sixth capacitor is connected to the differential negative signal line of the wireless receiving chip, the second end of the sixth capacitor is connected to the second end of the second resistor, the first end of the seventh capacitor is connected to the differential negative signal line of the wireless receiving chip, and the second end of the seventh capacitor is connected to the second end of the fourth resistor.

[0021] Optionally, the wireless receiver further comprises: a signal bias circuit;

[0022] The input end of the signal bias circuit is connected to the second end of the isolation voltage stabilization circuit, and the output end of the signal bias circuit is connected to the second end of the third resistor in the audio transmission circuit;

[0023] The signal bias circuit is used to perform bias processing on the power supply signal to generate a biased AC ground signal, and transmit the biased AC ground signal to the audio transmission circuit;

[0024] The audio transmission circuit is further used to amplify the AC signal in the audio differential signal of the wireless receiving chip when receiving the biased AC ground signal.

[0025] Optionally, the signal bias circuit includes: a sixth resistor, a seventh resistor and an eighth capacitor;

[0026] The first end of the sixth resistor is connected to the second end of the isolation voltage stabilization circuit, the second end of the sixth resistor is simultaneously connected to the first end of the seventh resistor, the first end of the eighth capacitor and the second end of the third resistor, and the second end of the seventh resistor and the second end of the eighth capacitor are both connected to the analog audio ground.

[0027] Optionally, the wireless receiver further comprises: a DC filter circuit consisting of an eighth resistor, a ninth resistor and a ninth capacitor;

[0028] The first end of the ninth capacitor is connected to the third end of the audio transmission circuit, the second end of the ninth capacitor is connected to the first end of the eighth resistor, the second end of the eighth resistor is connected to the first end of the ninth resistor and the audio device, and the second end of the ninth resistor is connected to the analog audio ground.

[0029] In addition, to achieve the above object, the utility model also provides a wireless audio system, the wireless audio system comprising: an audio device and the wireless receiver as described above;

[0030] The audio device transmits the power signal output by the system power supply to the wireless receiver through the USB interface, and the wireless receiver transmits the received audio differential signal to the audio device to drive the audio device to work.

[0031] The technical solution of the utility model proposes a wireless receiver and a wireless audio system. The wireless receiver includes a wireless receiving chip, an audio transmission circuit and an isolation voltage stabilizing circuit; the first end of the isolation voltage stabilizing circuit is connected to the bus of the system power supply, the second end of the isolation voltage stabilizing circuit is connected to the first end of the audio transmission circuit, the third end of the isolation voltage stabilizing circuit is connected to the system ground of the wireless audio system, the fourth end of the isolation voltage stabilizing circuit is connected to the analog audio ground of the wireless receiver, the second end of the audio transmission circuit is connected to the wireless receiving chip, and the third end of the audio transmission circuit is connected to the audio device; the isolation voltage stabilizing circuit is used to isolate and filter out the interference signal between the system ground and the analog audio ground of the power signal output by the system power supply, and transmit the power signal after the interference signal is filtered out to the audio transmission circuit; the audio transmission circuit is used to transmit the audio differential signal received by the wireless receiving chip to the audio device when receiving the power signal after the interference signal is filtered out. By setting up an isolation voltage stabilization circuit to achieve isolation between the system ground and the analog audio ground, the voltage drop of the ground network at both ends is reduced when the audio device uses USB to power the wireless receiver, thereby solving the noise problem when the wireless receiver outputs audio during USB power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0033] Figure 1 It is a schematic structural diagram of the first embodiment of the wireless receiver of the utility model;

[0034] Figure 2 It is a structural schematic diagram of the second embodiment of the wireless receiver of the utility model;

[0035] Figure 3 It is a schematic structural diagram of a third embodiment of the wireless receiver of the utility model;

[0036] Figure 4 This is a schematic diagram of functional modules of an embodiment of the wireless audio system of the utility model;

[0037] Figure 5This is a circuit diagram of an embodiment of the wireless audio system of the present utility model.

[0038] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0039] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0040] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0041] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back...) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0042] In addition, the descriptions of "first", "second", etc. in the present utility model are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0043] Reference Figure 1 , Figure 1 The structure diagram of the first embodiment of the wireless receiver of the utility model is shown in FIG. The utility model provides the first embodiment of the wireless receiver.

[0044] In this embodiment, the wireless receiver includes a wireless receiving chip 30, an audio transmission circuit 20 and an isolation voltage stabilization circuit 10; a first end of the isolation voltage stabilization circuit 10 is connected to the bus of the system power supply, a second end of the isolation voltage stabilization circuit 10 is connected to the first end of the audio transmission circuit 20, a third end of the isolation voltage stabilization circuit 10 is connected to the system ground of the wireless audio system, a fourth end of the isolation voltage stabilization circuit 10 is connected to the analog audio ground of the wireless receiver, a second end of the audio transmission circuit 20 is connected to the wireless receiving chip 30, and a third end of the audio transmission circuit 20 is connected to the audio device.

[0045] It should be noted that the isolation and voltage stabilization circuit 10 can be used to isolate and filter out interference signals between the system ground and the analog audio ground in the power signal output by the system power supply, and transmit the power signal after the interference signal is filtered out to the audio transmission circuit 20; the audio transmission circuit 20 can be used to transmit the audio differential signal received by the wireless receiving chip 30 to the audio device when receiving the power signal after the interference signal is filtered out.

[0046] It should be understood that the isolated voltage stabilizing circuit 10 can be a functional circuit constructed by an electronic device with voltage transmission capability, such as a voltage stabilizer or a filter, etc., which can transmit the power supply signal of the system power supply to various components in the system for power supply. Among them, the system power supply can be a power supply provided by an audio device (such as a speaker, etc.) using a USB interface for the normal operation of various components of the wireless receiver, through the bus V BUS And the ground wire G transmits the power signal to the wireless receiver.

[0047] Furthermore, the wireless receiving chip 30 may be a communication chip that uses a wireless communication protocol to transmit signals, such as a Bluetooth chip. The wireless receiving chip 30 may convert the wireless communication audio signal into an analog audio output signal and transmit it to the audio transmission circuit 20. The audio transmission circuit 20 may be a functional circuit with modulation and amplification effects, which may adjust the amplitude of the analog audio output signal of the wireless receiving chip 30 to an amplitude suitable for playback by an audio device. The transmission of the analog audio output signal is generally carried out in the form of a differential signal (i.e., the above-mentioned audio differential signal).

[0048] In the prior art, the USB interface of the audio device is directly connected to the power module of the wireless receiver. When the audio device supplies power to the wireless receiver, current will flow through the USB line. Assuming that the resistance on the USB ground line (i.e., the system ground G) is 60mΩ, and the transient current of the USB required for the normal operation of the wireless receiver is 300mA, then the voltage difference across the ground line (i.e., the voltage amplitude of the interference signal between the system ground G of the wireless audio system and the analog audio ground A of the wireless receiver) is 300mA×60mΩ=18mV. The amplitude of the audio signal of a normal microphone is generally 1mV~10mV, so the interference signal directly enters the amplifier circuit of the audio device, which will cause great interference to the normal audio output and affect the user experience.

[0049] In this embodiment, the above interference signal can be filtered out or the amplitude of the interference signal can be reduced by setting an isolation voltage stabilization circuit 10. For example, the interference signal in the power supply signal can be filtered out by setting a voltage stabilization filter, or a resistor or other element can be connected in series between the system ground and the analog audio ground to reduce the voltage difference between the two ends of the ground line, so as to reduce the influence of the interference signal on the normal audio signal. This is not specifically limited in this embodiment.

[0050] This embodiment proposes a wireless receiver, which includes a wireless receiving chip, an audio transmission circuit and an isolation voltage stabilizing circuit; the first end of the isolation voltage stabilizing circuit is connected to the bus of the system power supply, the second end of the isolation voltage stabilizing circuit is connected to the first end of the audio transmission circuit, the third end of the isolation voltage stabilizing circuit is connected to the system ground of the wireless audio system, the fourth end of the isolation voltage stabilizing circuit is connected to the analog audio ground of the wireless receiver, the second end of the audio transmission circuit is connected to the wireless receiving chip, and the third end of the audio transmission circuit is connected to the audio device; the isolation voltage stabilizing circuit is used to isolate and filter out the interference signal between the system ground and the analog audio ground of the power signal output by the system power supply, and transmit the power signal after the interference signal is filtered out to the audio transmission circuit; the audio transmission circuit is used to transmit the audio differential signal received by the wireless receiving chip to the audio device when receiving the power signal after the interference signal is filtered out. By setting the isolation voltage stabilizing circuit to achieve isolation between the system ground and the analog audio ground, the voltage drop of the ground network at both ends is reduced when the audio device uses USB to power the wireless receiver, thereby solving the noise problem when the wireless receiver outputs audio during USB power supply.

[0051] Reference Figure 2 , Figure 2 The second embodiment of the wireless receiver of the present invention is a schematic diagram of the structure of the second embodiment of the wireless receiver of the present invention. The second embodiment of the wireless receiver of the present invention is proposed based on the first embodiment of the wireless receiver.

[0052] In this embodiment, the isolation voltage stabilization circuit 10 includes a first resistor R1 ; the first resistor R1 is arranged between the system ground G and the analog audio ground A.

[0053] It should be noted that, due to the existence of the first resistor R1, the interference signal of the system power supply through both ends of the USB ground line needs to pass through the voltage division of the first resistor R1 and the analog audio ground A. Since the analog audio ground has internal resistance, its resistance value is generally between 100mΩ and 500mΩ. Taking the amplitude of the interference signal obtained by the above calculation as 18mV for illustration, the resistance value of the first resistor R1 can be between 100Ω and 1KΩ. Assuming that the resistance value of the analog audio ground is 200mΩ, the resistance of the first resistor R1 can be selected as 330Ω. After setting the first resistor R1, the interference signal at both ends of the USB ground line (between the system ground and the analog audio ground) becomes 18mV×200mΩ÷(200mΩ+330Ω)≈11uV. And 11uV is much smaller than the voltage amplitude of the normal audio signal (1mV~10mV). Therefore, the first resistor R1 realizes the isolation of the wireless receiver system ground and the audio analog ground, and improves the signal-to-noise ratio of the audio output.

[0054] Furthermore, the isolation voltage stabilization circuit 10 also includes a ripple filtering unit 101; the first end of the ripple filtering unit 101 is connected to the bus of the system power supply, the second end of the ripple filtering unit 101 is connected to the first end of the audio transmission circuit 20, and the third end of the ripple filtering unit 101 is simultaneously connected to one end of the first resistor R1 and the analog audio ground.

[0055] It should be noted that the ripple filtering unit 101 can be used to filter out ripples in the power signal and transmit the power signal after the ripple is filtered out to the audio transmission circuit 20 .

[0056] It should be understood that, since the wireless receiver and the hardware devices and circuits therein are inevitably affected by the electromagnetic interference in the environment during actual use, the amplitude of the power signal may fluctuate (i.e., ripple) during transmission. The ripple filtering unit 101 can filter the ripple of the power signal, for example, various DC voltage regulator chips or switch voltage regulator function circuits can be selected.

[0057] In a possible implementation, the ripple filtering unit 101 includes a first capacitor C1, a second capacitor C2, and an LDO chip; a first end of the LDO chip is connected to a bus of the system power supply and a first end of the first capacitor C1 at the same time, a second end of the LDO chip is connected to a first end of the second capacitor C2 and a first end of the audio transmission circuit 20 at the same time, and a second end of the first capacitor C1 is connected to the analog audio ground, a second end of the second capacitor C2, and a third end of the LDO chip at the same time.

[0058] It should be noted that the LDO chip can be a low voltage difference linear voltage regulator chip. The LDO chip receives the power supply signal and forms a regulated power supply of the wireless receiver with the first capacitor C1 and the second capacitor C2. For example, the power supply rejection ratio of the LDO chip can be adjusted to -70dB, which is 1 / 3162 times. That is, the ripple in the regulated power supply output by the LDO chip to power the wireless receiver is almost negligible.

[0059] This embodiment provides an isolation voltage stabilization circuit including a first resistor; wherein the first resistor is provided between the system ground and the analog audio ground. The interference signal between the system ground and the analog audio ground is reduced to a voltage amplitude far less than that of a normal audio signal. A ripple filtering unit including a first capacitor, a second capacitor and an LDO chip is provided at the same time, which is used to filter out ripples in the power supply signal and transmit the power supply signal after ripple filtering to the audio transmission circuit. This solves the noise problem when the wireless receiver outputs audio during USB power supply.

[0060] Reference Figure 3 , Figure 3 The third embodiment of the wireless receiver of the present invention is proposed based on the above embodiments of the wireless receiver.

[0061] In this embodiment, the audio transmission circuit 20 includes second to fifth resistors, third to fifth capacitors, and an operational amplifier OP1.

[0062] The in-phase input terminal of the operational amplifier OP1 is simultaneously connected to the first end of the second resistor R2, the first end of the third resistor R3, and the first end of the third capacitor C3; the inverting input terminal of the operational amplifier OP1 is simultaneously connected to the first end of the fourth resistor R4, the first end of the fifth resistor R5, and the first end of the fourth capacitor C4; the output terminal of the operational amplifier OP1 is simultaneously connected to the second end of the fifth resistor R5 and the second end of the fourth capacitor C4; the second end of the second resistor R2 is connected to the differential positive signal line of the wireless receiving chip 30; the second end of the third resistor R3 is connected to the second end of the third capacitor C3 and receives the bias AC ground signal VREF The second end of the fourth resistor R4 is connected to the differential negative signal line of the wireless receiving chip 30, the power supply end of the operational amplifier OP1 is connected to the first end of the fifth capacitor C5 and the second end of the isolation voltage stabilizing circuit 10, the second end of the fifth resistor R5 is connected to the analog audio ground A, and the common end of the operational amplifier OP1 is connected to the analog audio ground A.

[0063] It should be noted that the operational amplifier OP1 and the second to fifth resistors and the third to fourth capacitors form a standard differential amplifier circuit, which can be used to amplify the audio differential signal (MIC_P and MIC_N in the figure) received by the wireless receiving chip 30, and can also suppress the common mode noise signal. The fifth capacitor C5 can be used as a power input voltage stabilization and filtering capacitor for the operational amplifier OP1. Among them, the bias AC ground signal V REF A bias can be provided for the output voltage amplitude of the operational amplifier OP1 to adapt to the driving use of the audio device. At the same time, the biased AC ground signal is also a reference signal for the AC ground of the audio differential signal.

[0064] It should be understood that the operational amplifier OP1 can use an operational amplifier chip with low power consumption and high common mode rejection ratio. For example, the TLV9062 chip has a power supply voltage of 1.8V~5.5V, a static current of 0.538mA, and a common mode rejection ratio ≥80dB@1KHz. Since the current of the operational amplifier chip is small, the voltage drop across the first resistor R1 set in the above-mentioned isolation voltage stabilization circuit 10 is small. Taking 330Ω as an example, the voltage drop is equal to 330Ω×0.538mA≈177mV. Assuming that the minimum voltage drop required for the above-mentioned LDO chip to work is 200mV, plus the voltage drop of 177mV across the first resistor R1, the voltage drop under the condition of ensuring the normal operation of the LDO chip is 200mV+177mV=377mV. Since the operating voltage of the operational amplifier OP1 can work at 1.8V~5.5V. If the output voltage of the LDO is set to 2.0V, the voltage for the normal operation of the wireless receiver is usually 3.0V~4.4V or the bus voltage V of the system power supply. BUS Therefore, the resistance value of the first resistor R1 can be set according to actual needs, which can not only ensure the normal operation of the LDO chip and the operational amplifier OP1, but also achieve the isolation of the wireless receiver system ground and the analog audio ground.

[0065] Furthermore, the audio transmission circuit 20 also includes a sixth capacitor C6 and a seventh capacitor C7; the first end of the sixth capacitor C6 is connected to the differential negative signal line of the wireless receiving chip 30, the second end of the sixth capacitor C6 is connected to the second end of the second resistor R2, the first end of the seventh capacitor C7 is connected to the differential negative signal line of the wireless receiving chip 30, and the second end of the seventh capacitor C7 is connected to the second end of the fourth resistor R4.

[0066] It should be noted that the sixth capacitor C6 and the seventh capacitor C7 can be used to isolate the DC voltage signal in the audio differential signal to prevent the rear operational amplifier OP1 from amplifying the DC voltage signal in the audio differential signal.

[0067] Furthermore, in order to provide the above-mentioned biased AC ground signal, the wireless receiver also includes: a signal bias circuit 40; the input end of the signal bias circuit 40 is connected to the second end of the isolation voltage stabilization circuit 10, and the output end of the signal bias circuit 40 is connected to the second end of the third resistor R3 in the audio transmission circuit 20.

[0068] It should be noted that the signal bias circuit 40 can be used to bias the power signal to generate a biased AC ground signal V REF and the bias AC ground signal V REF The audio transmission circuit 20 can also be used to receive the bias AC ground signal V REF At the same time, the AC signal in the audio differential signal of the wireless receiving chip 30 is amplified.

[0069] In a possible implementation, the signal bias circuit 40 includes a sixth resistor R6, a seventh resistor R7 and an eighth capacitor C8; the first end of the sixth resistor R6 is connected to the second end of the isolation voltage stabilization circuit 10, the second end of the sixth resistor R6 is simultaneously connected to the first end of the seventh resistor R7, the first end of the eighth capacitor C8 and the second end of the third resistor R3, and the second end of the seventh resistor R7 and the second end of the eighth capacitor C8 are both connected to the analog audio ground.

[0070] It should be understood that the amplitude of the bias AC ground signal can be adjusted by adjusting the resistance ratio of the sixth resistor R6 and the seventh resistor R7.

[0071] Furthermore, the wireless receiver also includes a DC filtering circuit 50 composed of an eighth resistor R8, a ninth resistor R9 and a ninth capacitor C9; the first end of the ninth capacitor C9 is connected to the third end of the audio transmission circuit 20, the second end of the ninth capacitor C9 is connected to the first end of the eighth resistor R8, the second end of the eighth resistor R8 is connected to the first end of the ninth resistor R9 and the audio device, and the second end of the ninth resistor R9 is connected to the analog audio ground.

[0072] It should be noted that the ninth capacitor C9 is used to isolate the DC output of the operational amplifier OP1, and the eighth resistor R8 is used to protect the operational amplifier OP1 to avoid chip damage caused by a short circuit at the output terminal. The ninth resistor R9 is used to discharge the ninth capacitor C9 after shutdown.

[0073] In addition, the present invention also provides a wireless audio system, referring to Figure 4 and Figure 5 , Figure 4 This is a schematic diagram of functional modules of an embodiment of the wireless audio system of the utility model; Figure 5 This is a circuit diagram of an embodiment of the wireless audio system of the utility model. The wireless audio system includes the above-mentioned wireless receiver.

[0074] The audio device transmits the power signal output by the system power supply to the wireless receiver through the USB interface, and the wireless receiver transmits the received audio differential signal to the audio device to drive the audio device to work.

[0075] Since the wireless audio system adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0076] The above description is only a preferred embodiment of the utility model, and does not limit the patent scope of the utility model. All equivalent structural changes made by using the contents of the utility model specification and drawings under the utility model concept, or directly / indirectly used in other related technical fields are included in the patent protection scope of the utility model.

Claims

1. A wireless receiver, characterized in that: The wireless receiver is applied to a wireless audio system, and the wireless receiver comprises: a wireless receiving chip, an audio transmission circuit and an isolation voltage stabilization circuit; The first end of the isolation voltage stabilizing circuit is connected to the bus of the system power supply, the second end of the isolation voltage stabilizing circuit is connected to the first end of the audio transmission circuit, the third end of the isolation voltage stabilizing circuit is connected to the system ground of the wireless audio system, the fourth end of the isolation voltage stabilizing circuit is connected to the analog audio ground of the wireless receiver, the second end of the audio transmission circuit is connected to the wireless receiving chip, and the third end of the audio transmission circuit is connected to the audio device; The isolation voltage stabilization circuit is used to isolate and filter out interference signals between the system ground and the analog audio ground of the power signal output by the system power supply, and transmit the power signal after the interference signal is filtered out to the audio transmission circuit; The audio transmission circuit is used to transmit the audio differential signal received by the wireless receiving chip to the audio device when receiving the power signal after the interference signal is filtered out.

2. The wireless receiver according to claim 1, wherein: The isolation voltage stabilization circuit comprises: a first resistor; The first resistor is arranged between the system ground and the analog audio ground.

3. The wireless receiver according to claim 2, wherein: The isolation voltage stabilization circuit further includes: a ripple filtering unit; The first end of the ripple filtering unit is connected to the bus of the system power supply, the second end of the ripple filtering unit is connected to the first end of the audio transmission circuit, and the third end of the ripple filtering unit is simultaneously connected to one end of the first resistor and the analog audio ground; The ripple filtering unit is used to filter out ripples in the power supply signal and transmit the power supply signal after the ripple is filtered out to the audio transmission circuit.

4. The wireless receiver according to claim 3, wherein: The ripple filtering unit includes: a first capacitor, a second capacitor and an LDO chip; The first end of the LDO chip is connected to the bus of the system power supply and the first end of the first capacitor at the same time, the second end of the LDO chip is connected to the first end of the second capacitor and the first end of the audio transmission circuit at the same time, and the second end of the first capacitor is connected to the analog audio ground, the second end of the second capacitor and the third end of the LDO chip at the same time.

5. The wireless receiver according to claim 1, wherein: The audio transmission circuit comprises: second to fifth resistors, third to fifth capacitors and an operational amplifier; The in-phase input terminal of the operational amplifier is simultaneously connected to the first end of the second resistor, the first end of the third resistor and the first end of the third capacitor, the inverting input terminal of the operational amplifier is simultaneously connected to the first end of the fourth resistor, the first end of the fifth resistor and the first end of the fourth capacitor, the output terminal of the operational amplifier is simultaneously connected to the second end of the fifth resistor and the second end of the fourth capacitor, the second end of the second resistor is connected to the differential positive signal line of the wireless receiving chip, the second end of the third resistor is connected to the second end of the third capacitor and receives the biased AC ground signal; the second end of the fourth resistor is connected to the differential negative signal line of the wireless receiving chip, the power supply terminal of the operational amplifier is connected to the first end of the fifth capacitor and the second end of the isolation voltage stabilizing circuit, the second end of the fifth resistor is connected to the analog audio ground, and the common terminal of the operational amplifier is connected to the analog audio ground.

6. The wireless receiver according to claim 5, characterized in that The audio transmission circuit further includes: a sixth capacitor and a seventh capacitor; The first end of the sixth capacitor is connected to the differential negative signal line of the wireless receiving chip, the second end of the sixth capacitor is connected to the second end of the second resistor, the first end of the seventh capacitor is connected to the differential negative signal line of the wireless receiving chip, and the second end of the seventh capacitor is connected to the second end of the fourth resistor.

7. The wireless receiver according to claim 5, characterized in that The wireless receiver further includes: a signal bias circuit; The input end of the signal bias circuit is connected to the second end of the isolation voltage stabilization circuit, and the output end of the signal bias circuit is connected to the second end of the third resistor in the audio transmission circuit; The signal bias circuit is used to perform bias processing on the power supply signal to generate a biased AC ground signal, and transmit the biased AC ground signal to the audio transmission circuit; The audio transmission circuit is further used to amplify the AC signal in the audio differential signal of the wireless receiving chip when receiving the biased AC ground signal.

8. The wireless receiver according to claim 7, wherein: The signal bias circuit comprises: a sixth resistor, a seventh resistor and an eighth capacitor; The first end of the sixth resistor is connected to the second end of the isolation voltage stabilization circuit, the second end of the sixth resistor is simultaneously connected to the first end of the seventh resistor, the first end of the eighth capacitor and the second end of the third resistor, and the second end of the seventh resistor and the second end of the eighth capacitor are both connected to the analog audio ground.

9. The wireless receiver according to claim 1, wherein: The wireless receiver further comprises: a DC filter circuit composed of an eighth resistor, a ninth resistor and a ninth capacitor; The first end of the ninth capacitor is connected to the third end of the audio transmission circuit, the second end of the ninth capacitor is connected to the first end of the eighth resistor, the second end of the eighth resistor is connected to the first end of the ninth resistor and the audio device, and the second end of the ninth resistor is connected to the analog audio ground.

10. A wireless audio system, characterized in that: The wireless audio system comprises: an audio device and a wireless receiver according to any one of claims 1 to 9; The audio device transmits the power signal output by the system power supply to the wireless receiver through the USB interface, and the wireless receiver transmits the received audio differential signal to the audio device to drive the audio device to work.

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