Control circuit of a projection device and projection device

Abstract

The utility model discloses a control circuit and projection device of projection device, control circuit includes: audio filter synthesis module is used for the first audio signal and second audio signal synthesis audio signal of receiving, wherein, audio filter synthesis module is used for still to the first audio signal and second audio signal of before synthesis filters and / or to the audio signal filters and handles, power amplifier module is respectively with audio filter synthesis module, loudspeaker module electricity is connected, power amplifier module is used for sending to loudspeaker module after the power amplifier handles to the audio signal, to make loudspeaker module according to audio signal plays sound, through audio filter synthesis module to the first audio signal and second audio signal before synthesis filters and / or to the audio signal filters and handles, to improve the quality of sound.

Description

Technical Field

[0001] This utility model relates to the technical field of projection devices, and in particular to a control circuit and projection device for a projection device. Background Technology

[0002] In a sound system, the left and right channels refer to two independent audio tracks. The left channel primarily plays audio signals from the left side and is typically output through the left speaker. The right channel primarily plays audio signals from the right side and is typically output through the right speaker.

[0003] In existing technology, two channels can be connected in a Y-shape using two resistors to output a single channel. This allows the output to control a single speaker using a single channel signal, eliminating the need for a separate speaker. However, this direct connection method may reduce sound quality. Summary of the Invention

[0004] In view of the problems faced by the prior art, this utility model provides a control circuit and projection device for a projection device to improve sound quality.

[0005] To achieve the above objectives, the present invention employs the following technical means: The first aspect of this utility model provides a control circuit for a projection device, comprising: An audio filtering and synthesis module is used to synthesize an audio signal from a received first audio signal and a second audio signal. The audio filtering and synthesis module is also used to filter the first audio signal and the second audio signal before synthesis, and / or to filter the audio signal. The power amplifier module is electrically connected to the audio filtering and synthesis module and the speaker module respectively. The power amplifier module is used to process the audio signal and send it to the speaker module so that the speaker module can play sound according to the audio signal.

[0006] In some embodiments, the audio filtering and synthesis module includes: A first audio receiving module is used to receive the first audio signal; The second audio receiving module is used to receive the second audio signal; An audio synthesis module is electrically connected to the first audio receiving module and the second audio receiving module respectively. The audio synthesis module is used to synthesize the first audio signal and the second audio signal into an audio signal. The first audio receiving module and the second audio receiving module are further configured to filter the first audio signal and the second audio signal before synthesis, respectively; and / or the audio synthesis module is further configured to filter the audio signal.

[0007] In some embodiments, the first audio receiving module includes: Forty-second capacitor; The 37th resistor has its first terminal electrically connected to the second terminal of the 42nd capacitor, and its second terminal is electrically connected to the audio synthesis module; and / or The second audio receiving module includes: Forty-fifth capacitor; The 39th resistor has its first terminal electrically connected to the second terminal of the 45th capacitor, and the second terminal of the 39th resistor is electrically connected to the audio synthesis module; and / or The audio synthesis module includes: The forty-third capacitor has its first terminal electrically connected to both the first audio receiving module and the second audio receiving module. The first end of the thirty-eighth resistor is electrically connected to the second end of the forty-third capacitor, and the second end of the thirty-eighth resistor is electrically connected to the power amplifier module.

[0008] In some embodiments, it also includes: A filtering module is electrically connected between the power amplifier module and the speaker module. The filtering module is used to filter the audio signal and send it to the speaker module so that the speaker module can play sound according to the audio signal.

[0009] In some embodiments, the filtering module includes: A first filtering module is electrically connected between the first output terminal of the power amplifier module and the first terminal of the speaker module, and performs filtering processing on the audio signal; and / or The second filtering module is electrically connected between the second output terminal of the power amplifier module and the second terminal of the speaker module, and performs filtering processing on the audio signal.

[0010] In some embodiments, when the filtering module includes the first filtering module, the first filtering module includes: The third inductor has its first end electrically connected to the first output end of the power amplifier module. The fortieth capacitor has its first terminal electrically connected to the second terminal of the third inductor and the first terminal of the speaker module, and its second terminal is grounded; and / or When the filtering module includes the second filtering module, the second filtering module includes: The fourth inductor has its first end electrically connected to the second output terminal of the power amplifier module; The forty-fourth capacitor has its first terminal electrically connected to the second terminal of the fourth inductor and the second terminal of the speaker module, and its second terminal is grounded.

[0011] In some embodiments, it also includes: A boost module is electrically connected to the power amplifier module and is used to boost the voltage provided by the power supply terminal to a set value to power the power amplifier module.

[0012] In some embodiments, the boost module includes: The second inductor has its first end electrically connected to the power supply terminal. The fifth diode has its first terminal electrically connected to the second terminal of the second inductor; The first terminal of the second capacitor is electrically connected to the second terminal of the fifth diode and the power amplifier module, and the second terminal of the second capacitor is grounded. The 37th capacitor has its first terminal electrically connected to the first terminal of the second capacitor, and its second terminal is electrically connected to the second terminal of the second capacitor. The 36th capacitor has its first terminal electrically connected to the first terminal of the second capacitor, and its second terminal electrically connected to the second terminal of the second capacitor.

[0013] In some embodiments, it also includes: The lyrics projection module is used to receive video signals and project lyrics outward based on the video signals.

[0014] A second aspect of this invention provides a projection device, including the control circuit of the projection device of the first aspect.

[0015] Compared with the prior art, the control circuit and projection device of the projection device of this utility model have the following advantages: The audio filtering and synthesis module filters the first and second audio signals before synthesis, and / or filters the audio signals to improve the sound quality. Attached Figure Description

[0016] Figure 1 A circuit diagram of the control circuit for the audio section of a projection device provided in an embodiment of this utility model; Figure 2 A circuit diagram of the control circuit of the main control part of the projection device provided in an embodiment of the present invention; Figure 3Another circuit diagram of the control circuit for the audio section of the projection device provided in an embodiment of the present invention; Figure 4 A circuit diagram of the connector for the video portion of a projection device provided in an embodiment of this utility model; Figure 5 A circuit diagram of the light source control circuit for the video portion of a projection device provided in an embodiment of this utility model.

[0017] Explanation of reference numerals in the accompanying drawings for specific embodiments: Audio Synthesis Module 113 Power Amplifier Module 120 Boost module 130 Voltage setting module 140 Voltage filter module 150 Boost filter module 160 Filtering module 170 First filtering module 171 Second filter module 172 LCD panel control module 210 Main control module 211 Light source control module 220 Detailed Implementation

[0018] To better understand the above-mentioned objectives, features, and advantages of this utility model, the present utility model will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features of this utility model can be combined with each other.

[0019] The following description sets forth many specific details in order to provide a full understanding of the present invention. The described embodiments are only some, not all, of the embodiments of the present invention.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0021] It should be further noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0022] In this utility model, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone, where A and B can be singular or plural. The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and drawings of this utility model are used to distinguish similar objects, not to describe a specific order or sequence.

[0023] In this embodiment of the invention, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" or "for example" in this embodiment of the invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0024] This utility model embodiment provides a projection device, which includes a control circuit section, such as... Figure 1 As shown, the control circuit includes an audio filtering and synthesis module 110, a power amplifier module 120, a boost module 130, a voltage setting module 140, a voltage filtering module 150, and a boost filtering module 160.

[0025] like Figure 1 As shown, the audio filtering and synthesis module 110 is used to receive a first audio signal and a second audio signal. For example, the first audio signal is a left channel signal and the second audio signal is a right channel signal. The left channel is mainly responsible for playing the audio signal from the left side, and usually controls the left speaker to produce sound through the left channel signal. The right channel is mainly responsible for playing the audio signal from the right side, and usually controls the right speaker to produce sound through the right channel signal. In this embodiment, the audio filtering and synthesis module 110 is used to synthesize the received first audio signal and the second audio signal into an audio signal. The audio filtering and synthesis module is also used to filter the first audio signal and the second audio signal before synthesis, and / or filter the audio signal, and then control a speaker to play sound through the audio signal to improve the sound quality.

[0026] like Figure 2As shown, the first and second audio signals received by the audio filtering and synthesis module 110 are sent by the main control module 211. For example, the main control module 211 can be an LQFP48 chip. The pins of the main control module 211 that send the first and second audio signals are pin 39 (i.e., DACL pin) and pin 38 (i.e., DAR pin), respectively. The DACL pin of the main control module 211 is electrically connected to one of the receiving terminals of the audio filtering and synthesis module 110 to receive the first audio signal. The DAR pin of the main control module 211 is electrically connected to the other receiving terminal of the audio filtering and synthesis module 110 to receive the second audio signal. The second pin of the main control module 211 (i.e., VBAT pin) is electrically connected to the battery or charging port (such as a USB charging port). The second pin of the main control module 211 is also grounded through the fifth capacitor C5 and the sixth capacitor C6, respectively. The fourth pin of the main control module 211 (i.e., IOVDD pin) is grounded through the seventh capacitor C7. The 13th pin of the main control module 211 (i.e., VSS pin) is grounded.

[0027] More specifically, the sources of the first and second audio signals can be: the main control module retrieves pre-stored first and second audio signals from the memory and sends them to the audio filtering and synthesis module 110; or the main control module uses a communication module (such as USB, Bluetooth, etc.) to receive the first and second audio signals sent by external devices (such as mobile phones, computers, etc.) and sends them to the audio filtering and synthesis module 110; or the main control module retrieves pre-stored audio signals from the memory, divides the audio signals into first and second audio signals, and sends them to the audio filtering and synthesis module 110; or the main control module uses a communication module (such as USB, Bluetooth, etc.) to receive audio signals sent by external devices (such as mobile phones, computers, etc.), divides the audio signals into first and second audio signals, and sends them to the audio filtering and synthesis module 110, etc. This embodiment does not specifically limit the sources of the first and second audio signals.

[0028] like Figure 1 As shown, the audio filtering and synthesis module 110 includes a first audio receiving module 111, a second audio receiving module 112, and an audio synthesis module 113.

[0029] like Figure 1As shown, the first audio receiving module 111 includes a first end and a second end. The first end of the first audio receiving module 111 serves as a receiving end to receive the first audio signal and also constitutes one of the receiving ends of the audio filtering and synthesis module 110. The second end of the first audio receiving module 111 serves as a transmitting end to send the received first audio signal to the audio synthesis module 113. The first audio receiving module 111 is also used to filter the first audio signal before synthesis (i.e. before sending it to the audio synthesis module 113).

[0030] like Figure 1 As shown, the second audio receiving module 112 includes a first end and a second end. The first end of the second audio receiving module 112 serves as a receiving end for receiving the second audio signal and also constitutes another receiving end of the audio filtering and synthesis module 110. The second end of the second audio receiving module 112 serves as a transmitting end for sending the received second audio signal to the audio synthesis module 113. The second audio receiving module 112 is also used to filter the second audio signal before synthesis (i.e. before sending it to the audio synthesis module 113).

[0031] like Figure 1 As shown, the audio synthesis module 113 includes a first end and a second end. The first end of the audio synthesis module 113 serves as a receiving end and is electrically connected to the second end (i.e., its transmitting end) of the first audio receiving module 111 and the second end (i.e., its transmitting end) of the second audio receiving module 112, and is used to receive the first audio signal and the second audio signal. The audio synthesis module 113 is used to synthesize (e.g., mix) the received first audio signal and the second audio signal into a complete audio signal. The second end of the audio synthesis module 113 serves as a transmitting end and is used to send the audio signal to the power amplifier module 120. The second end of the audio synthesis module 113 also constitutes the transmitting end of the audio filtering synthesis module 110. The audio synthesis module 113 is also used to filter the audio signal.

[0032] In some embodiments, such as Figure 1 As shown, the first audio receiving module 111 includes a forty-second capacitor C42 and a thirty-seventh resistor R37. The first end of the forty-second capacitor C42 constitutes the first end of the first audio receiving module 111, and the first end of the thirty-seventh resistor R37 is electrically connected to the second end of the forty-second capacitor C42. The second end of the thirty-seventh resistor R37 constitutes the second end of the first audio receiving module 111.

[0033] In some embodiments, such as Figure 1As shown, the second audio receiving module 112 includes a forty-fifth capacitor C45 and a thirty-ninth resistor R39. The first end of the forty-fifth capacitor C45 constitutes the first end of the second audio receiving module 112, and the first end of the thirty-ninth resistor R39 is electrically connected to the second end of the forty-fifth capacitor C45. The second end of the thirty-ninth resistor R39 constitutes the second end of the second audio receiving module 112.

[0034] In some embodiments, such as Figure 1 As shown, the audio synthesis module 113 includes a forty-third capacitor C43 and a thirty-eighth resistor R38. The first end of the forty-third capacitor C43 forms the first end of the audio synthesis module 113, and the first end of the thirty-eighth resistor R38 is electrically connected to the second end of the forty-third capacitor C43. The second end of the thirty-eighth resistor R38 forms the second end of the audio synthesis module 113.

[0035] In other embodiments, only the first and second audio signals before synthesis may be filtered; or only the audio signals may be filtered; correspondingly, the capacitors in the audio synthesis module 113 or the capacitors in the first audio receiving module 111 and the second audio receiving module 112 may be omitted.

[0036] like Figure 1As shown, the power amplifier module 120 is electrically connected to the audio filtering and synthesis module 110 and the speaker module, respectively. The power amplifier module 120 can be a power amplifier chip; for example, the model of the power amplifier module 120 is XA9812B. The power amplifier module 120 includes pins 1 to 8, wherein pin 6 (i.e., the INP pin) of the power amplifier module 120 is electrically connected to the transmitting end of the audio filtering and synthesis module 110 as a receiving end to receive audio signals. The speaker module includes a speaker, which includes a first input end and a second input end. Pins 4 (i.e., the first output end of the power amplifier module 120, i.e., the OUTP pin) and pin 5 (i.e., the second output end of the power amplifier module 120, i.e., the OUTN pin) of the power amplifier module 120 are electrically connected to the first input end and the second input end of the speaker, respectively. For example, the power amplifier module 120 and the speaker are electrically connected through a fifth connector J5. The power amplifier module 120 is used to amplify the received audio signals and then transmit them through its own pin 4. Pin 1 and pin 5 are sent to the speaker module so that the speaker module plays sound according to the audio signal; pin 7 (i.e., INN pin) of power amplifier module 120 is connected to analog ground through the 34th resistor R34 and the 41st capacitor C41 connected in series; pin 9 (i.e., PGND pin) of power amplifier module 120 is grounded; pin 8 (i.e., CTR pin) of power amplifier module 120 is electrically connected to the 30th resistor R30; power amplifier module 120 receives switch signals through the 30th resistor R30 to operate or stop operating. The switch signal can be sent by the main control module 211, i.e., pin 9 (i.e., MUTE pin) of the main control module 211 is electrically connected to the 30th resistor R30; more specifically, the switch signal can be the switch signal generated by the button collected by the main control module 211, or the switch signal sent by the main control module to external devices (such as mobile phones, computers, etc.) through the communication module (such as USB, Bluetooth, etc.). This embodiment does not specifically limit the source of the switch signal.

[0037] The loudspeaker described in this embodiment is an electroacoustic device that converts electrical signals into sound. Ordinary audio signals are very weak and cannot drive a loudspeaker to produce sound; they must be amplified by voltage and power before they can drive the loudspeaker. The power amplifier module 120 in this embodiment amplifies the audio signal and provides a certain power output to drive the loudspeaker to produce sound. The power amplifier module 120 and the loudspeaker can be two different modules, or the power amplifier module 120 can be integrated into the loudspeaker itself to form a loudspeaker with power amplifier functionality; this embodiment does not impose specific limitations on this.

[0038] like Figure 1As shown, the boost module 130 is electrically connected to the power supply terminal (i.e., +5V-IN). The boost module 130 is also electrically connected to the power amplifier module 120 through its second pin (i.e., SW pin) and third pin (i.e., PVDD pin). The boost module 130 is used to boost the voltage provided by the power supply terminal (i.e., +5V-IN) to a set value to power the power amplifier module 120.

[0039] In some embodiments, such as Figure 1 As shown, the boost module 130 includes a second inductor L2, a fifth diode D5, a second capacitor EC2, a thirty-seventh capacitor C37, and a thirty-sixth capacitor C36. The first terminal of the second inductor L2 is electrically connected to the power supply terminal (i.e., +5V-IN), and the second terminal of the second inductor L2 is electrically connected to the second pin of the power amplifier module 120. The first terminal of the fifth diode D5 is electrically connected to the second terminal of the second inductor L2. The first terminal of the second capacitor EC2 is electrically connected to the second terminal of the fifth diode D5, and the second terminal of the second capacitor EC2 is grounded (i.e., electrically connected to the ground terminal GND). The first and second terminals of the thirty-seventh capacitor C37 are electrically connected to the first and second terminals of the second capacitor EC2, respectively. The first and second terminals of the thirty-sixth capacitor C36 are also electrically connected to the first and second terminals of the second capacitor EC2, respectively. In other embodiments, one or two of the capacitors in the boost module 130 can be removed from the second capacitor EC2, the thirty-seventh capacitor C37, and the thirty-sixth capacitor C36.

[0040] like Figure 1 As shown, the voltage setting module 140 is electrically connected to the first pin (i.e., the FV pin) and the third pin of the power amplifier module 120 (and also electrically connected to the boost module 130). The voltage setting module 140 can set the voltage value input from the boost module 130 to the third pin of the power amplifier module 120.

[0041] In some embodiments, such as Figure 1 As shown, the voltage setting module 140 includes a ninth resistor R9 and a thirty-fifth capacitor C35. The first end of the ninth resistor R9 is electrically connected to the third pin of the power amplifier module 120 (and simultaneously electrically connected to the boost module 130). The second end of the ninth resistor R9 is electrically connected to the first pin of the power amplifier module 120. The first end of the thirty-fifth capacitor C35 is electrically connected to the second end of the ninth resistor R9, and the second end of the thirty-fifth capacitor C35 is grounded.

[0042] like Figure 1 As shown, the voltage filtering module 150 is electrically connected to the power supply terminal (i.e., +5V-IN) (and also electrically connected to the boost module 130). The voltage filtering module 150 can filter the voltage supplied by the power supply terminal to the boost module 130, reduce the ripple and noise in the voltage, thereby improving the stability and reliability of the voltage supplied by the power supply terminal.

[0043] In some embodiments, such as Figure 1 As shown, the voltage filtering module 150 includes a first capacitor EC1 and a thirtieth capacitor C30. The first terminal of the first capacitor EC1 is electrically connected to the power supply terminal (i.e., +5V-IN), and the second terminal of the first capacitor EC1 is grounded. The first and second terminals of the thirtieth capacitor C30 are electrically connected to the first and second terminals of the first capacitor EC1, respectively.

[0044] like Figure 1 As shown, the boost filter module 160 is electrically connected to the boost module 130. The boost filter module 160 can filter the boost module 130 to reduce voltage ripple and noise, thereby improving the stability and reliability of the voltage supplied by the power supply terminal.

[0045] In some embodiments, such as Figure 1 As shown, the boost filter module 160 includes a 26th resistor R26 and a 28th capacitor C28. The first end of the 26th resistor R26 is electrically connected to the second end of the second inductor L2, the first end of the 28th capacitor C28 is electrically connected to the second end of the 26th resistor R26, and the second end of the 28th capacitor C28 is grounded.

[0046] In some embodiments, such as Figure 2 As shown, a filter module 170 is electrically connected between the power amplifier module 120 and the speaker module. The filter module 170 is used to filter the audio signal and send it to the speaker module so that the speaker module can play sound according to the audio signal.

[0047] In some embodiments, such as Figure 3 As shown, since the audio signal driving the speaker is an AC signal, it is generally necessary to electrically connect a filter module to both the first and second ends of the speaker for filtering. Of course, if the sound effect requirements are not high, the filter module can be electrically connected to only the first or second end of the speaker for filtering. Therefore, the filter module 170 includes a first filter module 171 and / or a second filter module 172. The first filter module 171 is electrically connected between the first output end of the power amplifier module 120 and the first end of the speaker module, and performs filtering on the audio signal sent to the first end of the speaker module. The second filter module 172 is electrically connected between the second output end of the power amplifier module 120 and the second end of the speaker module, and performs filtering on the audio signal sent to the second end of the speaker module.

[0048] In some embodiments, such as Figure 3As shown, the first filter module 171 includes a third inductor L3 and a fortieth capacitor C40. The first end of the third inductor L3 is electrically connected to the first output end of the power amplifier module 120. The first end of the fortieth capacitor C40 is electrically connected to the second end of the third inductor L3 and the first end of the speaker module, respectively. The second end of the fortieth capacitor C40 is grounded.

[0049] In some embodiments, such as Figure 3 As shown, the second filter module 172 includes a fourth inductor L4 and a forty-fourth capacitor C44. The first end of the fourth inductor L4 is electrically connected to the second output end of the power amplifier module 120. The first end of the forty-fourth capacitor C44 is electrically connected to the second end of the fourth inductor L4 and the second end of the speaker module, respectively. The second end of the forty-fourth capacitor C44 is grounded.

[0050] In some embodiments, the control circuit further includes a lyrics projection module, which receives a video signal and projects lyrics outward based on the video signal. The video signal includes lyrics information. The source of the video signal received by the lyrics projection module may be that the main control module retrieves a pre-stored video signal from the memory and sends it to the lyrics projection module, or the main control module uses a communication module (such as USB, Bluetooth, etc.) to receive a video signal sent by an external device (such as a mobile phone, computer, etc.) and sends the video signal to the lyrics projection module. Alternatively, the main control module may retrieve a pre-stored audio signal from the memory, convert it into a video signal, and then send it to the lyrics projection module, or the main control module uses a communication module (such as USB, Bluetooth, etc.) to receive an audio signal sent by an external device (such as a mobile phone, computer, etc.), convert it into a video signal, and then send it to the lyrics projection module. This embodiment does not specifically limit the source of the video signal.

[0051] The lyrics projection module can employ single-LCD projector technology. The working principle of a single-LCD projector is that white light emitted from a light source passes through a liquid crystal panel and an optical system, ultimately projecting an image onto a screen. The lyrics projection module is the electronic control component of a single-LCD projector, comprising a liquid crystal panel (LCD) control section and a light source control section, as shown below. Figure 2 , Figure 4 and Figure 5 As shown, the lyrics projection module includes a main control module 210 and a light source control module 220.

[0052] In some embodiments, such as Figure 2 and Figure 4As shown, the LCD panel control module 210 includes a main control module 211. The main control module 211 controls the LCD panel using pins 32 (RS pin), 31 (CS pin), 29 (RESET pin), 26 (SDA pin), and 25 (SCL pin). The main control module 211 is electrically connected to the LCD panel via a second connector J2. The second connector J2 includes pins 1-8. Pins 1 and 7 of the second connector J2 are electrically connected to a 3.3V power supply terminal (3.3V_OUT). Pin 7 of the second connector J2 is also grounded through a 27th capacitor. Pin 2 is grounded. Pin 3 of the second connector J2 is electrically connected to the RESET pin of the main control module 211. Pin 4 of the second connector J2 is electrically connected to the RS pin of the main control module 211. Pin 5 of the second connector J2 is electrically connected to the SDA pin of the main control module 211 through the thirteenth resistor R13. Pin 6 of the second connector J2 is electrically connected to the SCL pin of the main control module 211 through the fourteenth resistor R14. Pin 8 of the second connector J2 is electrically connected to the CS pin of the main control module 211. The main control module 211 sends the video signal to the LCD panel through the second connector J2. After receiving the video signal, the LCD panel displays the lyrics line by line. In other embodiments, other control modules can be used to control the LCD panel instead of the main control module 211.

[0053] In some embodiments, such as Figure 5As shown, the light source control module 220 includes a fifth MOSFET Q5, which is electrically connected to a light source (such as an LED) via a third connector J3. The third connector J3 includes a first terminal and a second terminal. The first terminal of the third connector J3 is electrically connected to the 3.3V power supply terminal and the first terminal of the light source, respectively. The second terminal of the third connector J3 is electrically connected to the second terminal of the light source and the drain of the fifth MOSFET Q5, respectively. The source of the fifth MOSFET Q5 is grounded. The source and gate of the fifth MOSFET Q5 are connected via a thirty-fifth resistor R35. The gate of the fifth MOSFET Q5 receives the light source control signal via a thirty-second resistor R32 to control the light source. The light source can be turned on or off. When the light source is on, it can emit white light and, in conjunction with the optical system, project the lyrics displayed on the LCD panel outward (such as onto a screen). The light source control signal can be sent by the main control module 211, that is, the 16th pin (i.e., the MOTOR_CTRL pin) of the main control module 211 is electrically connected to the 32nd resistor R32. More specifically, the source of the light source control signal can be the light source control signal generated by the button collected by the main control module 211, or the light source control signal sent by the main control module to external devices (such as mobile phones, computers, etc.) through a communication module (such as USB, Bluetooth, etc.). This embodiment does not specifically limit the source of the switch signal.

[0054] In summary, the control circuit of this utility model has the following beneficial effects: The audio filtering and synthesis module 110 filters the first and second audio signals before synthesis, and / or filters the audio signals to improve the sound quality.

[0055] The above detailed description is only a description of the preferred embodiment of this utility model and is not intended to limit the patent scope of this utility model. Therefore, all equivalent technical changes made using the content of this invention's specification and illustrations are included within the patent scope of this invention.

Claims

1. A control circuit for a projection device, characterized in that, include: An audio filtering and synthesis module is used to synthesize an audio signal from a received first audio signal and a second audio signal. The audio filtering and synthesis module is also used to filter the first audio signal and the second audio signal before synthesis, and / or to filter the audio signal. The power amplifier module is electrically connected to the audio filtering and synthesis module and the speaker module respectively. The power amplifier module is used to process the audio signal and send it to the speaker module so that the speaker module can play sound according to the audio signal.

2. The control circuit of the projection device as described in claim 1, characterized in that, The audio filtering and synthesis module includes: A first audio receiving module is used to receive the first audio signal; The second audio receiving module is used to receive the second audio signal; An audio synthesis module is electrically connected to the first audio receiving module and the second audio receiving module respectively. The audio synthesis module is used to synthesize the first audio signal and the second audio signal into an audio signal. The first audio receiving module and the second audio receiving module are further configured to filter the first audio signal and the second audio signal before synthesis, respectively; and / or the audio synthesis module is further configured to filter the audio signal.

3. The control circuit of the projection device as described in claim 2, characterized in that, The first audio receiving module includes: Forty-second capacitor; The 37th resistor has its first terminal electrically connected to the second terminal of the 42nd capacitor, and its second terminal is electrically connected to the audio synthesis module; and / or The second audio receiving module includes: Forty-fifth capacitor; The 39th resistor has its first terminal electrically connected to the second terminal of the 45th capacitor, and the second terminal of the 39th resistor is electrically connected to the audio synthesis module; and / or The audio synthesis module includes: The forty-third capacitor has its first terminal electrically connected to both the first audio receiving module and the second audio receiving module. The first end of the thirty-eighth resistor is electrically connected to the second end of the forty-third capacitor, and the second end of the thirty-eighth resistor is electrically connected to the power amplifier module.

4. The control circuit of the projection device according to any one of claims 1 to 3, characterized in that, Also includes: A filtering module is electrically connected between the power amplifier module and the speaker module. The filtering module is used to filter the audio signal and send it to the speaker module so that the speaker module can play sound according to the audio signal.

5. The control circuit of the projection device as described in claim 4, characterized in that, The filtering module includes: A first filtering module is electrically connected between the first output terminal of the power amplifier module and the first terminal of the speaker module, and performs filtering processing on the audio signal; and / or The second filtering module is electrically connected between the second output terminal of the power amplifier module and the second terminal of the speaker module, and performs filtering processing on the audio signal.

6. The control circuit of the projection device as described in claim 5, characterized in that, When the filtering module includes the first filtering module, the first filtering module includes: The third inductor has its first end electrically connected to the first output end of the power amplifier module. The fortieth capacitor has its first terminal electrically connected to the second terminal of the third inductor and the first terminal of the speaker module, and its second terminal is grounded; and / or When the filtering module includes the second filtering module, the second filtering module includes: The fourth inductor has its first end electrically connected to the second output terminal of the power amplifier module; The forty-fourth capacitor has its first terminal electrically connected to the second terminal of the fourth inductor and the second terminal of the speaker module, and its second terminal is grounded.

7. The control circuit of the projection device according to any one of claims 1 to 3, characterized in that, Also includes: A boost module is electrically connected to the power amplifier module and is used to boost the voltage provided by the power supply terminal to a set value to power the power amplifier module.

8. The control circuit of the projection device as described in claim 7, characterized in that, The boost module includes: The second inductor has its first end electrically connected to the power supply terminal. The fifth diode has its first terminal electrically connected to the second terminal of the second inductor; The first terminal of the second capacitor is electrically connected to the second terminal of the fifth diode and the power amplifier module, and the second terminal of the second capacitor is grounded. The 37th capacitor has its first terminal electrically connected to the first terminal of the second capacitor, and its second terminal is electrically connected to the second terminal of the second capacitor. The 36th capacitor has its first terminal electrically connected to the first terminal of the second capacitor, and its second terminal electrically connected to the second terminal of the second capacitor.

9. The control circuit of the projection device according to any one of claims 1 to 3, characterized in that, Also includes: The lyrics projection module is used to receive video signals and project lyrics outward based on the video signals.

10. A projection device, characterized in that, It includes the control circuit of the projection device as described in any one of claims 1 to 9.

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