A horn end audio selector

Abstract

The utility model relates to the technical field of sound system, specifically relates to a loudspeaker end audio frequency selector, it includes the selection relay and audio frequency transformer, first sensing unit, second sensing unit and controller, wherein, first sensing unit is used for the perception indoor fixed resistance power amplifier whether sends out power amplifier signal, when indoor fixed resistance power amplifier sends out power amplifier signal, the controller controls selection relay and will indoor fixed resistance loudspeaker electric connection in indoor fixed resistance power amplifier, second sensing unit is used for the perception outdoor fixed voltage power amplifier whether produces power amplifier signal, when outdoor fixed voltage power amplifier sends out power amplifier signal, the controller controls selection relay and will indoor fixed resistance loudspeaker electric connection in audio frequency transformer and outdoor fixed voltage power amplifier, the utility model provides a loudspeaker end audio frequency selector, can break through the fixed resistance, fixed voltage power amplifier boundary of large -scale building sound system, realizes a loudspeaker connection two kinds of types power amplifier, has saved outdoor fixed voltage loudspeaker, thereby has reduced the overall construction, the cost of transformation and maintenance.

Description

Technical Field

[0001] This utility model relates to the field of audio system technology, specifically to a speaker-end audio selector. Background Technology

[0002] In large buildings such as school campuses, two independent audio systems are typically required to meet the audio transmission needs of different scenarios: a multimedia music playback system and a public address system. The multimedia music playback system primarily serves the indoor environment, working in conjunction with dedicated indoor speakers distributed throughout various rooms to achieve functions such as classroom teaching and meetings. The public address system, on the other hand, is responsible for audio coverage in outdoor areas and needs to work in conjunction with dedicated outdoor speakers to achieve functions such as announcements.

[0003] In other words, existing building sound playback systems typically consist of both indoor and outdoor speakers, which increases the overall construction and renovation costs, as well as the subsequent maintenance costs. Utility Model Content

[0004] This invention addresses the technical problem of increased construction, renovation, and maintenance costs caused by the simultaneous installation of indoor and outdoor speakers in existing building sound systems. It provides a speaker-end audio selector that bridges the gap between constant impedance and constant voltage amplifiers in large building sound systems, allowing a single speaker to connect to both types of amplifiers. This eliminates the need for an outdoor constant voltage speaker, thereby reducing overall construction, renovation, and maintenance costs.

[0005] The technical solution adopted in this utility model is as follows:

[0006] A speaker-end audio selector includes a selection relay and an audio transformer. The selection relay is used to select whether to electrically connect an indoor constant-impedance speaker to an indoor constant-impedance power amplifier, or to electrically connect the indoor constant-impedance speaker to the audio transformer and an outdoor constant-voltage power amplifier.

[0007] The speaker-end audio selector further includes a first sensing unit, a second sensing unit, and a controller. The first sensing unit is used to sense whether the indoor constant-impedance power amplifier emits a power amplifier signal. When the indoor constant-impedance power amplifier emits a power amplifier signal, the controller controls the selection relay to electrically connect the indoor constant-impedance speaker to the indoor constant-impedance power amplifier. The second sensing unit is used to sense whether the outdoor constant-voltage power amplifier generates a power amplifier signal. When the outdoor constant-voltage power amplifier emits a power amplifier signal, the controller controls the selection relay to electrically connect the indoor constant-impedance speaker to the audio transformer and the outdoor constant-voltage power amplifier.

[0008] Furthermore, the speaker-end audio selector also includes a power amplifier priority selection unit, which is used to select the priority of the indoor constant impedance power amplifier and the outdoor constant voltage power amplifier connected to the indoor constant impedance speaker.

[0009] Furthermore, the common contact of the selection relay is connected to the first terminal of the indoor constant-impedance speaker, the normally closed contact of the selection relay is directly or indirectly connected to the first terminal of the indoor constant-impedance power amplifier, the normally open contact of the selection relay is connected to the first terminal on one side of the audio transformer, the coil of the selection relay is controlled by the controller to switch on and off, the second terminal of the indoor constant-impedance speaker is connected to the second terminal of the indoor constant-impedance power amplifier and the second terminal on one side of the audio transformer; the first terminal on the other side of the audio transformer is directly or indirectly connected to the first terminal of the outdoor constant-voltage power amplifier, and the second terminal on the other side of the audio transformer is connected to the second terminal of the outdoor constant-voltage power amplifier.

[0010] Furthermore, the first sensing unit includes a first resistor and a second resistor, the first end of the first resistor is connected to the first end of the indoor constant impedance power amplifier, the second end of the first resistor is connected to the first end of the second resistor and the controller, and the second end of the second resistor is connected to the second end of the indoor constant impedance power amplifier.

[0011] The second sensing unit includes a third resistor and a fourth resistor. The first end of the third resistor is connected to the first end of the outdoor constant voltage power amplifier. The second end of the third resistor is connected to the first end of the fourth resistor and the controller. The second end of the fourth resistor is connected to the second end of the outdoor constant voltage power amplifier.

[0012] Furthermore, the power amplifier priority selection unit includes a DIP switch, the first terminal of which is connected to the power supply via a thirteenth resistor and to the first terminal of a fourteenth resistor, the second terminal of which is grounded and connected to the second terminal of a fifteenth resistor, and the second terminal of the fourteenth resistor is connected to the first terminal of the fifteenth resistor and the controller.

[0013] Furthermore, the speaker-end audio selector also includes a first soft-start relay. The common contact of the first soft-start relay is connected to the normally closed contact of the selection relay. The normally closed contact of the first soft-start relay is connected to the first terminal of the indoor constant-impedance power amplifier. The normally open contact of the first soft-start relay is connected to the first terminal of the indoor constant-impedance power amplifier via an eleventh resistor. The coil of the first soft-start relay is controlled to be switched on and off by the controller. When the selection relay switches to the position where its common contact and normally closed contact are connected, the controller controls the coil of the first soft-start relay to be energized for a set time and then turned off.

[0014] The speaker-end audio selector also includes a second soft-start relay. The common contact of the second soft-start relay is connected to the first terminal on the other side of the audio transformer. The normally closed contact of the second soft-start relay is connected to the first terminal of the outdoor constant voltage power amplifier. The normally open contact of the second soft-start relay is connected to the first terminal of the outdoor constant voltage power amplifier via a twelfth resistor. The coil of the second soft-start relay is controlled to open and close by the controller. When the selection relay switches to the position where its common contact and normally open contact are connected, the controller controls the coil of the second soft-start relay to be energized for a set time and then turned off.

[0015] Furthermore, the speaker-end audio selector includes a first MOSFET, the first end of the coil of the selection relay is connected to the first pin of the first MOSFET, the second pin of the first MOSFET is connected to a first power supply, the control pin of the first MOSFET is connected to the controller via a first operational amplifier, and the second end of the coil of the selection relay is grounded.

[0016] The speaker-end audio selector also includes a second MOSFET. The first end of the coil of the first soft-start relay is connected to the first pin of the second MOSFET. The second pin of the second MOSFET is connected to the first power supply. The control pin of the second MOSFET is connected to the controller via a second operational amplifier. The second end of the coil of the first soft-start relay is grounded.

[0017] The speaker-end audio selector also includes a third MOSFET. The first end of the coil of the second soft-start relay is connected to the first pin of the third MOSFET. The second pin of the third MOSFET is connected to the first power supply. The control pin of the third MOSFET is connected to the controller via a third operational amplifier. The second end of the coil of the second soft-start relay is grounded.

[0018] Furthermore, the power supply for the speaker-end audio selector is a lithium battery. The speaker-end audio selector also includes a voltage regulator unit, a first boost unit, and a second boost unit. The voltage regulator unit is used to regulate the voltage of the lithium battery into a working power supply for the controller. The first boost unit is used to boost the voltage of the lithium battery into a first power supply for the selection relay, the first soft-start relay, and the second soft-start relay. The second boost unit is used to boost the voltage of the lithium battery into a second power supply for the first operational amplifier, the second operational amplifier, and the third operational amplifier.

[0019] The beneficial effects of this utility model are as follows: The speaker-end audio selector of this utility model connects to an indoor constant-impedance speaker and an indoor constant-impedance power amplifier and an outdoor constant-voltage power amplifier. This speaker-end audio selector allows switching between the indoor constant-impedance speaker receiving signals from the indoor constant-impedance power amplifier and the outdoor constant-voltage power amplifier, thus eliminating the need for an outdoor constant-voltage speaker. Compared with existing technologies, this breaks down the boundaries between constant-impedance and constant-voltage power amplifiers in large building sound systems, allowing one speaker to connect to two types of amplifiers, saving the need for an outdoor constant-voltage speaker, thereby reducing overall construction, renovation, and maintenance costs. Furthermore, this utility model also includes a first sensing unit and a second sensing unit to sense the indoor constant-impedance power amplifier and the outdoor constant-voltage power amplifier respectively, achieving intelligent sensing switching, which can better meet practical needs and improve flexibility. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a basic principle block diagram of the speaker-end audio selector of this utility model;

[0022] Figure 2 This is a circuit diagram of the selection relay, audio transformer, first sensing unit, and second sensing unit of this utility model;

[0023] Figure 3 This is a circuit diagram of the power amplifier priority selection unit of this utility model;

[0024] Figure 4 This is a circuit diagram of the controller and its peripheral circuits of this utility model;

[0025] Figure 5 This is a circuit diagram of the voltage regulator unit of this utility model;

[0026] Figure 6 This is a circuit diagram of the first boost unit of this utility model;

[0027] Figure 7 This is a circuit diagram of the second boost unit of this utility model;

[0028] Figure 8 This is a basic principle block diagram of the power supply and auxiliary power supply of this utility model. Detailed Implementation

[0029] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0030] like Figure 1-4 As shown, this embodiment provides a speaker-end audio selector, which includes a selection relay RELAY1 and an audio transformer J1. The selection relay RELAY1 is used to select whether to electrically connect an indoor constant-impedance speaker U1 to an indoor constant-impedance power amplifier U2, causing the indoor constant-impedance speaker U1 to play sound corresponding to the indoor constant-impedance power amplifier U2; or to electrically connect the indoor constant-impedance speaker U1 to the audio transformer J1 and an outdoor constant-voltage power amplifier U3, causing the indoor constant-impedance speaker U1 to play sound corresponding to the outdoor constant-voltage power amplifier U3. The outdoor power amplifier is generally a constant-voltage power amplifier to meet the requirements of stable transmission over long distances, while the indoor power amplifier is generally a constant-impedance power amplifier. The outdoor constant-voltage power amplifier U3 needs to be connected to the indoor constant-impedance speaker U1 through the audio transformer J1, which is used to achieve voltage reduction and impedance matching.

[0031] A timed switching strategy can be used for switching selection. Alternatively, in this embodiment, the speaker-end audio selector further includes a first sensing unit, a second sensing unit, and a controller U4. The first sensing unit is used to sense whether the indoor constant-impedance power amplifier U2 emits a power amplifier signal. When the indoor constant-impedance power amplifier U2 emits a power amplifier signal, the controller U4 controls the selection relay RELAY1 to electrically connect the indoor constant-impedance speaker U1 to the indoor constant-impedance power amplifier U2. The second sensing unit is used to sense whether the outdoor constant-voltage power amplifier U3 generates a power amplifier signal. When the outdoor constant-voltage power amplifier U3 emits a power amplifier signal, the controller U4 controls the selection relay RELAY1 to electrically connect the indoor constant-impedance speaker U1 to the audio transformer J1 and the outdoor constant-voltage power amplifier U3.

[0032] In this embodiment, a speaker-end audio selector is installed inside or near the housing of the indoor constant-impedance speaker U1. This selector connects to the indoor constant-impedance speaker U1, the indoor constant-impedance power amplifier U2, and the outdoor constant-voltage power amplifier U3. This speaker-end audio selector allows switching between the indoor constant-impedance speaker U1 receiving signals from the indoor constant-impedance power amplifier U2 and the outdoor constant-voltage power amplifier U3, thus eliminating the need for an outdoor constant-voltage speaker. Compared to existing technologies, the speaker-end audio selector of this embodiment breaks down the boundaries between constant-impedance and constant-voltage power amplifiers in large building sound systems, allowing one speaker to connect to two types of amplifiers, saving the need for an outdoor constant-voltage speaker, and thereby reducing overall construction, renovation, and maintenance costs. Furthermore, this embodiment uses a first sensing unit and a second sensing unit to sense the indoor constant-impedance power amplifier U2 and the outdoor constant-voltage power amplifier U3 respectively, achieving intelligent sensing switching. Compared to timed switching, this better meets practical needs and improves flexibility.

[0033] Since the indoor constant - resistance power amplifier U2 and the outdoor constant - voltage power amplifier U3 may send signals at the same time, it is necessary to determine the priority of their electrical connection to the indoor constant - resistance speaker U1. In this regard, the audio selector at the speaker end of this embodiment further includes a priority selection unit for selecting the indoor constant - resistance power amplifier U2 as the high - priority level or selecting the outdoor constant - voltage power amplifier U3 as the high - priority level. When the indoor constant - resistance power amplifier U2 is selected as the high - priority level, if the indoor constant - resistance power amplifier U2 and the outdoor constant - voltage power amplifier U3 send signals simultaneously, the selection relay RELAY1 is preferentially switched to conduct with the indoor constant - resistance power amplifier U2, which is applicable to scenarios such as important meetings. When the outdoor constant - voltage power amplifier U3 is selected as the high - priority level, if the indoor constant - resistance power amplifier U2 and the outdoor constant - voltage power amplifier U3 send signals simultaneously, the selection relay RELAY1 is preferentially switched to conduct with the outdoor constant - voltage power amplifier U3, which is applicable to scenarios such as examinations and teaching. Thus, by setting the priority selection unit, various application scenarios can be more flexibly adapted.

[0034] As Figure 2 shown, the common contact of the selection relay RELAY1 in this embodiment, that is, its pin 5, is connected to the first end of the indoor constant - resistance speaker U1, that is, its positive - pole input terminal. The normally - closed contact of the selection relay RELAY1, that is, its pin 3, is directly or indirectly connected to the first end of the indoor constant - resistance power amplifier U2, that is, its positive - pole output terminal. The normally - open contact of the selection relay RELAY1, that is, its pin 2, is connected to the first end of one side of the audio transformer J1. The coil of the selection relay RELAY1 is controlled by the controller U4 for on - off. The second end of the indoor constant - resistance speaker U1, that is, its negative - pole input terminal, is connected to the second end of the indoor constant - resistance power amplifier U2, that is, its negative - pole output terminal, and is connected to the second end of one side of the audio transformer J1. The first end of the other side of the audio transformer J1 is directly or indirectly connected to the first end of the outdoor constant - voltage power amplifier U3, that is, its positive - pole output terminal. The second end of the other side of the audio transformer J1 is connected to the second end of the outdoor constant - voltage power amplifier U3, that is, its negative - pole output terminal.

[0035] Further, the first induction unit includes a first resistor R1 and a second resistor R2. The first end of the first resistor R1 is connected to the first end of the indoor constant - resistance power amplifier U2, that is, its positive - pole output terminal. The second end of the first resistor R1 is connected to the first end of the second resistor R2 and the controller U4. The second end of the second resistor R2 is connected to the second end of the indoor constant - resistance power amplifier U2, that is, its negative - pole output terminal. Thus, when the indoor constant - resistance power amplifier U2 sends a signal and does not send a signal, the controller U4 can receive different high - and low - level signals, so as to determine whether the indoor constant - resistance power amplifier U2 sends a signal. In this embodiment, a first TVS diode D4 is also connected in parallel across the two ends of the second resistor R2 for protection.

[0036] Similarly, the second sensing unit includes a third resistor R3 and a fourth resistor R4. The first end of the third resistor R3 is connected to the first terminal of the outdoor constant voltage power amplifier U3, i.e., its positive output terminal. The second end of the third resistor R3 is connected to the first terminal of the fourth resistor R4 and the controller U4. The second end of the fourth resistor R4 is connected to the second terminal of the outdoor constant voltage power amplifier U3, i.e., its negative output terminal. Thus, when the outdoor constant voltage power amplifier U3 emits a signal or not, the controller U4 can receive different high and low level signals, thereby determining whether the outdoor constant voltage power amplifier U3 is emitting a signal. In this embodiment, a second TVS diode D5 is also connected in parallel across the fourth resistor R4 for protection.

[0037] like Figure 3-4 As shown, the power amplifier priority selection unit in this embodiment includes a DIP switch DIP1. The first terminal of DIP1 is connected to the power supply via the thirteenth resistor R13 and to the first terminal of the fourteenth resistor R14. The second terminal of DIP1 is grounded and connected to the second terminal of the fifteenth resistor R15. The second terminal of the fourteenth resistor R14 is connected to the first terminal of the fifteenth resistor R15 and the controller U4. When DIP1 is pressed, the controller U4 can receive different high and low level signals, thereby determining the priority of the indoor constant impedance power amplifier U2 and the outdoor constant voltage power amplifier U3.

[0038] Furthermore, the speaker-end audio selector in this embodiment also includes a first soft-start relay RELAY2. The common contact of the first soft-start relay RELAY2, i.e., its pin 5, is connected to the normally closed contact of the selection relay RELAY1, i.e., its pin 3. The normally closed contact of the first soft-start relay RELAY2, i.e., its pin 3, is connected to the first terminal of the indoor constant-impedance power amplifier U2, i.e., its positive output terminal. The normally open contact of the first soft-start relay RELAY2, i.e., its pin 2, is connected to the first terminal of the indoor constant-impedance power amplifier U2 via the eleventh resistor R11. The coil of the first soft-start relay RELAY2 is controlled to be switched on and off by the controller U4. When the selection relay RELAY1 switches to the point where its common contact, i.e., its pin 5, and its normally closed contact, i.e., its pin 3, are connected, the controller U4 controls the coil of the first soft-start relay RELAY2 to be energized for a set time and then turned off. That is to say, the common contact, i.e., its pin 5, and its normally open contact, i.e., its pin 2, of the first soft-start relay RELAY2 are first connected for a set time, and then switched to the point where its normally closed contact, i.e., its pin 3, is connected. This solves the problem of sudden sound intrusion during power amplifier switching caused by the selector relay RELAY1, eliminating the "popping" noise generated during switching and achieving a soft start. The set time can be adjusted as needed, for example, to 1-2 seconds; the resistance value of the eleventh resistor R11 can also be adjusted as needed.

[0039] Similarly, the speaker-end audio selector also includes a second soft-start relay RELAY3. The common contact of the second soft-start relay RELAY3, i.e., its pin 5, is connected to the first terminal on the other side of the audio transformer J1. The normally closed contact of the second soft-start relay RELAY3, i.e., its pin 3, is connected to the first terminal of the outdoor constant voltage power amplifier U3, i.e., its positive output terminal. The normally open contact of the second soft-start relay RELAY3, i.e., its pin 2, is connected to the first terminal of the outdoor constant voltage power amplifier U3 via the twelfth resistor R12. The coil of the second soft-start relay RELAY3 is controlled by the controller U4. When the selector relay RELAY1 switches to the state where its common contact, i.e., its contact 5, and its normally open contact, i.e., its contact 2, are connected, the controller U4 controls the coil of the second soft-start relay RELAY3 to be energized for a set time and then turned off. That is to say, the common contact, i.e., its pin 5, and its normally open contact, i.e., its pin 2, of the second soft-start relay RELAY3 are first connected for a set time, and then switched to the state where its normally closed contact, i.e., its pin 3, is connected. This solves the problem of sudden sound intrusion during power amplifier switching caused by the selector relay RELAY1, eliminating the "popping" noise generated during switching and achieving a soft start. The set time can be adjusted as needed, for example, to 1-2 seconds; the resistance value of the twelfth resistor R12 can also be set as required.

[0040] Furthermore, the speaker-end audio selector of this embodiment also includes a first MOSFET Q1, preferably a PMOS. The first terminal of the coil of the selection relay RELAY1, i.e., its pin 4, is connected to the first pin of the first MOSFET Q1, i.e., its drain, via a first anti-reverse diode D1. The second pin of the first MOSFET Q1, i.e., its source, is connected to a first power supply, which is set to correspond to the selection relay RELAY1, for example, 5V. The control pin of the first MOSFET Q1, i.e., its gate, is connected to the controller U4 via a first operational amplifier U11. The second terminal of the coil of the selection relay RELAY1, i.e., its pin 1, is grounded. The first operational amplifier U11 is powered by a second power supply, for example, 12V. The controller U4 sends a signal to control the first MOSFET Q1. For example, when the controller U4 sends a high-level signal, the first operational amplifier U11 amplifies the signal, for example, to about 5-10V, and the first MOSFET Q1 turns off. At this time, the coil of the selection relay RELAY1 is also de-energized. When the controller U4 sends a low-level signal, the first MOSFET Q1 turns on, and the coil of the selection relay RELAY1 is energized.

[0041] Similarly, the speaker-end audio selector also includes a second MOSFET Q2, preferably a PMOS. The first end of the coil of the first soft-start relay RELAY2, i.e., its pin 4, is connected to the first pin of the second MOSFET Q2, i.e., its drain, via the second anti-reverse diode D2. The second pin of the second MOSFET Q2, i.e., its source, is connected to a first power supply. The first power supply is set according to the first soft-start relay RELAY2, for example, 5V. The control pin of the second MOSFET Q2, i.e., its gate, is connected to the controller U4 via the second operational amplifier U12. The second end of the coil of the first soft-start relay RELAY2, i.e., its pin 1, is grounded. The second operational amplifier U12 is powered by a second power supply, for example, 12V. The controller U4 sends a signal to control the second MOSFET Q2. For example, when the controller U4 sends a high-level signal, it is amplified by the second operational amplifier U12, for example, to about 5-10V, and the second MOSFET Q2 is turned off. At this time, the coil of the first soft-start relay RELAY2 is also de-energized. When the controller U4 sends a low-level signal, the second MOSFET Q2 is turned on, and the coil of the first soft-start relay RELAY2 is energized.

[0042] Similarly, the speaker-end audio selector also includes a third MOSFET Q3, preferably a PMOS. The first end of the coil of the second soft-start relay RELAY3, i.e., its pin 4, is connected to the first pin of the third MOSFET Q3, i.e., its drain, via the third anti-reverse diode D3. The second pin of the third MOSFET Q3, i.e., its source, is connected to the first power supply. The first power supply is set according to the second soft-start relay RELAY3, for example, 5V. The control pin of the third MOSFET Q3, i.e., its gate, is connected to the controller U4 via the third operational amplifier U13. The second end of the coil of the second soft-start relay RELAY3, i.e., its pin 1, is grounded. The third operational amplifier U13 is powered by the second power supply, for example, 12V. The controller U4 sends a signal to control the third MOSFET Q3. For example, when the controller U4 sends a high-level signal, it is amplified by the third operational amplifier U13, for example, to about 5-10V, and the third MOSFET Q3 is turned off. At this time, the coil of the second soft-start relay RELAY3 is also de-energized. When the controller U4 sends a low-level signal, the third MOSFET Q3 is turned on, and the coil of the second soft-start relay RELAY3 is energized.

[0043] Furthermore, in this embodiment, the power supply for the speaker-end audio selector is preferably a lithium battery with a nominal voltage of 3.7V. The speaker-end audio selector also includes a voltage regulator unit, a first boost unit, and a second boost unit, such as... Figure 5As shown, the voltage regulator unit includes a voltage regulator chip U5 and its peripheral circuitry. The voltage regulator chip U5 can be, but is not limited to, MT3608L or CS5517T, etc. The voltage regulator unit is used to regulate the lithium battery voltage to, for example, 3.3V, to provide a working power supply to the controller U4. The controller U4 can be, but is not limited to, STM32F103C8T6. Figure 6 As shown, the first boost unit includes a first voltage conversion chip U6 and its peripheral circuitry. The voltage conversion chip U6 can be, but is not limited to, FP6276AXR-G1. The first boost unit is used to boost the voltage of the lithium battery to provide a first power supply to the selection relay RELAY1, the first soft-start relay RELAY2, and the second soft-start relay RELAY3. Figure 7 As shown, the second boost unit includes a second voltage conversion chip U7 and its peripheral circuits, and a third voltage conversion chip U8 and its peripheral circuits. The second voltage conversion chip U7 can be, but is not limited to, FP6276AXR-G1, and works with its peripheral circuits to boost the voltage to 5V. The third voltage conversion chip U8 can be, but is not limited to, LGS6302, and works with its peripheral circuits to boost the 5V voltage to 12V. This embodiment uses a two-stage boost method. The aforementioned 5V voltage can also be provided by the second conversion chip U7 and its peripheral circuits. Of course, in other embodiments, any other existing boost circuit can be used. The second boost unit is used to boost the voltage of the lithium battery to a second power supply to provide to the first operational amplifier U11, the second operational amplifier U12, and the third operational amplifier U13.

[0044] In this embodiment, the speaker-end audio selector, during use, first selects the priority of the indoor constant-impedance amplifier U2 and the outdoor constant-voltage amplifier U3 according to the specific scenario via the DIP switch DIP1. Then, the first sensing unit and the second sensing unit respectively sense whether the indoor constant-impedance amplifier U2 and the outdoor constant-voltage amplifier U3 are emitting signals. If only the outdoor constant-voltage amplifier U3 is detected to be emitting a signal, or if both the outdoor constant-voltage amplifier U3 and the indoor constant-impedance amplifier U2 are emitting signals but the outdoor constant-voltage amplifier U3 has a higher priority, the controller U4 controls the selection relay RELAY1 to switch to its normally open contact. At this time, the second soft-start relay RELAY3 also switches to its normally open contact and, after a set time, switches back to its normally closed contact. If only the indoor constant-impedance amplifier U2 emits a signal, or if both the indoor constant-impedance amplifier U2 and the outdoor constant-voltage amplifier U3 emit signals but the indoor constant-impedance amplifier U2 has higher priority, the controller U4 controls the selection relay RELAY1 to switch to its normally closed contact. At this time, the first soft-start relay RELAY2 simultaneously switches to its normally open contact, and after a set time, the first soft-start relay RELAY2 switches back to its normally closed contact. This process continues in this manner.

[0045] The power supply in this embodiment is a lithium battery, which can be replaced after a period of use, such as about a month. Alternatively, as... Figure 8 As shown, the power supply can also be charged via charging. Specifically, this embodiment includes an auxiliary power supply connected in parallel with the power supply. The auxiliary power supply is also a lithium battery of the same model as the power supply. A first switch is provided between the positive terminal of the power supply and the positive terminal of the auxiliary power supply. Furthermore, it includes a rectifier module, a filter and voltage regulator module, a second switch, and a charging management module connected in sequence. The input terminal of the rectifier module is connected to an indoor constant-impedance power amplifier or an outdoor constant-voltage power amplifier to convert AC power into pulsating DC power. Then, the filter and voltage regulator module filters and regulates the voltage to stabilize it to the operating voltage of the charging management module, which can then charge the auxiliary power supply. This embodiment also includes a voltage detection module, which can use a resistor voltage divider detection method. When the voltage detection module detects that the voltage of the auxiliary power supply is insufficient, for example, below a preset value, it sends a signal to the controller. The controller then controls the first switch to open and the second switch to open, allowing the auxiliary power supply to charge. Meanwhile, the main power supply continues to supply power to the aforementioned controller, relays, MOSFETs, operational amplifiers, and the first and second switches. When the voltage detection module detects that the voltage of the auxiliary power supply has reached the set value, it sends a signal to the controller. The controller then controls the second switch to open and the first switch to open, allowing the auxiliary power supply and the main power supply to supply power to the aforementioned controller, relays, MOSFETs, operational amplifiers, and the first and second switches together. At this time, the auxiliary power supply also charges the main power supply. This process repeats continuously. In this way, the main power supply can be charged, and by setting the first switch to open when the auxiliary power supply is charging, unstable current during the charging of the auxiliary power supply can be prevented from affecting the subsequently powered components.

[0046] In summary, the speaker-end audio selector provided in this embodiment can break down the boundaries between constant impedance and constant voltage power amplifiers in large building sound systems, enabling one speaker to connect to two types of power amplifiers, saving the need for outdoor constant voltage speakers, thereby reducing the overall construction, renovation and maintenance costs.

[0047] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0048] The above embodiments are merely descriptions of preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Various modifications and improvements made to the technical solutions of the present utility model by those skilled in the art without departing from the spirit of the present utility model should fall within the protection scope defined by the claims of the present utility model.

Claims

1. A speaker-end audio selector, characterized in that, It includes a selection relay and an audio transformer. The selection relay is used to select whether to electrically connect the indoor constant impedance speaker to the indoor constant impedance power amplifier, or to electrically connect the indoor constant impedance speaker to the audio transformer and the outdoor constant voltage power amplifier. The speaker-end audio selector further includes a first sensing unit, a second sensing unit, and a controller. The first sensing unit is used to sense whether the indoor constant-impedance power amplifier emits a power amplifier signal. When the indoor constant-impedance power amplifier emits a power amplifier signal, the controller controls the selection relay to electrically connect the indoor constant-impedance speaker to the indoor constant-impedance power amplifier. The second sensing unit is used to sense whether the outdoor constant-voltage power amplifier generates a power amplifier signal. When the outdoor constant-voltage power amplifier emits a power amplifier signal, the controller controls the selection relay to electrically connect the indoor constant-impedance speaker to the audio transformer and the outdoor constant-voltage power amplifier.

2. The speaker-end audio selector according to claim 1, characterized in that, The speaker-end audio selector also includes a power amplifier priority selection unit, which is used to select the priority of the indoor constant impedance power amplifier and the outdoor constant voltage power amplifier connected to the indoor constant impedance speaker.

3. The speaker-end audio selector according to claim 2, characterized in that, The common contact of the selection relay is connected to the first terminal of the indoor constant impedance speaker. The normally closed contact of the selection relay is directly or indirectly connected to the first terminal of the indoor constant impedance power amplifier. The normally open contact of the selection relay is connected to the first terminal on one side of the audio transformer. The coil of the selection relay is controlled by the controller to open and close. The second terminal of the indoor constant impedance speaker is connected to the second terminal of the indoor constant impedance power amplifier and to the second terminal on one side of the audio transformer. The first terminal on the other side of the audio transformer is directly or indirectly connected to the first terminal of the outdoor constant voltage power amplifier. The second terminal on the other side of the audio transformer is connected to the second terminal of the outdoor constant voltage power amplifier.

4. The speaker-end audio selector according to claim 3, characterized in that, The first sensing unit includes a first resistor and a second resistor. The first end of the first resistor is connected to the first end of the indoor constant impedance power amplifier. The second end of the first resistor is connected to the first end of the second resistor and the controller. The second end of the second resistor is connected to the second end of the indoor constant impedance power amplifier. The second sensing unit includes a third resistor and a fourth resistor. The first end of the third resistor is connected to the first end of the outdoor constant voltage power amplifier. The second end of the third resistor is connected to the first end of the fourth resistor and the controller. The second end of the fourth resistor is connected to the second end of the outdoor constant voltage power amplifier.

5. The speaker-end audio selector according to claim 4, characterized in that, The power amplifier priority selection unit includes a DIP switch. The first terminal of the DIP switch is connected to the power supply via a thirteenth resistor and to the first terminal of a fourteenth resistor. The second terminal of the DIP switch is grounded and connected to the second terminal of a fifteenth resistor. The second terminal of the fourteenth resistor is connected to the first terminal of the fifteenth resistor and the controller.

6. The speaker-end audio selector according to claim 5, characterized in that, The speaker-end audio selector also includes a first soft-start relay. The common contact of the first soft-start relay is connected to the normally closed contact of the selection relay. The normally closed contact of the first soft-start relay is connected to the first terminal of the indoor constant-impedance power amplifier. The normally open contact of the first soft-start relay is connected to the first terminal of the indoor constant-impedance power amplifier via an eleventh resistor. The coil of the first soft-start relay is controlled to open and close by the controller. When the selection relay switches to the position where its common contact and normally closed contact are connected, the controller controls the coil of the first soft-start relay to be energized for a set time and then turned off. The speaker-end audio selector also includes a second soft-start relay. The common contact of the second soft-start relay is connected to the first terminal on the other side of the audio transformer. The normally closed contact of the second soft-start relay is connected to the first terminal of the outdoor constant voltage power amplifier. The normally open contact of the second soft-start relay is connected to the first terminal of the outdoor constant voltage power amplifier via a twelfth resistor. The coil of the second soft-start relay is controlled to open and close by the controller. When the selection relay switches to the position where its common contact and normally open contact are connected, the controller controls the coil of the second soft-start relay to be energized for a set time and then turned off.

7. The speaker-end audio selector according to claim 6, characterized in that, The speaker-end audio selector includes a first MOSFET, the first end of the coil of the selection relay is connected to the first pin of the first MOSFET, the second pin of the first MOSFET is connected to a first power supply, the control pin of the first MOSFET is connected to the controller via a first operational amplifier, and the second end of the coil of the selection relay is grounded. The speaker-end audio selector also includes a second MOSFET. The first end of the coil of the first soft-start relay is connected to the first pin of the second MOSFET. The second pin of the second MOSFET is connected to the first power supply. The control pin of the second MOSFET is connected to the controller via a second operational amplifier. The second end of the coil of the first soft-start relay is grounded. The speaker-end audio selector also includes a third MOSFET. The first end of the coil of the second soft-start relay is connected to the first pin of the third MOSFET. The second pin of the third MOSFET is connected to the first power supply. The control pin of the third MOSFET is connected to the controller via a third operational amplifier. The second end of the coil of the second soft-start relay is grounded.

8. The speaker-end audio selector according to claim 7, characterized in that, The speaker-end audio selector is powered by a lithium battery. The speaker-end audio selector also includes a voltage regulator unit, a first boost unit, and a second boost unit. The voltage regulator unit is used to regulate the voltage of the lithium battery into a working power supply for the controller. The first boost unit is used to boost the voltage of the lithium battery into a first power supply for the selection relay, the first soft-start relay, and the second soft-start relay. The second boost unit is used to boost the voltage of the lithium battery into a second power supply for the first operational amplifier, the second operational amplifier, and the third operational amplifier.

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