Bidirectional communication level shift circuit

Abstract

An embodiment of the present invention relates to the technical field of power supply control, and discloses a bidirectional communication level shifting circuit, including: a Bluetooth module, a first shifting circuit, a second shifting circuit, and a main control chip that performs bidirectional communication with the Bluetooth module; the second shifting circuit receives a second communication signal based on a second voltage output from a second signal sending end of the main control chip, converts it into a second communication signal based on a first voltage, and transmits it to a second signal receiving end of the Bluetooth module; the first shifting circuit includes a first resistor, a second resistor, and a first triode. A first end of the first triode is connected to a first voltage through the first resistor, a second end is connected to a first signal receiving end of the main control chip, the second end of the first triode is further connected to a second voltage through the second resistor, and a third end of the first triode is connected to a first signal sending end of the Bluetooth module. By the above method, the embodiment of the present invention can achieve bidirectional conversion between different levels, and the circuit structure is simple and the cost is low.

Description

Technical Field

[0001] Embodiments of the present invention relate to the technical field of power control, and particularly to a bidirectional communication level shift circuit. Background Art

[0002] In electronic engineering design, electronic devices and module units with different power supplies are often used. Common examples include transistor - transistor logic (TTL) devices and Complementary Metal Oxide Semiconductor (CMOS) devices. Due to the different power supply voltage values of the devices, the voltage value definitions of high and low levels are also different. Therefore, there is a problem of input - output signal matching during communication. Designers need to perform level conversion on the signals.

[0003] In the prior art, an inverter composed of the switching characteristics of a triode plus a pull - up resistor is often used to achieve high - low level conversion and migration. The signal will be inverted during the signal transmission process, and additional processing must be performed in the software. For some general protocols such as UART, general microcontrollers (MCUs) usually integrate these functions. The port output of the starting level during the data transmission process has been automatically determined according to the protocol and cannot be inverted. Therefore, this type of communication process requires in - phase transmission. In order to achieve in - phase level shift, two - stage inversion is required, resulting in more devices and increased costs. The level conversion in the prior art can basically also directly use application - specific integrated circuit chips, but the cost of application - specific integrated circuit chips is relatively high, and the cost performance is too low for the applications of many circuits with relatively low overall working frequencies. Summary of the Invention

[0004] In view of the above problems, embodiments of the present invention provide a bidirectional communication level shift circuit, which overcomes or at least partially solves the above problems.

[0005] According to one aspect of an embodiment of the present invention, a bidirectional communication level shift circuit is provided, including: a Bluetooth module, a first shift circuit, a second shift circuit, and a main control chip that communicates bidirectionally with the Bluetooth module; the first shift circuit receives a first communication signal based on a first voltage output from a first signal sending end of the Bluetooth module, converts it into the first communication signal based on a second voltage, and transmits it to a first signal receiving end of the main control chip. The second shift circuit receives a second communication signal based on the second voltage output from a second signal sending end of the main control chip, converts it into the second communication signal based on the first voltage, and transmits it to a second signal receiving end of the Bluetooth module; the first shift circuit includes a first resistor, a second resistor, and a first triode. A first end of the first triode is connected to the first voltage through the first resistor, a second end of the first triode is connected to the first signal receiving end of the main control chip, the second end of the first triode is also connected to the second voltage through the second resistor, and a third end of the first triode is connected to the first signal sending end of the Bluetooth module.

[0006] In an alternative manner, the first voltage is the supply voltage of the Bluetooth module, and the second voltage is the supply voltage of the main control chip.

[0007] In an alternative manner, the second shift circuit includes a third resistor, a fourth resistor, and a first diode. The cathode of the first diode is connected to the second signal sending end of the main control chip and is also connected to the second voltage through the third resistor; the anode of the first diode is connected to the second signal receiving end of the Bluetooth module and is also connected to the first voltage through the fourth resistor.

[0008] In an alternative manner, the second shift circuit includes a fifth resistor, a sixth resistor, and a second triode. A first end of the second triode is connected to the first voltage through the fifth resistor, a second end of the second triode is connected to the second signal receiving end of the Bluetooth module and is also connected to the first voltage through the sixth resistor, and a third end of the second triode is connected to the second signal sending end of the main control chip.

[0009] In an alternative manner, the bidirectional communication level shift circuit includes a first capacitor, a second capacitor, a third capacitor, and a third diode. A first power supply end of the Bluetooth module is connected to the first voltage, and at the same time, the first power supply end of the Bluetooth module is also grounded through the first capacitor and the second capacitor connected in parallel; a second power supply end of the Bluetooth module is connected to the cathode of the third diode, the anode of the third diode is connected to a first reference voltage, and the second power supply end of the Bluetooth module is also grounded through the third capacitor.

[0010] In an alternative manner, the bidirectional communication level shift circuit further includes a reset circuit connected to the reset terminal of the Bluetooth module. The main control chip includes a main control connection interface. The first end of the main control connection interface is connected to the second voltage. The second end of the main control connection interface is connected to the input end of the second transfer circuit. The third end of the main control connection interface is connected to the second end of the first triode. The fourth end of the main control connection interface is connected to the reset circuit. The fifth end of the main control connection interface is grounded. The sixth end of the main control connection interface is connected to the second reference voltage.

[0011] In an alternative manner, the reset circuit includes a third triode and a seventh resistor. The first end of the third triode is connected to the main control connection interface through the seventh resistor. The second end of the third triode is connected to the reset terminal of the Bluetooth module. The third end of the third triode is grounded.

[0012] In an alternative manner, the reset circuit includes a second diode. The cathode of the second diode is connected to the main control connection interface. The anode of the second diode is connected to the reset terminal of the Bluetooth module.

[0013] In an alternative manner, the bidirectional communication level shift circuit further includes a power supply circuit. The power supply circuit includes: a first connection terminal, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, an eighth resistor, and a first inductor. The first end and the third end of the first connection terminal are grounded. The second end of the first connection terminal is grounded through the parallel-connected fourth capacitor. The second end of the first connection terminal is also connected to one end of the fifth capacitor and one end of the first inductor, and is also connected to the second voltage. The other end of the fifth capacitor is grounded and is connected to the reference ground through the eighth resistor. The other end of the first inductor is grounded through the mutually parallel-connected sixth capacitor, the seventh capacitor, and the eighth capacitor, and outputs a first reference voltage.

[0014] In an alternative manner, the bidirectional communication level shift circuit further includes a charging circuit. The charging circuit includes: a charging management chip, a second connection terminal for installing a charging battery, a ninth resistor, a tenth resistor, and a ninth capacitor. The first end of the charging management chip is connected to the first reference voltage through the ninth resistor. The second end of the charging management chip is grounded. The third end of the charging management chip is grounded through the ninth capacitor. The third end of the charging management chip is also connected to the positive electrode of the charging battery and the second end of the second connection terminal. The negative electrode of the charging battery and the first end of the second connection terminal are grounded. The fourth end of the charging management chip is connected to the first reference voltage. The fifth end of the charging management chip is grounded through the tenth resistor. The third end of the charging management chip also outputs a second reference voltage.

[0015] The bidirectional communication level shifting circuit according to an embodiment of the present invention includes: a Bluetooth module, a first shifting circuit, a second shifting circuit, and a main control chip that performs bidirectional communication with the Bluetooth module; the first shifting circuit receives a first communication signal based on a first voltage output from a first signal sending end of the Bluetooth module, converts it into the first communication signal based on a second voltage, and transmits it to a first signal receiving end of the main control chip, and the second shifting circuit receives a second communication signal based on the second voltage output from a second signal sending end of the main control chip, converts it into the second communication signal based on the first voltage, and transmits it to a second signal receiving end of the Bluetooth module; the first shifting circuit includes a first resistor, a second resistor, and a first triode, a first end of the first triode is connected to the first voltage through the first resistor, a second end of the first triode is connected to the first signal receiving end of the main control chip, the second end of the first triode is also connected to the second voltage through the second resistor, and a third end of the first triode is connected to the first signal sending end of the Bluetooth module, which can realize bidirectional conversion between different levels, and has a simple circuit structure and low cost.

[0016] The above description is only an overview of the technical solution of the embodiment of the present invention. In order to be able to understand the technical means of the embodiment of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the embodiment of the present invention more obvious and understandable, the following specifically describes the embodiments of the present invention. Description of the Drawings

[0017] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. And throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0018] Figure 1 shows a schematic structural diagram of the bidirectional communication level shifting circuit provided by the embodiment of the present invention;

[0019] Figure 2 shows a specific circuit schematic diagram of the bidirectional communication level shifting circuit provided by the embodiment of the present invention;

[0020] Figure 3 shows another specific circuit schematic diagram of the bidirectional communication level shifting circuit provided by the embodiment of the present invention;

[0021] Figure 4 shows an application schematic diagram of the bidirectional communication level shifting circuit provided by the embodiment of the present invention;

[0022] Figure 5The schematic diagram of the reset circuit in the bidirectional communication level shift circuit provided by the embodiment of the present invention is shown;

[0023] Figure 6 The schematic diagram of another reset circuit in the bidirectional communication level shift circuit provided by the embodiment of the present invention is shown;

[0024] Figure 7 The schematic diagram of the power supply circuit in the bidirectional communication level shift circuit provided by the embodiment of the present invention is shown;

[0025] Figure 8 The schematic diagram of the charging circuit in the bidirectional communication level shift circuit provided by the embodiment of the present invention is shown;

[0026] Figure 9 The schematic diagram of the speaker drive circuit in the bidirectional communication level shift circuit provided by the embodiment of the present invention is shown. Detailed implementation manners

[0027] Hereinafter, the exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present invention can be more thoroughly understood and the scope of the present invention can be fully conveyed to those skilled in the art.

[0028] Figure 1 The schematic diagram of the structure of the bidirectional communication level shift circuit provided by the embodiment of the present invention is shown. As Figure 1 shown, the bidirectional communication level shift circuit 10 includes: a Bluetooth module 11, a first shift circuit 12, a second shift circuit 13, and a main control chip 14 that communicates bidirectionally with the Bluetooth module 11. The first shift circuit 12 receives the first communication signal based on the first voltage output by the first signal sending end TXD of the Bluetooth module 11, converts it into the first communication signal based on the second voltage, and transmits it to the first signal receiving end RXD1 of the main control chip 14. The second shift circuit 13 receives the second communication signal based on the second voltage output by the second signal sending end TXD1 of the main control chip 14, converts it into the second communication signal based on the first voltage, and transmits it to the second signal receiving end RXD of the Bluetooth module 11. The first shift circuit 12 includes a first resistor R1, a second resistor R2, and a first triode Q1. The first end of the first triode Q1 is connected to the first voltage +3.3V through the first resistor R1. The second end of the first triode Q1 is connected to the first signal receiving end RXD1 of the main control chip 14. The second end of the first triode Q1 is also connected to the second voltage +5V through the second resistor R2. The third end of the first triode Q1 is connected to the first signal sending end TXD of the Bluetooth module 11.

[0029] Among them, the first voltage +3.3V is the power supply voltage of the Bluetooth module 11, and the second voltage +5V is the power supply voltage of the main control chip 14. Correspondingly, the first communication signal or the second communication signal based on the first voltage can be 0 - 3.3V or 0.3V - 3.3V, and the first communication signal or the second communication signal based on the second voltage can be 0 - 5V or 0.3V - 5V. Preferably, the first triode Q1 is an NPN transistor, the first end is the base of the NPN transistor, the second end is the collector of the NPN transistor, and the third end is the emitter of the NPN transistor. The first resistor R1 is a pull-up resistor.

[0030] When the first communication signal based on the first voltage input by the first signal transmission end TXD of the Bluetooth module 11 to the first transfer circuit 12 is high, such as 3.3V, the voltage between the base and the emitter (BE) of the first triode Q1 is 0 or reverse-biased, the first triode Q1 is cut off, and the first communication signal based on the second voltage output by the collector (C) is high, which is transmitted to the first signal reception end RXD1 of the main control chip 14, and in-phase transmission of high levels between different voltages can be realized. When the first communication signal based on the first voltage input by the first signal transmission end TXD of the Bluetooth module 11 to the first transfer circuit 12 is low, such as 0V, the BE of the first triode Q1 is forward-biased, the first triode Q1 is turned on, and the first communication signal based on the second voltage output by the collector C is low, specifically the saturation conduction voltage of the first triode Q1, which is about 0.3V, and in-phase transmission of low levels between different voltages can be realized. Combining the above two situations, level transfer or data transmission from a low voltage to a high voltage unit can be realized, that is, in-phase transmission of levels from the low voltage end to the high voltage end can be realized. Among them, the second resistor R2 is a pull-up resistor, which can be not installed, and the built-in pull-up resistor of the main control chip 14 can be directly configured, which can make the whole circuit simpler.

[0031] Optionally, such as Figure 2As shown, the second transfer circuit 13 includes a third resistor R3, a fourth resistor R4, and a first diode D1. The cathode of the first diode D1 is connected to the second signal transmission end TXD1 of the main control chip 14, and is also connected to the second voltage through the third resistor R3; the anode of the first diode D1 is connected to the second signal reception end RXD of the Bluetooth module 11, and is also connected to the first voltage through the fourth resistor R4. The second transfer circuit 13 of the embodiment of the present invention uses a diode to achieve the transfer of a high voltage level to a low voltage level end or data transmission. When the second communication signal based on the second voltage output by the second signal transmission end TXD1 of the main control chip 14 is high, such as 5V, the first diode D1 is cut off, and the second communication signal based on the first voltage output by the second transfer circuit 13 is 3.3V, which is a high level. In this way, in-phase transmission of high levels between different voltages can be achieved. When the second communication signal based on the second voltage output by the second signal transmission end TXD1 of the main control chip 14 is low, such as 0V, the first diode D1 is forward-conducted, and the second communication signal based on the first voltage output by the second transfer circuit 13 is 0.3V, which is a low level. In this way, in-phase transmission of low levels between different voltages can be achieved. Combining the above two situations, in-phase transmission of the level from the high voltage end to the low voltage end can be achieved. Among them, the third resistor R3 and the fourth resistor R4 are pull-up resistors, and they can be not installed. The third resistor R3 directly uses the built-in pull-up resistor configured by the main control chip 14, and the fourth resistor R4 directly uses the built-in pull-up resistor configured by the Bluetooth module 11, which can make the entire circuit simpler. With just one diode, in-phase transmission of the level from the high voltage end to the low voltage end can be achieved. And combining Figure 2 with the first transfer circuit 12 and the second transfer circuit 13 in

[0032] The bidirectional communication between the main control chip 14 and the Bluetooth module 11 is as follows: When the main control chip 14 sends data to the Bluetooth module 11, the first signal receiving end RXD1 of the main control chip 14 sends 1 (such as 5V) to the negative electrode of the first diode D1. The positive electrode of the first diode D1 is connected to the first voltage +3.3V through the third resistor R3 serving as a pull-up resistor. The voltage of the first diode D1 is reverse-biased, the first diode D1 is cut off, the positive electrode of the first diode D1 is +3.3V, and the second signal receiving end RXD of the Bluetooth module 11 receives 1. The first signal receiving end RXD1 of the main control chip 14 sends 0 (such as 0V) to the negative electrode of the first diode D1. The positive electrode of the first diode D1 is connected to +3.3V through the third resistor R3. The first diode D1 is forward-biased and conducts. The positive electrode of the first diode D1 is the diode conduction voltage (0.3V), and the second signal receiving end RXD of the Bluetooth module 11 receives 0. When the Bluetooth module 11 sends data to the main control chip 14, the first signal sending end TXD of the Bluetooth module 11 sends 1 (such as 3.3V) to the emitter E of the first triode Q1. The base B of the first triode Q1 is connected to +3.3V through the first resistor R1 serving as a pull-up resistor. The voltage drop between the base and emitter of the first triode Q1 is 0, the first triode Q1 is cut off, the collector C of the first triode Q1 is connected to +5V through the second resistor R2 serving as a pull-up resistor, and the first signal receiving end RXD1 of the main control chip 14 receives 1. The first signal sending end TXD of the Bluetooth module 11 sends 0 (such as 0V) to the emitter E of the first triode Q1. The base B of the first triode Q1 is connected to +3.3V through the first resistor R1. The first triode Q1 is forward-conductive between the base and emitter, the first triode Q1 is saturated and conductive, and the voltage of the collector C between the base and emitter of the first triode Q1 is the saturation conduction voltage drop (V CE ) 0.3V, and the first signal receiving end RXD1 of the main control chip 14 receives 0. Among them, the main control chip 14 can adopt any model of single-chip microcomputer that can realize the above functions existing in the market. Of course, in other embodiments of the present invention, other processors can also be adopted, which is not limited herein.

[0033] As Figure 3 shown, the second transfer circuit 13 includes a fifth resistor R5, a sixth resistor R6, and a second triode Q2. The first end of the second triode Q2 is connected to the first voltage through the fifth resistor R5. The second end of the second triode Q2 is connected to the second signal receiving end RXD of the Bluetooth module 11 and is also connected to the first voltage through the sixth resistor R6. The third end of the second triode Q2 is connected to the second signal sending end TXD1 of the main control chip 14. The second triode Q2 is an NPN transistor. The first end is the base of the NPN transistor, the second end is the collector of the NPN transistor, and the third end is the emitter of the NPN transistor.

[0034] When the second communication signal based on the second level output by the second signal sending end TXD1 of the main control chip 14 is high, such as 5V, the voltage between the base and emitter of the second triode Q2 is 0 or reverse-biased, the second triode Q2 is cut off, and the second communication signal based on the first level output by the collector C is high. The voltage value of the high level is determined by the power supply connected to the sixth resistor R6, realizing the in-phase transfer of the high level between different voltages. When the second communication signal based on the second level output by the second signal sending end TXD1 of the main control chip 14 is low, such as 0, the base-emitter of the second triode Q2 is forward-biased, the second triode Q2 is turned on, and the second communication signal based on the first level output by the collector C is low, specifically the saturation conduction voltage of the second triode Q2, about 0.3V. In this way, the level transfer or data transmission from the high-voltage unit to the low-voltage unit is realized, that is, the in-phase transmission of the low level between different voltages is realized. Among them, the sixth resistor R6 is a pull-up resistor, which can be not installed, and the built-in pull-up resistor of the Bluetooth module 11 can be directly configured, which can make the whole circuit simpler.

[0035] In the embodiment of the present invention, as Figure 4 shown, the bidirectional communication level transfer circuit 10 includes a first capacitor C1, a second capacitor C2, a third capacitor C3, and a third diode D3. The first power supply terminal D-3V3 of the Bluetooth module 11 is connected to the first voltage. At the same time, the first power supply terminal D-3V3 of the Bluetooth module 11 is also grounded to GND through the first capacitor C1 and the second capacitor C2 connected in parallel with each other. The second power supply terminal VBAT of the Bluetooth module 11 is connected to the cathode of the third diode D3, the anode of the third diode D3 is connected to the first reference voltage VDD, and the second power supply terminal VBAT of the Bluetooth module 11 is also grounded to GND through the third capacitor C3. The first capacitor C1, the second capacitor C2, and the third capacitor C3 are filter capacitors, which are used to filter out possible spike pulses in the power supply signal. The first signal sending end TXD of the Bluetooth module 11 is connected to the third terminal of the first triode Q1 through the twelfth resistor R12, and the second signal receiving end RXD of the Bluetooth module 11 is connected to the output end of the second transfer circuit 13 through the eleventh resistor R11, such as connected to the anode of the first diode D1. The eleventh resistor R11 and the twelfth resistor R12 are current-limiting resistors. Among them, the Bluetooth module 11 can be an existing one, such as the Bluetooth module with the model D3851A. Of course, in other embodiments of the present invention, other processors can also be used, which are not limited herein.

[0036] As Figure 5As shown, the bidirectional communication level shifter circuit 10 further includes a reset circuit 15 connected to the reset terminal RST of the Bluetooth module 11. The main control chip 14 includes a main control connection interface CN1. The first end 1 of the main control connection interface CN1 is connected to the second voltage. The second end 2 of the main control connection interface CN1 is connected to the input end of the second transfer circuit 13, such as connected to the cathode of the first diode D1. The second end 2 of the main control connection interface CN1 is also connected to the second signal sending end TXD1 inside the main control chip 14. The third end 3 of the main control connection interface CN1 is connected to the second end of the first triode Q1, that is, the output end of the first transfer circuit 12. The third end 3 of the main control connection interface CN1 is also connected to the first signal receiving end RXD1 inside the main control chip 14. The fourth end 4 of the main control connection interface CN1 is connected to the reset circuit 15. The fifth end 5 of the main control connection interface CN1 is grounded to GND. The sixth end 6 of the main control connection interface CN1 is connected to the second reference voltage V_BAT.

[0037] Continue to refer to Figure 5 , the reset circuit 15 includes a third triode Q3 and a seventh resistor R7. The first end of the third triode Q3 is connected to the main control connection interface CN1 through the seventh resistor R7. The second end of the third triode Q3 is connected to the reset terminal RST of the Bluetooth module 11. The third end of the third triode Q3 is grounded to GND. Preferably, the third triode Q3 is an NPN transistor. Among them, the first end of the third triode Q3 is the base, the second end of the third triode Q3 is the collector, and the third end of the third triode Q3 is the emitter. The reset circuit 15 of the embodiment of the present invention is a high-level reset. When the main control chip 14 outputs a high level through the main control connection interface CN1, the third triode Q3 is turned on, and the collector of the third triode Q3 outputs a low level to reset the Bluetooth module 11.

[0038] In another embodiment of the present invention, as Figure 6 shown, the reset circuit 15 includes a second diode D2. The cathode of the second diode D2 is connected to the main control connection interface CN1. The anode of the second diode D2 is connected to the reset terminal RST of the Bluetooth module 11. The reset circuit 15 of the embodiment of the present invention is a low-level reset. When the main control chip 14 outputs a low level through the main control connection interface CN1, the second diode D2 is turned on, and a low level is output to the Bluetooth module 11 to reset the Bluetooth module 11.

[0039] In the embodiment of the present invention, as Figure 7As shown, the bidirectional communication level shifter circuit 10 further includes a power supply circuit 16, and the power supply circuit 16 includes: a first connection terminal J1, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, an eighth resistor R8, and a first inductor L1. The first end and the third end of the first connection terminal J1 are grounded to GND. The second end of the first connection terminal J1 is grounded to GND through the parallel-connected fourth capacitor C4. The second end of the first connection terminal J1 is also connected to one end of the fifth capacitor C5 and one end of the first inductor L1, and is also connected to a second voltage. The other end of the fifth capacitor C5 is grounded to GND and is connected to the reference ground AGND through the eighth resistor R8. The other end of the first inductor L1 is grounded to GND through the mutually parallel-connected sixth capacitor C6, the seventh capacitor C7, and the eighth capacitor C8, and outputs a first reference voltage VDD. The first connection terminal J1 is used to connect to the mains through an adapter (not shown in the figure). The power supply circuit 16 performs conversion according to the mains and outputs the first reference voltage VDD, which is connected to Figure 4 the anode of the third diode D3 in, to provide the first reference voltage VDD for the Bluetooth module 11.

[0040] As Figure 8 shown, the bidirectional communication level shifter circuit 10 further includes a charging circuit 17, and the charging circuit 17 includes: a charging management chip U1, a second connection terminal J2 for installing a charging battery BAT, a ninth resistor R9, a tenth resistor R10, and a ninth capacitor C9. The first end of the charging management chip U1 is connected to the first reference voltage VDD through the ninth resistor R9. The second end of the charging management chip U1 is grounded to GND. The third end of the charging management chip U1 is grounded to GND through the ninth capacitor C9. The third end of the charging management chip U1 is also connected to the positive electrode of the charging battery BAT and the second end of the second connection terminal J2. The negative electrode of the charging battery BAT and the first end of the second connection terminal J2 are grounded to GND. The fourth end of the charging management chip U1 is connected to the first reference voltage VDD. The fifth end of the charging management chip U1 is grounded to GND through the tenth resistor R10. The third end of the charging management chip U1 also outputs a second reference voltage V_BAT. The charging management chip U1 performs charging management on the charging battery BAT according to the input first reference voltage VDD and outputs the second reference voltage V_BAT to Figure 5 the sixth terminal 6 in the main control connection interface CN1 in. Among them, the charging management chip U1 can adopt any model of charging management chip that can implement the above functions, such as the charging management chip with the model BL4054.

[0041] Continue to refer to Figure 4, the bidirectional communication level shifter circuit 10 includes a storage circuit 18, and the storage circuit 18 includes a storage chip U2, a tenth capacitor C10, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, and a sixteenth resistor R16. The first pin, second pin, fifth pin, and sixth pin of the storage chip U2 are respectively connected to different pins of the Bluetooth module 11 through the thirteenth resistor R13, the fourteenth resistor R14, the fifteenth resistor R15, and the sixteenth resistor R16. The third pin, seventh pin, and eighth pin of the storage chip U2 are connected to the fifth voltage and are also grounded to GND through the tenth capacitor C10. The fourth pin of the storage chip U2 is grounded to GND. The storage chip U2 is used to store various communication data and the music that can be played. The LED terminal BT_LED of the Bluetooth module 11 is also connected to the anode of the light-emitting diode D4 through the twenty-fourth resistor R24, and the cathode of the light-emitting diode D4 is grounded to GND. The Bluetooth module 11 completes signal indication by controlling the lighting of the light-emitting diode D4. The storage chip U2 can be any model of chip that can implement the storage function, such as the storage chip with the model W25Q128FVSIG.

[0042] The Bluetooth module 11 is also connected to the speaker driving circuit 19. Such as Figure 9As shown, the speaker circuit 19 includes: a power amplifier unit U3, an eleventh capacitor C11, a twelfth capacitor C12, a thirteenth capacitor C13, a fourteenth capacitor C14, a fifteenth capacitor C15, a sixteenth capacitor C16, a seventeenth capacitor C17, an eighteenth capacitor C18, a nineteenth capacitor C19, a twentieth capacitor C20, a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, a twenty-first resistor R21, a twenty-second resistor R22, a twenty-third resistor R23, a second inductor L2, a third inductor L3, and a third connection terminal J3. The first terminal of the power amplifier unit U3 is connected to the Bluetooth module 11 through the twenty-first resistor R21 and is connected to the first reference voltage VDD through the twenty-second resistor R22. The second terminal of the power amplifier unit U3 is connected to the reference ground AGND through the fifteenth capacitor C15. The third terminal of the power amplifier unit U3 is connected to the first reference voltage VDD through the twenty-third resistor R23. The fourth terminal of the power amplifier unit U3 is connected to the Bluetooth module 11 through the twentieth resistor R20, the fourteenth capacitor C14, the twelfth capacitor C12, the seventeenth resistor R17, and the eleventh capacitor C11 connected in series in sequence. The eighteenth resistor R18 is connected in parallel with the twelfth capacitor C12. One end of the thirteenth capacitor C13 is connected between the twelfth capacitor and the fourteenth capacitor, and the other end is connected to the reference ground AGND through the nineteenth resistor R19. The fifth terminal of the power amplifier unit U3 is connected to one end of the third inductor L3. The other end of the third inductor L3 is grounded to GND through the nineteenth capacitor C19 and is also connected to the first end of the third connection terminal J3. The sixth terminal of the power amplifier unit U3 is connected to the first reference voltage VDD and is also grounded to GND through the sixteenth capacitor C16, the seventeenth capacitor C17, and the eighteenth capacitor C18 connected in parallel with each other. The seventh terminal of the power amplifier unit U3 is grounded to GND, and the eighth terminal is connected to one end of the second inductor L2. The other end of the second inductor L2 is grounded to GND through the twentieth capacitor C20 and is also connected to the second end of the third connection terminal J3. The third connection terminal J3 is used to connect a speaker (not shown in the figure). The first terminal of the power amplifier unit U3 is used to receive music transmitted from the storage chip U2 by the Bluetooth module 11. The control signal output by the Bluetooth module 11 is power-amplified by the power amplifier unit U3 and then output to the third connection terminal J3, and then transmitted to the speaker to play the music transmitted from the storage chip U2. Among them, the power amplifier unit U3 can be any integrated circuit capable of realizing power amplification, such as a power amplification module of model MAXI2018E.

[0043] The two-way communication level shifting circuit 10 according to an embodiment of the present invention includes: a Bluetooth module 11, a first shifting circuit 12, a second shifting circuit 13, and a main control chip 14 that performs two-way communication with the Bluetooth module 11; the first shifting circuit 12 receives a first communication signal based on a first voltage output from a first signal transmitting end TXD of the Bluetooth module 11, converts it into the first communication signal based on a second voltage, and transmits it to a first signal receiving end RXD1 of the main control chip 14, and the second shifting circuit 13 receives a second communication signal based on the second voltage output from a second signal transmitting end TXD1 of the main control chip 14, converts it into the second communication signal based on the first voltage, and transmits it to a second signal receiving end RXD of the Bluetooth module 11; the first shifting circuit 12 includes a first resistor R1, a second resistor R2, and a first triode Q1, a first end of the first triode Q1 is connected to the first voltage through the first resistor R1, a second end of the first triode Q1 is connected to the first signal receiving end RXD1 of the main control chip 14, the second end of the first triode Q1 is also connected to the second voltage through the second resistor R2, and a third end of the first triode Q1 is connected to the first signal transmitting end TXD of the Bluetooth module 11, which can realize two-way conversion between different levels, and has a simple circuit structure and low cost.

[0044] In the specification provided herein, a large number of specific details are set forth. It is understood, however, that embodiments of the present invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0045] Similarly, it should be understood that in order to streamline the present invention and assist in understanding one or more of the various inventive aspects, in the foregoing description of the exemplary embodiments of the present invention, the various features of the embodiments of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, the disclosed method should not be construed as reflecting an intention that: the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, the inventive aspects lie in less than all the features of the single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of the present invention.

[0046] In addition, those skilled in the art will appreciate that although some embodiments herein include certain features included in other embodiments but not others, the combination of features of different embodiments means within the scope of the present invention and forms different embodiments. For example, in the following claims, any one of the claimed embodiments can be used in any combination.

[0047] It should be noted that the above embodiments illustrate the present invention rather than limit the present invention, and those skilled in the art can design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in the claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present invention can be implemented by means of hardware including several different elements and by means of a suitably programmed computer. In a unit claim listing several devices, several of these devices can be embodied by the same item of hardware. The use of the words first, second, and third, etc. does not denote any order. These words can be interpreted as names. The steps in the above embodiments, unless otherwise specified, should not be construed as limiting the order of execution.

Claims

1. A bidirectional communication level shift circuit, characterized in that, The bidirectional communication level shifting circuit (10) includes: a Bluetooth module (11), a first shifting circuit (12), a second shifting circuit (13), and a main control chip (14) that communicates bidirectionally with the Bluetooth module (11); the first shifting circuit (12) receives a first communication signal based on a first voltage output from a first signal sending end (TXD) of the Bluetooth module (11), converts it into the first communication signal based on a second voltage, and transmits it to a first signal receiving end (RXD1) of the main control chip (14), and the second shifting circuit (13) receives a second communication signal based on the second voltage output from a second signal sending end (TXD1) of the main control chip (14), converts it into the second communication signal based on the first voltage, and transmits it to a second signal receiving end (RXD) of the Bluetooth module (11); the first shifting circuit (12) includes a first resistor (R1), a second resistor (R2), and a first triode (Q1), a first end of the first triode (Q1) is connected to the first voltage through the first resistor (R1), a second end of the first triode (Q1) is connected to the first signal receiving end (RXD1) of the main control chip (14), the second end of the first triode (Q1) is also connected to the second voltage through the second resistor (R2), and a third end of the first triode (Q1) is connected to the first signal sending end (TXD) of the Bluetooth module (11); the first resistor (R1) is a pull-up resistor.

2. The bidirectional communication level shift circuit according to claim 1, characterized in that, The first voltage is the power supply voltage of the Bluetooth module (11), and the second voltage is the power supply voltage of the main control chip (14).

3. The bidirectional communication level shift circuit according to claim 1, characterized in that, The second shifting circuit (13) includes a third resistor (R3), a fourth resistor (R4), and a first diode (D1), a cathode of the first diode (D1) is connected to the second signal sending end (TXD1) of the main control chip (14), and is also connected to the second voltage through the third resistor (R3); an anode of the first diode (D1) is connected to the second signal receiving end (RXD) of the Bluetooth module (11), and is also connected to the first voltage through the fourth resistor (R4).

4. The bidirectional communication level shift circuit according to claim 1, characterized in that, The second shifting circuit (13) includes a fifth resistor (R5), a sixth resistor (R6), and a second triode (Q2), a first end of the second triode (Q2) is connected to the first voltage through the fifth resistor (R5), a second end of the second triode (Q2) is connected to the second signal receiving end (RXD) of the Bluetooth module (11), and is also connected to the first voltage through the sixth resistor (R6), and a third end of the second triode (Q2) is connected to the second signal sending end (TXD1) of the main control chip (14).

5. The bidirectional communication level shift circuit according to claim 1, characterized in that, The two-way communication level shifting circuit (10) includes a first capacitor (C1), a second capacitor (C2), a third capacitor (C3), and a third diode (D3). The first power supply terminal of the Bluetooth module (11) is connected to the first voltage. At the same time, the first power supply terminal of the Bluetooth module (11) is also grounded through the first capacitor (C1) and the second capacitor (C2) connected in parallel; the second power supply terminal of the Bluetooth module (11) is connected to the cathode of the third diode (D3), the anode of the third diode (D3) is connected to the first reference voltage, and the second power supply terminal of the Bluetooth module (11) is also grounded through the third capacitor (C3).

6. The bidirectional communication level shift circuit according to claim 1, characterized in that, The two-way communication level shifting circuit (10) further includes a reset circuit (15) connected to the reset terminal of the Bluetooth module (11). The main control chip (14) includes a main control connection interface (CN1). The first terminal of the main control connection interface (CN1) is connected to the second voltage. The second terminal of the main control connection interface (CN1) is connected to the input terminal of the second transfer circuit (13). The third terminal of the main control connection interface (CN1) is connected to the second terminal of the first triode (Q1). The fourth terminal of the main control connection interface (CN1) is connected to the reset circuit (15). The fifth terminal of the main control connection interface (CN1) is grounded. The sixth terminal of the main control connection interface (CN1) is connected to the second reference voltage.

7. The bidirectional communication level shift circuit according to claim 6, characterized in that, The reset circuit (15) includes a third triode (Q3) and a seventh resistor (R7). The first terminal of the third triode (Q3) is connected to the main control connection interface (CN1) through the seventh resistor (R7). The second terminal of the third triode (Q3) is connected to the reset terminal of the Bluetooth module (11). The third terminal of the third triode (Q3) is grounded.

8. The bidirectional communication level shift circuit according to claim 6, characterized in that, The reset circuit (15) includes a second diode (D2). The cathode of the second diode (D2) is connected to the main control connection interface (CN1). The anode of the second diode (D2) is connected to the reset terminal of the Bluetooth module (11).

9. The bidirectional communication level shift circuit according to claim 1, characterized in that, The two-way communication level shift circuit (10) further includes a power supply circuit (16), and the power supply circuit (16) includes: a first connection terminal (J1), a fourth capacitor (C4), a fifth capacitor (C5), a sixth capacitor (C6), a seventh capacitor (C7), an eighth capacitor (C8), an eighth resistor (R8), and a first inductor (L1); the first end and the third end of the first connection terminal (J1) are grounded, the second end of the first connection terminal (J1) is grounded (GND) through the parallel-connected fourth capacitor (C4), the second end of the first connection terminal (J1) is also connected to one end of the fifth capacitor (C5) and one end of the first inductor (L1), and is also connected to the second voltage, the other end of the fifth capacitor (C5) is grounded and is connected to the reference ground through the eighth resistor (R8); the other end of the first inductor (L1) is grounded through the mutually parallel-connected sixth capacitor (C6), the seventh capacitor (C7), and the eighth capacitor (C8), and outputs a first reference voltage.

10. The bidirectional communication level shift circuit according to claim 9, characterized in that, The two-way communication level shift circuit (10) further includes a charging circuit (17), and the charging circuit (17) includes: a charging management chip (U1), a second connection terminal (J2) for mounting a charging battery (BAT), a ninth resistor (R9), a tenth resistor (R10), and a ninth capacitor (C9); the first end of the charging management chip (U1) is connected to the first reference voltage through the ninth resistor (R9), the second end of the charging management chip (U1) is grounded, the third end of the charging management chip (U1) is grounded through the ninth capacitor (C9), the third end of the charging management chip (U1) is also connected to the positive electrode of the charging battery (BAT) and the second end of the second connection terminal (J2), the negative electrode of the charging battery (BAT) and the first end of the second connection terminal (J2) are grounded (GND), the fourth end of the charging management chip (U1) is connected to the first reference voltage, the fifth end of the charging management chip (U1) is grounded through the tenth resistor (R10), and the third end of the charging management chip (U1) also outputs a second reference voltage.

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