CN111669172A

CN111669172A - Bidirectional communication level transfer circuit

Info

Publication number: CN111669172A
Application number: CN202010582619.3A
Authority: CN
Inventors: 邹志华
Original assignee: Shenzhen Shuliantianxia Intelligent Technology Co Ltd
Current assignee: Shenzhen Shuliantianxia Intelligent Technology Co Ltd
Priority date: 2020-06-23
Filing date: 2020-06-23
Publication date: 2020-09-15

Abstract

The embodiment of the invention relates to the technical field of power supply control, and discloses a bidirectional communication level transfer circuit, which comprises: the Bluetooth module comprises a Bluetooth module, a first transfer circuit, a second transfer circuit and a main control chip which is in bidirectional communication with the Bluetooth module; the second transfer circuit receives a second communication signal based on a second voltage output by a second signal sending end of the main control chip, converts the second communication signal based on the first voltage into a second communication signal based on the first voltage and transmits the second communication signal to a second signal receiving end of the Bluetooth module; the first transfer circuit comprises a first resistor, a second resistor and a first triode, the first end of the first triode is connected with first voltage through the first resistor, the second end of the first triode is connected with a first signal receiving end of the main control chip, the second end of the first triode is connected with second voltage through the second resistor, and the third end of the first triode is connected with a first signal sending end of the Bluetooth module. Through the mode, the embodiment of the invention can realize bidirectional conversion among different levels, and has the advantages of simple circuit structure and low cost.

Description

Bidirectional communication level transfer circuit

Technical Field

The embodiment of the invention relates to the technical field of power supply control, in particular to a bidirectional communication level transfer circuit.

Background

In electronic engineering design, electronic devices and module units with different power supplies are commonly used, such as transistor-transistor logic (TTL) devices and Complementary Metal Oxide Semiconductor (cmos) devices, and the voltage values of the devices are different, so that the voltage values of high and low levels are different, and therefore, an input and output signal matching problem exists in the communication process. A designer is required to level-convert the signal.

In the prior art, a phase inverter formed by triode switching characteristics and pull-up resistors is often adopted to realize high-low level conversion and migration, and signals are inverted in the transmission process and must be additionally processed in software. For some common protocols such as UART, a general single chip computer (MCU) integrates these functions, the port output of the initial level in the data transmission process is automatically determined according to the protocol and can not be inverted, so that the communication process of the type requires in-phase transmission. In order to realize the level in-phase transfer, two-stage inversion is necessary, so that more devices are needed, and the cost is increased. The level conversion in the prior art can also basically and directly adopt an application specific integrated circuit chip, and the cost performance of the application specific integrated circuit chip is relatively high, and is too low for a plurality of circuits with lower working frequency.

Disclosure of Invention

In view of the above, embodiments of the present invention provide a bidirectional communication level shift circuit that overcomes or at least partially solves the above-mentioned problems.

According to an aspect of an embodiment of the present invention, there is provided a bidirectional communication level shift circuit including: the Bluetooth module comprises a Bluetooth module, a first transfer circuit, a second transfer circuit and a main control chip which is in bidirectional communication with the Bluetooth module; the first transfer circuit receives a first communication signal based on a first voltage output by a first signal sending end of the Bluetooth module, converts the first communication signal based on a second voltage into the first communication signal based on the second voltage and transmits the first communication signal to a first signal receiving end of the main control chip, and the second transfer circuit receives a second communication signal based on the second voltage output by a second signal sending end of the main control chip, converts the second communication signal based on the first voltage into the second communication signal based on the first voltage and transmits the second communication signal to a second signal receiving end of the Bluetooth module; first transfer circuit includes first resistance, second resistance and first triode, the first end of first triode passes through first resistance connects first voltage, the second end of first triode is connected the main control chip first signal receiving terminal, the second end of first triode still passes through second resistance connects the second voltage, the third end connection of first triode the bluetooth module first signal sending terminal.

In an optional manner, the first voltage is a power supply voltage of the bluetooth module, and the second voltage is a power supply voltage of the main control chip.

In an optional manner, the second transfer circuit includes a third resistor, a fourth resistor, and a first diode, and a cathode of the first diode is connected to the second signal sending terminal 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 with the second signal receiving end of the Bluetooth module, and is connected with the first voltage through the fourth resistor.

In an optional mode, the second transfer 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 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.

In an optional 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 terminal of the bluetooth module is connected to the first voltage, and meanwhile, a first power supply terminal of the bluetooth module is also connected to ground through the first capacitor and the second capacitor connected in parallel; the second power supply end of the Bluetooth module is connected with the cathode of the third diode, the anode of the third diode is connected with the first reference voltage, and the second power supply end of the Bluetooth module is grounded through the third capacitor.

In an optional mode, the bidirectional communication level transfer circuit further comprises a reset circuit connected with a reset end of the bluetooth module, the main control chip comprises a main control connection interface, a first end of the main control connection interface is connected with the second voltage, a second end of the main control connection interface is connected with an input end of the second transfer circuit, a third end of the main control connection interface is connected with a second end of the first triode, a fourth end of the main control connection interface is connected with the reset circuit, a fifth end of the main control connection interface is grounded, and a sixth end of the main control connection interface is connected with the second reference voltage.

In an optional mode, the reset circuit includes a third triode and a seventh resistor, the first end of the third triode is connected to the interface through the seventh resistor, the second end of the third triode is connected to the reset end of the bluetooth module, and the third end of the third triode is grounded.

In an optional mode, the reset circuit includes a second diode, a cathode of the second diode is connected to the master control connection interface, and an anode of the second diode is connected to the reset terminal of the bluetooth module.

In an optional manner, the bidirectional communication level shift circuit further includes a power supply circuit, the power supply circuit including: the first capacitor is connected with the first connecting terminal; 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 fourth capacitor connected in parallel, the second end of the first connection terminal is also connected with one end of the fifth capacitor and one end of the first inductor, and is also connected with the second voltage, the other end of the fifth capacitor is grounded, and is also connected with the reference ground through the eighth resistor; the other end of the first inductor is grounded through the sixth capacitor, the seventh capacitor and the eighth capacitor which are connected in parallel, and a first reference voltage is output at the same time.

In an optional manner, the bidirectional communication level shift circuit further includes a charging circuit, and the charging circuit includes: the charging management chip, a second connecting terminal for mounting a rechargeable battery, a ninth resistor, a tenth resistor and a ninth capacitor; the first end of the charging management chip is connected with 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 connected with the anode of the rechargeable battery and the second end of the second connecting terminal, the cathode of the rechargeable battery is grounded through the first end of the second connecting terminal, the fourth end of the charging management chip is connected with the first reference voltage, the fifth end of the charging management chip is grounded through the tenth resistor, and the third end of the charging management chip outputs the second reference voltage.

The bidirectional communication level transfer circuit of the embodiment of the invention comprises: the Bluetooth module comprises a Bluetooth module, a first transfer circuit, a second transfer circuit and a main control chip which is in bidirectional communication with the Bluetooth module; the first transfer circuit receives a first communication signal based on a first voltage output by a first signal sending end of the Bluetooth module, converts the first communication signal based on a second voltage into the first communication signal based on the second voltage and transmits the first communication signal to a first signal receiving end of the main control chip, and the second transfer circuit receives a second communication signal based on the second voltage output by a second signal sending end of the main control chip, converts the second communication signal based on the first voltage into the second communication signal based on the first voltage and transmits the second communication signal to a second signal receiving end of the Bluetooth module; first transfer circuit includes first resistance, second resistance and first triode, the first end of first triode passes through first resistance connects first voltage, the second end of first triode is connected the main control chip first signal receiving terminal, the second end of first triode still passes through second resistance connects the second voltage, the third end connection of first triode the bluetooth module first signal sending terminal can realize the two-way conversion between the different levels, circuit structure is simple, low cost.

The foregoing description is only an overview of the technical solutions of the embodiments of the present invention, and the embodiments of the present invention can be implemented according to the content of the description in order to make the technical means of the embodiments of the present invention more clearly understood, and the detailed description of the present invention is provided below in order to make the foregoing and other objects, features, and advantages of the embodiments of the present invention more clearly understandable.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

fig. 1 is a schematic diagram illustrating a bidirectional communication level shift circuit according to an embodiment of the present invention;

FIG. 2 is a detailed circuit diagram of a bidirectional communication level shift circuit according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a bidirectional communication level shifter circuit according to an embodiment of the present invention;

FIG. 4 is a schematic diagram illustrating an application of a bidirectional communication level shift circuit according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a reset circuit in a bi-directional communication level shift circuit provided by an embodiment of the invention;

FIG. 6 is a schematic diagram of yet another reset circuit in a bi-directional communication level shift circuit provided by an embodiment of the present invention;

FIG. 7 is a schematic diagram of a power supply circuit in a bi-directional communication level shift circuit provided by an embodiment of the invention;

fig. 8 is a schematic diagram of a charging circuit in a bidirectional communication level shifter circuit provided by an embodiment of the invention;

fig. 9 is a schematic diagram of a speaker driving circuit in a bidirectional communication level shift circuit according to an embodiment of the present invention.

Detailed Description

Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

Fig. 1 shows a schematic structural diagram of a bidirectional communication level shift circuit according to an embodiment of the present invention, and as shown in fig. 1, a bidirectional communication level shift circuit 10 includes: the bluetooth module 11, the first transfer circuit 12, the second transfer circuit 13 and the main control chip 14 that carries out the two-way communication with the bluetooth module 11. The first transfer circuit 12 receives a first communication signal based on a first voltage output by a first signal transmitting terminal TXD of the bluetooth module 11, converts the first communication signal based on a second voltage, and transmits the first communication signal to a first signal receiving terminal RXD1 of the main control chip 14. The second transfer circuit 13 receives a second communication signal based on a second voltage output by a second signal sending terminal TXD1 of the main control chip 14, converts the second communication signal based on the first voltage into the second communication signal based on the first voltage, and transmits the second communication signal to a second signal receiving terminal RXD of the bluetooth module 11. The first transfer circuit 12 includes a first resistor R1, a second resistor R2, and a first transistor Q1, a first end of the first transistor Q1 is connected to a first voltage +3.3V through the first resistor R1, a second end of the first transistor Q1 is connected to a first signal receiving terminal RXD1 of the main control chip 14, a second end of the first transistor Q1 is further connected to a second voltage +5V through the second resistor R2, and a third end of the first transistor Q1 is connected to a first signal transmitting terminal TXD of the bluetooth module 11.

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 may be 0-3.3V or 0.3V-3.3V, and the first communication signal or the second communication signal based on the second voltage may be 0-5V or 0.3V-5V. Preferably, the first triode Q1 is an NPN transistor, the first terminal is a base of the NPN transistor, the second terminal is a collector of the NPN transistor, and the third terminal is an emitter of the NPN transistor. The first resistor R1 is a pull-up resistor.

When the first communication signal based on the first voltage input to the first transfer circuit 12 by the first signal transmitting terminal TXD of the bluetooth module 11 is high, for example, 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 turned off, the first communication signal based on the second voltage output by the collector (C) is high, and the first communication signal is transmitted to the first signal receiving terminal RXD1 of the main control chip 14, so that high-level in-phase transmission between different voltages can BE realized. When the first communication signal based on the first voltage input from the first signal transmitting terminal 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 biased forward, the first triode Q1 is turned on, the first communication signal based on the second voltage output by the collector C is low, specifically, the saturated conduction voltage of the first triode Q1 is about 0.3V, and low-level in-phase transmission between different voltages can BE realized. By combining the two situations, the level transfer or data transmission from the low voltage to the high voltage unit can be realized, namely the level in-phase transmission from the low voltage end to the high voltage end is realized. The second resistor R2 is a pull-up resistor, and may be configured with a built-in pull-up resistor directly by the main control chip 14 without mounting, so that the whole circuit is simpler.

Alternatively, as shown in fig. 2, 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 transmitting terminal TXD1 of the host 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 receiving terminal RXD of the bluetooth module 11, and is also connected to the first voltage via the fourth resistor R4. The second transfer circuit 13 of the embodiment of the present invention uses a diode to realize transfer of a high voltage level to a low voltage level terminal or data transmission. When the second communication signal based on the second voltage output by the second signal transmitting terminal TXD1 of the main control chip 14 is high, such as 5V, the first diode D1 is turned off, and the second communication signal based on the first voltage output by the second transfer circuit 13 is 3.3V, which is at a high level, so that high-level in-phase transmission between different voltages can be realized. When the second communication signal based on the second voltage output by the second signal transmitting terminal TXD1 of the main control chip 14 is low, such as 0V, the first diode D1 is turned on in the forward direction, and the second communication signal based on the first voltage output by the second transfer circuit 13 is 0.3V, and is at a low level, so that low-level in-phase transmission between different voltages can be realized. By combining the two situations, the same-phase transmission of the level from the high-voltage end to the low-voltage end can be realized. The third resistor R3 and the fourth resistor R4 are pull-up resistors and may not be installed, the third resistor R3 directly configures the built-in pull-up resistor with the main control chip 14, and the fourth resistor R4 directly configures the built-in pull-up resistor with the bluetooth module 11, so that the whole circuit is simpler, one diode can be used to realize the level in-phase transmission from the high-voltage end to the low-voltage end, and after the second resistor R2, the third resistor R3 and the fourth resistor R4 are not installed, three devices (the first resistor R1, the first triode Q1 and the first diode D1) are used to realize bidirectional level transfer or data communication, so that the whole circuit is extremely simple and has low cost.

The two-way 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 terminal RXD1 of the main control chip 14 sends 1 (for example, 5V) to the cathode of the first diode D1, the anode of the first diode D1 is the first voltage +3.3V connected through the third resistor R3 as a pull-up resistor, the voltage of the first diode D1 is reversely biased, the first diode D1 is cut off, the anode of the first diode D1 is +3.3V, and the second signal receiving terminal RXD of the bluetooth module 11 receives 1. The first signal receiving terminal RXD1 of the main control chip 14 sends 0 (e.g. 0V) to the cathode of the first diode D1, the anode of the first diode D1 is connected to +3.3V through the third resistor R3, the first diode D1 is biased to be turned on, the anode of the first diode D1 is diode turn-on voltage (0.3V), and the second signal receiving terminal RXD of the bluetooth module 11 receives 0. When the bluetooth module 11 transmits data to the main control chip 14, a first signal transmitting terminal TXD of the bluetooth module 11 transmits 1 (for example, 3.3V) to an emitter E of a first triode Q1, a base B of the first triode Q1 is connected with +3.3V through a first resistor R1 serving as a pull-up resistor, a voltage drop between BEs of the first triode Q1 is 0, the first triode Q1 is cut off, a collector C of the first triode Q1 is connected with +5V through a second resistor R2 serving as a pull-up resistor, and a first signal receiving terminal RXD1 of the main control chip 14 receives 1. The first signal transmitting terminal TXD of the Bluetooth module 11 transmits 0 (e.g., 0V) to the emitter E of the first transistor Q1, the base of the first transistor Q1The pole B is connected to +3.3V through a first resistor R1, the BE of the first triode Q1 is conducted in the forward direction, the first triode Q1 is conducted in saturation, and the voltage of the collector C between the BE of the first triode Q1 is saturated conduction voltage drop (V_CE)0.3V, the first signal receiving terminal RXD1 of the main control chip 14 receives 0. The main control chip 14 may be any type of existing single chip microcomputer capable of implementing the above functions. Of course, in other embodiments of the invention, other processors may be used, and are not limited herein.

As shown in fig. 3, the second transfer circuit 13 includes a fifth resistor R5, a sixth resistor R6, and a second transistor 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 terminal RXD of the bluetooth module 11, and is 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 transmitting terminal TXD1 of the main control chip 14. The second triode Q2 is an NPN transistor, a first end is a base of the NPN transistor, a second end is a collector of the NPN transistor, and a third end is an emitter of the NPN transistor.

When the second communication signal based on the second level output by the second signal transmitting terminal TXD1 of the main control chip 14 is high, such as 5V, the voltage between the BE of the second triode Q2 is 0 or reverse biased, the second triode Q2 is turned off, the second communication signal based on the first level output by the collector C is high, and the voltage value of the high level is determined according to the power source connected to the sixth resistor R6, so that high-level in-phase transfer between different voltages is realized. When the second communication signal based on the second level output by the second signal transmitting terminal TXD1 of the main control chip 14 is low, for example, 0, the BE of the second transistor Q2 is biased positively, the second transistor Q2 is turned on, and the second communication signal based on the first level output by the collector C is low, specifically, the saturated conduction voltage of the second transistor Q2 is about 0.3V, so that level transfer or data transmission from the high-voltage unit to the low-voltage unit is realized, that is, low-level in-phase transmission between different voltages is realized. The sixth resistor R6 is a pull-up resistor, and may not be installed, and the built-in pull-up resistor is directly configured with the bluetooth module 11, so that the whole circuit is simpler.

In the embodiment of the present invention, as shown in fig. 4, the bidirectional communication level shift 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, and the first power supply terminal D-3V3 of the Bluetooth module 11 is also connected to the ground GND through the first capacitor C1 and the second capacitor C2 connected in parallel. 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 further connected to the ground GND through the third capacitor C3. The first capacitor C1, the second capacitor C2, and the third capacitor C3 are filter capacitors for filtering spikes and the like that may be generated in the power signal. The first signal transmitting terminal TXD of the bluetooth module 11 is connected to the third terminal of the first transistor Q1 through a twelfth resistor R12, and the second signal receiving terminal RXD of the bluetooth module 11 is connected to the output terminal of the second transfer circuit 13 through an eleventh resistor R11, for example, connected to the anode of the first diode D1. The eleventh resistor R11 and the twelfth resistor R12 are current limiting resistors. The bluetooth module 11 may be an existing bluetooth module, such as a bluetooth module with a model number D3851A. Of course, in other embodiments of the invention, other processors may be used, and are not limited herein.

As shown in fig. 5, the bidirectional communication level shift 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 terminal 1 of the main control connection interface CN1 is connected to the second voltage, the second end 2 of the master connection interface CN1 is connected to the input end of the second transfer circuit 13, for example, the second terminal 2 of the master connection interface CN1 is connected to the cathode of the first diode D1, and the second signal transmitting terminal TXD1 inside the master chip 14, the third terminal 3 of the master connection interface CN1 is connected to the second terminal of the first transistor Q1, namely, the output end of the first transfer circuit 12 is connected, the third end 3 of the master control connection interface CN1 is further connected with the first signal receiving end RXD1 inside the master control chip 14, the fourth terminal 4 of the master connection interface CN1 is connected to the reset circuit 15, the fifth terminal 5 of the master connection interface CN1 is grounded to GND, and the sixth terminal 6 of the master connection interface CN1 is connected to the second reference voltage V _ BAT.

With reference to fig. 5, the reset circuit 15 includes a third transistor Q3 and a seventh resistor R7, a first end of the third transistor Q3 is connected to the main control connection interface CN1 through the seventh resistor R7, a second end of the third transistor Q3 is connected to the reset terminal RST of the bluetooth module 11, and a third end of the third transistor Q3 is grounded to GND. Preferably, the third transistor Q3 is an NPN transistor, wherein the first terminal of the third transistor Q3 is a base, the second terminal of the third transistor Q3 is a collector, and the third terminal of the third transistor Q3 is an 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 transistor Q3 is turned on, and the collector of the third transistor Q3 outputs a low level, so that the bluetooth module 11 is reset.

In another embodiment of the present invention, as shown in fig. 6, the reset circuit 15 includes a second diode D2, a cathode of the second diode D2 is connected to the master connection interface CN1, and an 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 outputs the low level to the bluetooth module 11, so that the bluetooth module 11 is reset.

In the embodiment of the present invention, as shown in fig. 7, the bidirectional communication level shift circuit 10 further includes a power supply circuit 16, and the power supply circuit 16 includes: the inductor comprises 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 fourth capacitor C4 connected in parallel, the second end of the first connection terminal J1 is further 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 also connected to ground AGND through the eighth resistor R8; the other end of the first inductor L1 is connected to ground GND through the sixth capacitor C6, the seventh capacitor C7 and the eighth capacitor C8, which are connected in parallel, and outputs a first reference voltage VDD. The first connection terminal J1 is used for pulling the commercial power through an adapter (not shown). The power circuit 16 converts the power according to the commercial power, outputs the first reference voltage VDD, is connected to the anode of the third diode D3 in fig. 4, and provides the first reference voltage VDD for the bluetooth module 14.

As shown in fig. 8, the bidirectional communication level shift circuit 10 further includes a charging circuit 17, the charging circuit 17 including: a charge management chip U1, a second connection terminal J2 for mounting a rechargeable 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 connected to the ground GND, the third end of the charging management chip U1 is connected to the ground GND through the ninth capacitor C9, the third end of the charging management chip U1 is further connected to the positive electrode of the rechargeable battery BAT and the second end of the second connection terminal J2, the negative electrode of the rechargeable battery BAT and the first end of the second connection terminal J2 are connected to the ground 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 connected to the ground GND through the tenth resistor R10, and the third end of the charging management chip U1 is further connected to output a second reference voltage V _ BAT. The charging management chip U1 performs charging management on the rechargeable battery BAT according to the input first reference voltage VDD, and outputs the second reference voltage V _ BAT to the sixth terminal 6 in the master control connection interface CN1 in fig. 5. The charging management chip U1 may be any type of charging management chip capable of implementing the above functions, such as a charging management chip with a type BL 4054.

With continued reference to fig. 4, the bidirectional communication level shift circuit 10 includes a memory circuit 18, and the memory circuit 18 includes a memory 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, the second pin, the fifth pin and the sixth pin of the memory chip U2 are connected to different pins of the bluetooth module 11 through a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15 and a sixteenth resistor R16, respectively. The third pin, the seventh pin and the eighth pin of the memory chip U2 are connected to the fifth voltage, and are also connected to the ground GND through the tenth capacitor C10. The fourth pin of the memory chip U2 is connected to ground GND. The memory chip U2 is used for storing various communication data and music that can be played. The LED terminal BT _ LED of the bluetooth module 11 is further connected to the anode of the light emitting diode D4 through a twenty-four resistor R24, and the cathode of the light emitting diode D4 is grounded to GND. The bluetooth module 11 completes the signal prompt by controlling the light emitting of the light emitting diode D4. The memory chip U2 may be any type of chip capable of performing a memory function, such as a W25Q128FVSIG memory chip.

The bluetooth module 11 is also connected to a speaker driving circuit 19. As shown in fig. 9, the speaker circuit 19 includes: the power amplifier comprises 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 connecting terminal J3. The first end of the power amplifier unit U3 is connected to the bluetooth module 11 through a twenty-first resistor R21 and is connected to the first reference voltage VDD through a twenty-second resistor R22. The second terminal of the power amplifier unit U3 is connected to ground AGND through a fifteenth capacitor C15. The third terminal of the power amplifier unit U3 is connected to the first reference voltage VDD through a twenty-third resistor R23. The fourth end of the power amplifier unit U3 is connected to the bluetooth module 11 through a twentieth resistor R20, a fourteenth capacitor C14, a twelfth capacitor C12, a seventeenth resistor R17 and an eleventh capacitor C11, which are connected in series in sequence. An 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 ground AGND through a nineteenth resistor R19. The fifth end of the power amplifier unit U3 is connected to one end of the third inductor L3, and the other end of the third inductor L3 is connected to the ground GND through the nineteenth capacitor C19 and is also connected to the first end of the third connection terminal J3. The sixth end of the power amplifier unit U3 is connected to the first reference voltage VDD, and is also connected to the ground GND through a sixteenth capacitor C16, a seventeenth capacitor C17 and an eighteenth capacitor C18, which are connected in parallel. The seventh end of the power amplifier unit U3 is grounded GND, the eighth end is connected to one end of the second inductor L2, and the other end of the second inductor L2 is grounded 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 for connecting a speaker (not shown). The first end of the power amplification unit U3 is used for receiving the music that the bluetooth module 11 transmitted from memory chip U2, and the bluetooth module 11 output control signal carries out output to third connecting terminal J3 after power amplification through power amplification unit U3, and then transmits to the speaker, plays the music that transmits from memory chip U2. The power amplifier unit U3 may be any integrated circuit capable of implementing power amplification, such as a power amplifier module of type MAXI 2018E.

The bidirectional communication level shift circuit 10 of the embodiment of the present invention includes: the Bluetooth module comprises a Bluetooth module 11, a first transfer circuit 12, a second transfer circuit 13 and a main control chip 14 which is in bidirectional communication with the Bluetooth module 11; the first transfer circuit 12 receives a first communication signal based on a first voltage output by a first signal transmitting terminal TXD of the bluetooth module 11, converts the first communication signal based on a second voltage into the first communication signal based on the second voltage and transmits the first communication signal to a first signal receiving terminal RXD1 of the main control chip 14, and the second transfer circuit 13 receives a second communication signal based on a second voltage output by a second signal transmitting terminal TXD1 of the main control chip 14, converts the second communication signal based on the first voltage into the second communication signal based on the first voltage and transmits the second communication signal to a second signal receiving terminal RXD of the bluetooth module 11; the first transfer 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 a first voltage through the first resistor R1, a second end of the first triode Q1 is connected to a first signal receiving terminal RXD1 of the main control chip 14, a second end of the first triode Q1 is also connected to a second voltage through the second resistor R2, and a third end of the first triode Q1 is connected to a first signal sending terminal TXD of the bluetooth module 11, so that bidirectional transfer between different levels can be achieved, the circuit structure is simple, and the cost is low.

In the description provided herein, numerous specific details are set forth. It is understood, however, that embodiments of the 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.

Similarly, it should be appreciated that in the foregoing description of exemplary embodiments of the invention, various features of the embodiments of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the invention and aiding in the understanding of one or more of the various inventive aspects. However, the disclosed method should not be interpreted as reflecting an intention that: that the invention as claimed requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a 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 this invention.

Furthermore, those skilled in the art will appreciate that while some embodiments herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the following claims, any of the claimed embodiments may be used in any combination.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to 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 a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The usage of the words first, second and third, etcetera do not indicate any ordering. These words may be interpreted as names. The steps in the above embodiments should not be construed as limiting the order of execution unless specified otherwise.

Claims

1. A bidirectional communication level shift circuit, characterized in that the bidirectional communication level shift circuit (10) comprises: the Bluetooth module comprises a Bluetooth module (11), a first transfer circuit (12), a second transfer circuit (13) and a main control chip (14) which is in bidirectional communication with the Bluetooth module (11); the first transfer circuit (12) receives a first communication signal based on a first voltage output by a first signal transmitting Terminal (TXD) of the Bluetooth module (11), converts the first communication signal based on a second voltage and transmits the first communication signal to a first signal receiving terminal (RXD1) of the master control chip (14), the second transfer circuit (13) receives a second communication signal based on a second voltage output by a second signal transmitting terminal (TXD1) of the master control chip (14), converts the second communication signal based on the first voltage and transmits the second communication signal to a second signal receiving terminal (RXD) of the Bluetooth module (11); the first transfer circuit (12) comprises a first resistor (R1), a second resistor (R2) and a first triode (Q1), wherein a first end of the first triode (Q1) is connected with a first voltage through the first resistor (R1), a second end of the first triode (Q1) is connected with the first signal receiving end (RXD1) of the main control chip (14), a second end of the first triode (Q1) is also connected with a second voltage through the second resistor (R2), and a third end of the first triode (Q1) is connected with the first signal transmitting end (TXD) of the Bluetooth module (11).

2. The bi-directional communication level shift circuit of claim 1, wherein the first voltage is a supply voltage of the bluetooth module (11) and the second voltage is a supply voltage of the master control chip (14).

3. The bidirectional communication level shifter circuit of claim 1, wherein the second shifter circuit (13) includes a third resistor (R3), a fourth resistor (R4), and a first diode (D1), a cathode of the first diode (D1) being connected to the second signal transmitting terminal (TXD1) of the master chip (14) while also being connected to the second voltage through the third resistor (R3); the anode of the first diode (D1) is connected with the second signal receiving terminal (RXD) of the Bluetooth module (11), and meanwhile, the first voltage is connected with the fourth resistor (R4).

4. The bi-directional communication level shift circuit according to claim 1, wherein the second shift circuit (13) comprises a fifth resistor (R5), a sixth resistor (R6) and a second transistor (Q2), a first terminal of the second transistor (Q2) is connected to the first voltage through the fifth resistor (R5), a second terminal of the second transistor (Q2) is connected to the second signal receiving terminal (RXD) of the bluetooth module (11) and is connected to the first voltage through the sixth resistor (R6), and a third terminal of the second transistor (Q2) is connected to the second signal transmitting terminal (TXD1) of the master chip (14).

5. The bidirectional communication level shift circuit of claim 1, wherein the bidirectional communication level shift circuit (10) comprises 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, and the first power supply terminal of the bluetooth module (11) is also connected to ground through the first capacitor (C1) and the second capacitor (C2) which are connected in parallel to each other; the second power supply end of the Bluetooth module (11) is connected with the cathode of the third diode (D3), the anode of the third diode (D3) is connected with a first reference voltage, and the second power supply end of the Bluetooth module (11) is also connected with the ground through the third capacitor (C3).

6. The bi-directional communication level shift circuit according to claim 1, wherein the bi-directional communication level shift circuit (10) further comprises a reset circuit (15) connected to a reset terminal of the bluetooth module (11), the main control chip (14) comprises a main control connection interface (CN1), a first terminal of the main control connection interface (CN1) is connected to the second voltage, a second terminal of the main control connection interface (CN1) is connected to an input terminal of the second shift circuit (13), a third terminal of the main control connection interface (CN1) is connected to a second terminal of the first transistor (Q1), a fourth terminal of the main control connection interface (CN1) is connected to the reset circuit (15), a fifth terminal of the main control connection interface (CN1) is connected to ground, and a sixth terminal of the main control connection interface (CN1) is connected to the second reference voltage.

7. The bi-directional communication level shift circuit of claim 6, wherein the reset circuit (15) comprises a third transistor (Q3) and a seventh resistor (R7), a first terminal of the third transistor (Q3) is connected to the main control connection interface (CN1) through the seventh resistor (R7), a second terminal of the third transistor (Q3) is connected to the reset terminal of the bluetooth module (11), and a third terminal of the third transistor (Q3) is grounded.

8. The bi-directional communication level shift circuit according to claim 6, characterized in that the reset circuit (15) comprises a second diode (D2), the cathode of the second diode (D2) is connected to the master connection interface (CN1), and 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 of claim 1, wherein the bidirectional communication level shift circuit (10) further comprises a power supply circuit (16), the power supply circuit (16) comprising: 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 fourth capacitor (C4) connected in parallel, the second end of the first connection terminal (J1) is further connected with one end of the fifth capacitor (C5) and one end of the first inductor (L1), and is also connected with the second voltage, the other end of the fifth capacitor (C5) is grounded, and is also connected with the reference ground through the eighth resistor (R8); the other end of the first inductor (L1) is grounded through the sixth capacitor (C6), the seventh capacitor (C7) and the eighth capacitor (C8) which are connected in parallel with each other, and outputs a first reference voltage.

10. The bidirectional communication level shift circuit of claim 9, wherein the bidirectional communication level shift circuit (10) further comprises a charging circuit (17), the charging circuit (17) comprising: a charge management chip (U1), a second connection terminal (J2) for mounting a rechargeable 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 with the first reference voltage through the ninth resistor (R9), the second end of the charging management chip (U1) is connected with the ground, the third end of the charging management chip (U1) is connected with the ground through the ninth capacitor (C9), the third end of the charging management chip (U1) is further connected with the anode of the rechargeable Battery (BAT) and the second end of the second connecting terminal (J2), the cathode of the rechargeable Battery (BAT) and the first end of the second connecting terminal (J2) are connected with the Ground (GND), the fourth end of the charging management chip (U1) is connected with the first reference voltage, the fifth end of the charging management chip (U1) is connected with the ground through the tenth resistor (R10), and the third end of the charging management chip (U1) is further used for outputting the second reference voltage.