CN222073142U

CN222073142U - Interface multiplexing circuit

Info

Publication number: CN222073142U
Application number: CN202420317951.0U
Authority: CN
Inventors: 王志宏; 邹佩龙; 李志强
Original assignee: Shanghai Yingheng Electronic Co ltd
Current assignee: Shanghai Yingheng Electronic Co ltd
Priority date: 2024-02-21
Filing date: 2024-02-21
Publication date: 2024-11-26
Anticipated expiration: 2034-02-21

Abstract

The utility model discloses an interface multiplexing circuit, which comprises: the device comprises an interface unit, a working mode switching unit and a reset signal generating unit; the interface unit is used for connecting external equipment and comprises a first pin, a second pin, a third pin and a fourth pin; the first pin and the second pin are communication pins, and the first pin is multiplexed as a power pin; the working mode switching unit is connected with the first pin, the second pin and the third pin, and is used for identifying external equipment according to the potential of the third pin and switching to a corresponding working mode; the working mode switching unit comprises an output power supply end, an input power supply end, a first signal end, a second signal end and a third signal end; the reset signal generating unit is connected with the third pin and is used for generating a reset signal according to the potential of the third pin, and the reset signal is used for resetting the controller. The limitation of small-volume products or products with only one interface in the aspect of function expansion is solved.

Description

Interface multiplexing circuit

Technical Field

The present utility model relates to the field of electronic circuits, and in particular, to an interface multiplexing circuit.

Background

At present, aiming at small-volume products or products with only one interface, the interfaces of common products only can provide functions such as power input, data transmission and the like, and other functions cannot be realized.

Disclosure of utility model

The utility model provides an interface multiplexing circuit which is used for solving the limitation of small-volume products or products with only one interface in the aspect of function expansion.

According to an aspect of the present utility model, there is provided an interface multiplexing circuit, the circuit comprising: the device comprises an interface unit, a working mode switching unit and a reset signal generating unit;

The interface unit is used for connecting external equipment and comprises a first pin, a second pin, a third pin and a fourth pin; the first pin and the second pin are communication pins, and the first pin is multiplexed as a power pin;

The working mode switching unit is connected with the first pin, the second pin and the third pin, and is used for identifying external equipment according to the potential of the third pin and switching to a corresponding working mode; the working mode switching unit comprises an output power supply end, an input power supply end, a first signal end, a second signal end and a third signal end;

The reset signal generating unit is connected with the third pin and is used for generating a reset signal according to the potential of the third pin, and the reset signal is used for resetting the controller.

The technical scheme of the utility model provides an interface multiplexing circuit, an interface unit can be connected with different devices, and a working mode switching unit can realize switching of different working modes by identifying external devices. The multifunctional portable electronic device realizes a multi-purpose function, and a user can select proper external equipment according to the needs so as to add new functions to the product. The limitation of small-volume products or products with only one interface in the aspect of function expansion is solved.

It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the utility model or to delineate the scope of the utility model. Other features of the present utility model will become apparent from the description that follows.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of an interface multiplexing circuit according to an embodiment of the present utility model;

fig. 2 is a schematic structural diagram of another interface multiplexing circuit according to an embodiment of the present utility model;

fig. 3 is a schematic structural diagram of another interface multiplexing circuit according to an embodiment of the present utility model;

fig. 4 is a schematic structural diagram of an operation mode switching unit according to an embodiment of the present utility model;

Fig. 5 is a schematic structural diagram of another operation mode switching unit according to an embodiment of the present utility model;

Fig. 6 is a schematic structural diagram of another operation mode switching unit according to an embodiment of the present utility model;

Fig. 7 is a schematic structural diagram of another operation mode switching unit according to an embodiment of the present utility model;

Fig. 8 is a schematic structural diagram of another operation mode switching unit according to an embodiment of the present utility model;

Fig. 9 is a schematic diagram of a configuration of a reset signal generating unit according to an embodiment of the present utility model;

Fig. 10 is a schematic diagram of another reset signal generating unit according to an embodiment of the present utility model.

Detailed Description

In order that those skilled in the art will better understand the present utility model, a technical solution in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present utility model, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present utility model without making any inventive effort, shall fall within the scope of the present utility model.

It should be noted that the terms "first," "second," and the like in the description and the claims of the present utility model and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the utility model described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Fig. 1 is a schematic structural diagram of an interface multiplexing circuit according to an embodiment of the present utility model. As shown in fig. 1, the circuit includes: an interface unit 1, an operation mode switching unit 2, and a reset signal generating unit 3.

The interface unit 1 is used for connecting external equipment and comprises a first pin A1, a second pin A2, a third pin TM and a fourth pin A4; the first pin A1 and the second pin A2 are communication pins, and the first pin A1 is multiplexed as a power supply pin.

The working mode switching unit 2 is connected with the first pin A1, the second pin A2 and the third pin TM, and is used for identifying external equipment according to the potential of the third pin TM and switching to a corresponding working mode; the operation mode switching unit 2 includes an output power terminal V1, an input power terminal P01, a first signal terminal TX, a second signal terminal RX, and a third signal terminal DATA.

The reset signal generating unit 3 is connected to the third pin TM, and is configured to generate a reset signal RST according to a potential of the third pin TM, where the reset signal RST is configured to reset the controller.

In the present embodiment, the interface unit 1 is an interface having four pins, and the interface unit 1 may be a Micro USB interface, an earphone interface, or the like, for example.

Specifically, the interface unit 1 may access an external device, which may be, for example, a charging device, a serial communication module, a program downloading module, or a single bus sensor module. The interface unit 1 may include four pins, and the first pin A1 and the second pin A2 may be communication pins, and the first pin A1 may also be a power pin. The potential of the third pin may be a first level signal or a second level signal, and the first level signal may be a high level and the second level signal may be a low level. The fourth leg A4 is connected to ground GND.

The operation mode switching unit 2 is connected to the first pin A1, the second pin A2, and the third pin TM, and the operation mode switching unit 2 may include an output power supply terminal V1, an input power supply terminal P01, a first signal terminal TX, a second signal terminal RX, and a third signal terminal DATA. The operation mode switching unit 2 can switch to the corresponding operation mode according to the potential of TM.

For example, when the external device to which the interface unit 1 is connected is a charging device, the third pin TM may be a first level signal, and at this time, the working mode switching unit 2 may switch to the charging mode, where the first pin A1 is a power pin, the charging device inputs a certain voltage value through the first pin A1, and the output power terminal V1 outputs a voltage to charge the battery or other devices according to the voltage value input by the first pin A1. When the external device accessed by the interface unit 1 is a serial communication module, the third pin TM may also be a first level signal, and at this time, the working mode switching unit 2 may switch to a communication mode, where the serial communication module communicates with the controller, and the controller may be, for example, a single-chip microcomputer. The first pin A1 is a communication pin, the controller sends data to the first pin A1 through the first signal end TX, so that the serial communication module obtains the data sent by the controller, the second pin A2 is also a communication pin, and the serial communication module sends the data to the controller through the second signal end RX by utilizing the second pin A2. When the external device accessed by the interface unit 1 is a program downloading module, the third pin TM may also be a first level signal, and at this time, the working mode switching unit 2 may switch to a program downloading mode, and the program downloading module may also use the second pin A2 to download a program to the controller through the second signal terminal RX. When the external device to which the interface unit 1 is connected is a single-bus sensor module, for example, the single-bus sensor module may be a temperature sensor detection module, a humidity sensor detection module, a pressure sensor detection module, or the like, and the third pin TM may also be a second level signal, at this time, the working mode switching unit 2 may switch to a mode of reading DATA of the sensor detection module, the controller outputs a high level, power is supplied to the single-bus sensor module through the input power supply terminal P01 and the first pin A1, and the single-bus sensor module may also utilize the second pin A2 and send DATA to the controller through the third signal terminal DATA, so that the controller may read a detection result of the single-bus sensor module.

The reset signal generating unit 3 is configured to generate a reset signal RST according to the potential of the third pin TM, thereby implementing a reset of the controller. When the potential of the third pin TM is the first potential signal, the reset signal generating unit 3 outputs a reset signal RST to reset the controller; when the potential of the third pin TM is the second potential signal, the reset signal generation unit 3 outputs a signal opposite to the reset signal RST level, and the controller does not generate a reset operation at this time.

According to the technical scheme, the interface multiplexing circuit is provided, the interface unit can be connected with different devices, and the working mode switching unit can realize switching of different working modes by identifying external devices. The multifunctional portable electronic device realizes a multi-purpose function, and a user can select proper external equipment according to the needs so as to add new functions to the product. The limitation of small-volume products or products with only one interface in the aspect of function expansion is solved.

Fig. 2 is a schematic structural diagram of another interface multiplexing circuit according to an embodiment of the utility model. As shown in fig. 2, the interface multiplexing circuit further includes: a charging unit 4.

The charging unit 4 is connected to the output power source terminal V1 of the operation mode switching unit 3, and is configured to charge the battery when the external device is a charging device.

In the present embodiment, the charging unit 4 is a circuit structure that converts the output voltage of the output power supply terminal V1 into the required charging voltage Vbat. The charging unit 4 may include a charge management chip, a capacitor, a resistor, and other circuit elements.

Specifically, the charging unit 4 is connected to the output power supply terminal V1 of the working mode switching unit 3, when the external device connected to the interface unit 1 is a charging device, at this time, the first pin A1 is a power supply pin, the working mode switching unit 2 can switch the working mode to the charging mode, the charging device inputs a certain voltage value through the first pin A1, the output power supply terminal V1 outputs a voltage to the charging unit 4 according to the voltage value input by the first pin A1, the charging unit 4 can also be connected to a battery or other devices needing to be charged, and the charging unit 4 converts the output voltage of the output power supply terminal V1 into a required charging voltage Vbat to charge the battery or other devices.

Fig. 3 is a schematic structural diagram of another interface multiplexing circuit according to an embodiment of the utility model. As shown in fig. 3, the interface multiplexing circuit further includes: LDO unit 5 and controller U1.

The LDO unit 5 is connected to the charging unit 4 and the controller U1, and is configured to obtain an output voltage of the charging unit 4 and provide an operating voltage VCC for the controller U1.

The controller U1 is connected to the working mode switching unit 2, and is configured to perform a corresponding action according to the working mode switched by the working mode switching unit 2.

In the present embodiment, the LDO unit is a unit that converts the output voltage of the charging unit 4 into the operation voltage VCC required by the controller U1. The controller U1 can be a single-chip microcomputer.

Specifically, the LDO unit 5 is connected to the charging unit 4, the charging unit 4 may include a charging management chip, a first pin of the charging management chip may output a charging voltage Vbat to charge a battery or other devices, a second pin of the charging management chip may be connected to the LDO unit 5, and an output voltage of the second pin of the charging management chip is the same as a voltage of two ends of the rechargeable battery. The LDO unit 5 acquires the output voltage of the second pin of the charge management chip and converts it into the operation voltage VCC required by the controller U1. The LDO unit 5 may continuously provide the controller U1 with the operating voltage VCC.

The 1 pin of the controller U1 is connected with the LDO unit 5, and the LDO unit 5 outputs the working voltage VCC required by the controller U1 and transmits the working voltage VCC to the 1 pin of the controller U1. The 2 feet of the controller U1 are connected with the first signal end TX, the 3 feet of the controller U1 are connected with the second signal end RX, the 4 feet of the controller U1 are connected with the third signal end DATA, the 5 feet of the controller U1 are connected with the third pin TM, the 6 feet of the controller U1 are connected with the reset signal generating unit 3, the reset signal generating unit 3 outputs a reset signal RST to the 6 feet of the controller U1, the 7 feet of the controller U1 are connected with the input power end P01, and the 9 feet of the controller U1 are connected with the ground GND.

The controller U1 performs a corresponding operation according to the operation mode switched by the operation mode switching unit 2. For example, when the external device to which the interface unit 1 is connected is a charging device, the 5 pin of the controller U1 outputs a first level signal, so that the third pin TM is the first level signal, and at this time, the working mode switching unit 2 may switch to the charging mode, where the first pin A1 is a power pin, the charging device inputs a certain voltage value through the first pin A1, the output power terminal V1 outputs a voltage to the charging unit 4 according to the voltage value input by the first pin A1, and the charging unit 4 converts the output voltage of the output power terminal V1 into a required charging voltage Vbat to charge a battery or other devices. When the external device accessed by the interface unit 1 is a serial port communication module, the external device can control the third pin TM to be a first level signal, at this time, the working mode switching unit 2 can switch to a communication mode, the serial port communication module communicates with the controller U1, the first pin A1 is a communication pin, the 2 pin of the controller U1 sends data to the first pin A1 through the first signal end TX, so that the serial port communication module obtains the data sent by the 2 pin of the controller U1, the second pin A2 is also a communication pin, and the serial port communication module uses the second pin A2 and sends data to the 3 pin of the controller U1 through the second signal end RX. When the external device accessed by the interface unit 1 is a program downloading module, the external device can control the third pin TM to be a first level signal, and at this time, the working mode switching unit 2 can switch to a program downloading mode, and the program downloading module can also utilize the second pin A2 and connect to the 3 pin of the controller U1 through the second signal terminal RX to download a program into the controller U1. When the external device to which the interface unit 1 is connected is a single-bus sensor module, for example, the single-bus sensor module may be a temperature sensor detection module, a humidity sensor detection module, a pressure sensor detection module, or the like, and the third pin TM may also be a second level signal, at this time, the working mode switching unit 2 may switch to a mode of reading DATA of the sensor detection module, and the 7 pin of the controller U1 outputs a high level, and supplies power to the single-bus sensor module through the input power supply terminal P01 and the first pin A1, and the single-bus sensor module may also utilize the second pin A2 and send DATA to the 4 pin of the controller U1 through the third signal terminal DATA, so that the controller U1 may read a detection result of the single-bus sensor module.

When the potential of the third pin TM is the first potential signal, the reset signal generating unit 3 outputs a reset signal RST to the 6 pin of the controller U1, and resets the controller U1; when the potential of the third pin TM is the second potential signal, the reset signal generating unit 3 outputs a signal opposite to the level of the reset signal RST to the 6 pin of the controller U1, and the controller U1 does not generate a reset operation at this time.

Fig. 4 is a schematic structural diagram of an operation mode switching unit according to an embodiment of the present utility model. As shown in fig. 3 and 4, the operation mode switching unit 2 includes: a switch control unit 21 and a first switch unit 22.

The control end of the switch control unit 21 is connected with the third pin TM, the first end of the switch control unit 21 is connected with the control end of the first switch unit 22, and the second end of the switch control unit 21 is connected with the ground GND; the switch control unit 21 is configured to output an on signal when the third pin TM is the first level signal.

A first end of the first switch unit 22 is connected with the first pin A1, and a second end of the first switch unit 22 is used as an output power supply end V1; the first switch unit 22 is configured to control the first pin A1 to connect with the output power terminal V1 according to the on signal.

In the present embodiment, the switch control unit 21 is a unit that controls the first switch unit 22 to be turned on or off, and the switch control unit 21 includes, but is not limited to, a field effect transistor or a bipolar transistor. The first switching unit 22 is a unit that controls the connection or disconnection of the first pin A1 to the output power source terminal V1, and the first switching unit 22 includes, but is not limited to, a field effect transistor or a bipolar transistor.

Specifically, the control terminal of the switch control unit 21 is connected to the third pin TM, the first terminal of the switch control unit 21 is connected to the control terminal of the first switch unit 22, and the second terminal of the switch control unit 21 is connected to the ground GND. A first end of the first switching unit 22 is connected to the first pin A1, and a second end of the first switching unit 22 serves as an output power supply terminal V1. When the third pin TM is the first level signal, the first end of the switch control unit 21 outputs a conducting signal to the control end of the first switch unit 22, the first switch unit 22 is turned on, and the first pin A1 is connected to the output power source end V1. When the third pin TM is the second level signal, the first end of the switch control unit 21 outputs a turn-off signal to the control end of the first switch unit 22, the first switch unit 22 is turned off, and the first pin A1 is disconnected from the output power supply end V1.

For example, when the external device to which the interface unit 1 is connected is a charging device, the pin 5 of the controller U1 outputs a first level signal, so that the pin TM is the first level signal, at this time, the first terminal of the switch control unit 21 outputs a conducting signal to the control terminal of the first switch unit 22, the first switch unit 22 is turned on, and the first pin A1 is connected to the output power source terminal V1. The first pin A1 is a power pin, the charging device inputs a certain voltage value through the first pin A1, the output power terminal V1 outputs a voltage to the charging unit 4 according to the voltage value input by the first pin A1, and the charging unit 4 converts the output voltage of the output power terminal V1 into a required charging voltage Vbat to charge a battery or other devices.

Illustratively, the switch control unit 21 may be an N-type metal oxide semiconductor (N Metal Oxide Semiconductor, NMOS) transistor, and the first switch unit 22 may be a P-type metal oxide semiconductor (P Metal Oxide Semiconductor, PMOS) transistor. The first level signal is high level and the second level signal is low level. When the external device connected to the interface unit 1 is a charging device, the 5 pin of the controller U1 outputs a high level to make the third pin TM be a high level, and at this time, the first end of the switch control unit 21 outputs a low level to the control end of the first switch unit 22, the first switch unit 22 is turned on, and the first pin A1 is connected to the output power supply end V1. The first pin A1 is a power pin, the charging device inputs a certain voltage value through the first pin A1, the output power terminal V1 outputs a voltage to the charging unit 4 according to the voltage value input by the first pin A1, and the charging unit 4 converts the output voltage of the output power terminal V1 into a required charging voltage Vbat to charge a battery or other devices.

With continued reference to fig. 3 and 4, the operation mode switching unit 2 may further include: resistor R1, resistor R4, resistor R5 and resistor R6. The resistor R1 is connected between the first pin A1 and the first end of the first switch unit 22, and mainly plays a role in current limiting. The resistor R6 is connected between the third pin TM and the control terminal of the switch control unit 21, and mainly plays a role in current limiting. The resistor R5 is connected between the first end of the switch control unit 21 and the control end of the first switch unit 22, and mainly plays a role of current limiting. The resistor R4 is connected between the first end and the control end of the first switch unit 22, and the resistor R4 can provide a turn-on bias voltage for the first switch unit 22, and can also be used as a bleeder resistor to avoid malfunction of the first switch unit 22, thereby damaging the first switch unit 22.

Fig. 5 is a schematic structural diagram of another operation mode switching unit according to an embodiment of the present utility model. As shown in fig. 5, the operation mode switching unit 2 further includes: a first diode D5.

The anode of the first diode D5 is connected to the second terminal of the first switching unit 22, and the cathode of the first diode D5 is used as the output power source terminal V1.

Specifically, the first diode D5 is connected between the second terminal of the first switch unit 22 and the output power terminal V1, and the negative electrode of the first diode D5 is used as the output power terminal V1. By the arrangement, the reverse flow phenomenon of the rechargeable battery can be avoided, namely, the current backflow is prevented.

Fig. 6 is a schematic structural diagram of another operation mode switching unit according to an embodiment of the present utility model. As shown in fig. 3 and 6, the operation mode switching unit 2 further includes: a second diode D1 and a third diode D4.

The positive electrode of the second diode D1 is used as the first signal terminal TX, and the negative electrode of the second diode D1 is connected to the second terminal of the first switching unit 22.

The positive electrode of the third diode D4 is used as the input power terminal P01, and the negative electrode of the third diode D4 is connected to the second terminal of the first switching unit 22.

Specifically, the anode of the second diode D1 is used as the first signal terminal TX, and the cathode is connected to the second terminal of the first switch unit 22. When the external device connected to the interface unit 1 is a serial communication module, the external device may control the third pin TM to be a first level signal, and at this time, the first end of the switch control unit 21 outputs a conducting signal to the control end of the first switch unit 22, the first switch unit 22 is turned on, and the first signal end TX is communicated with the first pin A1. The serial port communication module is communicated with the controller U1, the first pin A1 is a communication pin, and the 2 pin of the controller U1 sends data to the first pin A1 through the first signal end TX and the second diode D1, so that the serial port communication module obtains the data sent by the 2 pin of the controller U1.

The anode of the third diode D4 is used as the input power terminal P01, and the cathode is connected to the second terminal of the first switching unit 22. When the external device to which the interface unit 1 is connected is a single bus sensor module, for example, the single bus sensor module may be a temperature sensor detection module, a humidity sensor detection module, or a pressure sensor detection module, and the third pin TM may also be a second level signal, where the first end of the switch control unit 21 outputs a cut-off signal to the control end of the first switch unit 22, and the first switch unit 22 is turned off. The 7 pin of the controller U1 outputs a high level, i.e. the input power terminal P01 is at a high level, and the high level is input to the first pin A1 through the third diode D4 and the body diode of the first switch unit 22 to supply power to the single bus sensor module.

The second diode D1 and the third diode D4 are arranged such that the pins 2 and 7 of the controller U1 are not damaged by the input voltage when the interface unit 1 is connected to the charging device.

Fig. 7 is a schematic structural diagram of another operation mode switching unit according to an embodiment of the present utility model. As shown in fig. 3 and 7, the operation mode switching unit 2 further includes: a first resistor R14 and a second resistor R15.

The first end of the first resistor R14 is connected with the first pin A1, the second end of the first resistor R14 is connected with the first end of the second resistor R15, and the second end of the second resistor R15 is connected with the ground GND; the common connection terminal ADC of the first resistor R14 and the second resistor R15 is connected to the controller U1.

Specifically, the first resistor R14 and the second resistor R15 are connected in series between the first pin A1 and the ground GND, and the common connection terminal ADC of the first resistor R14 and the second resistor R15 is connected to the 8 pin of the controller U1. When the external device connected to the interface unit 1 is a charging device, the controller U1 controls the 5 pin to output the first level signal or the second level signal by detecting the voltage value of the common connection terminal ADC. When the voltage of the common connection terminal ADC is smaller than the first voltage, the first voltage is preset according to the actual requirement, the 5 pins of the controller U1 output a first level signal, the first end of the switch control unit 21 outputs a conducting signal to the control end of the first switch unit 22, the first switch unit 22 is turned on, the first pin A1 is connected to the output power source terminal V1 through the first diode D5, and the battery or other devices are charged through the charging unit 4. When the voltage of the common connection terminal ADC is greater than or equal to the first voltage, the 5 pin of the controller U1 outputs a second level signal, the first terminal of the switch control unit 21 outputs a cut-off signal to the control terminal of the first switch unit 22, the first switch unit 22 is turned off, and the first pin A1 is disconnected from the output power terminal V1, so as to prevent the battery or other charging devices from being damaged by the large voltage input.

Fig. 8 is a schematic structural diagram of another operation mode switching unit according to an embodiment of the present utility model. As shown in fig. 3 and 8, the operation mode switching unit 2 further includes: a second switching unit 23, a third resistor R7 and a fourth diode D3.

The control end of the second switch unit 23 is connected with the third pin TM, the first end of the second switch unit 23 is connected with the first end of the third resistor R7, and the second end of the second switch unit 23 is connected with the ground GND; the second end of the third resistor R7 is used as a second signal end RX; the second switching unit 23 is used for realizing correct communication between the controller U1 and the external device when the third pin TM is the first level signal.

The positive pole of the fourth diode D3 is connected to the second pin A2, and the negative pole of the fourth diode D3 is connected to the second end of the third resistor R7.

In the present embodiment, the second switching unit 23 includes, but is not limited to, a field effect transistor or a bipolar transistor, and the second switching unit 23 may be an NPN type transistor, for example.

Specifically, the control end of the second switch unit 23 is connected to the third pin TM, the second end of the second switch unit 23 is connected to the ground GND, the first end of the second switch unit 23 is connected to the first end of the third resistor R7, and the second end of the third resistor R7 is used as the second signal end RX. The fourth diode D3 is connected between the second pin A2 and the second signal terminal RX. The 3 pin of the controller U1 is connected to the second signal terminal RX, and the second pin A2 may also be directly used as the third signal terminal DATA, and the 4 pin of the controller U1 is connected to the third signal terminal DATA.

When the external device accessed by the interface unit 1 is a serial communication module, the external device can control the third pin TM to be a first level signal, at this time, the second switch unit 23 is turned on, the serial communication module communicates with the controller U1, the second pin A2 is a communication pin, and the serial communication module sends data to the 3 pins of the controller U1 through the fourth diode D3 and the second signal terminal RX by using the second pin A2. When the external device accessed by the interface unit 1 is a program downloading module, the external device may control the third pin TM to be a first level signal, and at this time, the second switch unit 23 is turned on, and the program downloading module may also use the second pin A2 and connect to the 3 pin of the controller U1 through the fourth diode D3 and the second signal terminal RX to download the program into the controller U1. The third resistor R7 is to ensure that the potential of the second signal terminal RX is low when the second switch unit 23 is turned on. When the external device to which the interface unit 1 is connected is a single bus sensor module, the third pin TM may be a second level signal, and at this time, the second switch unit 23 is turned off, and the single bus sensor module may also use the second pin A2 and send DATA to the 4 pins of the controller U1 through the third signal terminal DATA, so that the controller U1 may read the detection result of the single bus sensor module. When the second switch unit 23 is turned off, the potential of the second signal terminal RX is at a high level, and the fourth diode D3 is configured to avoid the third signal terminal DATA from affecting the second signal terminal RX during the DATA transmission with the controller U1.

With continued reference to fig. 8, the operation mode switching unit 2 may optionally further include a resistor R9, where the resistor R9 is connected between the third pin TM and the control terminal of the second switching unit 23, and may perform a current limiting function.

Fig. 9 is a schematic structural diagram of a reset signal generating unit according to an embodiment of the present utility model. As shown in fig. 3 and 9, the reset signal generation unit 3 includes: a first capacitor C2, a fourth resistor R8 and a third switching unit 31.

The first end of the first capacitor C2 is connected to the third pin TM, and the second end of the first capacitor C2 is connected to the first end of the fourth resistor R8.

The control end of the third switch unit 31 is connected with the second end of the fourth resistor R8, the first end of the third switch unit 31 is connected with the controller U1, and the second end of the third switch unit 31 is connected with the ground GND; the third switching unit 31 is configured to generate a reset signal RST to reset the controller U1 when the third pin TM is the first level signal.

In the present embodiment, the third switching unit 31 includes, but is not limited to, a field effect transistor or a bipolar transistor, and the third switching unit 31 may be an NPN transistor, for example.

Specifically, the first end of the first capacitor C2 is connected to the third pin TM, the fourth resistor R8 is connected between the second end of the first capacitor C2 and the control end of the third switch unit 31, the first end of the third switch unit 31 is connected to the 6 pin of the controller U1, and the second end of the third switch unit 31 is connected to the ground GND. When the potential of the third pin TM is the first level signal, the first capacitor C2 is charged instantaneously to generate a high level pulse, and at the moment when the first capacitor C2 starts to be charged to be full, the third switch unit 31 is turned on, and the first end of the third switch unit 31 outputs the reset signal RST to the 6 pin of the controller U1 to reset the controller U1. When the potential of the third pin TM is the second level signal, the third switch unit 31 is turned off, the first terminal of the third switch unit 31 outputs a signal opposite to the reset signal RST level to the 6 pin of the controller U1, and the controller U1 does not perform the reset operation.

When the external device connected to the interface unit 1 is a program downloading module, the external device may control the third pin TM to be a first level signal, and at this time, the first capacitor C2 may be charged instantaneously to generate a high level pulse, and at the moment when the first capacitor C2 begins to be charged to be full, the third switch unit 31 is turned on, and the first end of the third switch unit 31 outputs a reset signal RST to the 6 pin of the controller U1 to reset the controller U1. The fourth resistor R8 may function as a current limiting protection.

With continued reference to fig. 9, optionally, the reset signal generating unit 3 may further include a resistor R11, where the resistor R11 is connected between the control end and the second end of the third switch unit 31, and the resistor R11 may provide a turn-on bias voltage for the third switch unit 31 and may also be used as a bleeder resistor, so as to avoid malfunction of the third switch unit 31 and damage the third switch unit 31.

Fig. 10 is a schematic diagram of another reset signal generating unit according to an embodiment of the present utility model. As shown in fig. 3 and 10, the reset signal generation unit 3 further includes: and a fifth resistor R11.

The first end of the fifth resistor R11 is connected to the third pin TM, and the second end of the fifth resistor R11 is connected to the ground GND.

Specifically, the fifth resistor R11 is connected between the third pin TM and the ground GND. The potential of the third pin TM may be a first level signal or a second level signal, the first level signal may be a high level, and the second level signal may be a low level. The potential of the third pin TM is the second level signal due to the presence of the fifth resistor R11. When the external device connected to the interface unit 1 is a charging device, the controller U1 controls the potential of the third pin TM through 5 pins according to the voltage detected by 8 pins, and when the external device connected to the interface unit 1 is a serial communication module or a program downloading module, the external device controls the potential of the third pin TM to be a first level signal. When the external device to which the interface unit 1 is connected is a single bus sensor module, the third pin TM is set to a second level signal through the fifth resistor R11.

In any of the drawings provided in any of the embodiments above, like-named symbols represent a connection relationship.

It should be appreciated that various forms of the flows shown above may be used to reorder, add, or delete steps. For example, the steps described in the present utility model may be performed in parallel, sequentially, or in a different order, so long as the desired results of the technical solution of the present utility model are achieved, and the present utility model is not limited herein.

The above embodiments do not limit the scope of the present utility model. It will be apparent to those skilled in the art that various modifications, combinations, sub-combinations and alternatives are possible, depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included in the scope of the present utility model.

Claims

1. An interface multiplexing circuit, comprising: the device comprises an interface unit, a working mode switching unit and a reset signal generating unit;

2. The interface multiplexing circuit of claim 1, further comprising: a charging unit;

The charging unit is connected with the output power end of the working mode switching unit and is used for charging the battery when the external equipment is charging equipment.

3. The interface multiplexing circuit of claim 2, further comprising: an LDO unit and a controller;

The LDO unit is connected with the charging unit and the controller and is used for obtaining the output voltage of the charging unit and providing working voltage for the controller;

The controller is connected with the working mode switching unit and is used for performing corresponding actions according to the working mode switched by the working mode switching unit.

4. The interface multiplexing circuit of claim 1, wherein the operation mode switching unit comprises: a switch control unit and a first switch unit;

The control end of the switch control unit is connected with the third pin, the first end of the switch control unit is connected with the control end of the first switch unit, and the second end of the switch control unit is connected with the ground; the switch control unit is used for outputting a conducting signal when the third pin is a first level signal;

the first end of the first switch unit is connected with the first pin, and the second end of the first switch unit is used as the output power supply end; the first switch unit is used for controlling the first pin to be connected with the output power end according to the conduction signal.

5. The interface multiplexing circuit of claim 4, wherein the operation mode switching unit further comprises: a first diode;

The positive electrode of the first diode is connected with the second end of the first switch unit, and the negative electrode of the first diode is used as the output power supply end.

6. The interface multiplexing circuit of claim 4, wherein the operation mode switching unit further comprises: a second diode and a third diode;

The anode of the second diode is used as the first signal end, and the cathode of the second diode is connected with the second end of the first switch unit;

The positive electrode of the third diode is used as the input power supply end, and the negative electrode of the third diode is connected with the second end of the first switch unit.

7. The interface multiplexing circuit of claim 4, wherein the operation mode switching unit further comprises: a first resistor and a second resistor;

The first end of the first resistor is connected with the first pin, the second end of the first resistor is connected with the first end of the second resistor, and the second end of the second resistor is connected with ground; and the common connection end of the first resistor and the second resistor is connected with the controller.

8. The interface multiplexing circuit of claim 1, wherein the operation mode switching unit further comprises: the second switch unit, the third resistor and the fourth diode;

The control end of the second switch unit is connected with the third pin, the first end of the second switch unit is connected with the first end of the third resistor, and the second end of the second switch unit is connected with ground; the second end of the third resistor is used as the second signal end; the second switch unit is used for realizing correct communication between the controller and the external equipment when the third pin is a first level signal;

and the anode of the fourth diode is connected with the second pin, and the cathode of the fourth diode is connected with the second end of the third resistor.

9. The interface multiplexing circuit of claim 1, wherein the reset signal generation unit comprises: the first capacitor, the fourth resistor and the third switch unit;

the first end of the first capacitor is connected with the third pin, and the second end of the first capacitor is connected with the first end of the fourth resistor;

The control end of the third switch unit is connected with the second end of the fourth resistor, the first end of the third switch unit is connected with the controller, and the second end of the third switch unit is connected with the ground; the third switch unit is used for generating a reset signal to reset the controller when the third pin is the first level signal.

10. The interface multiplexing circuit of claim 9, wherein the reset signal generation unit further comprises: a fifth resistor;

the first end of the fifth resistor is connected with the third pin, and the second end of the fifth resistor is connected with ground.