Connection protection circuit, master device and slave device

Abstract

The invention discloses a connection protection circuit, a master device and a slave device, the connection protection circuit comprises a second detection end, a third connection end, a fourth connection end and a first switching circuit, when the first detection end and the second detection end are in normal contact, the first detection end pulls down a control end of the first switching circuit to a low level signal through the second detection end; the first switching circuit responds to a low-level signal input by the control end of the first switching circuit and conducts the first end and the second end of the first switching circuit, so that the master equipment can supply power to the slave equipment; when the first detection end and the second detection end are disconnected, the initial level of the control end of the first switching circuit is a non-low level signal, and the first switching circuit responds to the non-low level signal input by the control end of the first switching circuit and disconnects the first end and the second end of the first switching circuit, so that the master device stops supplying power to the slave device. When the first detection end and the second detection end are disconnected, the master device stops supplying power to the slave device, so that the phenomenon of sparks caused by friction is avoided, the safety is improved, and the cost is low.

Description

Technical Field

[0001] This invention relates to the field of equipment connection protection circuit technology, specifically to a connection protection circuit, a master device, and a slave device. Background Technology

[0002] In some devices, a master device and a slave device need to be interconnected so that the master device can supply power to the slave device. The master device can be a mobile phone, and the slave device can be any external device that needs to connect to the mobile phone and be powered by the mobile phone.

[0003] In related technologies, when a master device supplies power to a slave device, both the master and slave devices have connection contacts. These connection contacts connect the master and slave devices for power supply. In some cases, the connection contacts of the master and slave devices may be unstable, and sparks may be generated due to friction between the contact points, posing a safety hazard. Summary of the Invention

[0004] The main technical problem solved by this invention is that the connection between the master device and the slave device may be unstable, and sparks may be generated due to friction between the connection points, which poses a safety hazard.

[0005] According to a first aspect, one embodiment of this application provides a connection protection circuit applied to a master device and a slave device. The slave device includes a pull-down resistor, a first connection terminal, a second connection terminal, and a first detection terminal. The first connection terminal is used to connect a power supply to the slave device, the second connection terminal is used to connect to the ground of the master device, and the first detection terminal is connected to the ground of the slave device through the pull-down resistor. The connection protection circuit is disposed in the master device, and the connection protection circuit includes: Second detection end; The third connection terminal is used to output the supply voltage to the first connection terminal; The fourth connection terminal is used to connect to the grounding terminal of the main device; A first switching circuit includes a first terminal, a second terminal, and a control terminal. The first terminal of the first switching circuit is connected to the voltage output terminal of the main device, the second terminal of the first switching circuit is connected to the third connection terminal, and the control terminal of the first switching circuit is connected to the second detection terminal. When the master device and the slave device are connected, the second detection end is in contact with the first detection end, the first connection end is in contact with the third connection end, and the second connection end is in contact with the fourth connection end. The contact state of the first detection end and the second detection end is used to characterize the contact state of the first connection end and the third connection end, as well as the contact state of the second connection end and the fourth connection end. When the first detection terminal and the second detection terminal are in normal contact, the first detection terminal pulls down the control terminal of the first switching circuit to a low level signal through the second detection terminal. In response to the low level signal input to its control terminal, the first switching circuit turns on its first terminal and second terminal, so that the master device can supply power to the slave device. When the first detection terminal and the second detection terminal disconnect from each other, the initial level of the control terminal of the first switching circuit is a non-low level signal. In response to the non-low level signal input to its control terminal, the first switching circuit disconnects the connection between its first terminal and the second terminal, causing the master device to stop supplying power to the slave device.

[0006] According to a second aspect, in one embodiment of this application, a master device is provided, the master device being used to connect to a slave device; the slave device includes a pull-down resistor, a first connection terminal, a second connection terminal, and a first detection terminal, the first connection terminal being used to connect a power supply to the slave device, the second connection terminal being used to connect to the ground of the master device, and the first detection terminal being connected to the ground of the slave device through the pull-down resistor; The main device includes a connection protection circuit; the connection protection circuit includes: Second detection end; The third connection terminal is used to output the supply voltage to the first connection terminal; The fourth connection terminal is used to connect to the grounding terminal of the main device; A first switching circuit includes a first terminal, a second terminal, and a control terminal. The first terminal of the first switching circuit is connected to the voltage output terminal of the main device, the second terminal of the first switching circuit is connected to the third connection terminal, and the control terminal of the first switching circuit is connected to the second detection terminal. When the master device and the slave device are connected, the second detection end is in contact with the first detection end, the first connection end is in contact with the third connection end, and the second connection end is in contact with the fourth connection end. The contact state of the first detection end and the second detection end is used to characterize the contact state of the first connection end and the third connection end, as well as the contact state of the second connection end and the fourth connection end. When the first detection terminal and the second detection terminal are in normal contact, the first detection terminal pulls down the control terminal of the first switching circuit to a low level signal through the second detection terminal. In response to the low level signal input to its control terminal, the first switching circuit turns on its first terminal and second terminal, so that the master device can supply power to the slave device. When the first detection terminal and the second detection terminal disconnect from each other, the initial level of the control terminal of the first switching circuit is a non-low level signal. In response to the non-low level signal input to its control terminal, the first switching circuit disconnects the connection between its first terminal and the second terminal, causing the master device to stop supplying power to the slave device.

[0007] In one embodiment, the first switching circuit is a transistor switching circuit.

[0008] In one embodiment, two second detection terminals are provided, and each second detection terminal corresponds to one first detection terminal; The transistor switching circuit includes: a first transistor, a second transistor, a third transistor, a first resistor, a second resistor, a third resistor, and a fourth resistor; The first terminal of the first transistor is connected to the voltage output terminal, and the second terminal of the first transistor is connected to the second terminal of the second transistor; The first terminal of the second transistor is connected to the third terminal; The first terminal of the third transistor is connected to one of the second detection terminals through the first resistor. The second terminal of the third transistor is connected to the connection terminal of the second terminal of the first transistor and the first terminal of the second transistor through the second resistor. The control terminal of the third transistor is connected to the connection terminal of the second terminal of the first transistor and the first terminal of the second transistor through the third resistor. The control terminal of the third transistor is also connected to another second detection terminal through the fourth resistor. The connection between the first resistor and the second detection terminal and the connection between the fourth resistor and the second detection terminal are the control terminals of the first switching circuit.

[0009] In one embodiment, the non-low level signal includes a high level signal and a high impedance signal.

[0010] In one embodiment, two second detection terminals are provided, and each second detection terminal corresponds to one first detection terminal; The first terminal of the third transistor is connected to one of the second detection terminals through the first resistor, and the control terminal of the third transistor is also connected to the other second detection terminal through the fourth resistor. The two second detection ends are misaligned.

[0011] In one embodiment, the connection protection circuit further includes: a second switching circuit, the second switching circuit including a first terminal, a second terminal, a control terminal and a feedback terminal; The first terminal of the second switching circuit is used to connect to ground; The second terminal of the second switching circuit is used to connect to the power supply; The feedback terminal of the second switching circuit is connected to the second terminal of the second switching circuit; The control terminal of the second switching circuit is connected to the second detection terminal; The initial level of the control terminal of the second switching circuit is a high-level signal. In response to the high-level signal input to its control terminal, the second switching circuit turns on its first and second terminals, so that the feedback terminal outputs a first-level signal to the control module of the main device. The first-level signal is used to characterize the contact state of the first detection terminal and the second detection terminal as disconnected contact. When the control terminal of the second switching circuit is pulled down to a low level signal, the second switching circuit responds to the low level signal input to its control terminal and disconnects the connection between its first terminal and second terminal, so that the feedback terminal outputs a second level signal to the control module. The second level signal is used to indicate that the first detection terminal and the second detection terminal are in normal contact. The contact state of the first detection end and the second detection end is also used to characterize the contact state of the communication end of the master device and the communication end of the slave device; the control module is used to determine the contact state of the communication end of the master device and the communication end of the slave device according to the feedback signal output by the second switching circuit, so as to determine whether to perform data transmission.

[0012] In one embodiment, the second switching circuit is a transistor switching circuit.

[0013] In one embodiment, the transistor switching circuit includes: a fourth transistor, a fifth resistor, a sixth resistor, and a seventh resistor; The first terminal of the fourth transistor is connected to its control terminal through the fifth resistor, the control terminal of the fourth transistor is connected to the second detection terminal through the sixth resistor, and the second terminal of the second switching circuit is connected to the power supply through the seventh resistor. Wherein, the connection node between the seventh resistor and the fourth transistor is the feedback terminal, the first terminal of the fourth transistor is the first terminal of the second switching circuit, the connection terminal between the sixth resistor and the second detection terminal is the control terminal of the second switching circuit, the connection terminal between the seventh resistor and the power supply is the second terminal of the second switching circuit, and the connection terminal between the seventh resistor and the fourth transistor is the feedback terminal of the second switching circuit.

[0014] According to a third aspect, in one embodiment of this application, a slave device is provided, the slave device being used to connect to a master device. The slave device includes a pull-down resistor, a first connection terminal, a second connection terminal, and a first detection terminal. The first connection terminal is used to connect a power supply to the slave device, the second connection terminal is used to connect to the ground of the master device, and the first detection terminal is connected to the ground of the slave device through the pull-down resistor. The master device is the master device as described above.

[0015] According to the connection protection circuit, master device, and slave device of the above embodiments, since the contact state of the first detection terminal and the second detection terminal represents the contact state of the first connection terminal and the third connection terminal, and the second connection terminal and the fourth connection terminal, the master device can supply power to the slave device when the first connection terminal and the third connection terminal, and the second connection terminal and the fourth connection terminal have poor contact, and stop supplying power to the slave device when the connection is broken. This avoids the phenomenon of sparks generated by friction due to the connection terminal still having voltage when the contact is poor, thus improving safety. In addition, the first switching circuit does not need to occupy the pins of the control chip during the conduction and turn-off process, so that the master device can use a control chip with fewer pins, further reducing costs. Attached Figure Description

[0016] Figure 1 A circuit diagram showing the connection of the protection circuit; Figure 2 This is a partial enlarged view of the first switching circuit in one embodiment; Figure 3 This is a structural diagram of the first connecting end and the second connecting end in one embodiment; Figure 4 This is a structural diagram of two first detection ends in one embodiment; Figure 5 This is a structural diagram of an external circuit board in one embodiment.

[0017] Reference numerals: 100, First switching circuit; 200, Second switching circuit; 300, External circuit board; 301, First position; 302, Second position; 303, Third position; Q1, First transistor; Q2, Second transistor; Q3, Third transistor; Q4, Fourth transistor; R1, First resistor; R2, Second resistor; R3, Third resistor; R4, Fourth resistor; R5, Fifth resistor; R6, Sixth resistor; R7, Seventh resistor; R8, Pull-down resistor; TP7, First connection terminal; TP8, Second connection terminal; TP5, Third connection terminal; TP9, Fourth connection terminal; TP1, First detection terminal; TP3, Second detection terminal; VCC, Power supply; TP6, Voltage output terminal. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of this application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to this application are not shown or described in the specification. This is to avoid obscuring the core parts of this application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0019] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can be rearranged or adjusted in a manner obvious to those skilled in the art. Therefore, the various orders in the specification and drawings are only for the clear description of a particular embodiment and do not imply a necessary order, unless otherwise stated that a particular order must be followed.

[0020] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages). Rugged or explosion-proof mobile phones and other communication devices are often used in unstable outdoor environments or special indoor environments. Due to differences in usage, the protection measures for external charging interfaces or external power outputs will vary depending on the usage scenario. Taking a main device with an external interface that connects to an external device via the external interface contacts as an example, if the connection between the external interface contacts of the slave device and the main device is unstable, abnormal communication signals will occur, and functions will fail to be realized.

[0021] When the master device supplies high voltage and high current to the slave device through an external interface, unstable connection may cause friction at the contacts of the external device, generating sparks and posing a safety hazard. If the master device is an explosion-proof communication device operating in a hazardous environment, such as with flammable gases, these sparks could ignite the gas, creating a danger. If foreign objects obstruct the connection between the external device and the master device, preventing the external device from being properly secured, supplying power to the slave device from the master device could also result in a high current flow, posing a short-circuit risk to the slave device.

[0022] To address the aforementioned technical problems, this application provides a connection protection circuit applied to a master device and a slave device. The master device can supply power to the slave device through this connection protection circuit. Since the contact state of the first detection terminal TP1 and the second detection terminal TP3 represents the contact state of the first connection terminal TP7 and the third connection terminal TP5, and the second connection terminal TP8 and the fourth connection terminal TP9, when the first connection terminal TP7 and the third connection terminal TP5, and the second connection terminal TP8 and the fourth connection terminal TP9 have poor contact, the master device can supply power to the slave device when there is contact and stop supplying power to the slave device when the contact is broken. This avoids the phenomenon of sparks generated by friction due to the voltage still existing at the connection terminal when there is poor contact, thus improving safety. Furthermore, the first switching circuit 100 does not need to occupy the pins of the control chip during the conduction and turn-off processes, allowing the master device to use a control chip with fewer pins, further reducing costs.

[0023] In some embodiments, such as Figure 3 , Figure 4 As shown, the slave device may include a pull-down resistor R8, a first connection terminal TP7, a second connection terminal TP8, and a first detection terminal TP1. The first connection terminal TP7, the second connection terminal TP8, the first detection terminal TP1, and the pull-down resistor R8 can be disposed on the printed circuit board of the slave device. The first connection terminal TP7 can be used to connect the supply voltage to the slave device, and the second connection terminal TP8 is used to connect to the ground of the master device. That is, when the master device supplies power to the slave device, it can output the supply voltage to the slave device through the first connection terminal TP7 to power the slave device. The first detection terminal TP1 is connected to the ground of the slave device through the pull-down resistor R8.

[0024] In other words, the slave device can access the power supply output from the master device through the first connection terminal TP7 and connect to the ground of the master device through the second connection terminal TP8. When the power supply is connected to the first connection terminal TP7, the power consumption module in the slave device can... Figure 3 Power is drawn from the OUT terminal.

[0025] In some embodiments, the connection protection circuitry is located in the main device. For example... Figure 1 As shown, the connection protection circuit may include a second detection terminal TP3, a third connection terminal TP5, a fourth connection terminal TP9, and a first switching circuit 100. When the master device and the slave device are connected, the third connection terminal TP5 and the first connection terminal TP7 are in contact, and the third connection terminal TP5 is used to output the supply voltage to the first connection terminal TP7; the fourth connection terminal TP9 and the second connection terminal TP8 are in contact, and the fourth connection terminal TP9 is used to connect to the ground terminal of the master device; the first detection terminal TP1 and the second detection terminal TP3 are in contact, wherein the contact state of the first detection terminal TP1 and the second detection terminal TP3 is used to characterize the contact state of the first connection terminal TP7 and the third connection terminal TP5, and the contact state of the second connection terminal TP8 and the fourth connection terminal TP9.

[0026] The first switching circuit 100 includes a first terminal, a second terminal, and a control terminal. The first terminal of the first switching circuit 100 is used to connect to the voltage output terminal of the main device. The second terminal of the first switching circuit 100 is connected to the third connection terminal TP5. The control terminal of the first switching circuit 100 is connected to the second detection terminal TP3.

[0027] When the first detection terminal TP1 and the second detection terminal TP3 are in normal contact, the first detection terminal TP1 pulls down the control terminal of the first switching circuit 100 to a low level signal through the second detection terminal TP3. In response to the low level signal input to its control terminal, the first switching circuit 100 conducts its first and second terminals, enabling the master device to supply power to the slave device. When the first detection terminal TP1 and the second detection terminal TP3 are disconnected, the initial level of the control terminal of the first switching circuit 100 is a non-low level signal. In response to the non-low level signal input to its control terminal, the first switching circuit 100 disconnects the connection between its first and second terminals, causing the master device to stop supplying power to the slave device.

[0028] In practical applications, the master device and slave device are connected. If the second detection terminal TP3 and the first detection terminal TP1 are in normal contact, the control terminal of the first switching circuit 100 is input with a low-level signal. That is, the control terminal is pulled down to a low-level signal through the pull-down resistor R8 of the first detection terminal TP1. At this time, the first and second terminals of the first switching circuit 100 are in a conducting state, and the voltage output terminal of the master device can output voltage to the slave device through the first terminal, the second terminal, the first connection terminal TP7, and the third connection terminal TP5. That is, the slave device is powered by the master device. This indicates that the first connection terminal TP7 and the third connection terminal TP5, the second connection terminal TP8, and the fourth connection terminal TP9 are all in normal contact. If the second detection terminal TP3 and the first detection terminal TP1 are disconnected, the control terminal of the first switching circuit 100 maintains its initial level. That is, the control terminal of the first switching circuit 100 receives a non-low-level signal, and the first and second terminals of the first switching circuit 100 are disconnected. At this time, the voltage output terminal of the master device cannot output voltage to the slave device. That is, the master device stops supplying power to the slave device.

[0029] Therefore, when the second detection terminal TP3 and the first detection terminal TP1 are in normal contact, the master device supplies power to the slave device; when the second detection terminal TP3 and the first detection terminal TP1 are disconnected, the master device stops supplying power to the slave device. Furthermore, since the contact state of the first detection terminal TP1 and the second detection terminal TP3 represents the contact state of the first connection terminal TP7 and the third connection terminal TP5, and the second connection terminal TP8 and the fourth connection terminal TP9, when the first connection terminal TP7 and the third connection terminal TP5, and the second connection terminal TP8 and the fourth connection terminal TP9 have poor contact, the master device can supply power to the slave device when these terminals are in contact (i.e., the third connection terminal TP5 outputs a supply voltage), and stop supplying power to the slave device when they are disconnected (i.e., the third connection terminal TP5 does not output a supply voltage). This avoids the phenomenon of sparks generated by friction due to voltage still existing at the connection terminals when there is poor contact, thus improving safety. Moreover, the first switching circuit 100 does not need to occupy the pins of the control chip during its conduction and turn-off processes, allowing the master device to use a control chip with fewer pins, further reducing costs.

[0030] In some embodiments, the first switching circuit 100 is a transistor switching circuit. For example... Figure 1 , Figure 2 As shown, the transistor circuit may include a first transistor Q1, a second transistor Q2, a third transistor Q3, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4.

[0031] In this circuit, the first terminal of the first transistor Q1 is connected to the voltage output terminal of the master device. When the first and second terminals of the first switching circuit 100 are turned on, the voltage output terminal can supply voltage to the slave device. The second terminal of the first transistor Q1 is connected to the second terminal of the second transistor Q2. The first terminal of the second transistor Q2 is connected to the third connection terminal TP5. The first terminal of the third transistor Q3 is connected to the second detection terminal TP3 through the first resistor R1. The second terminal of the third transistor Q3 is connected to the connection terminal of the second terminal of the first transistor Q1 and the first terminal of the second transistor Q2 through the second resistor R2. The control terminal of the third transistor Q3 is connected to the connection terminal of the second terminal of the first transistor Q1 and the first terminal of the second transistor Q2 through the third resistor R3. The control terminal of the third transistor Q3 is also connected to the second detection terminal TP3 through the fourth resistor R4. The control terminal and the first terminal of the third transistor Q3 are the control terminals of the first switching circuit 100, that is, the connection terminal of the first resistor R1 and the second detection terminal TP3 and the connection terminal of the fourth resistor R4 and the second detection terminal TP3 are the control terminals of the first switching circuit 100.

[0032] In this embodiment, when the initial level of the control terminal of the third transistor Q3 is a non-low level signal and the initial level of the first terminal of the third transistor Q3 is a non-low level signal, the initial level of the control terminal of the first switching circuit 100 is a non-low level signal. Similarly, when the level signal of the control terminal of the third transistor Q3 is a low level signal and the first terminal of the third transistor Q3 is a low level signal, the control terminal of the first switching circuit 100 receives a low level signal.

[0033] In this embodiment, the second resistor R2 and the third resistor R3 are current-limiting resistors. The first resistor R1 and the fourth resistor R4 are pull-down resistors R8.

[0034] In some embodiments, the non-low level signal may include a high level signal and a high impedance signal. Figure 1 When the first detection terminal TP1 and the second detection terminal TP3 in the transistor switching circuit shown are disconnected, the voltage output terminal in the main device turns on the internal diode of the first transistor Q1. The voltage output terminal outputs a high voltage to the second terminal of the third transistor Q3 through the turned-on internal diode and the second resistor R2. It then outputs a high voltage to the control terminal of the third transistor Q3 through the third resistor R3. The initial level of the first terminal of the third transistor Q3 is a high-impedance signal. At this time, the third transistor Q3 is in the off state, and the first transistor Q1 and the second transistor Q2 are also in the off state. That is, the first terminal and the second terminal of the first switching circuit 100 are in the off state. Figure 1 When the first detection terminal TP1 and the second detection terminal TP3 are in normal contact in the transistor switching circuit shown, the control terminal of the third transistor Q3 is pulled down to a low level signal by the pull-down resistor R8, and the first terminal of the third transistor Q3 is pulled down to a low level signal by the pull-down resistor R8. At this time, the third transistor Q3 is in the conducting state. After the third transistor Q3 is turned on, the second transistor Q2 and the first transistor Q1 are also in the conducting state. That is, the first terminal and the second terminal of the first switching circuit 100 are in the conducting state.

[0035] It should be noted that a high-impedance signal refers to a transistor pin being floated. From Figure 1 It can be seen that the first terminal of the third transistor Q3 is floated when the first detection terminal TP1 and the second detection terminal TP3 are disconnected. That is, when the first detection terminal TP1 and the second detection terminal TP3 are disconnected, the first terminal of the third transistor Q3 is a high-impedance signal.

[0036] In some embodiments, two second detection terminals TP3 may be provided, with each second detection terminal TP3 corresponding to a first detection terminal TP1. The first terminal of the third transistor Q3 is connected to one of the second detection terminals TP3 via a first resistor R1, and the control terminal of the third transistor Q3 is also connected to the other second detection terminal TP3 via a fourth resistor R4. Each first detection terminal TP1 is grounded via a pull-down resistor R8.

[0037] When the master and slave devices are in contact, if the two second detection terminals TP3 and the two first detection terminals TP1 are in normal contact, the control terminal of the third transistor Q3 is pulled down to a low level signal, the first terminal of the third transistor Q3 is pulled down to a low level signal, and the third transistor Q3 is in the on state. If one or both of the two second detection terminals TP3 and the two first detection terminals TP1 are out of contact, the control terminal of the third transistor Q3 and one or both of the first terminals are non-low level signals, and the third transistor Q3 is in the off state.

[0038] Therefore, when the master device supplies power to the slave device, it will only supply power to the slave device when the two second detection terminals TP3 and the two first detection terminals TP1 are in contact. When one or both of the second detection terminals TP3 are disconnected from one or both of the first detection terminals TP1, the master device will stop supplying power to the slave device, which further improves safety.

[0039] In some embodiments, the two second detection terminals TP3 are staggered, and each second detection terminal TP3 corresponds to a first detection terminal TP1.

[0040] like Figure 5 As shown, the external circuit board 300 for connecting the master and slave devices can be set at two diagonal positions when the two second detection terminals TP3 are set. Figure 5 The first position 301 and the second position 302 in the middle, in this way, when the two second detection ends TP3 and the two first detection ends TP1 are in contact, it is further ensured that the first connection end TP7 and the third connection end TP5, the second connection end TP8 and the fourth connection end TP9 are in contact.

[0041] Of course, the two second detection terminals TP3 can also be configured in other staggered ways. For example, one of the two second detection terminals TP3 can be set in the first position 301 and the third position 303. As another example, one of the two second detection terminals TP3 can be set in the second position 302 and the third position 303. Those skilled in the art can determine the specific settings of the two second detection terminals TP3 according to the actual situation, and no further limitations are imposed here.

[0042] In some embodiments, the first transistor Q1 may be, but is not limited to, a field-effect transistor (FET). The second transistor Q2 may be, but is not limited to, a FET. The third transistor Q3 may be, but is not limited to, a FET.

[0043] In some embodiments, the first transistor Q1, the second transistor Q2, and the third transistor Q3 are all field-effect transistors. In one specific embodiment, the first transistor Q1, the second transistor Q2, and the third transistor Q3 are all P-MOS transistors (P-channel Metal-Oxide-Semiconductor Field-Effect Transistors).

[0044] like Figure 1 As shown, in some embodiments, the connection protection circuit further includes a second switching circuit 200, which includes a first terminal, a second terminal, a control terminal, and a feedback terminal. The first terminal of the second switching circuit 200 is used to connect to ground; the second terminal of the second switching circuit 200 is used to connect to the power supply VCC; the feedback terminal of the second switching circuit 200 is connected to the second terminal of the second switching circuit 200; the control terminal of the second switching circuit 200 is connected to the second detection terminal TP3; the initial level of the control terminal of the second switching circuit 200 is a high-level signal; in response to the high-level signal input to its control terminal, the second switching circuit 200 conducts its first and second terminals, causing the feedback terminal to output a first-level signal to the control module of the main device. The first-level signal is used to characterize the contact state of the first detection terminal TP1 and the second detection terminal TP3 as open contact; when the control terminal of the second switching circuit 200 is pulled down to a low-level signal, the second switching circuit 200 disconnects its first and second terminals in response to the low-level signal input to its control terminal, causing the feedback terminal to output a second-level signal to the control module. The second-level signal is used to characterize the first detection terminal TP1 and the second detection terminal TP3 as normal contact. The contact state of the first detection terminal TP1 and the second detection terminal TP3 is also used to characterize the contact state of the communication terminal of the master device and the communication terminal of the slave device; the control module is used to determine the contact state of the communication terminal of the master device and the communication terminal of the slave device according to the feedback signal output by the second switching circuit 200, so as to determine whether to perform data transmission.

[0045] Specifically, when the first detection terminal TP1 and the second detection terminal TP3 are in normal contact, the control terminal of the second switching circuit 200 is pulled down by the pull-down resistor R8, causing the control terminal of the second switching circuit 200 to input a low-level signal. The first and second terminals of the second switching circuit 200 are in an open state. At this time, the feedback terminal outputs a second-level signal to the control module. When the first detection terminal TP1 and the second detection terminal TP3 are out of contact, the initial level of the control terminal of the second switching circuit 200 is a high-level signal, and the first and second terminals of the second switching circuit 200 are in a conducting state. At this time, the feedback terminal outputs a first-level signal to the control module. The control module then determines whether to perform data transmission with the slave device based on the feedback signal output by the feedback terminal. That is, when the control module receives the first-level signal, it considers the communication terminals of the master device and the slave device to be out of contact, and no data transmission occurs. When the control module receives the second-level signal, it considers the communication terminals of the master device and the slave device to be in normal contact, and data transmission can occur. The first-level signal is a low-level signal, and the second-level signal is a high-level signal.

[0046] Since the contact state of the first detection terminal TP1 and the second detection terminal TP3 represents the contact state of the communication terminal of the master device and the communication terminal of the slave device, when the first detection terminal TP1 and the second detection terminal TP3 are in normal contact, the communication terminal of the master device and the communication terminal of the slave device are also in normal contact. At this time, data transmission can be performed between the master device and the slave device, which improves the security of data transmission.

[0047] In some embodiments, when there are two second detection terminals TP3, two corresponding second switching circuits 200 can also be provided. The control terminal of one second switching circuit 200 is connected to one of the second detection terminals TP3, and the control terminal of the other second switching circuit 200 is connected to the other second detection terminal TP3. When the two second detection terminals TP3 are in normal contact with the two first detection terminals TP1 respectively, the feedback terminals of the two second switching circuits 200 output a second-level signal to the control module. At this time, data transmission can be performed between the master device and the slave device.

[0048] In other words, data transmission between the master and slave devices is only possible when the control module receives feedback signals from the feedback terminals of both second switch circuits 200, both of which are second-level signals. When the control module receives only a second-level signal from the feedback terminal of one second switch circuit 200, data transmission between the master and slave devices is not possible, further improving the security of data transmission.

[0049] In some embodiments, the control module may be a central processing unit.

[0050] like Figure 1As shown, in some embodiments, the second switching circuit 200 may also be a transistor switching circuit. This transistor switching circuit may include a fourth transistor Q4, a fifth resistor R5, a sixth resistor R6, and a seventh resistor R7.

[0051] In this circuit, the first terminal of the fourth transistor Q4 is connected to its control terminal via the fifth resistor R5, and the control terminal of the fourth transistor Q4 is connected to the second detection terminal TP3 via the sixth resistor R6. The second terminal of the second switching circuit 200 is connected to the power supply VCC via the seventh resistor R7. The first terminal of the fourth transistor Q4 is the first terminal of the second switching circuit 200, the connection between the sixth resistor R6 and the second detection terminal TP3 is the control terminal of the second switching circuit 200, the connection between the seventh resistor R7 and the power supply VCC is the second terminal of the second switching circuit 200, and the connection between the seventh resistor R7 and the fourth transistor Q4 is the feedback terminal of the second switching circuit 200.

[0052] When the second detection terminal TP3 and the first detection terminal TP1 are disconnected, the input level signal to the control terminal of the fourth transistor Q4 is a high-level signal. At this time, the fourth transistor Q4 is in the off state. Since the fourth transistor Q4 is in the off state, the feedback signal output from the feedback terminal is a high-level signal, i.e., the first level signal. When the second detection terminal TP3 and the first detection terminal TP1 are in normal contact, the input level signal to the control terminal of the fourth transistor Q4 is a low-level signal (pulled down to a low level by the pull-down resistor R8). At this time, the fourth transistor Q4 is in the on state. Since the fourth transistor Q4 is in the on state, the feedback signal output from the feedback terminal is a low-level signal, i.e., the second level signal.

[0053] In some embodiments, the fourth transistor Q4 may be, but is not limited to, an N-MOS transistor (N-channel Metal-Oxide-Semiconductor Field-Effect Transistor).

[0054] In some embodiments, when the transistor is an N-MOS transistor, the first terminal refers to the source of the N-MOS transistor; the second terminal refers to the drain of the N-MOS transistor; and the control terminal refers to the gate of the N-MOS transistor. When the transistor is a P-MOS transistor, the first terminal refers to the drain of the P-MOS transistor; the second terminal refers to the source of the P-MOS transistor; and the control terminal refers to the gate of the P-MOS transistor.

[0055] This application also provides a master device for connecting a slave device. The slave device includes a pull-down resistor R8, a first connection terminal TP7, a second connection terminal TP8, and a first detection terminal TP1. The first connection terminal TP7 is used to supply voltage to the slave device, the second connection terminal TP8 is used to connect to the ground of the master device, and the first detection terminal TP1 is connected to the ground of the slave device through the pull-down resistor R8. The master device includes a connection protection circuit. The connection protection circuit includes: a second detection terminal TP3; a third connection terminal TP5, used to output supply voltage to the first connection terminal TP7; and a fourth connection terminal TP9, used to connect to the ground of the master device. A first switching circuit 100 includes a first terminal, a second terminal, and a control terminal. The first terminal of the first switching circuit 100 is used to connect to the voltage output terminal of the master device, the second terminal of the first switching circuit 100 is connected to the third connection terminal TP5, and the control terminal of the first switching circuit 100 is connected to the second detection terminal TP3. When the master device and the slave device are connected, the second detection terminal TP3 and the first detection terminal TP1 are connected to each other. When terminal TP1 is in contact, first connection terminal TP7 and third connection terminal TP5 are in contact, and second connection terminal TP8 and fourth connection terminal TP9 are in contact, the contact state of the first detection terminal TP1 and the second detection terminal TP3 is used to characterize the contact state of the first connection terminal TP7 and the third connection terminal TP5, and the contact state of the second connection terminal TP8 and the fourth connection terminal TP9. When the first detection terminal TP1 and the second detection terminal TP3 are disconnected, the initial level of the control terminal of the first switching circuit 100 is a high-level signal. In response to the high-level signal input to its control terminal, the first switching circuit 100 disconnects the connection between its first terminal and the second terminal, causing the master device to stop supplying power to the slave device. When the first detection terminal TP1 and the second detection terminal TP3 are in normal contact, the first detection terminal TP1 pulls down the control terminal of the first switching circuit 100 to a low-level signal through the second detection terminal TP3. In response to the low-level signal input to its control terminal, the first switching circuit 100 turns on its first terminal and the second terminal, allowing the master device to supply power to the slave device. This is as described in the specific embodiment of the connection protection circuit above, and will not be elaborated further here.

[0056] This application also provides a slave device for connecting to a master device. The slave device includes a pull-down resistor R8, a first connection terminal TP7, a second connection terminal TP8, and a first detection terminal TP1. The first connection terminal TP7 is used to connect the supply voltage to the slave device, the second connection terminal TP8 is used to connect to the ground of the master device, and the first detection terminal TP1 is connected to the ground of the slave device through the pull-down resistor R8. The master device is as described above. Specific details are as described in the above embodiment of a connection protection circuit, and will not be elaborated further here.

[0057] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A connection protection circuit, characterized in that, This device is applied to master and slave devices. The slave device includes a pull-down resistor, a first connection terminal, a second connection terminal, and a first detection terminal. The first connection terminal is used to connect a power supply to the slave device. The second connection terminal is used to connect to the ground of the master device. The first detection terminal is connected to the ground of the slave device through the pull-down resistor. A connection protection circuit is provided in the master device. The connection protection circuit includes: a second detection terminal; and a third connection terminal for outputting a power supply to the first connection terminal. The fourth connection terminal is used to connect to the grounding terminal of the main device; A first switching circuit, comprising a first terminal, a second terminal, and a control terminal, wherein the first terminal of the first switching circuit is used to connect to the voltage output terminal of the main device, the second terminal of the first switching circuit is connected to the third connection terminal, and the control terminal of the first switching circuit is connected to the second detection terminal. When the master device and the slave device are connected, the second detection end is in contact with the first detection end, the first connection end is in contact with the third connection end, and the second connection end is in contact with the fourth connection end. The contact state of the first detection end and the second detection end is used to characterize the contact state of the first connection end and the third connection end, as well as the contact state of the second connection end and the fourth connection end. When the first detection terminal and the second detection terminal are in normal contact, the first detection terminal pulls down the control terminal of the first switching circuit to a low level signal through the second detection terminal. In response to the low level signal input to its control terminal, the first switching circuit turns on its first terminal and second terminal, so that the master device can supply power to the slave device. When the first detection terminal and the second detection terminal disconnect from each other, the initial level of the control terminal of the first switching circuit is a non-low level signal. In response to the non-low level signal input to its control terminal, the first switching circuit disconnects the connection between its first terminal and the second terminal, causing the master device to stop supplying power to the slave device.

2. A main device, characterized in that, The master device is used to connect to the slave device; the slave device includes a pull-down resistor, a first connection terminal, a second connection terminal, and a first detection terminal. The first connection terminal is used to connect the supply voltage to the slave device, the second connection terminal is used to connect to the ground of the master device, and the first detection terminal is connected to the ground of the slave device through the pull-down resistor. The main device includes a connection protection circuit; the connection protection circuit includes: Second detection end; The third connection terminal is used to output the supply voltage to the first connection terminal; The fourth connection terminal is used to connect to the grounding terminal of the main device; A first switching circuit includes a first terminal, a second terminal, and a control terminal. The first terminal of the first switching circuit is connected to the voltage output terminal of the main device, the second terminal of the first switching circuit is connected to the third connection terminal, and the control terminal of the first switching circuit is connected to the second detection terminal. When the master device and the slave device are connected, the second detection end is in contact with the first detection end, the first connection end is in contact with the third connection end, and the second connection end is in contact with the fourth connection end. The contact state of the first detection end and the second detection end is used to characterize the contact state of the first connection end and the third connection end, as well as the contact state of the second connection end and the fourth connection end. When the first detection terminal and the second detection terminal are in normal contact, the first detection terminal pulls down the control terminal of the first switching circuit to a low level signal through the second detection terminal. In response to the low level signal input to its control terminal, the first switching circuit turns on its first terminal and second terminal, so that the master device can supply power to the slave device. When the first detection terminal and the second detection terminal disconnect from each other, the initial level of the control terminal of the first switching circuit is a non-low level signal. In response to the non-low level signal input to its control terminal, the first switching circuit disconnects the connection between its first terminal and the second terminal, causing the master device to stop supplying power to the slave device.

3. The main equipment as described in claim 2, characterized in that, The first switching circuit is a transistor switching circuit.

4. The main equipment as described in claim 3, characterized in that, The second detection terminal is provided in two parts, and each second detection terminal corresponds to one first detection terminal; the transistor switching circuit includes: a first transistor, a second transistor, a third transistor, a first resistor, a second resistor, a third resistor, and a fourth resistor; The first terminal of the first transistor is connected to the voltage output terminal, and the second terminal of the first transistor is connected to the second terminal of the second transistor; The first terminal of the second transistor is connected to the third terminal; The first terminal of the third transistor is connected to one of the second detection terminals through the first resistor. The second terminal of the third transistor is connected to the connection terminal of the second terminal of the first transistor and the first terminal of the second transistor through the second resistor. The control terminal of the third transistor is connected to the connection terminal of the second terminal of the first transistor and the first terminal of the second transistor through the third resistor. The control terminal of the third transistor is also connected to another second detection terminal through the fourth resistor. The connection between the first resistor and the second detection terminal and the connection between the fourth resistor and the second detection terminal are the control terminals of the first switching circuit.

5. The main equipment as described in claim 4, characterized in that, The non-low level signals include high level signals and high impedance signals.

6. The main equipment as described in claim 4, characterized in that, There are two second detection terminals, and each second detection terminal corresponds to one first detection terminal; The first terminal of the third transistor is connected to one of the second detection terminals through the first resistor. The control terminal of the third transistor is also connected to another second detection terminal through the fourth resistor; The two second detection ends are misaligned.

7. The main equipment as described in any one of claims 2-6, characterized in that, The connection protection circuit further includes: a second switching circuit, which includes a first terminal, a second terminal, a control terminal, and a feedback terminal; The first terminal of the second switching circuit is used to connect to ground; The second terminal of the second switching circuit is used to connect to the power supply; The feedback terminal of the second switching circuit is connected to the second terminal of the second switching circuit; The control terminal of the second switching circuit is connected to the second detection terminal; The initial level of the control terminal of the second switching circuit is a high-level signal. In response to the high-level signal input to its control terminal, the second switching circuit turns on its first and second terminals, so that the feedback terminal outputs a first-level signal to the control module of the main device. The first-level signal is used to characterize the contact state of the first detection terminal and the second detection terminal as disconnected contact. When the control terminal of the second switching circuit is pulled down to a low level signal, the second switching circuit responds to the low level signal input to its control terminal and disconnects the connection between its first terminal and second terminal, so that the feedback terminal outputs a second level signal to the control module. The second level signal is used to indicate that the first detection terminal and the second detection terminal are in normal contact. The contact state of the first detection end and the second detection end is also used to characterize the contact state of the communication end of the master device and the communication end of the slave device; the control module is used to determine the contact state of the communication end of the master device and the communication end of the slave device according to the feedback signal output by the second switching circuit, so as to determine whether to perform data transmission.

8. The connection protection circuit as described in claim 7, characterized in that, The second switching circuit is a transistor switching circuit.

9. The connection protection circuit as described in claim 8, characterized in that, The transistor switching circuit includes: a fourth transistor, a fifth resistor, a sixth resistor, and a seventh resistor; The first terminal of the fourth transistor is connected to its control terminal through the fifth resistor, the control terminal of the fourth transistor is connected to the second detection terminal through the sixth resistor, and the second terminal of the second switching circuit is connected to the power supply through the seventh resistor. Wherein, the connection node between the seventh resistor and the fourth transistor is the feedback terminal, the first terminal of the fourth transistor is the first terminal of the second switching circuit, the connection terminal between the sixth resistor and the second detection terminal is the control terminal of the second switching circuit, the connection terminal between the seventh resistor and the power supply is the second terminal of the second switching circuit, and the connection terminal between the seventh resistor and the fourth transistor is the feedback terminal of the second switching circuit.

10. A slave device for connecting to a master device, characterized in that, The slave device includes a pull-down resistor, a first connection terminal, a second connection terminal, and a first detection terminal. The first connection terminal is used to connect the supply voltage to the slave device, the second connection terminal is used to connect to the ground of the master device, and the first detection terminal is connected to the ground of the slave device through the pull-down resistor. The master device is the master device as described in any one of claims 2-9.

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