Anti-backflow circuit

Abstract

The utility model provides an anti-backflow circuit. The anti-backflow circuit is connected with a main control module and a sub-control module. The anti-backflow circuit comprises a diode, and the cathode end and the anode end of the diode are respectively connected with the transmitting end of the main control module and the receiving end of the sub-control module; a pull-up resistor is connected between the anode end of the diode and the sub-control module, and the pull-up resistor and the sub-control module are respectively connected with a first power supply; and the main control module is connected with the second power supply. The anti-backflow circuit is arranged between the main control module and the sub-control module, so that when the main control module transmits the control signal to the sub-control module, the second power supply supplies power, the current cannot flow back to the sub-control module no matter the first power supply starts to supply power or does not start to supply power, and the anti-backflow circuit is simple in structure and low in cost.

Description

Technical Field

[0001] This utility model relates to the field of anti-backflow technology, and in particular to an anti-backflow circuit. Background Technology

[0002] Control systems typically include a main control module and sub-control modules. The main control module communicates and controls the sub-control modules via specific communication interfaces and protocols. To achieve low energy consumption in the control system, the main control module usually powers off sub-control modules that do not require control; only when the main control module needs to control a sub-control module does it power it on and initiate communication. Using this control method, if the main control module's communication interface is at a high level while the sub-control module is powered off, current will flow back into the sub-control module. This can cause the sub-control module to malfunction due to the backflow, or even damage its components.

[0003] Chinese patent application CN105704537A discloses a set-top box reset system, including an anti-backflow circuit. This anti-backflow circuit is connected to the main control system, subsystem, and hardware reset module. The anti-backflow circuit includes a first resistor, an NPN transistor, and a second resistor. One end of the first resistor is connected to the GPIO port of the main control system, and the other end is connected to the base of the transistor. The emitter of the transistor is grounded, and the collector is connected to one end of the second resistor and the subsystem. The other end of the second resistor is connected to the second power supply. When resetting the subsystem, the GPIO port of the main control system outputs a high-level soft reset signal to the first resistor, turning on the transistor. The anti-backflow circuit is provided between the main control system and the subsystem to isolate leakage current and prevent it from flowing back into the main control system, ensuring the normal operation of the main control system. However, the above-mentioned anti-backflow circuit cannot prevent current from flowing back into the subsystem.

[0004] Therefore, existing technologies still need to be improved and developed. Utility Model Content

[0005] The purpose of this invention is to provide an anti-backflow circuit that addresses the shortcomings and deficiencies of existing technologies.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] This utility model provides an anti-backflow circuit, which is connected to a main control module and a sub-control module, characterized in that...

[0008] The backflow prevention circuit includes a diode, the cathode and anode of which are connected to the transmitter of the main control module and the receiver of the sub-control module, respectively.

[0009] A pull-up resistor is connected between the anode of the diode and the sub-control module, and the pull-up resistor and the sub-control module are respectively connected to the first power supply.

[0010] The main control module is connected to the second power supply.

[0011] The main control module sends control commands to the sub-main control module, and the sub-control module sends feedback information to the main control module. When the control system starts, the second power supply takes precedence over the first power supply, or both are supplied simultaneously, creating a voltage difference between the main control module and the sub-control module. By incorporating an anti-backflow circuit between the main control module and the sub-control module, current will not flow back to the sub-control module when the main control module transmits control signals to the sub-control module, regardless of whether the first power supply is activated or not.

[0012] According to the above scheme, the anti-backflow circuit also includes a transistor. The collector of the transistor is connected to the receiving end of the main control module, the emitter of the transistor is connected to the transmitting end of the sub-control module, and the base B of the transistor is connected to the first power supply through a resistor.

[0013] The above structural design ensures that when the sub-control module transmits feedback signals to the main control module, the current will not flow back to the main control module.

[0014] According to the above scheme, the resistance value of the resistor is 10KΩ.

[0015] According to the above scheme, the transistor is an NPN type transistor.

[0016] According to the above scheme, the resistance value of the pull-up resistor is 1KΩ.

[0017] According to the above scheme, there are multiple sub-control modules, and each of the multiple sub-control modules is connected to the main control module through the anti-backflow circuit.

[0018] With the above structural setup, each sub-control module is independently powered by its corresponding first power source, and each sub-control module is equipped with a separate anti-backflow circuit, so that multiple sub-control modules and their corresponding anti-backflow circuits can work independently without any connection between them.

[0019] The beneficial effects of this utility model are as follows:

[0020] This utility model includes an anti-backflow circuit comprising a diode, the cathode and anode of which are connected to the transmitting end of the main control module and the receiving end of the sub-control module, respectively. A pull-up resistor is connected between the anode of the diode and the sub-control module. The pull-up resistor and the sub-control module are connected to a first power supply. By setting an anti-backflow circuit between the main control module and the sub-control module, when the main control module transmits control signals to the sub-control module, the second power supply provides power, and regardless of whether the first power supply is started or not, the current will not flow back to the sub-control module. The anti-backflow circuit has a simple structure and low cost. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of this utility model. Figure 1 ;

[0022] Figure 2 This is a schematic diagram of the structure of this utility model. Figure 2 .

[0023] In the diagram: M, main control module; MT, transmitter of the main control module; MR, receiver of the main control module; S, sub-control module; ST, transmitter of the sub-control module; SR, receiver of the sub-control module; VCC, first power supply; VDD, second power supply; 1, diode; 2, pull-up resistor; 3, transistor; C, collector; E, emitter; B, base; 4, resistor. Detailed Implementation

[0024] The technical solution of this utility model will be described below with reference to the accompanying drawings and embodiments.

[0025] like Figure 1 As shown, this utility model provides an anti-backflow circuit, which is connected to the main control module M and the sub-control module S. Its characteristic is that...

[0026] The backflow prevention circuit includes a diode 1, the cathode and anode of which are connected to the transmitter MT of the main control module M and the receiver SR of the sub-control module S, respectively.

[0027] A pull-up resistor 2 is connected between the anode of diode 1 and the sub-control module S. The pull-up resistor 2 and the sub-control module S are respectively connected to the first power supply VCC.

[0028] The main control module M is connected to the second power supply VDD.

[0029] The main control module M sends control commands to the sub-main control module S, and the sub-control module S sends feedback information to the main control module M. When the control system starts, the second power supply VDD takes precedence over the first power supply VCC, or both are supplied simultaneously, creating a voltage difference between the main control module M and the sub-control module S. By setting up an anti-backflow circuit between the main control module M and the sub-control module S, when the main control module M transmits control signals to the sub-control module S, the second power supply VDD supplies power, and regardless of whether the first power supply VCC is started or not, current will not flow back to the sub-control module S.

[0030] Furthermore, the anti-backflow circuit also includes a transistor 3, the collector C of which is connected to the receiving terminal MR of the main control module M, the emitter E of which is connected to the transmitting terminal ST of the sub-control module S, and the base B of which is connected to the first power supply VCC through a resistor 4.

[0031] With the above structural setup, when the sub-control module S transmits feedback signals to the main control module M, the current will not flow back to the main control module M.

[0032] Furthermore, the resistance of resistor 4 is 10KΩ.

[0033] Furthermore, the transistor 3 is an NPN transistor.

[0034] Furthermore, the pull-up resistor 2 has a resistance of 1KΩ.

[0035] like Figure 2 As shown, there are three sub-control modules S, each connected to the main control module M via the anti-backflow circuit. In some embodiments, the number of sub-control modules S can be set according to actual needs.

[0036] With the above structural setup, each sub-control module S is independently powered by its corresponding first power supply VCC, and each sub-control module S is equipped with a separate anti-backflow circuit, so that the three sub-control modules S and their corresponding anti-backflow circuits can work independently without any connection between them.

[0037] To facilitate understanding of the operation of the backflow prevention circuit, this embodiment describes several scenarios that may occur during its operation:

[0038] 1. The main control module M transmits control signals to the sub-control module S (MT sends level signals to SR). During the power-on initialization process of the control system, the following situations occur:

[0039] (1) If the first power supply VCC has not started supplying power, the receiving end SR of the sub-control module is at a low level (0V);

[0040] (1.1) If the transmitting end MT of the main control module is high, the cathode level of diode 1 is higher than its anode level. Diode 1 is in reverse cutoff state, which makes the transmitting end MT of the main control module and the receiving end SR of the sub-control module in cutoff state (equivalent to open circuit). The uncontrolled signal of the transmitting end MT of the main control module cannot flow back to the sub-control module S through the receiving end SR of the sub-control module.

[0041] (1.2) If the transmitting end MT of the main control module is low, both sides of diode 1 are low, and there will be no reverse current. At the same time, diode 1 is in the reverse cut-off state, which disconnects the transmitting end MT of the main control module and the receiving end SR of the sub-control module. Even if there is reverse current, it will be isolated by diode 1.

[0042] Since the first power supply VCC is not powered, the sub-control module S has not yet started working, so signal transmission issues are not considered.

[0043] (2) If the first power supply VCC has started to supply power, the receiving end SR of the sub-control module is connected to the first power supply VCC through the pull-up resistor 2, so that the receiving end SR of the sub-control module is in a high level state.

[0044] (2.1) If the main control module M needs to send a high-level signal to the sub-control module S, the transmitting end MT of the main control module is at a high level. At this time, both ends of diode 1 are at a high level, and diode 1 is in a reverse cutoff state, so that the transmitting end MT of the main control module and the receiving end SR of the sub-control module are in a cutoff state (equivalent to an open circuit). Since the receiving end SR of the sub-control module is itself in a high-level state, it can be regarded as the control signal of the transmitting end MT of the main control module has been transmitted to the receiving end SR of the sub-control module.

[0045] (2.2) If the main control module M needs to send a low-level signal to the sub-control module S, the transmitting end MT of the main control module is at a low level. At this time, the anode level of diode 1 is higher than its cathode level, and diode 1 is forward-biased, which makes the transmitting end MT of the main control module and the receiving end SR of the sub-control module conduct. The level of port SR is pulled down to a low level by the level of the transmitting end MT of the main control module, thereby completing the transmission of the low-level signal.

[0046] 2. Sub-control module S transmits feedback signals to main control module M (ST sends level signals to MR). During the power-on initialization process of the control system, the following situations occur:

[0047] (3) If the first power supply VCC has not started supplying power, the second power supply VDD has already supplied power. The receiver MR of the main control module is at a high level by default. The base B of transistor 3 is connected to the first power supply VCC through resistor 4. Therefore, the base B is at a low level (0V) and there is no current. In this way, transistor 3 is in the cutoff state (cutoff between collector C and emitter E). No matter what level the transmitter ST of the sub-control module is in, the receiver MR of the main control module and the transmitter ST of the sub-control module remain cut off. Even if there is current or residual voltage, due to the cutoff effect of transistor 3, leakage current is successfully isolated, and current backflow is effectively prevented.

[0048] (4) If the first power supply VCC has started to supply power, the receiver MR of the main control module is at a high level by default because the second power supply VDD has been supplied. The base B of transistor 3 is connected to the first power supply VCC through resistor 4. Therefore, the base B is at a high level and there is current.

[0049] (4.1) If the sub-control module S needs to send a low-level signal to the main control module M, the transmitting end ST of the sub-control module is at a low level, that is, the emitter E is also at a low level, and the base B level of the transistor 3 is VCC (greater than 0.7V), so that the collector C of the transistor 3 is connected to the emitter E. That is, the transmitting end ST of the sub-control module is connected to the receiving end MR of the main control module. The transmitting end ST of the sub-control module pulls the receiving end MR of the main control module from a high level to a low level, thereby completing the transmission of the low-level signal;

[0050] (4.2) If the sub-control module S needs to send a high-level signal to the main control module M, the transmitting end ST of the sub-control module is at a high level, that is, the emitter E is at a high level. Since the base B is at a high level, V BE When the voltage is less than 0.7V, transistor 3 is in the cutoff state. Since the receiver MR of the main control module is high by default (powered by VDD), both the transmitter ST of the sub-control module and the receiver MR of the main control module remain at a high level. Although transistor 3 is in the cutoff state, both the transmitter ST of the sub-control module and the receiver MR of the main control module are at a high level, which is equivalent to completing the signal transmission.

[0051] The above description is only a preferred embodiment of the present utility model. Therefore, all equivalent changes or modifications made to the structure, features and principles described in the claims of the present utility model patent application are included in the scope of the present utility model patent application.

Claims

1. A backflow prevention circuit, wherein the backflow prevention circuit is connected to a main control module M and a sub-control module S, characterized in that, The anti-backflow circuit includes a diode (1), the cathode and anode of the diode (1) are respectively connected to the transmitting end MT of the main control module M and the receiving end SR of the sub-control module S. A pull-up resistor (2) is connected between the anode of the diode (1) and the sub-control module S. The pull-up resistor (2) and the sub-control module S are respectively connected to the first power supply (VCC). The main control module M is connected to the second power supply (VDD).

2. The anti-backflow circuit according to claim 1, characterized in that, The backflow prevention circuit also includes a transistor (3), the collector (C) of which is connected to the receiving end MR of the main control module M, the emitter (E) of which is connected to the transmitting end ST of the sub-control module S, and the base (B) of which is connected to the first power supply (VCC) through a resistor (4).

3. The anti-backflow circuit according to claim 2, characterized in that, The resistance of the resistor (4) is 10KΩ.

4. The anti-backflow circuit according to claim 2, characterized in that, The transistor (3) is an NPN transistor.

5. The anti-backflow circuit according to claim 1, characterized in that, The pull-up resistor (2) has a resistance of 1 KΩ.

6. The anti-backflow circuit according to any one of claims 1-5, characterized in that, The sub-control modules S are configured as multiple, and the multiple sub-control modules S are respectively connected to the main control module M through the anti-backflow circuit.

Images