A charger reverse connection protection circuit

Abstract

The application relates to the technical field of protection circuits, in particular to a charger reverse connection protection circuit. The charger reverse connection protection circuit comprises a controller, a transformer and a relay K1. The first output end of the transformer is connected with a positive output BAT+ through the relay K1, the second output end of the transformer is connected with a negative output BAT-, the relay K1 is connected with the controller through a control module, and the acquisition end of the controller is connected with the positive output BAT+. When the battery is connected in normal mode, the acquisition end of the controller detects a 2.5V voltage, the controller sends a signal to the control module, the control module controls the relay K1 to be turned on, and the battery is normally charged. When the battery is connected in reverse mode, the acquisition end of the controller detects a voltage lower than 2.5V, the controller does not send a signal to the control module, and the relay K1 is in an off state, so that the protection effect can be achieved, the charger is prevented from being burnt due to reverse connection, and the charger has the advantages of simple circuit structure, small number of components and devices and cost saving.

Description

Technical Field

[0001] This application relates to the field of protection circuit technology, and in particular to a charger reverse connection protection circuit. Background Technology

[0002] Chargers have positive and negative outputs, and batteries also have positive and negative terminals. In actual use, there is a possibility that the positive and negative terminals may be reversed. If the positive and negative terminals of the battery are reversed, it may damage the battery and the charger.

[0003] Currently, the common method to prevent battery damage from reverse connection is to connect a diode or a fuse in series. However, connecting a diode in series can only be used in situations with low current, while replacing and installing a fuse is cumbersome, and these methods cannot protect the charger itself. Utility Model Content

[0004] To solve the above-mentioned technical problems, this application provides a charger reverse connection protection circuit, including a controller, a transformer, and a relay K1. The first output terminal of the transformer is connected to the positive output BAT+ through the relay K1, and the second output terminal of the transformer is connected to the negative output BAT-. The relay K1 is connected to the controller through a control module. The controller sends a signal to the control module to turn the relay K1 on or off. The acquisition terminal of the controller is connected to the positive output BAT+.

[0005] Preferably, the control module includes a resistor R41 and a transistor Q6. The collector of the transistor Q6 is connected to the relay K1. One end of the resistor R41 is connected to the first signal terminal of the controller, and the other end of the resistor R41 is connected to the base of the transistor Q6. The emitter of the transistor Q6 is grounded, and the base of the transistor Q6 is grounded through a resistor R42.

[0006] Preferably, the positive output BAT+ is connected to the acquisition terminal of the controller through a voltage divider circuit, which is composed of resistors R156, R159, R160 and R161.

[0007] Preferably, the first output terminal of the transformer is connected to the anode of diode D12, the cathode of diode D12 is connected to inductor L2, and the other end of inductor L2 is connected to the positive output BAT+ through relay K1; the second output terminal of the transformer is connected to the negative output BAT-, one end of capacitor C9 is connected to the junction of diode D12 and inductor L2, and the other end of capacitor C9 is grounded.

[0008] Preferably, the device further includes transistors Q1 and Q2. The base of transistor Q1 is connected to the collector of transistor Q2 through resistor R21. The collector of transistor Q1 is connected to the positive output BAT+ through a resistor branch consisting of R22, R26, and diode D10 connected in series. The emitter of transistor Q1 is connected to the first output terminal of the transformer. The base of transistor Q2 is connected to the second signal terminal of the controller through resistor R29. The base of transistor Q2 is grounded through resistor R30, and the emitter of transistor Q2 is grounded.

[0009] As can be seen from the above, the following beneficial effects can be obtained by applying the method provided in this application: The first output terminal of the transformer is connected to the positive output BAT+ via relay K1, and the second output terminal of the transformer is connected to the negative output BAT-. The input terminal of the transformer is connected to an external power supply. Relay K1 is connected to the controller via the control module. The controller sends a signal to the control module to turn relay K1 on or off. The acquisition terminal of the controller is connected to the positive output BAT+. Therefore, when the positive terminal of the battery is connected to the positive output BAT+ and the negative terminal of the battery is connected to the negative output BAT-, the acquisition terminal of the controller detects a voltage of 2.5V. The controller then sends a signal to the control module, which controls relay K1 to turn on, thereby charging the battery normally. When the positive terminal of the battery is connected to the negative output BAT- and the negative terminal of the battery is connected to the positive output BAT+, the acquisition terminal of the controller detects a voltage lower than 2.5V. The controller does not send a signal to the control module, and relay K1 is in the off state, thus providing protection and preventing the charger from being burned out due to reverse connection. This method has the advantages of simple circuit structure, few components, and cost savings. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments of this application or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only a part of the embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a circuit diagram of the reverse connection protection circuit for the charger in an embodiment of this application. Detailed Implementation

[0012] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0013] To address the aforementioned technical problems, this embodiment provides a charger reverse connection protection circuit, such as... Figure 1 As shown, the device includes a controller, a transformer, and a relay K1. The first output terminal of the transformer is connected to the positive output BAT+ via relay K1, and the second output terminal is connected to the negative output BAT-. The input terminal of the transformer is connected to an external power supply. Relay K1 is connected to the controller via a control module. The controller sends a signal to the control module to turn relay K1 on or off. The controller's acquisition terminal is connected to the positive output BAT+. Therefore, when the battery's positive terminal is connected to the positive output BAT+ and the battery's negative terminal is connected to the negative output BAT-, the controller's acquisition terminal detects a voltage of 2.5V. The controller then sends a signal to the control module, which turns on relay K1, thus charging the battery normally. When the battery's positive terminal is connected to the negative output BAT- and the battery's negative terminal is connected to the positive output BAT+, the controller's acquisition terminal detects a voltage below 2.5V. The controller does not send a signal to the control module, and relay K1 remains off, thus providing protection against reverse connection damage to the charger. This design features a simple circuit structure, fewer components, and cost savings.

[0014] Specifically, the controller uses chip U3 (model 16F1503). The control module includes resistor R41 and transistor Q6. The collector of transistor Q6 is connected to relay K1. One end of resistor R41 is connected to the first signal terminal of the controller, which is pin 11 of chip U3. The other end of resistor R41 is connected to the base of transistor Q6. The emitter of transistor Q6 is grounded, and the base of transistor Q6 is grounded through resistor R42. When the controller's acquisition terminal detects a 2.5V voltage, the first signal terminal sends an electrical signal to the base of transistor Q6. The collector of transistor Q6 then sends an electrical signal to relay K1, causing relay K1 to conduct, thus enabling the circuit to charge the battery normally. The controller's acquisition terminal is pin 13 of chip U3.

[0015] In the above scheme, the positive output BAT+ is connected to the acquisition terminal of the controller through a voltage divider circuit. The voltage divider circuit consists of resistors R156, R159, R160 and R161, which is used to provide a specific voltage for voltage detection at the acquisition terminal of the controller.

[0016] Furthermore, the first output terminal of the transformer is connected to the anode of diode D12, the cathode of diode D12 is connected to inductor L2, and the other end of inductor L2 is connected to the positive output BAT+ through relay K1; the second output terminal of the transformer is connected to the negative output BAT-, one end of capacitor C9 is connected to the junction of diode D12 and inductor L2, and the other end of capacitor C9 is grounded. Specifically, the second output terminal of the transformer is connected to the negative output BAT- through parallel connections RS21 and RS2, one end of capacitor C8 is connected to the junction between inductor L2 and relay K1, and the other end of capacitor C8 is connected to the negative output BAT-.

[0017] In some implementations, it is sometimes necessary to detect whether the battery is short-circuited before detecting whether the battery is reverse-connected. Therefore, this embodiment also includes transistors Q1 and Q2. The base of transistor Q1 is connected to the collector of transistor Q2 through resistor R21. The collector of transistor Q1 is connected to the positive output BAT+ through a resistor branch consisting of R22, R26, and diode D10 connected in series. The emitter of transistor Q1 is connected to the first output terminal of the transformer. The base of transistor Q2 is connected to the second signal terminal of the controller through resistor R29. The base of transistor Q2 is grounded through resistor R30, and the emitter of transistor Q2 is grounded. The second signal terminal of the controller is pin 8 of chip U3. When the positive output BAT+ is connected to the battery, pin 13 of chip U3 detects a 2.5V voltage. Pin 8 of chip U3 then sends a signal to transistor Q2, thereby controlling transistor Q1 to conduct. After transistor Q1 conducts, the controller detects whether the battery has a short-circuit abnormality. If there is no abnormality, the first signal terminal of the controller sends an electrical signal to the base of transistor Q6, and the collector of transistor Q6 sends an electrical signal to relay K1, causing relay K1 to conduct, and thus the circuit charges the battery normally.

[0018] In summary, this application's solution connects the first output terminal of the transformer to the positive output BAT+ via relay K1, and the second output terminal of the transformer to the negative output BAT-. The input terminal of the transformer is connected to an external power supply. Relay K1 is connected to the controller via a control module. The controller sends a signal to the control module to turn relay K1 on or off. The controller's acquisition terminal is connected to the positive output BAT+. Therefore, when the battery's positive terminal is connected to the positive output BAT+ and the battery's negative terminal is connected to the negative output BAT-, the controller's acquisition terminal detects a 2.5V voltage. The controller then sends a signal to the control module, which turns on relay K1, thus charging the battery normally. When the battery's positive terminal is connected to the negative output BAT- and the battery's negative terminal is connected to the positive output BAT+, the controller's acquisition terminal detects a voltage below 2.5V. The controller does not send a signal to the control module, and relay K1 remains off, thus providing protection against reverse connection damage to the charger. This solution has the advantages of a simple circuit structure, fewer components, and cost savings.

[0019] The embodiments described above do not constitute a limitation on the scope of protection of this technical solution. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the above embodiments should be included within the scope of protection of this technical solution.

Claims

1. A reverse connection protection circuit for a charger, characterized in that: The system includes a controller, a transformer, and a relay K1. The first output terminal of the transformer is connected to the positive output BAT+ via the relay K1, and the second output terminal of the transformer is connected to the negative output BAT-. The relay K1 is connected to the controller via a control module. The controller sends a signal to the control module to turn the relay K1 on or off. The acquisition terminal of the controller is connected to the positive output BAT+.

2. The charger reverse connection protection circuit according to claim 1, characterized in that: The control module includes a resistor R41 and a transistor Q6. The collector of the transistor Q6 is connected to the relay K1. One end of the resistor R41 is connected to the first signal terminal of the controller, and the other end of the resistor R41 is connected to the base of the transistor Q6. The emitter of the transistor Q6 is grounded, and the base of the transistor Q6 is grounded through a resistor R42.

3. The charger reverse connection protection circuit according to claim 1, characterized in that: The positive output BAT+ is connected to the acquisition terminal of the controller through a voltage divider circuit, which consists of resistors R156, R159, R160 and R161.

4. The charger reverse connection protection circuit according to claim 1, characterized in that: The first output terminal of the transformer is connected to the anode of diode D12, the cathode of diode D12 is connected to inductor L2, and the other end of inductor L2 is connected to the positive output BAT+ through relay K1; the second output terminal of the transformer is connected to the negative output BAT-, one end of capacitor C9 is connected to the junction of diode D12 and inductor L2, and the other end of capacitor C9 is grounded.

5. The charger reverse connection protection circuit according to claim 1, characterized in that: It also includes transistors Q1 and Q2. The base of transistor Q1 is connected to the collector of transistor Q2 through resistor R21. The collector of transistor Q1 is connected to the positive output BAT+ through a resistor branch consisting of R22, R26 and diode D10 connected in series. The emitter of transistor Q1 is connected to the first output terminal of the transformer. The base of transistor Q2 is connected to the second signal terminal of the controller through resistor R29. The base of transistor Q2 is grounded through resistor R30. The emitter of transistor Q2 is grounded.

Images