CN210985702U - Charger charging auxiliary circuit with reverse connection prevention function - Google Patents

Abstract

The utility model discloses a charger charging auxiliary circuit with anti-reverse connection function, which comprises a power output V + end, a power output V-end, a load interface, an MOS tube switch unit and a starting circuit unit, wherein the load interface is provided with a V + end and a switch control end, the V + end is connected with the power output V + end, the switch control end is connected with the MOS tube switch unit, an anti-reverse connection protection circuit is connected between the V + end and the switch control end, the anti-reverse connection protection circuit comprises a photoelectric coupler, a first pin of the photoelectric coupler is connected with the switch control end, a second pin of the photoelectric coupler is connected with the V + end after being connected with the anode of a first diode, a delay capacitor is connected between the third pin and the fourth pin of the photoelectric coupler, the fourth pin of the photoelectric coupler is connected with a voltage-dividing large resistor and then is connected with the power output V + end, the third pin of the photoelectric coupler is connected with the b pole of a third triode, the e pole of the third triode is connected with the V-end of the power output, and the c pole of the third triode is connected with the MOS tube switch unit and the starting circuit unit.

Description

A charger charging auxiliary circuit with anti-reverse connection function

Technical field:

The utility model relates to the technical field of chargers, in particular to a charging auxiliary circuit of a charger with an anti-reverse connection function.

Background technique:

The charger is a device for charging various electronic products, which is widely used and has become an indispensable part of electronic products.

When the current charger is reversely connected to the battery terminal, it is easy to burn the internal circuit of the charger and the battery, and it is easy to cause a safety accident.

In view of this, the inventors propose the following technical solutions.

Utility model content:

The purpose of the utility model is to overcome the deficiencies of the prior art, and to provide a charger charging auxiliary circuit with an anti-reverse connection function.

In order to solve the above-mentioned technical problems, the utility model adopts the following technical scheme: the charger charging auxiliary circuit with anti-reverse connection function includes a power output V+ terminal connected with the positive and negative poles of the charger output interface, a power output V- terminal and a load interface, a MOS switch unit and a start-up circuit unit connected between the power supply output V+ terminal and the power supply output V- terminal, the load interface has a V+ terminal and a switch control terminal respectively used for connecting with the positive and negative poles of the battery load. , the V+ terminal is connected to the power output V+ terminal, the switch control terminal is connected to the MOS tube switch unit, and an anti-reverse connection protection circuit is connected between the V+ terminal and the switch control terminal, and the anti-reverse connection protection circuit includes a photocoupler , the first pin of the optocoupler is connected to the switch control terminal, the second pin of the optocoupler is connected to the anode of the first diode, the cathode of the first diode is connected to the V+ terminal, and the A delay capacitor is connected between the third pin and the fourth pin, the fourth pin of the optocoupler is also connected to the voltage dividing large resistor and then connected to the power output V+ terminal, and the third pin of the optocoupler is connected to the third triode The b pole of the third transistor is connected to the power output V- terminal, and the c pole of the third transistor is connected to the MOS switch unit and the start-up circuit unit.

Further, in the above technical solution, the model of the optocoupler is LTV-357T-C; the model of the third triode is SS8050.

Further, in the above technical solution, a voltage divider resistor R9 is also connected between the cathode of the first diode and the V+ terminal, and the resistance value of the resistor R9 is 5.6kΩ.

Further, in the above technical solution, the MOS transistor switch unit includes a first MOS transistor and a second MOS transistor, the G pole of the first MOS transistor is connected to the c pole of the third triode, and the first MOS transistor is connected to the c pole of the third transistor. The G pole of the tube is also connected to the resistor R7 and then connected to the G pole of the second MOS tube, the D pole of the second MOS tube is connected to the switch control terminal, and the S pole of the first MOS tube is connected to the S pole of the second MOS tube. The D pole of the second MOS transistor is connected to the V- terminal of the power supply output.

Further, in the above technical solution, the S pole and the G pole of the second MOS transistor are also connected with a second capacitor with a charging delay function; the G pole of the first MOS transistor and the power output V- terminal A Zener diode is also connected.

After adopting the above-mentioned technical scheme, the utility model has the following beneficial effects compared with the prior art: when the utility model is in use, the power supply output V+ terminal and the power supply output V- terminal are respectively connected with the positive and negative poles of the charger output interface to Power on, so that the load interface in the utility model is equivalent to the charger output interface, which is used to connect the load battery; when the charger is connected to the mains and powered on, the V+ terminal and the switch control terminal of the load interface are connected with the positive and negative poles of the battery load. , the anti-reverse connection protection circuit will not work, and the start-up circuit unit will work to control the conduction of the MOS tube switch unit to achieve normal charging of the load battery; when the switch control terminal and V+ terminal of the load interface are connected to the positive and negative poles of the battery load When connected, that is, when reversed, the positive electrode of the battery load is connected to the negative electrode of the battery load from the switch control terminal through the photocoupler, the first diode, the voltage dividing resistor R9, and the V+ terminal to form a loop, because the photocoupler is turned on, charging The positive voltage of the device is provided with a forward bias to the third triode through a large voltage divider, a photocoupler, and the third triode is turned on, short-circuiting the control voltage of the MOS tube switch unit, and the MOS tube switch unit is turned off to achieve The purpose of preventing reverse connection without burning the circuit and the charger circuit board, and ensuring the service life of the product, makes the charger safer to use, and makes the utility model extremely competitive in the market. In addition, the utility model is applied to a small PCB board, which is designed independently from the charger, that is, a small PCB board is additionally added to the charger, so that the charger has the function of preventing fire, so as to assist the charging work of the charger, and is suitable for various charger.

Description of drawings:

Fig. 1 is the circuit diagram of the present utility model.

Detailed ways:

The present utility model will be further described below with reference to specific embodiments and accompanying drawings.

As shown in Figure 1, it is a charger charging auxiliary circuit with anti-reverse connection function, which includes a power output V+ terminal 1 connected to the positive and negative poles of the charger output interface, a power output V- terminal 2, and a power supply output terminal 2 connected to the power supply The load interface 3 between the output V+ terminal 1 and the power output V- terminal 2, the MOS switch unit 4 and the start-up circuit unit 5, the load interface 3 has the V+ terminal 31 for connecting with the positive and negative poles of the battery load 6 respectively. and switch control terminal 32, the V+ terminal 31 is connected to the power output V+ terminal 1, the switch control terminal 32 is connected to the MOS tube switch unit 4, and the V+ terminal 31 and the switch control terminal 32 are connected with an anti-reverse connection protection circuit 7 , the anti-reverse connection protection circuit 7 includes an optocoupler 71, the first pin of the optocoupler 71 is connected to the switch control terminal 32, the second pin of the optocoupler 71 is connected to the anode of the first diode 72, the The cathode of the first diode 72 is connected to the V+ terminal 31, a delay capacitor 711 is connected between the third pin and the fourth pin of the optocoupler 71, and the fourth pin of the optocoupler 71 is also connected to the voltage divider The large resistor 712 is connected to the power output V+ terminal 1, the third pin of the photocoupler 71 is connected to the b pole of the third transistor 73, and the e pole of the third transistor 73 is connected to the power output V- terminal 2. The c-pole of the third transistor 73 is connected to the MOS switch unit 4 and the start-up circuit unit 5 . When the utility model is in use, the power output V+ terminal 1 and the power output V- terminal 2 are respectively connected with the positive and negative poles of the charger output interface to energize, so that the load interface 3 in the present utility model is equivalent to the charger output interface, It is used to connect the load battery; when the charger is connected to the mains and powered on, the V+ terminal 31 (equivalent to the positive pole) and the switch control terminal 32 (equivalent to the negative pole) of the load interface 3 are connected to the positive and negative poles of the battery load 6. The reverse connection protection circuit 7 will not work, and the start-up circuit unit 5 will work to control the conduction of the MOS tube switch unit 4 to realize normal charging of the load battery; when the switch control terminal 32 (equivalent to the negative pole) of the load interface 3 and the V+ terminal When 31 (equivalent to the positive pole) is connected to the positive and negative poles of the battery load 6, that is, when the connection is reversed, the positive pole of the battery load 6 is connected by the switch control terminal 32 through the photocoupler 71, the first diode 72, the voltage dividing resistor R9, V+ The terminal 31 is connected to the negative electrode of the battery load 6 to form a loop. Because the photocoupler 71 is turned on, the positive voltage of the charger is provided with a forward bias to the third transistor 73 through the voltage divider large resistor 712 and the photocoupler 71. The The third triode 73 is turned on, short-circuits the control voltage of the MOS tube switch unit 4, and turns off the MOS tube switch unit 4, so as to prevent reverse connection without burning the circuit and the charger circuit board, and to ensure the service life of the product, so that the charging The device is safer to use, so that the utility model has strong market competitiveness. In addition, the utility model is applied to a small PCB board and is designed independently from the charger, that is, a small PCB board is additionally added to the charger, so that the charger has the function of preventing fire, so as to assist the charging work of the charger, and is suitable for various charger.

The resistance value of the large voltage dividing resistor 712 is 100kΩ. The model of the optocoupler 71 is LTV-357T-C; the model of the third triode 73 is SS8050.

A voltage dividing resistor R9 is also connected between the cathode of the first diode 72 and the V+ terminal 31 , and the resistance value of the resistor R9 is 5.6kΩ.

The start-up circuit unit 5 includes a first transistor 51 and a second transistor 52 for controlling the conduction of the first transistor 51 , and the connection between the e pole and the b pole of the first transistor 51 . A first capacitor 53 with a charging delay function, the e pole of the first transistor 51 is connected to the power output V+ terminal 1, the c pole of the first transistor 51 is connected to the MOS switch unit 4, the The b pole of the second transistor 52 is connected to the switch control terminal 32, the c pole of the second transistor 52 is connected to the b pole of the first transistor 51, and the e pole of the second transistor 52 is connected to the The power supply output V-terminal 2.

When the battery load 6 is connected to the load interface 3, the anti-reverse connection protection circuit 7 will not work, and the start-up circuit unit 5 will work, and the start-up circuit unit 5 and the load battery form a complete loop. At this time, the load battery 6 The negative pole of the second transistor 52 will provide the potential of the b pole in the second transistor 52, so that the second transistor 52 will be turned on and amplified, and the c pole of the second transistor will pull down the potential of the b pole in the first transistor 51. , so that the first transistor 51 is also turned on, so that the loop formed by the start-up circuit unit 5 and the load battery can be turned on. At this time, the c pole of the first transistor 51 will provide the MOS switch unit 4. A high level is used to drive the MOS switch unit 4 to conduct, so that the power output V+ terminal 1, the power output V- terminal 2, the load battery 6 and the MOS switch unit 4 form a path, so as to realize the load battery 6. Charging is performed, and because the first capacitor 53 can be charged with a delay, the potential of the b pole in the first transistor 51 is slowly lowered to achieve the purpose of delay, so that the load interface 3 and the load battery 6 are not connected at the moment. It will be turned on, but it will be delayed first, and then turned on, so as to prevent sparks from being generated instantaneously when connecting with the terminals of the load battery 6, so as to have the anti-sparking function, so that the charger is safer to use, so that the utility model has Strong market competitiveness.

A resistor R6 is also connected between the b pole of the second transistor 52 and the switch control terminal 32 , and the c pole of the second transistor 52 and the b pole of the first transistor 51 are also connected. There is resistor R4.

The MOS transistor switch unit 4 includes a first MOS transistor 41 and a second MOS transistor 42 , the G pole of the first MOS transistor 41 is connected to the c pole of the third transistor 73 , and the G pole of the first MOS transistor 41 is connected to the c pole of the third transistor 73 . The pole is also connected to the c pole of the first transistor 51, the G pole of the first MOS transistor 41 is also connected to the resistor R7 and then connected to the G pole of the second MOS transistor 42, and the D pole of the second MOS transistor 42 is connected to the The switch control terminal 32, the S pole of the first MOS transistor 41 is connected to the S pole of the second MOS transistor 42, and the D pole of the second MOS transistor 42 is connected to the power output V- terminal 2. When the c-pole of the first transistor 51 outputs a high level, it will be given to the G-pole of the first MOS transistor 41 and the G-pole of the second MOS transistor 42 to control the first MOS transistor 41 and the second MOS transistor 42 The MOS transistor 42 is turned on at the same time.

The S pole and the G pole of the second MOS tube 42 are also connected with a second capacitor 421 with a charging delay function; the G pole of the first MOS tube 41 and the power output V-terminal 2 are also connected with a voltage regulator. Diode 43. Because there are multiple electrolytic capacitors in the charger and the charger is not connected to the mains power supply, when the load interface 3 is connected to the load battery 6, because the resistor R7 and the second capacitor 421 are connected in series, the load battery 6 charges the second capacitor 421, and the voltage will rise slowly, that is, the second capacitor 421 and the G and S poles of the second MOS transistor 42 are connected in parallel, resulting in a delay in the conduction of the second MOS transistor 42 and a delay in the conduction of the MOS switch unit 4, so that the load battery 6 is connected to the During the contact period of the load interface 3, the load battery 6 will not charge the multiple electrolytic capacitors in the charger instantaneously, so as to have an anti-sparking function, making the charger safer to use, and making the utility model highly competitive in the market .

Both ends of the first capacitor 53 are also connected in parallel with a resistor R3. Both ends of the second capacitor 421 are also connected in parallel with a resistor R12. A resistor R11 , a resistor R5 and a resistor R2 are also connected between the G pole of the first MOS transistor 41 and the c pole of the first transistor 51 . The model of the first transistor 51 is MMBT5401; the model of the second transistor 52 is MMBT5551. The model of the first MOS transistor 41 is NCE1540K; the model of the second MOS transistor 42 is NCE1540K.

To sum up, when the utility model is in use, the power output V+ terminal 1 and the power output V- terminal 2 are respectively connected to the positive and negative poles of the charger output interface to energize, so that the load interface 3 in the present utility model is equivalent to The charger output interface is used to connect the load battery; when the charger is connected to the mains and powered on, the V+ terminal 31 (equivalent to the positive pole) and the switch control terminal 32 (equivalent to the negative pole) of the load interface 3 and the positive and negative poles of the battery load 6 When connected, the anti-reverse connection protection circuit 7 will not work, and the start-up circuit unit 5 will work to control the conduction of the MOS tube switch unit 4, so as to realize the normal charging of the load battery; when the switch control terminal 32 of the load interface 3 (equivalent to When the negative pole) and the V+ terminal 31 (equivalent to the positive pole) are connected to the positive and negative poles of the battery load 6, that is, when the connection is reversed, the positive pole of the battery load 6 is connected by the switch control terminal 32 through the photocoupler 71, the first diode 72, and the divider. The piezoresistor R9 and the V+ terminal 31 are connected to the negative electrode of the battery load 6 to form a loop. Because the photocoupler 71 is turned on, the positive voltage of the charger is supplied to the third transistor 73 through the voltage divider large resistor 712 and the photocoupler 71. To bias, the third transistor 73 is turned on, short-circuits the control voltage of the MOS tube switch unit 4, and the MOS tube switch unit 4 is turned off, so as to prevent reverse connection without burning the circuit and the charger circuit board, and to ensure the product The service life makes the charger safer to use, and the utility model has strong market competitiveness. In addition, the utility model is applied to a small PCB board, which is designed independently from the charger, that is, a small PCB board is additionally added to the charger, so that the charger has the function of preventing fire, so as to assist the charging work of the charger, and is suitable for various charger.

Of course, the above are only specific embodiments of the present invention, and are not intended to limit the scope of implementation of the present invention. Any equivalent changes or modifications made in accordance with the structures, features and principles described in the scope of the patent application of the present invention are not intended to limit the scope of the present invention. It should be included in the scope of the patent application of this utility model.

Claims (5)

1. The utility model provides a charger auxiliary circuit that charges with prevent reverse connection function which characterized in that: the charger comprises a power output V + end (1) connected with the positive pole and the negative pole of a charger output interface, a power output V-end (2), a load interface (3) connected between the power output V + end (1) and the power output V-end (2), a MOS tube switch unit (4) and a starting circuit unit (5), wherein the load interface (3) is provided with a V + end (31) and a switch control end (32) which are respectively used for being connected with the positive pole and the negative pole of a battery load (6), the V + end (31) is connected with the power output V + end (1), the switch control end (32) is connected with the MOS tube switch unit (4), an anti-reverse connection protection circuit (7) is connected between the V + end (31) and the switch control end (32), the anti-reverse connection protection circuit (7) comprises a photoelectric coupler (71), the first pin of the photoelectric coupler (71) is connected with the switch control end (32), the second pin of the photoelectric coupler (71) is connected with the anode of a first diode (72), the cathode of the first diode (72) is connected with the V + end (31), a delay capacitor (711) is connected between the third pin and the fourth pin of the photoelectric coupler (71), the fourth pin of the photoelectric coupler (71) is also connected with a voltage division large resistor (712) and then connected with a power output V + end (1), the third pin of the photoelectric coupler (71) is connected with the b pole of a third triode (73), the e pole of the third triode (73) is connected with a power output V-end (2), and the c pole of the third triode (73) is connected with the MOS tube switch unit (4) and the starting circuit unit (5).

2. The charging auxiliary circuit of the charger with the anti-reverse-connection function according to claim 1, wherein the model of the photoelectric coupler (71) is L TV-357T-C, and the model of the third triode (73) is SS 8050.

3. The charging auxiliary circuit of the charger with the reverse-connection preventing function according to claim 1, wherein: a voltage dividing resistor R9 is also connected between the cathode of the first diode (72) and the V + end (31), and the resistance value of the resistor R9 is 5.6k omega.

4. A charger charging auxiliary circuit with an anti-reverse function according to any one of claims 1 to 3, characterized in that: the MOS tube switch unit (4) comprises a first MOS tube (41) and a second MOS tube (42), the G pole of the first MOS tube (41) is connected with the c pole of the third triode (73), the G pole of the first MOS tube (41) is also connected with the G pole of the second MOS tube (42) after being connected with a resistor R7, the D pole of the second MOS tube (42) is connected with the switch control end (32), the S pole of the first MOS tube (41) is connected with the S pole of the second MOS tube (42), and the D pole of the second MOS tube (42) is connected with the power output V-end (2).

5. The charging auxiliary circuit of the charger with the reverse-connection preventing function according to claim 4, wherein: the S pole and the G pole of the second MOS tube (42) are also connected with a second capacitor (421) with a charging time delay function; the G pole of the first MOS tube (41) and the power output V-end (2) are also connected with a voltage stabilizing diode (43).

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