CN219892959U - Reverse connection protection circuit and reverse connection protection device - Google Patents

Abstract

The utility model is applicable to the technical field of reverse connection protection, and provides a reverse connection protection circuit and a reverse connection protection device. The reverse connection protection circuit comprises a comparison unit, a sampling unit and a first switch unit, wherein the first switch unit, the sampling unit and the battery are connected in series, two input ends of the comparison unit are correspondingly and electrically connected with two ends of the sampling unit, and an output end of the comparison unit is electrically connected with a control end of the first switch unit. When the battery charger is reversely connected with the battery, the sampling unit outputs a first voltage signal and a second voltage signal to the comparing unit, the comparing unit outputs a first comparison signal to the first switch unit according to the first voltage signal and the second voltage signal, and the first switch unit is used for being disconnected according to the first comparison signal. The reverse connection protection circuit provided by the embodiment of the utility model can disconnect the first switch unit when the charger and the battery are reversely connected, thereby avoiding the reverse charging of the battery by the charger, reducing the damage probability of the battery and prolonging the service life of the battery.

Description

Reverse connection protection circuit and reverse connection protection device

Technical Field

The utility model belongs to the technical field of reverse connection protection, and particularly relates to a reverse connection protection circuit and a reverse connection protection device.

Background

Lithium batteries are rapidly entering people's lives due to their advantages of high energy density, long service life, less pollution, and the like. For example, mobile phones, notebook computers, digital cameras, electric vehicles, and the like are powered by lithium batteries. Since the lithium battery cannot be reversely charged, the battery is swelled, and fire explosion occurs in severe cases. However, in the practical application process, the phenomenon that the charger is reversely connected with the battery can occur, so that the service life of the battery is shortened, and even the battery is scrapped.

Disclosure of Invention

The embodiment of the utility model provides a reverse connection protection circuit and a reverse connection protection device, which can solve the problems of shortening of the service life of a battery and even scrapping of the battery when a charger and the battery are reversely connected.

In a first aspect, an embodiment of the present utility model provides a reverse connection protection circuit, including a comparing unit, a sampling unit, and a first switch unit, where the first switch unit, the sampling unit, and a battery are connected in series, two input ends of the comparing unit are correspondingly electrically connected with two ends of the sampling unit, and an output end of the comparing unit is electrically connected with a control end of the first switch unit;

when the battery charger is reversely connected with the battery, the sampling unit outputs a first voltage signal and a second voltage signal to the comparing unit, the comparing unit outputs a first comparing signal to the first switching unit according to the first voltage signal and the second voltage signal, and the first switching unit is used for being disconnected according to the first comparing signal.

In a possible implementation manner of the first aspect, the first switching unit includes a first switching tube, a source electrode of the first switching tube is electrically connected to a negative electrode of the battery, a drain electrode of the first switching tube is electrically connected to the first end of the sampling unit, and a gate electrode of the first switching tube is electrically connected to the output end of the comparing unit.

In a possible implementation manner of the first aspect, the comparing unit includes a comparator, a forward input terminal of the comparator is electrically connected to the first terminal of the sampling unit, a reverse input terminal of the comparator is electrically connected to the second terminal of the sampling unit, and an output terminal of the comparator is electrically connected to the control terminal of the first switching unit.

In a possible implementation manner of the first aspect, the sampling unit includes a first resistor; the first end of the first resistor is electrically connected with the first input end of the comparison unit and the first switch unit respectively, and the second end of the first resistor is electrically connected with the second input end of the comparison unit.

In a possible implementation manner of the first aspect, the reverse connection protection circuit further includes a charge-discharge switch unit, and the charge-discharge switch unit is connected in series with the first switch unit.

In a possible implementation manner of the first aspect, the reverse connection protection circuit further includes a second switch unit, a reference voltage unit, and a logic unit, where a control end of the second switch unit is electrically connected to a negative electrode of the battery, a first end of the second switch unit is electrically connected to a negative electrode charging terminal of the battery, a second end of the second switch unit is electrically connected to a control end of the reference voltage unit, an output end of the reference voltage unit is electrically connected to a first input end of the logic unit, a second input end of the logic unit is electrically connected to an output end of the comparison unit, and an output end of the logic unit is electrically connected to a control end of the first switch unit.

In a possible implementation manner of the first aspect, the second switching unit includes a first triode, a base electrode of the first triode is electrically connected with a negative electrode of the battery, an emitter electrode of the first triode is electrically connected with a negative electrode charging terminal of the battery, and a collector electrode of the first triode is electrically connected with a control end of the reference voltage unit.

In a possible implementation manner of the first aspect, the reference voltage unit includes a reference voltage power supply and a second switching tube, a source electrode of the second switching tube is electrically connected to the reference voltage power supply, a drain electrode of the second switching tube is electrically connected to the first input terminal of the logic unit, and a gate electrode of the second switching tube is electrically connected to the second terminal of the second switching unit.

In a possible implementation manner of the first aspect, the logic unit includes an or gate, a first input terminal of the or gate is electrically connected to the output terminal of the reference voltage unit, a second input terminal of the or gate is electrically connected to the output terminal of the comparison unit, and an output terminal of the or gate is electrically connected to the control terminal of the first switch unit.

In a second aspect, an embodiment of the present utility model provides a reverse connection protection device, including a reverse connection protection circuit according to any one of the first aspects.

Compared with the prior art, the embodiment of the utility model has the beneficial effects that:

the reverse connection protection circuit provided by the embodiment of the utility model comprises a comparison unit, a sampling unit and a first switch unit. The sampling unit is used for collecting the first voltage signal and the second voltage signal and outputting the first voltage signal and the second voltage signal to the comparison unit. The two input ends of the comparison unit are correspondingly and electrically connected with the two ends of the sampling unit and are used for receiving the first voltage signal and the second voltage signal output by the sampling unit. The output end of the comparison unit is electrically connected with the control end of the first switch unit, and is further used for outputting a comparison signal (a first comparison signal or a second comparison signal) to the first switch unit according to the first voltage signal and the second voltage signal, and the first switch unit is used for being disconnected or connected according to the comparison signal (the first comparison signal or the second comparison signal). When the battery charger is correctly connected with the battery, the comparison unit is used for outputting a second comparison signal to the first switch unit according to the first voltage signal and the second voltage signal output by the sampling unit, and the first switch unit is used for being conducted according to the second comparison signal so as to charge the battery by the battery charger. When the battery is reversely connected with the charger, the comparison unit is used for outputting a first comparison signal to the first switch unit according to the first voltage signal and the second voltage signal output by the sampling unit, and the first switch unit is used for being disconnected according to the first comparison signal to prevent the charger from reversely charging the battery. The reverse connection protection circuit provided by the embodiment of the utility model can disconnect the first switch unit when the charger and the battery are reversely connected, thereby avoiding the reverse charging of the battery by the charger, reducing the damage probability of the battery and prolonging the service life of the battery.

Drawings

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

FIG. 1 is a schematic block diagram of a reverse connection protection circuit according to an embodiment of the present utility model;

FIG. 2 is a schematic diagram of a circuit connection of a reverse connection protection circuit according to an embodiment of the present utility model;

FIG. 3 is a schematic block diagram of a reverse connection protection circuit according to another embodiment of the present utility model;

fig. 4 is a schematic circuit connection diagram of a reverse connection protection circuit according to another embodiment of the present utility model.

In the figure: 01. a reverse connection protection circuit; 10. a comparison unit; 20. a sampling unit; 30. a first switching unit; 40. a charge/discharge switch unit; 50. a second switching unit; 60. a reference voltage unit; 70. a logic unit; 80. a controller; 02. a battery; 03. and (5) a charger.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth such as the particular system architecture, techniques, etc., in order to provide a thorough understanding of the embodiments of the present utility model. It will be apparent, however, to one skilled in the art that the present utility model may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present utility model with unnecessary detail.

It should be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It should also be understood that the term "and/or" as used in the present specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.

As used in the present description and the appended claims, the term "if" may be interpreted in context as "when …" or "upon" or "in response to a determination" or "in response to detection. Similarly, the phrase "if a determination" or "if a [ described condition or event ] is detected" may be interpreted in the context of meaning "upon determination" or "in response to determination" or "upon detection of a [ described condition or event ]" or "in response to detection of a [ described condition or event ]".

Furthermore, the terms "first," "second," "third," and the like in the description of the present specification and in the appended claims, are used for distinguishing between descriptions and not necessarily for indicating or implying a relative importance.

Reference in the specification to "one embodiment" or "some embodiments" or the like means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the utility model. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," and the like in the specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless expressly specified otherwise.

Because the material characteristics of the lithium battery can not be overcharged, overdischarged or shorted, if a lithium battery protection board is not installed, when a charger is reversely connected with the battery, the service life of the battery can be reduced, and even the battery is scrapped.

Based on the above problems, the reverse connection protection circuit provided by the embodiment of the utility model comprises a comparison unit, a sampling unit and a first switch unit. The sampling unit is used for collecting the first voltage signal and the second voltage signal and outputting the first voltage signal and the second voltage signal to the comparison unit. The two input ends of the comparison unit are correspondingly and electrically connected with the two ends of the sampling unit and are used for receiving the first voltage signal and the second voltage signal output by the sampling unit. The output end of the comparison unit is electrically connected with the control end of the first switch unit, and is further used for outputting a comparison signal (a first comparison signal or a second comparison signal) to the first switch unit according to the first voltage signal and the second voltage signal, and the first switch unit is used for being disconnected or connected according to the comparison signal (the first comparison signal or the second comparison signal). When the battery charger is correctly connected with the battery, the comparison unit is used for outputting a second comparison signal to the first switch unit according to the first voltage signal and the second voltage signal output by the sampling unit, and the first switch unit is used for being conducted according to the second comparison signal so as to charge the battery by the battery charger. When the battery is reversely connected with the charger, the comparison unit is used for outputting a first comparison signal to the first switch unit according to the first voltage signal and the second voltage signal output by the sampling unit, and the first switch unit is used for being disconnected according to the first comparison signal to prevent the charger from reversely charging the battery. The reverse connection protection circuit provided by the embodiment of the utility model can disconnect the first switch unit when the charger and the battery are reversely connected, thereby avoiding the reverse charging of the battery by the charger, reducing the damage probability of the battery and prolonging the service life of the battery.

In order to illustrate the technical scheme of the utility model, the following description is made by specific examples.

Fig. 1 shows a schematic block diagram of a reverse connection protection circuit 01 according to an embodiment of the present utility model. Referring to fig. 1, the reverse connection protection circuit 01 includes a comparing unit 10, a sampling unit 20 and a first switching unit 30, the sampling unit 20 and the battery 02 are connected in series, two input ends of the comparing unit 10 are correspondingly and electrically connected with two ends of the sampling unit 20, and an output end of the comparing unit 10 is electrically connected with a control end of the first switching unit 30.

Specifically, the sampling unit 20 is configured to collect the first voltage signal and the second voltage signal, and output the first voltage signal and the second voltage signal to the comparing unit 10. The two input ends of the comparing unit 10 are correspondingly and electrically connected with the two ends of the sampling unit 20, and are used for receiving the first voltage signal and the second voltage signal output by the sampling unit 20. The output terminal of the comparing unit 10 is electrically connected to the control terminal of the first switching unit 30, and is further configured to output a comparison signal (a first comparison signal or a second comparison signal) to the first switching unit 30 according to the first voltage signal and the second voltage signal, and the first switching unit 30 is configured to be turned off or turned on according to the comparison signal (the first comparison signal or the second comparison signal). When the charger 03 is correctly connected with the battery 02, the comparing unit 10 is configured to output a second comparing signal to the first switching unit 30 according to the first voltage signal and the second voltage signal output by the sampling unit 20, and the first switching unit 30 is configured to be turned on according to the second comparing signal, so as to charge the battery 02 by the charger 03. When the battery 03 is reversely connected to the battery 02, the comparing unit 10 is configured to output a first comparison signal to the first switching unit 30 according to the first voltage signal and the second voltage signal output by the sampling unit 20, and the first switching unit 30 is configured to disconnect according to the first comparison signal, so as to prevent the battery 02 from being reversely charged by the battery 03. The reverse connection protection circuit 01 provided by the embodiment of the utility model can disconnect the first switch unit 30 when the charger 03 and the battery 02 are reversely connected, so that the battery 02 is prevented from being reversely charged by the charger 03, the damage probability of the battery 02 is reduced, and the service life of the battery 02 is prolonged.

The first comparison signal and the second comparison signal are level signals (low level signal and high level signal). When the battery charger 03 is correctly connected with the battery 02, the comparing unit 10 is configured to output a high-level signal to the first switching unit 30 according to the first voltage signal and the second voltage signal output by the sampling unit 20, and the first switching unit 30 is configured to be turned on according to the high-level signal to realize that the battery charger 03 charges the battery 02. When the charger 03 is reversely connected with the battery 02, the comparing unit 10 is configured to output a low-level signal to the first switching unit 30 according to the first voltage signal and the second voltage signal output by the sampling unit 20, and the first switching unit 30 is configured to disconnect according to the low-level signal, so as to prevent the charger 03 from reversely charging the battery 02, reduce the damage probability of the battery 02, and improve the service life of the battery 02.

For example, if the comparing unit 10 receives the voltage difference between the first voltage signal and the second voltage signal output by the sampling unit 20, the first voltage value is greater than the second voltage value. At this time, it is determined that the charger 03 is correctly connected to the battery 02, and the comparing unit 10 outputs a high-level signal to the first switching unit 30, and the first switching unit 30 is configured to be turned on according to the high-level signal to charge the battery 02 by the charger 03. If the comparing unit 10 receives the first voltage signal and the second voltage signal output by the sampling unit 20, there is no voltage difference between the first voltage signal and the second voltage signal, or the first voltage value is smaller than the second voltage value. At this time, it is determined that the battery 02 is reversely connected to the charger 03, the comparing unit 10 outputs a low-level signal to the first switching unit 30, and the first switching unit 30 is configured to disconnect according to the low-level signal, so as to prevent the battery 02 from being reversely charged by the charger 03, reduce the damage probability of the battery 02, and improve the service life of the battery 02.

Fig. 2 shows a schematic circuit connection diagram of a reverse connection protection circuit 01 according to an embodiment of the utility model. Referring to fig. 2, the first switching unit 30 includes a first switching tube Q1, a source electrode of the first switching tube Q1 is electrically connected to a negative electrode of the battery 02, a drain electrode of the first switching tube Q1 is electrically connected to a first end of the sampling unit 20, and a gate electrode of the first switching tube Q1 is electrically connected to an output end of the comparing unit 10.

Specifically, the first switching tube Q1 is connected in series between the negative electrode of the battery 02 and the sampling unit 20 as a switching device. The source of the first switching transistor Q1 is electrically connected to the negative electrode of the battery 02, and the gate of the first switching transistor Q1 is electrically connected to the output terminal of the comparison unit 10. When the comparing unit 10 outputs a high level signal to the gate of the first switching tube Q1, the voltage difference between the gate and the source of the first switching tube Q1 is greater than or equal to the on voltage of the first switching tube Q1, and at this time, the first switching tube Q1 is in an on state, increasing the overcurrent capability of the first switching tube Q1. Meanwhile, when the first switching tube Q1 is in a conducting state, a closed loop is formed among the battery 02, the first switching tube Q1, the sampling unit 20 and the charger 03, so that the charger 03 can charge the battery 02. When the comparing unit 10 outputs a low-level signal to the gate of the first switching tube Q1, the voltage difference between the gate and the source of the first switching tube Q1 is smaller than the on voltage of the first switching tube Q1, and at this time, the first switching tube Q1 is in an off state, and a closed loop cannot be formed among the battery 02, the first switching tube Q1, the sampling unit 20 and the charger 03, so that the charger 03 is prevented from reversely charging the battery 02, and the service life of the battery 02 is prolonged.

It should be noted that, when the battery 02 is connected to the charger 03, the parasitic diode in the first switching tube Q1 may flow a small current, so that a small voltage difference exists between two ends of the sampling unit 20, and the comparing unit 10 may output a high-level signal to the gate of the first switching tube Q1, so that the first switching tube Q1 is in a conducting state, thereby improving the overcurrent capability of the first switching tube Q1, and realizing the charging of the battery 02 by the charger 03.

For example, a designer may choose the model of the first switching tube Q1 according to the actual situation of the circuit. For example, an NMOS type switching transistor may be selected as the first switching transistor Q1.

In one embodiment of the present utility model, as shown in fig. 2, the comparing unit 10 includes a comparator U1, wherein a positive input terminal of the comparator U1 is electrically connected to a first terminal of the sampling unit 20, a negative input terminal of the comparator U1 is electrically connected to a second terminal of the sampling unit 20, and an output terminal of the comparator U1 is electrically connected to a gate of the first switching tube Q1.

Specifically, the positive input end of the comparator U1 is configured to detect a first voltage signal at the first end of the sampling unit 20, the negative input end of the comparator U1 is configured to detect a second voltage signal at the second end of the sampling unit 20, and the output end of the comparator U1 is electrically connected to the gate of the first switching tube Q1 and is configured to control on and off of the first switching tube Q1. If the comparator U1 receives a voltage difference between the first voltage signal and the second voltage signal, the first voltage value is greater than the second voltage value. At this time, it is determined that the battery 03 is correctly connected to the battery 02, and the comparator U1 outputs a high-level signal to the gate of the first switching tube Q1, and the first switching tube Q1 is in a conductive state, so as to charge the battery 02 by the battery 03. If the comparator U1 receives no voltage difference between the first voltage signal and the second voltage signal, or the first voltage value is smaller than the second voltage value. At this time, it is determined that the battery 03 is reversely connected to the battery 02, and the comparator U1 outputs a low-level signal to the gate of the first switching tube Q1, and the first switching tube Q1 is in an off state, thereby preventing the battery 02 from being reversely charged by the battery 03.

For example, if the difference between the voltage at the first end and the voltage at the second end of the sampling unit 20 is 10V, the first voltage value is greater than the second voltage value. At this time, the comparator U1 outputs a high-level signal to the gate of the first switching transistor Q1, the first switching transistor Q1 is in an on state, and the battery 02 is in a charged state. If the difference between the voltage at the first end and the voltage at the second end of the sampling unit 20 is 0V, the comparator U1 outputs a low-level signal to the gate of the first switching tube Q1, and the first switching tube Q1 is in an off state, so as to prevent the battery 02 from being reversely charged by the charger 03.

In one embodiment of the present utility model, as shown in fig. 2, the sampling unit 20 includes a first resistor R1, a first end of the first resistor R1 is electrically connected to a positive input end of the comparator U1 and a drain electrode of the first switching tube Q1, and a second end of the first resistor R1 is electrically connected to a negative input end of the comparator U1.

Specifically, the first resistor R1 is used as a high-power sampling resistor, is a customized precise resistor with high precision, high power and small temperature drift coefficient, and can sample the current and the voltage flowing through the first resistor R1. When a voltage difference exists between the first end of the first resistor R1 and the second end of the first resistor R1 and the voltage of the first end is larger than that of the second end, the comparator U1 outputs a high-level signal to the grid electrode of the first switching tube Q1, otherwise, a low-level signal is output.

When a small current flows through the high-power sampling resistor, a voltage difference exists between the first end and the second end of the first resistor R1, and the comparator U1 can output a corresponding level signal.

For example, a designer may select the precision, the resistance value range and the temperature drift coefficient of the first resistor R1 according to practical situations, for example, select a high-power sampling resistor with the precision of 0.5%, the resistance value range of 4mohm to 5000mohm and the temperature drift coefficient of less than 100ppm/K under the low resistance of 4mohm to 10mohm as the first resistor R1.

In one embodiment of the present utility model, as shown in fig. 2, the reverse connection protection circuit 01 further includes a charge/discharge switch unit 40, and the charge/discharge switch unit 40 is connected in series with the first switch unit 30.

Specifically, the charge/discharge switch unit 40 is configured to provide a closed circuit when the charger 03 is properly connected to the battery 02. Meanwhile, the charge/discharge switch unit 40 is further used for controlling the charge/discharge switch unit 40 to be in an off state when the battery 02 is protected from voltage, current or temperature, so as to protect the battery 02, avoid the phenomena of overcharging, overcurrent, etc. of the battery 02, and improve the service life of the battery 02.

The charge/discharge switch unit 40 is always in an on state when no voltage, current, temperature protection, or the like occurs in the battery 02, and provides a circuit for charging the battery 02.

In one embodiment of the present utility model, the charge-discharge switching unit 40 includes a third switching tube Q3 and a fourth switching tube Q4, wherein the gate of the third switching tube Q3 and the gate of the fourth switching tube Q4 are electrically connected to the controller 80, the source of the third switching tube Q3 is electrically connected to the negative electrode of the battery 02, the drain of the third switching tube Q3 is electrically connected to the source of the first switching tube Q1, the drain of the fourth switching tube Q4 is electrically connected to the drain of the first switching tube Q1, and the source of the fourth switching tube Q4 is electrically connected to the first end of the first resistor R1.

Specifically, the third switching tube Q3 and the fourth switching tube Q4 are used to provide a closed loop when the charger 03 is properly connected to the battery 02. Meanwhile, the third switching tube Q3 and the fourth switching tube Q4 are further used for controlling the third switching tube Q3 and the fourth switching tube Q4 to be in an off state when the battery 02 is subjected to voltage, current or temperature protection and the like, so that the battery 02 is protected, phenomena of overcharging, overcurrent and the like of the battery 02 are avoided, and the service life of the battery 02 is prolonged.

When the voltage, current, temperature protection, or the like of the battery 02 does not occur in the third switching tube Q3 and the fourth switching tube Q4, the controller 80 controls the third switching tube Q3 and the fourth switching tube Q4 to be always in the on state, thereby providing a circuit for charging the battery 02.

For example, the designer may choose the types of the third switching tube Q3 and the fourth switching tube Q4 according to the actual situation of the circuit. For example, NMOS switching transistors may be selected as the third switching transistor Q3 and the fourth switching transistor Q4.

Fig. 3 shows a schematic block diagram of a reverse connection protection circuit 01 according to another embodiment of the present utility model. Referring to fig. 3, the reverse connection protection circuit 01 further includes a second switching unit 50, a reference voltage unit 60, and a logic unit 70, wherein a control terminal of the second switching unit 50 is electrically connected to a negative electrode of the battery 02, a first terminal of the second switching unit 50 is electrically connected to a negative electrode charging terminal of the battery 02, a second terminal of the second switching unit 50 is electrically connected to a control terminal of the reference voltage unit 60, an output terminal of the reference voltage unit 60 is electrically connected to a first input terminal of the logic unit 70, a second input terminal of the logic unit 70 is electrically connected to an output terminal of the comparison unit 10, and an output terminal of the logic unit 70 is electrically connected to a control terminal of the first switching unit 30.

Specifically, the control terminal of the second switching unit 50 is electrically connected to the negative electrode of the battery 02, and when the charger 03 is correctly connected to the battery 02, current flows from the positive electrode of the charger 03, flows through the positive electrode and the negative electrode of the battery 02, and flows into the second switching unit 50. At this time, the second switching unit 50 is in an on state, and outputs the first switching signal to the reference voltage unit 60. The reference voltage unit 60 is turned on according to the first switching signal, and outputs the first reference voltage signal to the first input terminal of the logic unit 70. The logic unit 70 is configured to output a first logic signal to the control terminal of the first switch unit 30 according to the first reference voltage signal. The first switch unit 30 is conducted according to the first logic signal, and the charger 03, the battery 02, the first switch unit 30 and the sampling unit 20 form a closed loop, so that the charger 03 can charge the battery 02. When the charger 03 is connected to the battery 02 in reverse, current cannot flow through the positive and negative electrodes of the battery 02. Since the control terminal of the second switching unit 50 is electrically connected to the negative electrode of the battery 02, the second switching unit 50 is in an off state and outputs a second switching signal to the reference voltage unit 60. The reference voltage unit 60 is turned off according to the second switching signal and outputs the second reference voltage signal to the first input terminal of the logic unit 70. The logic unit 70 is configured to output a second logic signal to the control terminal of the first switch unit 30 according to the second reference voltage signal. The first switch unit 30 is disconnected according to the second logic signal, so that the battery 02 is prevented from being reversely charged by the charger 03, the damage probability of the battery 02 is reduced, and the service life of the battery 02 is prolonged.

When the battery 03 is connected to the battery 02, the second switching unit 50 is in the on state instantaneously. At this time, since the comparison unit 10 outputs the comparison signal according to the voltages of both ends of the sampling unit 20, the comparison unit 10 may have a problem in that the comparison signal is inaccurate because a voltage difference does not yet occur between both ends of the sampling unit 20. The reverse connection protection circuit 01 provided by the utility model can solve the problem that the first switch unit 30 is in a conducting state at the moment when the charger 03 is connected with the battery 02, so that the battery 02 is charged by the charger 03.

Fig. 4 shows a schematic circuit connection diagram of a reverse connection protection circuit 01 according to another embodiment of the present utility model. Referring to fig. 4, the second switching unit 50 includes a first transistor VT1, a base electrode of the first transistor VT1 is electrically connected to a negative electrode of the battery 02, an emitter electrode of the first transistor VT1 is electrically connected to a negative electrode charging terminal of the battery 02, and a collector electrode of the first transistor VT1 is electrically connected to a control terminal of the reference voltage unit 60.

Specifically, the base of the first triode VT1 is electrically connected to the negative electrode of the battery 02, and the emitter of the first triode VT1 is electrically connected to the negative electrode charging terminal of the battery 02. When the charger 03 is correctly connected with the battery 02, the voltage difference between the base electrode of the first triode VT1 and the emitter electrode of the first triode VT1 is greater than or equal to the on voltage of the first triode VT1. At this time, the first transistor VT1 is turned on and outputs a first switching signal to the reference voltage unit 60. The reference voltage unit 60 is turned on according to the first switching signal, and outputs the first reference voltage signal to the first input terminal of the logic unit 70. The logic unit 70 is configured to output a first logic signal to the control terminal of the first switch unit 30 according to the first reference voltage signal. The first switch unit 30 is conducted according to the first logic signal, and the charger 03, the battery 02, the first switch unit 30 and the sampling unit 20 form a closed loop, so that the charger 03 can charge the battery 02. When the charger 03 is connected to the battery 02 in reverse, current cannot flow through the positive and negative electrodes of the battery 02. The voltage difference between the base of the first transistor VT1 and the emitter of the first transistor VT1 is smaller than the turn-on voltage of the first transistor VT1. The first triode VT1 is in a cut-off state, and the reference voltage unit 60 is in a cut-off state, so that the first switch unit 30 is in the cut-off state, the battery 02 is prevented from being reversely charged by the charger 03, the damage probability of the battery 02 is reduced, and the service life of the battery 02 is prolonged.

For example, a designer may choose the model of the first triode VT1 according to the actual condition of the circuit. For example, an NPN transistor may be selected as the first transistor VT1.

In one embodiment of the present utility model, as shown in fig. 4, the reference voltage unit 60 includes a reference voltage power supply VCC and a second switching tube Q2, wherein a source of the second switching tube Q2 is electrically connected to the reference voltage power supply VCC, a drain of the second switching tube Q2 is electrically connected to a first input terminal of the logic unit 70, and a gate of the second switching tube Q2 is electrically connected to a collector of the first triode VT1.

Specifically, the reference voltage power supply VCC supplies a voltage to the second switching tube Q2, and when the second switching tube Q2 is in a conducting state, the source and the drain of the second switching tube Q2 are conducted. At this time, the reference voltage power supply VCC and the logic unit 70 are turned on, and the first input terminal of the logic unit 70 receives the voltage signal output from the reference voltage power supply VCC. The logic unit 70 outputs a high-level signal to the first switch unit 30 according to the voltage signal output by the reference voltage power supply VCC, and controls the first switch unit 30 to be turned on, so as to charge the battery 02 by the charger 03. When the charger 03 is reversely connected with the battery 02, the second switching tube Q2 is in an off state, and the source electrode and the drain electrode of the second switching tube Q2 are disconnected. At this time, the reference voltage power VCC and the logic unit 70 are disconnected, the logic unit 70 cannot output a high level signal to the first switching unit 30, and the first switching unit 30 is disconnected, so that the battery 02 cannot be reversely charged by the charger 03, and the life of the battery 02 is prolonged.

For example, the designer may choose the model of the second switching tube Q2 according to the actual situation of the circuit. For example, a PMOS type switching transistor may be selected as the second switching transistor Q2.

In one embodiment of the present utility model, as shown in fig. 4, the logic unit 70 includes an or gate U2, a first input terminal of the or gate U2 is electrically connected to a drain electrode of the second switching transistor Q2, a second input terminal of the or gate U2 is electrically connected to an output terminal of the comparing unit 10, and an output terminal of the or gate U2 is electrically connected to a control terminal of the first switching unit 30.

Specifically, the or gate U2 includes a first input terminal, a second input terminal, and an output terminal. The voltage signal input by one of the first input end and the second input end of the or gate U2 is a high level signal, and the output end of the or gate U2 outputs the high level signal. If the voltage signal input by the first input terminal of the or gate U2 is a high level signal, the voltage signal input by the second input terminal of the or gate U2 is a low level signal, and the output terminal of the or gate U2 outputs a high level signal. If the voltage signal input by the first input terminal of the or gate U2 is a high level signal, the voltage signal input by the second input terminal of the or gate U2 is a high level signal, and the output terminal of the or gate U2 outputs the high level signal. If the voltage signal input by the first input terminal of the or gate U2 is a low level signal, the voltage signal input by the second input terminal of the or gate U2 is a high level signal, and the output terminal of the or gate U2 outputs the high level signal. Only when the voltage signal input from the first input terminal of the or gate U2 is a low level signal, and the voltage signal input from the second input terminal of the or gate U2 is also a low level signal, the output terminal of the or gate U2 outputs a low level signal.

When the charger 03 is properly connected to the battery 02, the second switching tube Q2 is in an on state. At this time, the signal input at the first input terminal of the or gate U2 is a high level signal, and the signal input at the second output terminal of the or gate U2 may be a low level signal or a high level signal. The output end of the or gate U2 outputs a high-level signal to the control end of the first switch unit 30, and the first switch unit 30 is in a conducting state, so that the battery 02 is charged by the charger 03. When the charger 03 is reversely connected with the battery 02, the second switching tube Q2 is in an off state. At this time, the signal input at the first input terminal of the or gate U2 is a low level signal. Since the battery 02 is reversely connected with the charger 03, the voltage at the first end of the sampling unit 20 is smaller than the voltage at the second end, so that the signal input by the second input end of the or gate U2 is also a low-level signal, the output end of the or gate U2 outputs the low-level signal to the control end of the first switch unit 30, and the first switch unit 30 is in an off state, so that the battery 02 is prevented from being reversely charged by the charger 03, the damage probability of the battery 02 is reduced, and the service life of the battery 02 is prolonged.

It should be noted that, when the battery 03 and the battery 02 are connected, there is no voltage difference between the two ends of the sampling unit 20, or the voltage difference is very small, which may cause the comparing unit 10 to make a misjudgment, so that the comparing unit 10 outputs a low level to the first switching unit 30.

The reverse connection protection circuit 01 provided by the embodiment of the utility model has a current flow protection function, and can enable the comparison unit 10 to output a correct comparison signal to the first switch unit 30 when a very small current (MA level) exists. Excessive electric energy cannot be consumed, and the energy-saving environment-friendly concept is met. When the battery charger 03 is correctly connected to the battery 02, the comparison unit 10 outputs a high-level signal to the first switching unit 30, and the first switching unit 30 is turned on to charge the battery 02 by the battery charger 03. When the battery 03 is reversely connected to the battery 02, the comparing unit 10 outputs a low-level signal to the first switching unit 30, and the first switching unit 30 is turned off to prevent the battery 02 from being reversely charged by the battery 03.

The reverse connection protection circuit 01 provided by the embodiment of the utility model also has a voltage comparison function, and when the charger 03 is connected, the voltage of the negative terminal of the charger 03 is smaller than the voltage of the negative terminal of the battery 02, so that the positive and negative connection of the charger 03 and the battery 02 can be accurately judged, and the reliability is high. Meanwhile, when the battery 02 is fully charged, that is, when the voltage of the negative terminal of the charger 03 is equal to the voltage of the negative terminal of the battery 02, the current flow direction protection control can be changed. The two reverse connection protection circuits can mutually compensate the defects, and the reliability of the reverse connection protection circuit 01 is improved.

The utility model also discloses a reverse connection protection device which comprises the reverse connection protection circuit 01, and the reverse connection protection device adopts the reverse connection protection circuit 01, so that the reverse charging of the battery 02 by the charger 03 can be avoided, the damage probability of the battery 02 is reduced, and the service life of the battery 02 is prolonged.

The reverse connection protection device is usually used in connection with the battery 02 to form a power supply device. The existing reverse connection protection device adopts an external diode, and utilizes the unidirectional conductive characteristic of the diode to block the power supply loop of the power supply, thereby realizing the effect of reverse connection protection. However, when the diode is used for reverse connection protection, the diode needs to bear very large current at the moment of connecting the charging equipment, and the diode may be short-circuited or even damaged, so that the diode is extremely dangerous and has poor practicability. The reverse connection protection circuit 01 and the reverse connection protection device provided by the embodiment of the utility model can prevent the battery 02 from being reversely charged by the charger 03, reduce the damage probability of the battery 02 and prolong the service life of the battery 02.

Since the processing and functions implemented by the reverse connection protection device in this embodiment basically correspond to the embodiments, principles and examples of the reverse connection protection circuit 01, the description of this embodiment is not exhaustive, and reference may be made to the related descriptions in the foregoing embodiments, which are not repeated herein.

The above embodiments are only for illustrating the technical solution of the present utility model, and not for limiting the same; although the utility model has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present utility model, and are intended to be included in the scope of the present utility model.

Claims (10)

1. The reverse connection protection circuit is characterized by comprising a comparison unit, a sampling unit and a first switch unit, wherein the first switch unit, the sampling unit and a battery are connected in series, two input ends of the comparison unit are correspondingly and electrically connected with two ends of the sampling unit, and an output end of the comparison unit is electrically connected with a control end of the first switch unit;

when the battery charger is reversely connected with the battery, the sampling unit outputs a first voltage signal and a second voltage signal to the comparing unit, the comparing unit outputs a first comparing signal to the first switching unit according to the first voltage signal and the second voltage signal, and the first switching unit is used for being disconnected according to the first comparing signal.

2. The reverse connection protection circuit according to claim 1, wherein the first switching unit comprises a first switching tube, a source electrode of the first switching tube is electrically connected with a negative electrode of the battery, a drain electrode of the first switching tube is electrically connected with a first end of the sampling unit, and a gate electrode of the first switching tube is electrically connected with an output end of the comparing unit.

3. The reverse connection protection circuit according to claim 1, wherein the comparing unit comprises a comparator, a forward input terminal of the comparator is electrically connected to the first terminal of the sampling unit, a reverse input terminal of the comparator is electrically connected to the second terminal of the sampling unit, and an output terminal of the comparator is electrically connected to the control terminal of the first switching unit.

4. The reverse connection protection circuit of claim 1, wherein the sampling unit comprises a first resistor; the first end of the first resistor is electrically connected with the first input end of the comparison unit and the first switch unit respectively, and the second end of the first resistor is electrically connected with the second input end of the comparison unit.

5. The reverse connection protection circuit according to any one of claims 1-4, further comprising a charge-discharge switch unit connected in series with the first switch unit.

6. The reverse connection protection circuit according to any one of claims 1 to 4, further comprising a second switching unit, a reference voltage unit, and a logic unit, wherein a control terminal of the second switching unit is electrically connected to a negative electrode of the battery, a first terminal of the second switching unit is electrically connected to a negative electrode charging terminal of the battery, a second terminal of the second switching unit is electrically connected to a control terminal of the reference voltage unit, an output terminal of the reference voltage unit is electrically connected to a first input terminal of the logic unit, a second input terminal of the logic unit is electrically connected to an output terminal of the comparison unit, and an output terminal of the logic unit is electrically connected to a control terminal of the first switching unit.

7. The reverse connection protection circuit according to claim 6, wherein the second switching unit comprises a first triode, a base electrode of the first triode is electrically connected with a negative electrode of the battery, an emitter electrode of the first triode is electrically connected with a negative electrode charging terminal of the battery, and a collector electrode of the first triode is electrically connected with a control end of the reference voltage unit.

8. The reverse connection protection circuit of claim 6, wherein the reference voltage unit comprises a reference voltage power supply and a second switching tube, a source of the second switching tube is electrically connected to the reference voltage power supply, a drain of the second switching tube is electrically connected to the first input terminal of the logic unit, and a gate of the second switching tube is electrically connected to the second terminal of the second switching unit.

9. The reverse connection protection circuit according to claim 6, wherein the logic unit includes an or gate, a first input terminal of the or gate is electrically connected to the output terminal of the reference voltage unit, a second input terminal of the or gate is electrically connected to the output terminal of the comparison unit, and an output terminal of the or gate is electrically connected to the control terminal of the first switch unit.

10. A reverse connection protection device comprising a reverse connection protection circuit according to any one of claims 1 to 9.