Anti-backflow charging circuit and battery

Abstract

The utility model provides an anti-backflow charging circuit and a battery. The anti-backflow charging circuit comprises a power supply circuit and a logic control circuit, the power supply circuit comprises a seventh resistor and a diversion diode, and the logic control circuit comprises a first electronic switching tube, a second electronic switching tube and an integrated chip; two ends of the seventh resistor are respectively connected with the anode of the charging circuit and the anode of the diversion diode; the first electronic switch tube is respectively connected with the first end and the second end of the seventh resistor and the input end of the integrated chip, the gate pole control end of the integrated chip is connected with the control end of the second electronic switch tube, and the first end and the second end of the second electronic switch tube are respectively connected with the negative electrode of the diversion diode and the negative electrode of the battery. When the battery is connected to the charging circuit, the voltage of the control end of the second electronic switching tube is adjusted through the integrated chip, so that the battery can be quickly charged, and the current can be prevented from flowing back to the charging circuit after the battery is fully charged; when the charger is short-circuited, the integrated chip can turn off the second electronic switching tube in time and protect the charging circuit.

Description

Technical Field

[0001] The present disclosure relates to the technical field of battery charging, and in particular to a charging circuit and a battery for preventing backflow. Background Art

[0002] As people's demand for the use of electronic devices increases, the safety requirements for battery charging circuits are becoming more and more stringent. As the key link between the power supply and the battery, the performance and safety of the charging circuit are particularly important. When the charger is short-circuited or the positive and negative poles of the external power supply are reversed, if the battery is connected for charging, it is easy to damage the battery.

[0003] On the other hand, after the battery is fully charged, the charger is disconnected from the power supply, but the battery is not separated from the charger, the battery voltage may be greater than the output voltage of the charger charging circuit, and the current generated will flow back into the charging circuit inside the charger and consume electrical energy, resulting in energy waste. For example, the patent application with application number CN201621129690.1 discloses a protection circuit against battery short circuit and reverse polarity connection. When the battery is connected normally, the short circuit protection circuit is composed of a thermistor and a MOS tube control circuit; when the battery is reversely connected, the MOS tube control circuit and the diode constitute a protection circuit against battery short circuit and excessive negative voltage difference of the system power supply. When the battery polarity is reversed or the battery is short-circuited, the battery discharge circuit can be quickly cut off to prevent the battery from being over-discharged or overheated, causing damage to the battery and its charging management components. However, in this solution, after the battery is fully charged, the charger is disconnected from the power supply, but the battery is not separated from the charger. Since the battery voltage may be greater than the power supply voltage, the battery is prone to reverse leakage current and releases electrical energy to the charging circuit, resulting in energy waste. In addition, this solution cannot accurately control the forward voltage drop of the conduction tube, making it difficult to improve the charging efficiency. Utility Model Content

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a charging circuit and a battery that are anti-backflow and anti-short circuit and can improve charging efficiency.

[0005] The purpose of this disclosure is achieved through the following technical solutions:

[0006] A charging circuit for preventing backflow, comprising a power supply circuit and a logic control circuit;

[0007] The power supply circuit includes a seventh resistor, a sixth resistor and a conducting diode, wherein the first end of the seventh resistor is connected to the positive charging electrode, the second end of the seventh resistor is connected to the first end of the sixth resistor, the second end of the sixth resistor is connected to the positive electrode of the conducting diode, and the negative electrode of the conducting diode is connected to the negative charging electrode;

[0008] The logic control circuit includes a first electronic switch tube, a second electronic switch tube, a third resistor and an integrated chip. The first end of the first electronic switch tube is connected to the first end of the seventh resistor, the control end of the first electronic switch tube is connected to the second end of the seventh resistor, the second end of the first electronic switch tube is connected to the power input end of the integrated chip, the gate control end of the integrated chip is connected to the control end of the second electronic switch tube, the gate control end of the integrated chip is also connected to the first end of the third resistor, the second end of the third resistor is connected to the second end of the second electronic switch tube, the first end of the second electronic switch tube is connected to the negative electrode of the guide diode, the negative electrode of the guide diode is also connected to the drain control end of the integrated chip, and the second end of the second electronic switch tube is used to be connected to the negative electrode of the battery.

[0009] In one embodiment, the model of the integrated chip is JW3332.

[0010] In one embodiment, the logic control circuit further includes a first resistor, the second end of the first electronic switch tube is connected to the first end of the first resistor, and the second end of the first resistor is connected to the power input end of the integrated chip.

[0011] In one embodiment, the logic control circuit further includes a first capacitor, a first end of the first capacitor is connected to the second end of the first resistor, and a second end of the first capacitor is connected to the negative electrode of the battery.

[0012] In one embodiment, the logic control circuit further includes a second resistor, a first end of the second resistor is connected to a second end of the first resistor, and a second end of the second resistor is connected to an enable control end of the integrated chip.

[0013] In one embodiment, the logic control circuit further includes a fourth resistor, a first end of the fourth resistor is connected to the gate control end of the integrated chip, and a second end of the fourth resistor is connected to the control end of the second electronic switch tube.

[0014] In one embodiment, the logic control circuit further includes a fifth resistor, a first end of the fifth resistor is connected to the drain control end of the integrated chip, and a second end of the fifth resistor is connected to the negative charging electrode.

[0015] In one embodiment, the power supply circuit further includes a second capacitor, a first end of the second capacitor is connected to the first end of the seventh resistor, and a second end of the second capacitor is connected to the second end of the seventh resistor.

[0016] In one of the embodiments, the power supply circuit further includes a voltage regulator diode, the anode of the voltage regulator diode is connected to the second end of the sixth resistor, and the cathode of the voltage regulator diode is connected to the anode of the current guiding diode.

[0017] A battery comprises any one of the above-mentioned charging circuits for preventing backflow.

[0018] Compared with the prior art, the present invention has at least the following advantages:

[0019] 1. When the battery is fully charged, the charger is disconnected from the power supply, but the battery and charger are not separated. The current generated by the battery will flow from the positive electrode of the charger through the internal circuit of the charger, through the negative electrode of the charger, and then flow to the guide diode. However, since the guide diode has unidirectional conductivity for current, the current generated by the battery cannot pass through the guide diode at this time, thereby avoiding the problem of backflow of the charging circuit after the battery is fully charged.

[0020] 2. When the positive and negative poles of the charger are reversely connected to the positive and negative poles of the external power supply, the control end of the first electronic switch tube loses voltage and is in the cut-off state, causing the integrated chip to stop working, thereby causing the second electronic switch tube to be in the cut-off state. In addition, since the guide diode has unidirectional conductivity to current, the current cannot flow back into the power supply circuit and the logic control circuit through the second electronic switch tube and the guide diode, thereby avoiding the problem of current backflow and anti-backflow charging circuit when the charger is reversely connected to the power supply.

[0021] 3. When the positive and negative poles of the charger are short-circuited, the high-level signal generated by the short-circuit of the charger is fed back to the inside of the integrated chip through the drain control terminal of the integrated chip, so that the integrated chip detects the voltage of the short-circuit state, and then the integrated chip outputs a low-voltage signal through the gate control terminal. Since the gate control terminal of the integrated chip is connected to the control terminal of the second electronic switch tube, the voltage at the control terminal of the second electronic switch tube is lower than the threshold voltage, thereby cutting off the second electronic switch tube, thereby avoiding the problem of current backflow of the external power supply to the anti-backflow charging circuit when the charger is short-circuited.

[0022] 4. When the positive and negative poles of the battery are correctly connected to the positive and negative poles of the charger, and the positive and negative poles of the charger are correctly connected to the positive and negative poles of the external power supply, the first electronic switch tube is in the on state, so that the integrated chip works normally, and the integrated chip adjusts the voltage of the control end of the second electronic switch tube through the gate control end. At this time, as the voltage of the control end of the second electronic switch tube gradually increases, the conduction internal resistance of the second electronic switch tube gradually decreases, thereby increasing the current flowing through the second electronic switch tube, thereby improving the charging efficiency of the anti-backflow charging circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 FIG. 4 is a circuit diagram of a charging circuit for preventing backflow according to an embodiment of the present invention.

[0025] Figure numerals: 10-anti-backflow charging circuit; 100-power supply circuit; 200-logic control circuit; RC7-seventh resistor; ZC1-voltage-stabilizing diode; DC1-current-conducting diode; QC1-first electronic switch tube; MB1-second electronic switch tube; UC1-integrated chip; RC1-first resistor; RC2-second resistor; RC3-third resistor; RC4-fourth resistor; RC5-fifth resistor; RC6-sixth resistor; CC1-first capacitor; CC2-second capacitor; VD-drain control terminal; GATE-gate control terminal; VCC-power input terminal; EN-enable control terminal. DETAILED DESCRIPTION

[0026] In order to facilitate the understanding of the present disclosure, the present disclosure will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present disclosure are given in the drawings. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present disclosure more thoroughly and comprehensively understood.

[0027] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present disclosure. The terms used herein in the specification of the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0029] In order to better understand the technical solutions and beneficial effects of the present invention, the present invention is further described in detail below in conjunction with specific embodiments:

[0030] like Figure 1 As shown, a charging circuit 10 for preventing backflow according to an embodiment of the present disclosure is ， The invention comprises a power supply circuit 100 and a logic control circuit 200 .

[0031] Furthermore, the power supply circuit 100 includes a seventh resistor RC7, a sixth resistor RC6 and a conducting diode DC1, the first end of the seventh resistor RC7 is used to be connected to the positive charging electrode, the second end of the seventh resistor RC7 is connected to the first end of the sixth resistor RC6, the second end of the sixth resistor RC6 is connected to the positive electrode of the conducting diode DC1, and the negative electrode of the conducting diode DC1 is used to be connected to the negative charging electrode; the positive charging electrode is the positive electrode of the charger, and the positive electrode of the charger is connected to the positive electrode of the battery.

[0032] Furthermore, the logic control circuit 200 includes a first electronic switch tube QC1, a second electronic switch tube MB1 and an integrated chip UC1, the first end of the first electronic switch tube QC1 is connected to the first end of the seventh resistor RC7, the control end of the first electronic switch tube QC1 is connected to the second end of the seventh resistor RC7, the second end of the first electronic switch tube QC1 is connected to the power input end VCC of the integrated chip UC1, the gate control end GATE of the integrated chip UC1 is connected to the control end of the second electronic switch tube MB1, the gate control end of the integrated chip is also connected to the first end of the third resistor, the second end of the third resistor is connected to the second end of the second electronic switch tube, the first end of the second electronic switch tube MB1 is connected to the cathode of the guide diode DC1, the cathode of the guide diode DC1 is also connected to the drain control end VD of the integrated chip UC1, and the second end of the second electronic switch tube MB1 is used to be connected to the cathode of the battery.

[0033] In this embodiment, the sixth resistor RC6 and the seventh resistor RC7 are connected in series. Specifically, the sixth resistor RC6 and the seventh resistor RC7 form a voltage divider circuit, wherein the voltage loaded on the seventh resistor RC7 varies with the resistance value of the sixth resistor. By adjusting the resistance value ratio of the seventh resistor RC7 and the sixth resistor RC6, the control terminal voltage of the first electronic switch tube QC1 can be adjusted, thereby adjusting the on-off state of the first electronic switch tube QC1.

[0034] Specifically, when the positive and negative electrodes of the battery are connected to the positive and negative electrodes of the charger, and the positive and negative electrodes of the charger are also connected to the positive and negative electrodes of the external power supply, since the first end of the first electronic switch tube QC1 and the first end of the seventh resistor RC7 are both connected to the positive electrode of the charger, the control end of the first electronic switch tube QC1 is connected to the second end of the seventh resistor RC7, and after the current passes through the seventh resistor RC7, the voltage of the second end of the seventh resistor RC7 is lower than the voltage of the first end of the seventh resistor RC7, so that the voltage of the first end of the first electronic switch tube QC1 is greater than the voltage of its control end, and the voltage of the control end of the first electronic switch tube QC1 is greater than its threshold voltage, so that the first electronic switch tube QC1 is in a conducting state. When the current passes through the sixth resistor RC6, since the sixth resistor RC6 and the seventh resistor RC7 form a voltage divider circuit, the voltage of the second end of the seventh resistor RC7 is reduced, avoiding excessive current at the control end of the second electronic switch tube, thereby confirming that the second electronic switch tube can work normally. When the current passes through the positive electrode of the conducting diode DC1, due to the connection between the negative electrode of the conducting diode DC1 and the first end of the second electronic switch tube MB1, the current flows into the first end of the second electronic switch tube MB1 through the negative electrode of the conducting diode DC1. When the first electronic switch tube QC1 is in the on state, the current flows into the input end of the integrated chip UC1, so that the integrated chip UC1 is in a normal working state, and at this time, the gate control end GATE of the integrated chip UC1 outputs a high level signal; because the gate control end GATE of the integrated chip UC1 is connected to the control end of the second electronic switch tube MB1, the second electronic switch tube MB1 is in the on state, so that the current flows from the first end of the second electronic switch tube MB1 to the second end of the second electronic switch tube MB1, and then flows to the negative electrode of the battery, so that the anti-backflow charging circuit 10 charges the battery through the integrated chip UC1.

[0035] In the above-mentioned anti-backflow charging circuit 10, when the battery is fully charged, the charger is disconnected from the power supply, but the battery and the charger are not separated, the current generated by the battery will flow from the positive electrode of the charger through the internal circuit of the charger through the negative electrode of the charger, and then flow to the guide diode DC1, but because the guide diode DC1 has unidirectional conductivity for current, the current generated by the battery cannot pass through the guide diode DC1 at this time, thereby avoiding the problem of backflow of the anti-backflow charging circuit 10 after the battery is fully charged. When the positive and negative electrodes of the charger are reversely connected to the positive and negative electrodes of the external power supply, the control end of the first electronic switch tube QC1 loses voltage and is in a cut-off state, causing the integrated chip UC1 to stop working, thereby causing the second electronic switch tube MB1 to be in a cut-off state, and because the guide diode DC1 has unidirectional conductivity for current, the current cannot flow back through the second electronic switch tube MB1 and the guide diode DC1 to the power supply circuit 100 and the logic control circuit 200, thereby avoiding the problem of current backflow of the anti-backflow charging circuit 10 when the charger is reversely connected to the power supply.

[0036] Furthermore, when the positive and negative electrodes of the charger are short-circuited, the high-level signal generated by the charger short-circuit is fed back to the inside of the integrated chip UC1 through the drain control terminal VD of the integrated chip UC1, so that the integrated chip UC1 detects the voltage signal of the short-circuit state, and then the integrated chip UC1 outputs a low-voltage signal through the gate control terminal GATE. Since the gate control terminal GATE of the integrated chip UC1 is connected to the control terminal of the second electronic switch tube MB1, the voltage at the control terminal of the second electronic switch tube MB1 is lower than its threshold voltage, so that the second electronic switch tube MB1 is cut off, thereby avoiding the problem of current backflow of the external power supply when the charger is short-circuited.

[0037] Furthermore, when the positive and negative electrodes of the battery are correctly connected to the positive and negative electrodes of the charger, and the positive and negative electrodes of the charger are correctly connected to the positive and negative electrodes of the external power supply, the first electronic switch tube QC1 is in the on state, so that the integrated chip UC1 works normally, and the integrated chip UC1 adjusts the voltage of the control end of the second electronic switch tube MB1 through the gate control end GATE. At this time, as the voltage of the control end of the second electronic switch tube MB1 gradually increases, the on-state internal resistance of the second electronic switch tube MB1 gradually decreases, thereby increasing the current flowing through the second electronic switch tube MB1, thereby improving the charging efficiency of the anti-backflow charging circuit 10.

[0038] In another embodiment, the first electronic switch tube QC1 is a PNP type triode, the control end of the first electronic switch tube QC1 is the base of the PNP type triode, the first end of the first electronic switch tube QC1 is the emitter of the PNP type triode, and the second end of the first electronic switch tube QC1 is the collector of the PNP type triode; the second electronic switch tube MB1 is an N-type MOS tube, the control end of the second electronic switch tube MB1 is the gate of the N-type MOS tube, the first end of the second electronic switch tube MB1 is the drain of the N-type MOS tube, and the second end of the second electronic switch tube MB1 is the source of the N-type MOS tube.

[0039] like Figure 1 As shown, in one of the embodiments, the model of the integrated chip UC1 is JW3332. In this embodiment, during the process of the anti-backflow charging circuit 10 charging the battery, if the anti-backflow charging circuit 10 is short-circuited, the integrated chip JW3332 can control the second electronic switch tube MB1 to turn off within 50KHz to 100KHz, thereby protecting the anti-backflow charging circuit 10 from being damaged by the short-circuit current; when the short-circuit state disappears, the integrated chip JW3332 can restore the anti-backflow charging circuit 10 within 50KHz to 100KHz and put it in a normal charging state, so that the anti-backflow charging circuit 10 can efficiently realize the anti-short circuit function, thereby improving the safety of the anti-backflow charging circuit 10.

[0040] like Figure 1 As shown, in one embodiment, the logic control circuit 200 further includes a first resistor RC1, the second end of the first electronic switch tube QC1 is connected to the first end of the first resistor RC1, and the second end of the first resistor RC1 is connected to the power input terminal VCC of the integrated chip UC1. In this embodiment, the two ends of the first resistor RC1 are respectively connected to the first electronic switch tube QC1 and the power input terminal VCC of the integrated chip UC1, so that the first resistor RC1 plays a current limiting role on the power input terminal VCC of the integrated chip UC1, avoiding excessive current flowing to the power input terminal VCC of the integrated chip UC1, thereby ensuring that the integrated chip UC1 can work normally.

[0041] like Figure 1 As shown, in one embodiment, the logic control circuit 200 further includes a first capacitor CC1, a first end of the first capacitor CC1 is connected to the second end of the first resistor RC1, and a second end of the first capacitor CC1 is connected to the negative electrode of the battery. In this embodiment, since the capacitor can store electrical energy, when the voltage in the power supply circuit 100 changes, the first capacitor CC1 will absorb or release charge to offset the change in the voltage in the power supply circuit 100, thereby maintaining the voltage stability, thereby ensuring that the integrated chip UC1 can work normally.

[0042] like Figure 1 As shown, in one embodiment, the logic control circuit 200 further includes a second resistor RC2, a first end of the second resistor RC2 is connected to the second end of the first resistor RC1, and a second end of the second resistor RC2 is connected to the enable control end EN of the integrated chip UC1. In this embodiment, the first end of the second resistor RC2 is also connected to the first end of the first capacitor CC1, and the second resistor RC2 limits the current at the input end of the integrated chip UC1 to prevent the integrated chip UC1 from being damaged by excessive current, thereby ensuring that the integrated chip UC1 can work normally; at the same time, the second resistor RC2 and the first capacitor CC1 form an RC filter network and can filter high-frequency noise and interference, so that the integrated chip UC1 can receive a stable voltage signal, thereby improving the stability of the integrated chip UC1.

[0043] like Figure 1As shown, in one embodiment, the logic control circuit 200 further includes a fourth resistor RC4, a first end of the fourth resistor RC4 is connected to the gate control terminal GATE of the integrated chip, and a second end of the fourth resistor RC4 is connected to the control terminal of the second electronic switch tube MB1. In this embodiment, the two ends of the fourth resistor RC4 are respectively connected to the gate control terminal GATE of the integrated chip UC1 and the control terminal of the second electronic switch tube MB1, so that the fourth resistor RC4 has a current limiting effect on the control terminal of the second electronic switch tube MB1, preventing the current flowing into the control terminal of the second electronic switch tube MB1 from being too large, thereby ensuring that the second electronic switch tube MB1 can work normally.

[0044] like Figure 1 As shown, in one embodiment, the logic control circuit 200 further includes a fifth resistor RC5, a first end of the fifth resistor RC5 is connected to the drain control terminal VD of the integrated chip UC1, and a second end of the fifth resistor RC5 is connected to the negative electrode of the charger. In this embodiment, since the fifth resistor RC5 is connected between the drain control terminal VD of the integrated chip UC1 and the drain of the N-type MOS tube, when the positive and negative electrodes of the charger are short-circuited, the drain voltage of the N-type MOS tube can be fed back to the integrated chip UC1 through the fifth resistor RC5, and a low-level signal is output through the gate control terminal GATE of the integrated chip UC1, so that the N-type MOS tube is turned off, thereby protecting the battery and the anti-backflow charging circuit 10. At the same time, the fifth resistor RC5 also limits the current flowing through the drain control terminal VD of the integrated chip UC1, thereby preventing the integrated chip UC1 from being damaged due to excessive current.

[0045] like Figure 1 As shown, in one embodiment, the power supply circuit 100 further includes a second capacitor CC2, a first end of the second capacitor CC2 is connected to a first end of a seventh resistor RC7, and a second end of the second capacitor CC2 is connected to a second end of the seventh resistor RC7. In this embodiment, when the power supply circuit 100 is frequently connected to or separated from an external power source, the voltage of the power supply circuit 100 is prone to fluctuations. Since the capacitor has the characteristic of storing electrical energy, the second capacitor CC2 can quickly supplement or absorb excess electrical energy, slowing down the voltage change speed of the power supply circuit 100, thereby maintaining the output voltage of the power supply circuit 100 stable, and further making the logic control circuit 200 in a stable working state.

[0046] like Figure 1As shown, in one embodiment, the power supply circuit 100 further includes a voltage stabilizing diode ZC1, the positive electrode of the voltage stabilizing diode ZC1 is connected to the second end of the sixth resistor RC6, and the negative electrode of the voltage stabilizing diode ZC1 is connected to the positive electrode of the current conducting diode DC1. In this embodiment, after the voltage of the positive electrode of the charger is divided by the sixth resistor RC6 and the seventh resistor RC7, the positive electrode voltage of the voltage stabilizing diode ZC1 reaches its reverse breakdown voltage, so that the voltage stabilizing diode ZC1 starts to conduct. Since the voltage of the voltage stabilizing diode ZC1 remains substantially unchanged after it is conducted, even if the voltage of the positive electrode of the charger fluctuates, the voltage stabilizing diode ZC1 can keep the voltage at both ends stable, thereby ensuring that the integrated chip UC1 maintains stable operation.

[0047] A battery includes any one of the above-mentioned anti-backflow charging circuits 10. In this embodiment, the sixth resistor RC6 and the seventh resistor RC7 are connected in series, and specifically, the sixth resistor RC6 and the seventh resistor RC7 form a voltage divider circuit, wherein the voltage loaded on the seventh resistor RC7 changes with the resistance value of the sixth resistor, and by adjusting the resistance value ratio of the seventh resistor RC7 to the sixth resistor RC6, the control terminal voltage of the first electronic switch tube QC1 can be adjusted, thereby adjusting the on-off state of the first electronic switch tube QC1. Specifically, when the positive and negative electrodes of the battery are connected to the positive and negative electrodes of the charger, and the positive and negative electrodes of the charger are also connected to the positive and negative electrodes of the external power supply, since the first end of the first electronic switch tube QC1 and the first end of the seventh resistor RC7 are both connected to the positive electrode of the charger, the control end of the first electronic switch tube QC1 is connected to the second end of the seventh resistor RC7, and after the current passes through the seventh resistor RC7, the voltage of the second end of the seventh resistor RC7 is lower than the voltage of the first end of the seventh resistor RC7, so that the voltage of the first end of the first electronic switch tube QC1 is greater than the voltage of its control end, and the voltage of the control end of the first electronic switch tube QC1 is greater than its threshold voltage, so that the first electronic switch tube QC1 is in a conducting state. When the current passes through the sixth resistor RC6, since the sixth resistor RC6 and the seventh resistor RC7 form a voltage divider circuit, the voltage of the second end of the seventh resistor RC7 is reduced, avoiding excessive current at the control end of the second electronic switch tube, thereby confirming that the second electronic switch tube can work normally. When the current passes through the positive electrode of the conducting diode DC1, due to the connection between the negative electrode of the conducting diode DC1 and the first end of the second electronic switch tube MB1, the current flows into the first end of the second electronic switch tube MB1 through the negative electrode of the conducting diode DC1. When the first electronic switch tube QC1 is in the on state, the current flows into the input end of the integrated chip UC1, so that the integrated chip UC1 is in a normal working state, and at this time, the gate control end GATE of the integrated chip UC1 outputs a high level signal; because the gate control end GATE of the integrated chip UC1 is connected to the control end of the second electronic switch tube MB1, the second electronic switch tube MB1 is in the on state, so that the current flows from the first end of the second electronic switch tube MB1 to the second end of the second electronic switch tube MB1, and then flows to the negative electrode of the battery, so that the anti-backflow charging circuit 10 charges the battery through the integrated chip UC1.

[0048] Compared with the prior art, the present invention has at least the following advantages:

[0049] 1. When the battery is fully charged, the charger is disconnected from the power supply, but the battery is not separated from the charger. The current generated by the battery will flow from the positive electrode of the charger through the internal circuit of the charger, through the negative electrode of the charger, and then flow to the guide diode DC1. However, since the guide diode DC1 has unidirectional conductivity for current, the current generated by the battery cannot pass through the guide diode DC1 at this time, thereby avoiding the problem of backflow of the charging circuit 10 after the battery is fully charged.

[0050] 2. When the positive and negative electrodes of the charger are reversely connected to the positive and negative electrodes of the external power supply, the control end of the first electronic switch tube QC1 loses voltage and is in a cut-off state, causing the integrated chip UC1 to stop working, thereby causing the second electronic switch tube MB1 to be in a cut-off state. In addition, since the guide diode DC1 has unidirectional conductivity to current, the current cannot flow back into the power supply circuit 100 and the logic control circuit 200 through the second electronic switch tube MB1 and the guide diode DC1, thereby avoiding the problem of current backflow into the anti-backflow charging circuit 10 when the charger is reversely connected to the power supply.

[0051] 3. When the positive and negative electrodes of the charger are short-circuited, the high-level signal generated by the short-circuit of the charger is fed back to the inside of the integrated chip UC1 through the drain control terminal VD of the integrated chip UC1, so that the integrated chip UC1 detects the voltage signal of the short-circuit state, and then the integrated chip UC1 outputs a low-voltage signal through the gate control terminal GATE. Since the gate control terminal GATE of the integrated chip UC1 is connected to the control terminal of the second electronic switch tube MB1, the voltage at the control terminal of the second electronic switch tube MB1 is lower than its threshold voltage, so that the second electronic switch tube MB1 is cut off, thereby avoiding the problem of current backflow of the external power supply when the charger is short-circuited.

[0052] 4. When the positive and negative electrodes of the battery are correctly connected to the positive and negative electrodes of the charger, and the positive and negative electrodes of the charger are correctly connected to the positive and negative electrodes of the external power supply, the first electronic switch tube QC1 is in the on state, so that the integrated chip UC1 works normally, and the integrated chip UC1 adjusts the voltage of the control end of the second electronic switch tube MB1 through the gate control end GATE. At this time, as the voltage of the control end of the second electronic switch tube MB1 gradually increases, the on-state internal resistance of the second electronic switch tube MB1 gradually decreases, thereby increasing the current flowing through the second electronic switch tube MB1, thereby improving the charging efficiency of the anti-backflow charging circuit 10.

[0053] The above-mentioned embodiments only express several implementation methods of the present disclosure, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the disclosed patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present disclosure, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the disclosed patent shall be subject to the attached claims.

Claims

1. A charging circuit for preventing backflow, characterized in that: Including power supply circuit and logic control circuit; The power supply circuit includes a seventh resistor, a sixth resistor and a conducting diode, wherein the first end of the seventh resistor is connected to the positive charging electrode, the second end of the seventh resistor is connected to the first end of the sixth resistor, the second end of the sixth resistor is connected to the positive electrode of the conducting diode, and the negative electrode of the conducting diode is connected to the negative charging electrode; The logic control circuit includes a first electronic switch tube, a second electronic switch tube, a third resistor and an integrated chip. The first end of the first electronic switch tube is connected to the first end of the seventh resistor, the control end of the first electronic switch tube is connected to the second end of the seventh resistor, the second end of the first electronic switch tube is connected to the power input end of the integrated chip, the gate control end of the integrated chip is connected to the control end of the second electronic switch tube, the gate control end of the integrated chip is also connected to the first end of the third resistor, the second end of the third resistor is connected to the second end of the second electronic switch tube, the first end of the second electronic switch tube is connected to the negative electrode of the guide diode, the negative electrode of the guide diode is also connected to the drain control end of the integrated chip, and the second end of the second electronic switch tube is used to be connected to the negative electrode of the battery.

2. The anti-backflow charging circuit according to claim 1, characterized in that: The model of the integrated chip is JW3332.

3. The anti-backflow charging circuit according to claim 1, characterized in that: The logic control circuit also includes a first resistor, the second end of the first electronic switch tube is connected to the first end of the first resistor, and the second end of the first resistor is connected to the power input end of the integrated chip.

4. The anti-backflow charging circuit according to claim 3, characterized in that: The logic control circuit further includes a first capacitor, a first end of the first capacitor is connected to the second end of the first resistor, and a second end of the first capacitor is connected to the negative electrode of the battery.

5. The anti-backflow charging circuit according to claim 4, characterized in that: The logic control circuit further includes a second resistor, a first end of the second resistor is connected to a second end of the first resistor, and a second end of the second resistor is connected to an enable control end of the integrated chip.

6. The anti-backflow charging circuit according to claim 4, characterized in that: The logic control circuit further includes a fourth resistor, a first end of the fourth resistor is connected to the gate control end of the integrated chip, and a second end of the fourth resistor is connected to the control end of the second electronic switch tube.

7. The anti-backflow charging circuit according to claim 4, characterized in that: The logic control circuit further includes a fifth resistor, a first end of the fifth resistor is connected to the drain control end of the integrated chip, and a second end of the fifth resistor is connected to the charging negative electrode.

8. The anti-backflow charging circuit according to claim 1, characterized in that: The power supply circuit further includes a second capacitor, a first end of the second capacitor is connected to the first end of the seventh resistor, and a second end of the second capacitor is connected to the second end of the seventh resistor.

9. The anti-backflow charging circuit according to claim 1, characterized in that: The power supply circuit further includes a voltage-stabilizing diode, an anode of the voltage-stabilizing diode is connected to the second end of the sixth resistor, and a cathode of the voltage-stabilizing diode is connected to the anode of the current-guiding diode.

10. A battery, characterized in that: A charging circuit comprising the anti-backflow charging circuit as claimed in any one of claims 1 to 9.

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