CN217984643U - Anti-reverse-connection and anti-reverse-flow lithium battery charger - Google Patents

Abstract

The utility model relates to the technical field of lithium battery chargers, in particular to an anti-reverse-flow lithium battery charger, which comprises a diode D2, an inductor L1, an MOS tube Q3, a resistor R12 and a capacitor EC2; the anode of the diode D2 is connected with the anode of an input power supply, and the cathode of the diode D2 is connected with one end of a load after passing through the inductor L1; the other end of the load is connected with the drain electrode of an MOS tube Q3, and the source electrode of the MOS tube Q3 is connected with a resistor R12 and a capacitor EC2 in sequence and then connected with the anode of a diode D2 to form a loop. The combination of the PTC and the MOS is added at the output end of the charger, the on-off of the MOS tube is controlled by detecting the voltage of the output end, when the battery is reversely connected, the current is increased, the PTC is increased to control the reverse connection current to be overlarge, and the damage caused by overlarge instantaneous current of the MOS is prevented. The problems that when a traditional lithium battery is charged, the dynamic response of an MOS tube control circuit is slow, and the MOS tube is broken down by instant pulse current are solved; the technical problems that the thyristor is directly connected in series in a strong circuit and is easy to damage and the reliability has hidden trouble are also avoided.

Description

Anti-reverse-connection and anti-reverse-flow lithium battery charger

Technical Field

The utility model relates to a lithium battery charger technical field, concretely relates to prevent reverse-flow and prevent flowing backward lithium battery charger.

Background

The lithium battery charger industry often encounters load battery reverse connection to cause battery damage, and battery explosion or ignition exists. The problem of serious injury to life and safety is solved, and while the cost performance is pursued, the market hopes to adopt a simple and reliable mode to effectively avoid the occurrence of accidents, and the safety of life and property is guaranteed.

At present, there are two ways in the industry for a reverse connection prevention switch circuit of a lithium battery: one is to detect the load current through the chip and design a control circuit to control the MOS tube to be hung up, but the reaction speed is low when the MOS tube is reversely connected, and the instantaneous pulse current is large, so that the MOS tube breaks down; the other is electronic switching by connecting a thyristor in series with the circuit. Although the silicon controlled rectifier has simple circuit and low price, the silicon controlled rectifier needs a bidirectional diode, is very easy to damage and has high failure rate. The former switching mode of the reverse connection prevention of the two lithium batteries is simple, reliable and low in cost, and the latter mode carries out electronic automatic switching through circuit detection, so that the defects that the silicon controlled rectifier is directly connected in series in a strong circuit and is extremely easy to damage, and the reliability has hidden danger.

Disclosure of Invention

The utility model provides a prevent joining conversely and prevent flowing backward lithium battery charger has solved above the lithium cell prevent that reverse connection circuit all damages electronic components easily, has potential safety hazard and cost of maintenance technical problem.

The utility model provides an anti-reverse-connection and anti-reverse-flow lithium battery charger for solving the above technical problems, which comprises an anti-reverse-connection and anti-reverse-flow stabilizing circuit, wherein the anti-reverse-flow stabilizing circuit comprises a diode D2, an inductor L1, an MOS tube Q3, a resistor R12 and a capacitor EC2;

the anode of the diode D2 is connected with the anode of the input power supply, and the cathode of the diode D2 is connected with one end of the load after passing through the inductor L1;

the other end of the load is connected with the drain electrode of an MOS tube Q3, and the source electrode of the MOS tube Q3 is connected with a resistor R12 and a capacitor EC2 in sequence and then connected with the anode of a diode D2 to form a loop.

Preferably, the charger further comprises an anti-reverse connection circuit, wherein the anti-reverse connection circuit comprises a triode Q2, a resistor R11, a resistor R15, a resistor R18, a resistor R22 and a positive temperature coefficient resistor PPTC;

one end of the resistor R11 is connected with the anode of the diode D2, and the other end of the resistor R11 is connected with the base electrode of the triode Q2 and then connected with the other end of the load after passing through the resistor R15;

the emitting electrode of the triode Q2 is connected with the positive electrode of the diode D2, the collecting electrode is connected with the resistor R18 and then respectively connected with the grid electrode of the MOS tube Q3 and the first end of the resistor R22, and the source electrode of the MOS tube Q3 is connected with the second end of the resistor R22 and then connected with the resistor R12.

Preferably, the anti-reverse connection circuit further comprises a positive temperature coefficient resistor PPTC;

the second end of the resistor R22 is connected with the resistor R12 through a positive temperature coefficient resistor PPTC.

Preferably, the charger further comprises an input voltage circuit, wherein the input voltage circuit comprises a fuse F1, a lightning protection piezoresistor VDR1 and a rectifying circuit;

the L end of the commercial power is connected with the N end of the commercial power after passing through the fuse F1 and the lightning protection piezoresistor VDR1, the fuse F1 is connected with the 2 nd end of the rectifying circuit, the 4 th end of the rectifying circuit is grounded, the 1 st end is connected to the anode of a diode D2 of the reverse-connection preventing and reverse-flow preventing stabilizing circuit, and the 3 rd end is connected with the N end of the commercial power.

Preferably, the 1 st end of the rectifying circuit is connected with the anode of the diode D2 through an NTC resistor RT 1.

Preferably, the input voltage circuit further comprises an EMI interference prevention circuit composed of a capacitor XC1 and an inductor LF 1;

one end of the capacitor XC1 and one end of the inductor LF1 are connected with the fuse F1, the other end of the inductor LF1 is connected with the 2 nd end of the rectifying circuit, and the other end of the capacitor XC1 is connected with the N end of the mains supply.

Preferably, the EMI anti-interference circuit further includes a release circuit, and the release circuit includes a resistor R4, a resistor R5, a resistor R7, and a resistor R8;

resistance R4's one end and resistance R5's one end all are connected with electric capacity XC 1's one end, resistance R7's one end and resistance R8's one end all with electric capacity XC 1's the other end is connected, resistance R4's the other end, resistance R5's the other end, resistance R7's the other end and resistance R8's the other end all are connected.

Preferably, the charger further comprises a transformer, the 1 st end of the rectifying circuit of the input voltage circuit is used as an output end to be connected with one side of the transformer, and the other side of the transformer is used as an output end to be connected with the anode of the diode D2 of the reverse-connection-preventing reverse-flow-preventing stabilizing circuit.

Preferably, the charger further comprises a primary spike absorption circuit comprising a capacitor C2, a resistor R6 and a diode D1;

the current sequentially passes through one end of one side of the transformer, the other end of one side of the transformer, the diode D1, the resistor R6 and the resistor R2 to form a loop;

the current sequentially passes through one end of one side of the transformer, the other end of one side of the transformer, the diode D1, the resistor R6 and the capacitor C2 to form another loop.

Has the beneficial effects that: the utility model provides a reverse-connection-prevention and reverse-flow-prevention lithium battery charger, which comprises a reverse-connection-prevention and reverse-flow-prevention stabilizing circuit, wherein the reverse-flow-prevention stabilizing circuit comprises a diode D2, an inductor L1, an MOS (metal oxide semiconductor) tube Q3, a resistor R12 and a capacitor EC2; the anode of the diode D2 is connected with the anode of an input power supply, and the cathode of the diode D2 is connected with one end of a load after passing through the inductor L1; the other end of the load is connected with the drain electrode of an MOS tube Q3, and the source electrode of the MOS tube Q3 is connected with a resistor R12 and a capacitor EC2 in sequence and then connected with the anode of a diode D2 to form a loop. The combination of the PTC and the MOS is added at the output end of the charger, the on-off of the MOS tube is controlled by detecting the voltage of the output end, when the battery is reversely connected, the current is increased, the PTC is increased to control the reverse connection current to be overlarge, and the damage caused by overlarge instantaneous current of the MOS is prevented. The problems that when a traditional lithium battery is charged, the dynamic response of an MOS tube control circuit is slow, and the MOS tube is broken down by instant pulse current are solved; the technical problems that the thyristor is directly connected in series in a strong circuit and is easy to damage and the reliability has hidden trouble are also avoided.

The above description is only an outline of the technical solution of the present invention, and in order to make the technical means of the present invention more clearly understood and to be implemented in accordance with the content of the specification, the following detailed description will be given of preferred embodiments of the present invention in conjunction with the accompanying drawings. The following examples and the accompanying drawings illustrate specific embodiments of the present invention.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without undue limitation to the invention. In the drawings:

FIG. 1 is a general design diagram of the anti-reverse-connection and anti-reverse-flow lithium battery charger of the present invention;

FIG. 2 is a circuit diagram of the utility model for preventing reverse connection;

FIG. 3 is a circuit diagram of the input voltage of the present invention;

fig. 4 is a circuit diagram of the transformer of the present invention;

fig. 5 is a feedback loop adjusting circuit of the present invention;

Detailed Description

The principles and features of the present invention are described below in conjunction with the following drawings, the examples given are only intended to illustrate the present invention and are not intended to limit the scope of the present invention. The invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more fully apparent from the following description and appended claims. It should be noted that the drawings are in simplified form and are not to precise scale, and are provided for convenience and clarity in order to facilitate the description of the embodiments of the present invention.

As shown in fig. 1 to 5, the utility model provides a reverse-connection-prevention and reverse-flow-prevention lithium battery charger, which comprises a reverse-connection-prevention and reverse-flow-prevention stabilizing circuit, wherein the reverse-flow-prevention stabilizing circuit comprises a diode D2, an inductor L1, a MOS tube Q3, a resistor R12 and a capacitor EC2;

the anode of the diode D2 is connected with the anode of an input power supply, and the cathode of the diode D2 is connected with one end of a load after passing through the inductor L1;

the other end of the load is connected with the drain electrode of an MOS tube Q3, and the source electrode of the MOS tube Q3 is connected with a resistor R12 and a capacitor EC2 in sequence and then connected with the anode of a diode D2 to form a loop.

Specifically, the charger further comprises an anti-reverse connection circuit, wherein the anti-reverse connection circuit comprises a triode Q2, a resistor R11, a resistor R15, a resistor R18, a resistor R22 and a positive temperature coefficient resistor PPTC; one end of the resistor R11 is connected with the anode of the diode D2, and the other end of the resistor R11 is connected with the base electrode of the triode Q2 and then connected to the other end of the load after passing through the resistor R15; the emitting electrode of the triode Q2 is connected with the anode of the diode D2, the collecting electrode is connected with the resistor R18 and then respectively connected with the grid electrode of the MOS tube Q3 and the first end of the resistor R22, and the source electrode of the MOS tube Q3 is connected with the second end of the resistor R22 and then connected with the resistor R12. The reverse connection preventing circuit also comprises a positive temperature coefficient resistor PPTC; the second end of the resistor R22 is connected with the resistor R12 through a positive temperature coefficient resistor PPTC.

Preferably, the charger further comprises an input voltage circuit, wherein the input voltage circuit comprises a fuse F1, a lightning protection piezoresistor VDR1 and a rectifying circuit; the L end of a mains supply is connected with the N end of the mains supply after passing through the fuse F1 and the lightning protection piezoresistor VDR1, the fuse F1 is connected with the 2 nd end of the rectifying circuit, the 4 th end of the rectifying circuit is grounded, the 1 st end of the rectifying circuit is connected to the anode of a diode D2 of the anti-reverse-connection anti-reverse-flow stabilizing circuit, and the 3 rd end of the rectifying circuit is connected with the N end of the mains supply. The 1 st end of the rectifying circuit is connected with the anode of the diode D2 through an NTC resistor RT 1. The input voltage circuit also comprises an EMI anti-interference circuit consisting of a capacitor XC1 and an inductor LF 1; one end of the capacitor XC1 and one end of the inductor LF1 are connected with the fuse F1, the other end of the inductor LF1 is connected with the 2 nd end of the rectifying circuit, and the other end of the capacitor XC1 is connected with the N end of the commercial power.

Commercial power AC220V is input through an input voltage circuit consisting of F1, VDR1, R4, R5, R8, R7, XC1 and LF1 circuits.

Wherein, F1 is the fuse, and when load current was greater than the design current, the fuse will blow, and protection poststage circuit receives the current surge and damages other devices. VDR1 is lightning protection piezoresistor, carrying 4KV lightning stroke. When the commercial power electric wire is hit by thunder and lightning, thousands of V high voltage electricity is generated, and when the L line or the N line is connected in series with a power supply, the high voltage is firstly filtered through the VDR1, the voltage is clamped at 470V, and a rear-stage circuit is protected from being damaged by the high voltage. And the capacitor XC1 and the inductor LF1 form an EMI anti-interference circuit to inhibit work mode and differential mode interference. The resistors R4, R5, R7 and R8 are used for releasing the stored electricity of the capacitor XC1, and when the power plug is unplugged according to the requirement of safety regulations, the capacitor XC1 is released to the safe voltage of 36V within 3 seconds.

DB1 is a rectifying circuit which rectifies the 220V commercial power into 310V pulsating direct current. RT1 is NTC resistance, and surge current is too big when can effectively preventing to start, prevents to wash out bridge heap and fuse.

EC1 is VBUS bus filter capacitance, and filters pulsating direct current to approximate direct current. R9 and R14 are chip starting resistors. C2, R6 and D1 form a primary spike absorption circuit.

U1 is the PWM chip, and R21, R16, D3 are drive circuit, provide switching signal for the MOS pipe.

And the SDB1 and the EC2 output rectification filtering, direct current voltage paths R39, R42 and RV1 obtained by rectification filtering are sampled, the duty ratio of the sampled output voltage is adjusted through a feedback loop, and the output voltage is adjusted.

The charger further comprises a feedback loop adjusting circuit, wherein the feedback loop adjusting circuit comprises U3, U5, C12, C13, R36 and the like, C5 and C15 dynamic response filter capacitors, R29 is a U3 and U5 power supply resistor, R34 is a bypass resistor, bias current is provided for U5, and U5 is prevented from working in a dead zone. U2 operational amplifier is constant voltage and constant current, and U4 is 2.5V as the reference of the operational amplifier comparator. C10, C11, R31, C14, C16 and R33 are used as feedback gain compensation of the U2 operational amplifier comparator, current sampling signals are respectively input into the 2-pin and 6-pin inverting input ends of the U2 operational amplifier through R23, the current sampling signals respectively enter the U2 operational amplifier, are independent and stronger and are used as a constant current and lamp-turning controller, the R28 operational amplifier is used as a power supply resistor, and the R30R 39 lamp-turning power supply resistor.

Preferably, the EMI anti-interference circuit further includes a release circuit, and the release circuit includes a resistor R4, a resistor R5, a resistor R7, and a resistor R8; one end of the resistor R4 and one end of the resistor R5 are connected with one end of the capacitor XC1, one end of the resistor R7 and one end of the resistor R8 are connected with the other end of the capacitor XC1, and the other end of the resistor R4, the other end of the resistor R5, the other end of the resistor R7 and the other end of the resistor R8 are connected.

Preferably, the charger further comprises a transformer, the 1 st end of the rectifying circuit of the input voltage circuit is used as an output end to be connected with one side of the transformer, and the other side of the transformer is used as an output end to be connected with the anode of the diode D2 of the reverse-connection-preventing reverse-flow-preventing stabilizing circuit.

Preferably, the charger further comprises a primary spike absorption circuit, wherein the primary spike absorption circuit comprises a capacitor C2, a resistor R6 and a diode D1; the current sequentially passes through one end of one side of the transformer, the other end of one side of the transformer, the diode D1, the resistor R6 and the resistor R2 to form a loop; and the current sequentially passes through one end of one side of the transformer, the other end of one side of the transformer, the diode D1, the resistor R6 and the capacitor C2 to form another loop.

In one particular implementation scenario:

1. in normal operation, the output current passes through D2 → L1 → load → Q3 → PPTC → R12 → EC2 to form a current loop.

During specific work, the voltage of the E pole of the Q2 is greater than the B pole due to the R11 and R15 partial pressure, according to the characteristics of the PNP triode, the Q2 has current from the E pole to the C pole, the current passes through the R18, the R18 is a buffer resistor, the R18 is also a driving resistor of the Q3, the oscillation formed by the junction capacitor of the Q3 and the PCB distributed inductor is prevented, and the damping attenuation is realized, so that the circuit is stable. Q3 is powered up to VGS due to R18 drive, at which time Q3 is on. The current from the load flows through the L1 and then flows to the Q3, the Q3 is in saturation conduction, the voltage drop is low, the loss is small, the efficiency of the whole machine is improved, and the current from the Q3 flows back to the capacitor EC2 through the PPTC. PPTC is a positive temperature coefficient resistor that blocks current flow to a negligible extent when the current is in the normal range.

2. When the output is reversely connected, no current loop exists, and a current path cannot be formed.

The specific work is that Q2 is divided by R11 and R15, the E pole voltage of Q2 is smaller than the B pole, and according to the characteristics of the PNP triode, the Q2 triode is cut off and has no current path, so that the reverse connection of the battery is prevented. However, this has not been done, if following such a working principle. The problem cannot be solved completely, and a hidden danger exists, when the battery is connected reversely, because the transient current is too large, the Q3 can be subjected to avalanche breakdown, in order to eliminate the hidden danger, a PPTC is added in a circuit, the PPTC is characterized in that the dynamic response time is fast, when the transient current is larger than a threshold value 2.5A, the resistance value of the PPTC is steep, the PPTC is directly disconnected, and the Q3 and the battery are effectively protected. The undercut effectively prevents the problem of reverse battery connection.

3. With regard to the prevention of the back-flow,

when the circuit is normal, current flows through D2, and the diode conducts in the forward direction. In order to prevent D2 from being damaged, D2 is additionally provided with a radiating fin. When the battery voltage is greater than the output voltage, D2 is in reverse bias cutoff, no current is reversed, thus preventing sinking.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way; the present invention can be smoothly implemented by those skilled in the art according to the drawings and the above description; however, those skilled in the art should understand that the equivalent embodiments of the present invention are equivalent embodiments of the present invention, and that the changes, modifications and evolutions made by the above-disclosed technical contents are not departed from the technical scope of the present invention; meanwhile, any changes, modifications, evolutions, etc. of the above embodiments, which are equivalent to the actual techniques of the present invention, still belong to the protection scope of the technical solution of the present invention.

Claims (9)

1. The anti-reverse-connection and anti-reverse-flow lithium battery charger is characterized by comprising an anti-reverse-connection and anti-reverse-flow stabilizing circuit, wherein the anti-reverse-flow stabilizing circuit comprises a diode D2, an inductor L1, an MOS (metal oxide semiconductor) tube Q3, a resistor R12 and a capacitor EC2;

the anode of the diode D2 is connected with the anode of an input power supply, and the cathode of the diode D2 is connected with one end of a load after passing through the inductor L1;

the other end of the load is connected with the drain electrode of an MOS tube Q3, and the source electrode of the MOS tube Q3 is connected with a resistor R12 and a capacitor EC2 in sequence and then connected with the anode of a diode D2 to form a loop.

2. The lithium battery charger of claim 1, further comprising an anti-reverse connection circuit, wherein the anti-reverse connection circuit comprises a triode Q2, a resistor R11, a resistor R15, a resistor R18, a resistor R22 and a positive temperature coefficient resistor PPTC;

one end of the resistor R11 is connected with the anode of the diode D2, and the other end of the resistor R11 is connected with the base electrode of the triode Q2 and then connected to the other end of the load after passing through the resistor R15;

the emitting electrode of the triode Q2 is connected with the anode of the diode D2, the collecting electrode is connected with the resistor R18 and then respectively connected with the grid electrode of the MOS tube Q3 and the first end of the resistor R22, and the source electrode of the MOS tube Q3 is connected with the second end of the resistor R22 and then connected with the resistor R12.

3. The lithium battery charger of claim 2, wherein the reverse connection prevention circuit further comprises a positive temperature coefficient resistor (PPTC);

the second end of the resistor R22 is connected with the resistor R12 through a positive temperature coefficient resistor PPTC.

4. The lithium battery charger of claim 1, further comprising an input voltage circuit, wherein the input voltage circuit comprises a fuse F1, a lightning protection piezoresistor VDR1 and a rectifying circuit;

the L end of the commercial power is connected with the N end of the commercial power after passing through the fuse F1 and the lightning protection piezoresistor VDR1, the fuse F1 is connected with the 2 nd end of the rectifying circuit, the 4 th end of the rectifying circuit is grounded, the 1 st end is connected to the anode of a diode D2 of the reverse-connection preventing and reverse-flow preventing stabilizing circuit, and the 3 rd end is connected with the N end of the commercial power.

5. The lithium battery charger of claim 4, wherein the connection between the 1 st end of the rectifying circuit and the anode of the diode D2 is through an NTC resistor RT 1.

6. The lithium battery charger of claim 4, wherein the input voltage circuit further comprises an EMI anti-interference circuit composed of a capacitor XC1 and an inductor LF 1;

one end of the capacitor XC1 and one end of the inductor LF1 are connected with the fuse F1, the other end of the inductor LF1 is connected with the 2 nd end of the rectifying circuit, and the other end of the capacitor XC1 is connected with the N end of the commercial power.

7. The lithium battery charger of claim 6, wherein the EMI prevention circuit further comprises a release circuit, the release circuit comprising a resistor R4, a resistor R5, a resistor R7, and a resistor R8;

one end of the resistor R4 and one end of the resistor R5 are connected with one end of the capacitor XC1, one end of the resistor R7 and one end of the resistor R8 are connected with the other end of the capacitor XC1, and the other end of the resistor R4, the other end of the resistor R5, the other end of the resistor R7 and the other end of the resistor R8 are connected.

8. The lithium battery charger of claim 4, wherein the charger further comprises a transformer, the 1 st end of the rectifying circuit of the input voltage circuit is connected with one side of the transformer as an output end, and the other side of the transformer is connected with the anode of the diode D2 of the anti-reverse-flow prevention stabilizing circuit as an output end.

9. The lithium battery charger of claim 8, further comprising a primary spike absorption circuit comprising a capacitor C2, a resistor R6, and a diode D1;

the current sequentially passes through one end of one side of the transformer, the other end of one side of the transformer, the diode D1, the resistor R6 and the resistor R2 to form a loop;

the current sequentially passes through one end of one side of the transformer, the other end of one side of the transformer, the diode D1, the resistor R6 and the capacitor C2 to form another loop.

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