CN210629125U

CN210629125U - Short circuit reverse connection protection circuit of automatic battery charger

Info

Publication number: CN210629125U
Application number: CN201920991129.1U
Authority: CN
Inventors: 梁干
Original assignee: Shenzhen Pinding Technology Co Ltd
Current assignee: Shenzhen Pinding Technology Co Ltd
Priority date: 2019-06-28
Filing date: 2019-06-28
Publication date: 2020-05-26
Anticipated expiration: 2029-06-28

Abstract

The utility model discloses an automatic battery charger short-circuit connects anti-protection circuit, including optical coupler U1, resistance R3, resistance R4 and MOS pipe Q1, electric capacity C2 and resistance R3 are connected to the positive pole of the inside diode of optical coupler U1, and input Vin +, electric capacity C1, resistance R4 and output Vout + are connected to resistance R3's the other end, electric capacity C2's the other end, resistance R4's the other end, MOS pipe Q1's drain electrode, output Vout-and the negative pole of the inside diode of optical coupler U1 are connected to electric capacity C1's the other end. The utility model discloses automatic battery charger short circuit connects anti-protection circuit can have wideer application range through the automatic battery charger of upgrading, and reason misjudgement returns the factory to overhaul, convenience of customers direct measurement when the reason is absolutely not of the quality.

Description

Short circuit reverse connection protection circuit of automatic battery charger

Technical Field

The utility model relates to a technical field that charges specifically is an automatic battery charger short circuit connects anti-protection circuit.

Background

In the prior art, in the aspect of reverse connection and short-circuit protection circuits of a charger, two protection modes of a relay and a P-type field effect transistor are generally used at present, but the two methods have limitations, the relay is connected through contacts, the damage of the relay is easily caused by poor contact of the contacts in the case of large current, the price of the P-type field effect transistor in the market is much higher than that of the N-type field effect transistor, and the types of the P-type field effect transistor are not as many as that of the N-type field effect transistor.

Although the charger reverse connection and short circuit protection circuit provided by application number 201120161506.2 can solve the above problems, the user cannot normally trigger output manually due to long-time contact oxidation of the manual mechanical trigger switch K1 in the use process, the automatic battery charger is judged by mistake to have no output quality problem and is returned to the factory for detection, and the bad record of the non-quality problem is increased.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing an automatic battery charger short circuit connects anti-protection circuit to solve the problem that proposes in the above-mentioned background art.

In order to achieve the above object, the utility model provides a following technical scheme:

the short circuit reverse protection circuit of the automatic battery charger comprises an optical coupler U1, a resistor R3, a resistor R4 and a MOS tube Q1, wherein the anode of a diode in the optical coupler U1 is connected with a capacitor C2 and a resistor R3, the other end of a resistor R3 is connected with an input end Vin +, a capacitor C1, a resistor R4 and an output end Vout +, the other end of a capacitor C1 is connected with the other end of a capacitor C2, the other end of a resistor R4, the drain of an MOS tube Q1, the output end Vout and the cathode of a diode in the optical coupler U1, the drain of the MOS tube Q1 is also connected with a resistor R5, the gate of the MOS tube Q1 is connected with the emitter of a triode in the optical coupler U1, the source of the MOS tube Q1 is connected with the other end of a resistor R1, the input end Vin-and the other end of the resistor R1, and the collector of the triode in the optical coupler U1 is connected with direct current 12V.

As a further technical solution of the present invention: the optocoupler U1 is of the type PC 817.

As a further technical solution of the present invention: the MOS tube Q1 is an NMOSFET.

As a further technical solution of the present invention: the resistance value of the resistor R5 is 5K1 omega.

As a further technical solution of the present invention: the capacitance values of the capacitor C1 and the capacitor C2 are both 100 pF.

Compared with the prior art, the beneficial effects of the utility model are that: the utility model discloses automatic battery charger short circuit connects anti-protection circuit can have wideer application range through the automatic battery charger of upgrading, and reason misjudgement returns the factory to overhaul, convenience of customers direct measurement when the reason is absolutely not of the quality.

Drawings

Fig. 1 is a circuit diagram of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Example 1: referring to fig. 1, a short-circuit reverse-connection protection circuit for an automatic battery charger is mainly improved over the prior art in that the use of switches is reduced, and the updating of the handle moving trigger output is upgraded to the electronic automatic trigger output, so that the operation process is reduced, and the intelligence degree is increased.

The circuit is shown in fig. 1, and includes an optical coupler U1, a resistor R3, a resistor R4 and a MOS transistor Q1, an anode of a diode in the optical coupler U1 is connected with a capacitor C2 and a resistor R3, the other end of the resistor R3 is connected with an input terminal Vin +, a capacitor C1, a resistor R4 and an output terminal Vout +, the other end of the capacitor C1 is connected with the other end of a capacitor C2, the other end of a resistor R4, a drain of the MOS transistor Q1, the output terminal Vout-, and a cathode of a diode in the optical coupler U1, a drain of the MOS transistor Q1 is further connected with a resistor R5, a gate of the MOS transistor Q1 is connected with a resistor R1 and an emitter of an internal triode in the optical coupler U1, a source of the MOS transistor Q1 is connected with the other end of the resistor R1, the input terminal Vin-and the other end of the resistor R1, a collector of the internal triode in the optical coupler. The MOS tube Q1 is a main output short circuit reverse connection protection power device, the load capacity of an output end can be changed by changing the number of the MOS tubes Q1, the circuit R4 is a discharge resistor, the capacitor C1 is an energy storage capacitor, and the capacitor C2 is a filter capacitor of the optical coupler U1.

The method comprises two triggering modes of output work: 1. when the normal access voltage +5V cannot be detected between the output end Vout + and the output end Vout-, if the output voltage is between the output end Vout + and the output end Vout-by the automatic battery charger, as long as the resistance type load is not connected between the output end Vout + and the output end Vout-, the output end Vout-can be connected to Vin-through the resistor R5, a negative electrode working circuit of the optical coupler U1 is provided, the optical coupler U1 is conducted to work, the normal driving voltage is provided for the MOS transistor Q1 through the resistor R1, and the optical coupler U1 can maintain the working output of the Q1. 2. The anode of the voltage larger than 5V is connected with the output end Vout +, the cathode is connected with the output end Vout-, the voltage is added to the resistor R3 and is connected to the output end Vout through the optical coupler U1, the optical coupler U1 is electrified to conduct and work, and the normal driving voltage which is supplied to the MOS tube Q1 through the resistor R1 and the optical coupler U1 is always supplied to maintain the work output of the MOS tube Q1.

When the polarity of the external voltage is detected to be opposite between the output end Vout + and the output end Vout-, the optocoupler U1 is not conducted, the MOS tube Q1 cannot obtain the normal working driving voltage, the reverse connection protection function is started, and the output end Vout-of the automatic battery charger is closed.

When a short circuit occurs between the output end Vout + and the output end Vout-, the output voltage is reduced to 0V due to the current-limiting function of the automatic battery charger, the working voltage of the optical coupler U1 is insufficient, the optical coupler U1 is not conducted, the MOS transistor Q1 cannot obtain the normal working driving voltage, the short-circuit protection function is started, and the output end Vout-of the automatic battery charger is closed.

In embodiment 2, based on embodiment 1, the type of the optocoupler U1 of the present design is PC817, which has the advantages of small size, long service life, no contact, high reliability, strong anti-interference capability, and the like, and the PC817 optocoupler has been widely applied to the voltage automatic gain circuit and the voltage regulator circuit, as well as the optoelectronic test circuit and the optical control circuit. And is therefore well suited for this design.

It is obvious to a person skilled in the art that the invention is not restricted to details of the above-described exemplary embodiments, but that it can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. A short circuit reverse connection protection circuit of an automatic battery charger comprises an optical coupler U1, a resistor R3, a resistor R4 and a MOS tube Q1, the anode of the diode in the optocoupler U1 is connected with a capacitor C2 and a resistor R3, the other end of the resistor R3 is connected with an input terminal Vin +, a capacitor C1, a resistor R4 and an output terminal Vout +, the other end of the capacitor C1 is connected with the other end of the capacitor C2, the other end of the resistor R4, the drain of a MOS transistor Q1, the output terminal Vout-and the cathode of the diode in the optocoupler U1, the transistor is characterized in that the drain electrode of the MOS transistor Q1 is further connected with a resistor R5, the gate electrode of the MOS transistor Q1 is connected with the resistor R1 and the emitter electrode of the triode in the optical coupler U1, the source electrode of the MOS transistor Q1 is connected with the other end of the resistor R1, the input end Vin-and the other end of the resistor R5, the collector electrode of the triode in the optical coupler U1 is connected with a resistor R2, and the other end of the resistor R2 is connected with 12V direct current.

2. The automatic battery charger short-circuit reverse-protection circuit as claimed in claim 1, wherein the optocoupler U1 is of type PC 817.

3. The short-circuit reverse-connection protection circuit of an automatic battery charger as claimed in claim 1, wherein the MOS transistor Q1 is an NMOSFET.

4. The short-circuit reverse-connection protection circuit of an automatic battery charger as claimed in claim 1, wherein the resistance of the resistor R5 is 5K1 Ω.

5. The short-circuit reverse protection circuit of automatic battery charger according to any one of claims 1-4, wherein the capacitance of capacitor C1 and capacitor C2 are both 100 pF.