CN201044350Y

CN201044350Y - Over-charge or short-circuit protection circuit capable of restarting on-line

Info

Publication number: CN201044350Y
Application number: CNU2007201199624U
Authority: CN
Inventors: 袁美照
Original assignee: SHENZHEN SED BAILI ELECTRONICS CO Ltd
Current assignee: Shenzhen SED Baili Electronics Co., Ltd.
Priority date: 2007-04-30
Filing date: 2007-04-30
Publication date: 2008-04-02
Anticipated expiration: 2017-04-30

Abstract

An online restarting overload or short circuit protective circuit comprises a controller U1, a switch K1, a capacitor C1 and a resistance R3. One terminal of the switch K1 is connected with a power input terminal Vin, and the other terminal of the K1 is connected with a resistance R1, and the other terminal of the R1 is connected with a power output terminal Vout; a control terminal of the switch K1 is connected with an inverse input terminal of the controller U1; one terminal of the resistance R3 is connected with the power input terminal Vin, and the other terminal of the resistance R3 is connected with the inverse input terminal of the controller U1; one terminal of the capacitor C1 is connected with the output terminal Vout, and the other terminal of the capacitor C1 is connected with wires of a resistance R2 and a resistance R4. The utility model has the advantage of online restarting timely after the circuit returning to normal state.

Description

The overload or short-circuit protection circuit that can onlinely restart

Technical field

The utility model relates to a kind of basic electronic circuit, the particularly a kind of overload or short-circuit protection circuit that can onlinely restart.

Background technology

A lot of overload or short-circuit protection circuit are arranged at present, but do not accomplish on-line automatic restarting, or effect is undesirable.See also Fig. 5, Fig. 5 is a kind of circuit theory diagrams of prior art, and it comprises controller, K switch 1, resistance R 1, R2, R3; One termination power input Vin of described K switch 1, the other end connecting resistance R1 of K1, another termination power output end Vout of resistance R 1; The control termination controller output end of described K switch 1; Inverting input connecting resistance R2 one end of controller, another termination output end vo ut of resistance R 2; One termination power input Vin of resistance R 3 is on the inverting input of other end connecting resistance R2 and controller.Though sort circuit can provide overload, short-circuit protection circuit,, it can not realize online effect of restarting.

Summary of the invention

The purpose of the present utility model is: provide a kind of overload or short-circuit protection circuit that can onlinely restart to society, and the automatic disconnection when overload or short circuit of this circuit, circuit can onlinely in time restart again after recovering normally.

The technical solution of the utility model is: design a kind of overload or short-circuit protection circuit that can onlinely restart, comprise controller U1, K switch 1, resistance R 3; One termination power input Vin of described K switch 1, another termination power output end Vout of K1; The control termination controller output end of described K switch 1; One termination power input Vin of resistance R 3 is characterized in that: also comprise by capacitor C 1, sample resistance R1 described capacitor C 1 one termination power output end vo ut, the inverting input of another termination controller U1 of capacitor C 1; Described sample resistance R1 is connected between K switch 1 and the power output end Vout.

Described K switch 1 is transistor, field effect transistor or relay.

As to improvement of the present utility model, the utility model also comprises diode D2, and described diode D2 is connected in parallel on the resistance R 3, and the negative electrode of described diode D2 is connected on power input Vin.

As to further improvement of the utility model, the utility model also comprises current-limiting resistance R2, and described current-limiting resistance R2 is connected between the inverting input of the common port of capacitor C 1 and resistance R 4 and controller U1.

The utility model is owing to adopted the on-line automatic restore circuit of being made up of resistance R 3 and capacitor C 1, and therefore, can realize again can the online in time purpose that restarts after circuit recovers normally.

Description of drawings

Fig. 1 is a circuit theory schematic diagram of the present utility model;

Fig. 2 is the improvement circuit theory schematic diagram to Fig. 1;

The electrical block diagram that Fig. 3 forms for a kind of concrete element of Fig. 1;

The electrical block diagram that Fig. 4 forms for the another kind of concrete element of Fig. 1;

Fig. 5 is a kind of circuit theory schematic diagram of prior art.

Embodiment

See also Fig. 1, Fig. 1 is a circuit theory schematic diagram of the present utility model, also is the equivalent electric circuit of Fig. 3, Fig. 4; It is a kind of overload or short-circuit protection circuit that can onlinely restart, and it comprises controller U1, K switch 1, capacitor C 1, resistance R 3; One termination power input Vin of described K switch 1, the other end connecting resistance R1 of K1, another termination power output end Vout of resistance R 1; The reverse input end of the control termination controller U1 of described K switch 1; One termination power input Vin of described resistance R 3 connects the reverse input end of controller U1; One of described capacitor C 1 terminates to output end vo ut, and the other end of described capacitor C 1 is received on the connecting line of resistance R 2 and resistance R 4.Mark Vref in the circuit is the meaning of reference voltage.

The workpiece principle of this circuit is as follows: as shown in Figure 1, when output short circuit or overload, the electric current of output increases, and the voltage drop at resistance R 1 two ends increases, and the voltage drop between output end vo ut and the Vin also increases, and the voltage of Vout reduces.Under the drive of capacitor C 1, the voltage on capacitor C 1 connecting line also reduces, and the voltage of the connecting line of controller also and then reduces, and when the voltage of the connecting line of controller is reduced to lower than reference voltage Vref the time, controller action disconnects K1; The voltage that K1 disconnects back output end vo ut is even lower, and has formed a positive feedback.Protection process when this is output overload or short circuit.

After K1 closes, the voltage of Vout is almost 0, at this moment circuit is by 1 charging of 3 pairs of capacitor C of resistance R, at this moment capacitor C 1 voltage raises gradually, voltage on the connecting line of controller also raises, voltage on the connecting line of controller is higher than in the reference voltage Vref of controller, and controller raises the voltage of output end vo ut.After the voltage of output end vo ut raise, the voltage that promotes the connecting line of controller again raise.Formed a positive feedback again.This is the process that starts.At this moment, as long as load restoration is normal, circuit just can be stably to electric, thereby reaches the online purpose that restarts.Certainly, the resistance R in the foregoing circuit 1 also can be cancelled; When cancellation resistance R 1, then be to utilize the internal resistance of switching tube K1 or the voltage drop of switching tube K1 to take a sample.

See also Fig. 2, Fig. 2 is the improvement circuit theory schematic diagram to Fig. 1.Fig. 2 compares with the described circuit theory diagrams of Fig. 1, and its general structure is identical, and different is to have increased a diode D2 and resistance R 2, and described diode D2 is in parallel with resistance R 3, and described resistance R 2 is serially connected between the inverting input of capacitor C 1 and controller U1.

See also Fig. 3 and Fig. 4, the electrical block diagram that Fig. 3 and Fig. 4 form for the concrete components and parts of the illustrated embodiment of Fig. 1.Fig. 3 compares with Fig. 2, having increased resistance R 5 and voltage-stabilizing controller ZD1 (being voltage-stabiliser tube shown in the figure) voltage-stabiliser tube ZD1 one end and power supply input joins, the other end and resistance R 5 are joined, and resistance R 5 is joined the other end ground connection of resistance R 5 with the common port of voltage-stabiliser tube ZD1 and the positive input of controller U1.

Fig. 4 is the practical case of another kind of the present utility model, and it comprises controller U1 and peripheral component thereof, and the model of described controller U1 is the S-8254 chip; The R3 corresponding among Fig. 1 among Fig. 2 is integrated in controller S-8254 chip internal, the K1 in the field effect transistor Q1 corresponding diagram 1 among Fig. 2, diode D1, D2 among Fig. 2, capacitor C 1, resistance R 4, R2 respectively with Fig. 1 in diode D1, D2, capacitor C 1, resistance R 4, R2 are corresponding one by one.R1 among Fig. 2 is the internal resistance of field effect transistor Q1.The effect of diode D2 is protection controller U1, and when the inverting input overtension of controller U1, then diode D2 conducting is let out.

As shown in Figure 4, the termination power input Vin of field effect transistor Q1, described field effect transistor Q1 one termination power input, 1 pin of the control termination controller U1 of described field effect transistor Q1, the other end of described field effect transistor Q1 connects battery cathode by field effect transistor Q2.Resistance R 4 of the negative electrode string of diode D1 is received resistance R 2, and the anode of described diode D1 is received output, 2 pin of another termination controller U1 of described resistance R 2.One of capacitor C 1 terminates to input, and the other end of described capacitor C 1 is received on the connecting line of resistance R 4 and resistance R 2.The anode of diode D2 connects 2 pin of controller U1, and the negative electrode of diode D2 is connected on power input.The connection of remaining peripheral component and described controller U1 is conventional connection, repeats no more among the application.

Claims

1. the overload or short-circuit protection circuit that can onlinely restart comprises controller (U1), K switch 1, resistance R 3; One termination power input (Vin) of described K switch 1, another termination power output end (Vout) of K1; The control termination controller output end of described K switch 1; One termination power input Vin of resistance R 3 is characterized in that: also comprise by capacitor C 1, sample resistance R1 described capacitor C 1 one termination power outputs (Vout), the inverting input of another termination controller (U1) of capacitor C 1; Described sample resistance R1 is connected between K switch 1 and the power output end (Vout).

2. the overload or short-circuit protection circuit that can onlinely restart according to claim 1 is characterized in that: described K switch 1 is transistor, field effect transistor or relay.

3. the overload or short-circuit protection circuit that can onlinely restart according to claim 1 and 2 is characterized in that: also comprise diode D2, described diode D2 is connected in parallel on the resistance R 3, and the negative electrode of described diode D2 is connected on power input Vin.

4. the overload or short-circuit protection circuit that can onlinely restart according to claim 3 is characterized in that: also comprise current-limiting resistance R2, described current-limiting resistance R2 is connected between the inverting input of the common port of capacitor C 1 and resistance R 4 and controller (U1).