CN208062771U

CN208062771U - A kind of current foldback circuit

Info

Publication number: CN208062771U
Application number: CN201820384844.4U
Authority: CN
Inventors: 孙启龙; 向东方
Original assignee: Ying Zhi Technology (changzhou) Co Ltd
Current assignee: Ying Zhi Technology (changzhou) Co Ltd
Priority date: 2018-03-21
Filing date: 2018-03-21
Publication date: 2018-11-06
Anticipated expiration: 2028-03-21

Abstract

The utility model discloses a kind of current foldback circuits, and the operating mode by improving existing current foldback circuit solves the technical issues of existing current foldback circuit can not cope with circuit overcurrent, and structure includes：Level detection module and protection control module further include：Triode Q1, triode Q2, triode Q3, triode Q4 and N-channel MOS pipe Q5.The utility model is by providing a kind of current foldback circuit, the technological deficiency of electric current when can cannot limit overcurrent efficiently against the normally-closed contact of existing relay.Electric current is in certain value during the utility model understands limiting circuit by using N-channel MOS pipe Q5 in circuit generation overcurrent; until circuit protection module sends out signal; N-channel MOS pipe Q5 is set to turn off; and then realize circuit protection, avoid the electricity device in available circuit from causing to damage due to flowing through larger current within the of short duration time that overcurrent protection acts.

Description

A kind of current foldback circuit

Technical field

The utility model is related to circuit current protection technology field more particularly to a kind of current foldback circuits.

Background technology

Current foldback circuit in the prior art shown in Fig. 1, when electric current is less than setting value in circuit, resistance R₁Both ends Pressure drop can not make Q₁Conducting, input are exported by relay normally closed contact to load；When electric current is more than certain value in circuit When, R₁Both ends pressure drop makes Q₁Conducting, relay coil both end voltage make relay normally closed contact disconnect, normally opened contact RL₁It is attracted, What is output and input is separated, and then realizes circuit protection.

For current foldback circuit in the prior art when overcurrent in circuit, relay coil, which is attracted, needs the of short duration time, In this of short duration time interval, load and circuit can bear excessive electric current, and the part electricity device in circuit is caused to occur Damage.

Therefore it provides a kind of current foldback circuit just becomes ability for solving at least one of above-mentioned technical problem Field technique personnel's urgent problem to be solved.

Utility model content

The purpose of this utility model is to provide a kind of current foldback circuit, by the work for improving existing current foldback circuit Pattern solves the technical issues of existing current foldback circuit can not cope with circuit overcurrent.

To achieve the goals above：The utility model provides a kind of current foldback circuit, including level detection module and guarantor Control module is protected, further includes：Triode Q1, triode Q2, triode Q3, triode Q4 and N-channel MOS pipe Q5；Three pole After the emitter of pipe Q1 is connected with resistance R2, resistance R1 successively, it is electrically connected with the base stage of triode Q1；The resistance R2 and resistance The junction of R1 is electrically connected with the anode of battery BAT；After the collector of the triode Q1 is connected with resistance R7, resistance R8 successively It is electrically connected with the emitter of the triode Q2；The base stage electricity of the junction of the resistance R7 and resistance R8 and the triode Q2 Connection；The resistance R8 is electrically connected place with the emitter of the triode Q2 and is electrically connected with the cathode of the battery BAT；Described three The collector of pole pipe Q2 connects with resistance R9 and is followed by 5V DC power supplies；The collector of the triode Q2 and the level detection mould Block is electrically connected；Collector with triode Q4 after the resistance R1 connects with the junction of the triode Q1 base stages with resistance R3 Electrical connection；The base stage of the triode Q4 is used for input pulse wave PUL after connecting with resistance R4；The emitter of the triode Q4 It is electrically connected with the cathode of the battery BAT；Diode D1 is connected in parallel on the both ends of the resistance R3 after connecting with capacitance C1, and described two The anode of pole pipe D1 is connected electrically in high potential one end of the resistance R3；The anode of the cathode and diode D2 of the diode D1 Electrical connection；The cathode of the diode D2 is electrically connected with after capacitance C2 series connection with the anode of the diode D1；N-channel MOS pipe The drain electrode of Q5 is electrically connected with the anode of diode D1；The grid of the N-channel MOS pipe Q5 connect with the resistance R5 after with it is described The cathode of diode D2 is electrically connected；It is connected in parallel to zener diode respectively between the grid and source electrode of the N-channel MOS pipe Q5 ZD1 and resistance R6；The anode of the zener diode ZD1 source electrode with the N-channel MOS pipe Q5, and load connecting pin respectively OUT is electrically connected；The grid of the N-channel MOS pipe Q5 is electrically connected with after resistance R10 series connection with the collector of the triode Q3； The collector of the triode Q1 successively with diode D3, resistance R

It is electrically connected with the base stage of the triode Q3 after 13 series connection, the sun of the collector and diode D3 of the triode Q1 Pole is electrically connected；The base stage of the triode Q3 is electrically connected by resistance R11 with the emitter of the triode Q3；The triode The emitter of Q3 is electrically connected with the cathode of the battery BAT；The base stage of the triode Q3 successively with resistance R12 and diode D4 It is electrically connected with the protection control module after series connection, the protection control module is electrically connected with the anode of the diode D4.

Preferably, further include microcontroller, the impulse wave PUL is sent out by the microcontroller.

The utility model, can be efficiently against the normally-closed contact of existing relay by providing a kind of current foldback circuit The technological deficiency of electric current when cannot limit overcurrent.The utility model is by using N-channel MOS pipe Q5 when overcurrent occurs for circuit Electric current is in certain value in meeting limiting circuit, until circuit protection module sends out signal, N-channel MOS pipe Q5 is made to turn off, and then realize Circuit protection, avoid the electricity device in available circuit within the of short duration time that overcurrent protection acts due to flowing through larger current and Cause to damage.

Description of the drawings

Fig. 1 is the electrical block diagram of current foldback circuit in the prior art；

Fig. 2 is the electrical block diagram of current foldback circuit in the utility model embodiment.

Specific implementation mode

The embodiments of the present invention are described below in detail, examples of the embodiments are shown in the accompanying drawings, wherein from beginning Same or similar element or element with the same or similar functions are indicated to same or similar label eventually.Below by ginseng The embodiment for examining attached drawing description is exemplary, it is intended to for explaining the utility model, and should not be understood as to the utility model Limitation.

Referring to FIG. 2, Fig. 2 is the electrical block diagram of the current foldback circuit provided in the present embodiment.In one kind In specific implementation mode, the structure of current foldback circuit provided by the utility model includes：Level detection module and protection are controlled Molding block further includes：Triode Q1, triode Q2, triode Q3, triode Q4 and N-channel MOS pipe Q5；The triode Q1 Emitter connect successively with resistance R2, resistance R1 after, be electrically connected with the base stage of triode Q1；The resistance R2 and resistance R1's Junction is electrically connected with the anode of battery BAT；The collector of the triode Q1 connect successively with resistance R7, resistance R8 after with institute State the emitter electrical connection of triode Q2；The junction of the resistance R7 and resistance R8 and the base stage of the triode Q2 are electrically connected It connects；The resistance R8 is electrically connected place with the emitter of the triode Q2 and is electrically connected with the cathode of the battery BAT；Three pole The collector of pipe Q2 connects with resistance R9 and is followed by 5V DC power supplies；The collector of the triode Q2 and the level detection module Electrical connection；The resistance R1 is electric with the collector of triode Q4 after connecting with resistance R3 with the junction of the triode Q1 base stages Connection；The base stage of the triode Q4 is used for input pulse wave PUL after connecting with resistance R4；The emitter of the triode Q4 with The cathode of the battery BAT is electrically connected；Diode D1 is connected in parallel on the both ends of the resistance R3, two pole after connecting with capacitance C1 The anode of pipe D1 is connected electrically in high potential one end of the resistance R3；The anode electricity of the cathode of the diode D1 and diode D2 Connection；The cathode of the diode D2 is electrically connected with after capacitance C2 series connection with the anode of the diode D1；N-channel MOS pipe Q5 Drain electrode be electrically connected with the anode of diode D1；The grid of the N-channel MOS pipe Q5 connect with the resistance R5 after with described two The cathode of pole pipe D2 is electrically connected；It is connected in parallel to zener diode respectively between the grid and source electrode of the N-channel MOS pipe Q5 ZD1 and resistance R6；The anode of the zener diode ZD1 source electrode with the N-channel MOS pipe Q5, and load connecting pin respectively OUT is electrically connected；The grid of the N-channel MOS pipe Q5 is electrically connected with after resistance R10 series connection with the collector of the triode Q3； The collector of the triode Q1 is electrically connected after connecting successively with diode D3, resistance R 13 with the base stage of the triode Q3, The collector of the triode Q1 is electrically connected with the anode of diode D3；The base stage of the triode Q3 passes through resistance R11 and institute State the emitter electrical connection of triode Q3；The emitter of the triode Q3 is electrically connected with the cathode of the battery BAT；Described three The base stage of pole pipe Q3 is electrically connected with after resistance R12 and diode D4 series connection with the protection control module successively, the protection control Molding block is electrically connected with the anode of the diode D4.

Wherein, level detection module controls the output signal of protection control module, electricity by the level signal detected Resistance R1 is current sampling resistor, and pressure drop is that the pressure drop of resistance R1 subtracts the pressure of resistance R2 between the base stage and emitter of triode Q1 Drop, when the electric current for flowing through resistance R1 is less than certain value, triode Q1 base voltages are less than conducting voltage, and triode Q1 is cut Only, without pressure drop between triode Q2 base stages and emitter, triode Q2 cut-offs, level detection end detects 5V high level at this time, The output signal of protection control module makes triode Q3 end, and impulse wave PUL controls triode Q4 turn-on and turn-off, makes capacitance C1 Bootstrap, it is high voltage end that capacitance C1, which connect one end with diode D2 anodes, and N-channel is connected on by diode D2, resistance R5 On the grid of metal-oxide-semiconductor Q5, N-channel MOS pipe Q5 grid voltages are higher than source voltage, and zener diode ZD1 makes N-channel MOS pipe Pressure difference is stablized in certain value, the Q5 conductings of N-channel MOS pipe between Q5 grids and source electrode, and output is normal；When the electric current for flowing through resistance R1 When more than certain value, between the base stage and emitter of triode Q1 pressure drop so that triode Q1 is connected, cell voltage passes through electricity respectively Hinder R2, R7, R8 partial pressure, between the base stage and emitter of triode Q2 pressure drop so that triode Q2 is connected, level detection is to low at this time Level 0V, at this time triode Q3 be in magnifying state, collector output voltage makes N-channel MOS pipe Q5 be in constant current area, in perseverance Area is flowed, the electric current for flowing through N-channel MOS pipe Q5 is its saturation current, and level detection module detects low level after a certain period of time, to Control module sends out signal, and control module, which sends out signal, makes triode Q3 be connected, after triode Q3 conductings, capacitance C1 Bootstraps Voltage by resistance R5, R10 divide, at this time N-channel MOS pipe Q5 grid voltages make N-channel MOS pipe Q5 turn off, circuit enter Guard mode.

Further, further include microcontroller in one of the present embodiment optimal technical scheme, the impulse wave PUL is sent out by the microcontroller.It is the prior art due to sending out impulse wave PUL using microcontroller, therefore about the correlation of microcontroller Technical information is not further illustrated and is repeated herein.

The various embodiments described above are only preferred embodiments of the present invention, in the art, every to be based on this reality With the changes and improvements in new technique scheme, should not exclude except the scope of protection of the utility model.

Claims

1. a kind of current foldback circuit, including level detection module and protection control module, which is characterized in that further include：Three poles Pipe Q1, triode Q2, triode Q3, triode Q4 and N-channel MOS pipe Q5；The emitter of the triode Q1 successively with resistance After R2, resistance R1 series connection, it is electrically connected with the base stage of triode Q1；The junction of the resistance R2 and resistance R1 is with battery BAT's Anode electrical connection；Transmitting with the triode Q2 after the collector of the triode Q1 is connected with resistance R7, resistance R8 successively Pole is electrically connected；The resistance R7 is electrically connected with the junction of resistance R8 with the base stage of the triode Q2；The resistance R8 and institute It states and is electrically connected with the cathode of the battery BAT at the emitter electrical connection of triode Q2；The collector of the triode Q2 and electricity Resistance R9 series connection is followed by 5V DC power supplies；The collector of the triode Q2 is electrically connected with the level detection module；The resistance R1 is electrically connected with the junction of the triode Q1 base stages with after resistance R3 series connection with the collector of triode Q4；The triode The base stage of Q4 is used for input pulse wave PUL after connecting with resistance R4；The emitter of the triode Q4 is negative with the battery BAT's Pole is electrically connected；Diode D1 is connected in parallel on the both ends of the resistance R3 after connecting with capacitance C1, the anode of the diode D1 is electrically connected It is connected on high potential one end of the resistance R3；The cathode of the diode D1 is electrically connected with the anode of diode D2；Two pole The cathode of pipe D2 is electrically connected with after capacitance C2 series connection with the anode of the diode D1；The drain electrode of N-channel MOS pipe Q5 and diode The anode of D1 is electrically connected；The grid of the N-channel MOS pipe Q5 is electric with the cathode of the diode D2 after connecting with the resistance R5 Connection；It is connected in parallel to zener diode ZD1 and resistance R6 respectively between the grid and source electrode of the N-channel MOS pipe Q5；It is described The anode of the zener diode ZD1 source electrode with the N-channel MOS pipe Q5, and load connecting pin OUT electrical connections respectively；The N ditches The grid of road metal-oxide-semiconductor Q5 is electrically connected with after resistance R10 series connection with the collector of the triode Q3；The current collection of the triode Q1 Pole is electrically connected with after diode D3, resistance R13 series connection with the base stage of the triode Q3 successively, the collector of the triode Q1 It is electrically connected with the anode of diode D3；The emitter electricity that the base stage of the triode Q3 passes through the resistance R11 and triode Q3 Connection；The emitter of the triode Q3 is electrically connected with the cathode of the battery BAT；The base stage of the triode Q3 successively with electricity It is electrically connected with the protection control module after resistance R12 and diode D4 series connection, the protection control module and the diode D4 Anode electrical connection.

2. current foldback circuit according to claim 1, which is characterized in that further include microcontroller, the impulse wave PUL by The microcontroller is sent out.