CN208337138U - Output overload protection circuit for low-voltage dc power supply system with self-locking function - Google Patents

Output overload protection circuit for low-voltage dc power supply system with self-locking function Download PDF

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CN208337138U
CN208337138U CN201821147138.4U CN201821147138U CN208337138U CN 208337138 U CN208337138 U CN 208337138U CN 201821147138 U CN201821147138 U CN 201821147138U CN 208337138 U CN208337138 U CN 208337138U
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resistance
triode
connect
control unit
output
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何林
陶利
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CHONGQING LIHUA TECHNOLOGY Co Ltd
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CHONGQING LIHUA TECHNOLOGY Co Ltd
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Abstract

The utility model provides a kind of output overload protection circuit for low-voltage dc power supply system with self-locking function, including powering on the current acquisition unit that stream is acquired to DC power supply output circuit, it is connect with current acquisition unit, and end the switch control unit for realizing shutdown with unlatching to output DC power supply with saturation workspace using triode, it is connect with switch control unit, and make to can control signal progress level conversion by externally input, phase transition goes the enabled control unit of control switch control unit, input terminal is connect with current acquisition unit, output end is connect with switch control unit, and when acquiring electric current and reaching protection threshold value in automatic locking guard mode, and control switch control unit close not output voltage from lock unit.This circuit is automatically shut down rapidly, after overload with response and locking, circuit are included makes can control, and reopening circuit makes after can control, if output, athermic advantage after protection can be restored automatically by overloading revocation.

Description

Output overload protection circuit for low-voltage dc power supply system with self-locking function
Technical field
The utility model relates to DC power system technical fields, and in particular to one kind is used for low-voltage dc power supply system band The output overload protection circuit of self-locking function.
Background technique
Low-pressure electronic equipment product in externally output DC power supply must design protection circuit, to prevent output loading from overloading or Circuit burnout occurs for short circuit, and the serious fortuitous event such as fire generates.Overload protection function is carried using power supply chip in this regard, having at present Can, or use dedicated overload protection chip.But the utility model inventor has found that power supply chip is included Overload protection function is generally used lasting current-limiting protection or overheating protection, and it is big that there are calorific values, and long-term sustained short-circuit can exist Certain risk, and some occasions for not needing power supply chip using directly power supply are not applicable;And dedicated overload protection chip one As using current-limiting protection is continued, equally exist that calorific value is big, and long-term sustained short-circuit can have certain risk, and higher cost.
Utility model content
For existing using the included overload protection function of power supply chip or using dedicated overload protection chip, to low pressure Electric equipment products prevent output loading overload or short circuit from occurring when externally exporting DC power supply, all using lasting current-limiting protection or mistake Thermal protection, it is big that there are calorific values, and long-term sustained short-circuit can there is technical issues that certain, and the utility model provides a kind of use In output overload protection circuit of the low-voltage dc power supply system with self-locking function.
In order to solve the above-mentioned technical problem, the utility model uses the following technical solution:
A kind of output overload protection circuit for low-voltage dc power supply system with self-locking function, including current acquisition list Member, switch control unit, enabled control unit and from lock unit;The current acquisition unit is used for DC power supply output circuit On electric current be acquired;The switch control unit is connect with current acquisition unit, and utilizes the cut-off and saturation of triode Workspace is realized shutdown to output DC power supply and is opened;The enabled control unit is connect with switch control unit, and is used for Make to can control signal progress level conversion by externally input, phase transition goes control switch control unit;It is described from lock unit Input terminal connect with current acquisition unit, output end is connect with switch control unit, and reaches protective door for acquiring electric current In automatic locking guard mode when limit value, and control switch control unit closes not output voltage.
Compared with prior art, provided by the utility model to be used for output of the low-voltage dc power supply system with self-locking function Protection circuit is carried, the electric current on DC power supply output circuit is acquired by current acquisition unit, can control list by making Member makes to can control signal progress level conversion by externally input, and phase transition (i.e. reverse-phase) goes control switch control unit Normal output voltage from lock unit when acquiring electric current and reaching protection threshold value in automatic locking guard mode, and is controlled and is opened The triode cut-off in control unit is closed, shutdown is realized to output DC power supply, switch control unit is made to close not output voltage. This circuit is automatically shut down rapidly, after overload with response and locking, circuit are included makes can control, and reopens circuit and enables control After system, if overload cancels this circuit and can restore automatically the advantages that exporting, not generating heat after protection, car multimedia master can be widely used for The occasions such as the backup camera power supply of machine output, antenna are powered, external indicator light is powered.
Further, the current acquisition unit is acquisition resistance R3, and one end of the acquisition resistance R3 and DC power supply are defeated Inbound port connection, the other end are connect with switch control unit.
Further, the switch control unit includes resistance R7, resistance R8, triode Q4, diode D1, electrolytic capacitor C3 With capacitor C4, one end of the resistance R7 and the emitter of triode Q4 are connect with the other end of acquisition resistance R3, the resistance The other end of R7 and the base stage of triode Q4 are connect with one end of resistance R8, the other end of the resistance R8 and enabled control unit Connected with from lock unit, the collector of the triode Q4 connect with the anode of diode D1, the cathode of the diode D1 and The anode of electrolytic capacitor C3, one end of capacitor C4 are connected with output voltage port.
Further, the enabled control unit includes resistance R5, resistance R6, resistance R9 and triode Q3, the resistance R5 One end connect with enabled control signal end mouth, the other end is connect with the base stage of one end of resistance R6 and triode Q3, the electricity The other end of R6 and the emitter ground connection of triode Q3 are hindered, the collector of the triode Q3 is connect with one end of resistance R9, institute The other end for stating resistance R9 is connect with the other end of resistance R8.
Further, it is described from lock unit include resistance R1, resistance R2, resistance R4, capacitor C1, capacitor C2, triode Q1 and One end of the emitter of Q2, the triode Q1, resistance R2 and capacitor C2 is connect with DC supply input mouth, the resistance One end of R4 is connect with the other end of resistance R3, and collector, resistance R2 and the resistance R4 of the triode Q2 and capacitor C2's is another One end is connect with the base stage of triode Q1, one end of the collector of the triode Q1, resistance R1 and capacitor C1 with three poles The base stage of pipe Q2 connects, the other end of the emitter of the other end and triode Q2 of the resistance R1 and capacitor C1 with resistance R8 Connection.
Detailed description of the invention
Fig. 1 is provided by the utility model for output overload protection circuit of the low-voltage dc power supply system with self-locking function Functional block diagram.
Fig. 2 is provided by the utility model for output overload protection circuit of the low-voltage dc power supply system with self-locking function Structural schematic diagram.
In figure, 1, current acquisition unit;2, switch control unit;3, control unit is enabled;4, from lock unit.
Specific embodiment
In order to be easy to understand the technical means, creative features, achievement of purpose, and effectiveness of the utility model, under Face combines and is specifically illustrating, and the utility model is further described.
In the description of the present invention, it should be understood that term " longitudinal direction ", " radial direction ", " length ", " width ", " thickness The side of the instructions such as degree ", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outside" Position or positional relationship are to be based on the orientation or positional relationship shown in the drawings, and are merely for convenience of description the utility model and simplification is retouched It states, rather than the device or element of indication or suggestion meaning must have a particular orientation, be constructed and operated in a specific orientation, Therefore it should not be understood as limiting the present invention.In the description of the present invention, unless otherwise indicated, " multiple " contain Justice is two or more.
In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, term " is pacified Dress ", " connected ", " connection " shall be understood in a broad sense, for example, it may be being fixedly connected, may be a detachable connection, or integrally Connection;It can be mechanical connection, be also possible to be electrically connected;Can be directly connected, can also indirectly connected through an intermediary, It can be the connection inside two elements.For the ordinary skill in the art, above-mentioned art can be understood with concrete condition The concrete meaning of language in the present invention.
Please refer to shown in Fig. 1 and Fig. 2, the utility model provide it is a kind of for low-voltage dc power supply system with self-locking function Output overload protection circuit, including current acquisition unit 1, switch control unit 2, enabled control unit 3 and from lock unit 4;Institute Current acquisition unit 1 is stated for being acquired to the electric current on DC power supply output circuit;The switch control unit 2 and electric current Acquisition unit 1 connects, and using the cut-off of triode and saturation workspace, realizes shutdown to output DC power supply and open;Institute It states enabled control unit 3 to connect with switch control unit 2, and for making to can control signal progress level turn by externally input It changes, phase transition goes control switch control unit 2;The input terminal from lock unit 4 is connect with current acquisition unit 1, output End is connect with switch control unit 2, and for acquiring when electric current reaches protection threshold value in automatic locking guard mode, and is controlled Switch control unit 2 processed closes not output voltage.
Compared with prior art, provided by the utility model to be used for output of the low-voltage dc power supply system with self-locking function Protection circuit is carried, the electric current on DC power supply output circuit is acquired by current acquisition unit, can control list by making Member makes to can control signal progress level conversion by externally input, and phase transition (i.e. reverse-phase) goes control switch control unit Normal output voltage from lock unit when acquiring electric current and reaching protection threshold value in automatic locking guard mode, and is controlled and is opened The triode cut-off in control unit is closed, shutdown is realized to output DC power supply, switch control unit is made to close not output voltage. This circuit is automatically shut down rapidly, after overload with response and locking, circuit are included makes can control, and reopens circuit and enables control After system, if overload cancels this circuit and can restore automatically the advantages that exporting, not generating heat after protection, car multimedia master can be widely used for The occasions such as the backup camera power supply of machine output, antenna are powered, external indicator light is powered.
It as specific embodiment, please refers to shown in Fig. 2, the current acquisition unit is acquisition resistance R3, the acquisition electricity One end of resistance R3 is connect with DC supply input mouth Vin, and the other end is connect with switch control unit 2.
It as specific embodiment, please refers to shown in Fig. 2, the switch control unit 2 includes resistance R7, resistance R8, three poles Pipe Q4, diode D1, one end of electrolytic capacitor C3 and capacitor C4, the resistance R7 and triode Q4 emitter and acquisition resistance The other end of R3 connects, and the other end of the resistance R7 and the base stage of triode Q4 are connect with one end of resistance R8, the resistance The other end of R8 is connect with enabled control unit 3 and from lock unit 4, the collector of the triode Q4 and the anode of diode D1 Connection, the cathode of the diode D1 are connect with the anode of electrolytic capacitor C3, one end of capacitor C4 and output voltage port Vout.
It as specific embodiment, please refers to shown in Fig. 2, the enabled control unit 3 includes resistance R5, resistance R6, resistance R9 and triode Q3, one end of the resistance R5 are connect with enabled control signal end mouth Control, and the one of the other end and resistance R6 End is connected with the base stage of triode Q3, the other end of the resistance R6 and the emitter ground connection of triode Q3, the triode Q3 Collector connect with one end of resistance R9, the other end of the resistance R9 is connect with the other end of resistance R8.
As specific embodiment, please refer to shown in Fig. 2, it is described to include resistance R1, resistance R2, resistance R4, electricity from lock unit 4 Hold C1, capacitor C2, triode Q1 and Q2, one end of the emitter of the triode Q1, resistance R2 and capacitor C2 is and direct current Source input port Vin connection, one end of the resistance R4 are connect with the other end of resistance R3, the collector of the triode Q2, The other end of resistance R2 and resistance R4 and capacitor C2 is connect with the base stage of triode Q1, collector, the electricity of the triode Q1 One end of resistance R1 and capacitor C1 is connect with the base stage of triode Q2, the other end and triode Q2 of the resistance R1 and capacitor C1 Emitter connect with the other end of resistance R8.
The output overloading provided by the present application for low-voltage dc power supply system with self-locking function is protected in order to better understand Protection circuit below will be introduced its working principle:
1, normal condition: microcontroller output make can control signal Control from enabled control port through resistance R5 and R6 partial pressure, reaches the base stage of triode Q3, makes triode Q3 saturation conduction, the Q3 collector of triode is pulled low, DC power supply Electric current on output circuit reaches triode through the resistance R8 and R9 of resistance R3, the emitter of triode Q4 and triode Q4 base stage The collector of Q3 forms the base current of triode Q4, and triode Q4 is connected, and direct current power source voltage flows through diode D1, then Output extremely loads after capacitor C3 and C4 filtering.The electric current on DC power supply output circuit is in protection threshold value hereinafter, electricity at this time Stream flows through the base stage that the voltage generated on acquisition resistance R3 reaches triode Q1 through resistance R4 and R2 and is less than 0.6V, and triode Q1 is cut Only, while triode Q2 is also switched off, and will not be acted from lock unit 4.
2, overload protection: when load current overload, current loop flows through acquisition resistance R3 and increases, when on acquisition resistance R3 The voltage that face generates reaches 0.6V or so after resistance R4 and R2 partial pressure, it is sufficient to when triode Q1 is connected, triode Q1 conducting, Making the output of triode Q1 collector is high level;And then keeping triode Q2 base stage high, its collector is drawn in triode Q2 conducting It is low, continue as triode Q1 base stage low, two triodes Q1 and Q2 realize interlocking conducting, and triode Q2 emitter is because of three at this time Pole pipe Q1 and Q2 are connected and export as height;Keep resistance R8 other end end high, triode Q4 base stage is accordingly drawn high, thus three poles Pipe Q4 cut-off, shutdown output, realizes defencive function.After output shutdown, acquisition resistance R3 electric current decline, acquisition resistance R3 is generated Voltage also decreases, but is connected since triode Q1 and Q2 are interlocked, and triode Q1 will not be by the voltage above acquisition resistance R3 It reduces and ends, so being able to maintain guard mode after output shutdown.Until microprocessor input make can control signal-off, then It opens, and output overloading state has cancelled, this circuit can just restore output voltage automatically.
In addition, the capacitor C2 and C1 in this circuit are delay protection capacitor, since the RC of resistance R4 and capacitor C2 are acted on, This circuit erroneous action will not be made by loading when powered on moment generates rush of current or when being interfered by external pulse, and diode D1 Effect designs to prevent load end electric current from flowing backward.
Finally, it is stated that above embodiments are merely intended for describing the technical solutions of the present application, but not for limiting the present application, although ginseng The utility model is described in detail according to preferred embodiment, those skilled in the art should understand that, it can be to this The technical solution of utility model is modified or replaced equivalently, without departing from the objective and model of technical solutions of the utility model It encloses, should all cover in the scope of the claims of the utility model.

Claims (5)

1. being used for output overload protection circuit of the low-voltage dc power supply system with self-locking function, which is characterized in that adopted including electric current Collect unit, switch control unit, enabled control unit and from lock unit;The current acquisition unit is used to export DC power supply Electric current on circuit is acquired;The switch control unit is connect with current acquisition unit, and using triode cut-off with It is saturated workspace, shutdown is realized to output DC power supply and is opened;The enabled control unit is connect with switch control unit, and For making to can control signal progress level conversion by externally input, phase transition goes control switch control unit;It is described self-locking The input terminal of unit is connect with current acquisition unit, and output end is connect with switch control unit, and reaches guarantor for acquiring electric current In automatic locking guard mode when protecting threshold value, and control switch control unit closes not output voltage.
2. according to claim 1 be used for output overload protection circuit of the low-voltage dc power supply system with self-locking function, It is characterized in that, the current acquisition unit is acquisition resistance R3, one end of the acquisition resistance R3 and DC supply input mouth Connection, the other end are connect with switch control unit.
3. according to claim 2 be used for output overload protection circuit of the low-voltage dc power supply system with self-locking function, It is characterized in that, the switch control unit includes resistance R7, resistance R8, triode Q4, diode D1, electrolytic capacitor C3 and capacitor One end of C4, the resistance R7 and the emitter of triode Q4 are connect with the other end of acquisition resistance R3, and the resistance R7's is another The base stage of one end and triode Q4 are connect with one end of resistance R8, the other end of the resistance R8 and enabled control unit and self-locking Unit connection, the collector of the triode Q4 are connect with the anode of diode D1, the cathode and electrolysis electricity of the diode D1 One end of the anode, capacitor C4 that hold C3 is connected with output voltage port.
4. according to claim 3 be used for output overload protection circuit of the low-voltage dc power supply system with self-locking function, It is characterized in that, the enabled control unit includes resistance R5, resistance R6, resistance R9 and triode Q3, one end of the resistance R5 It is connect with enabled control signal end mouth, the other end is connect with the base stage of one end of resistance R6 and triode Q3, the resistance R6's The emitter of the other end and triode Q3 ground connection, the collector of the triode Q3 are connect with one end of resistance R9, the resistance The other end of R9 is connect with the other end of resistance R8.
5. according to claim 3 be used for output overload protection circuit of the low-voltage dc power supply system with self-locking function, Be characterized in that, it is described from lock unit include resistance R1, resistance R2, resistance R4, capacitor C1, capacitor C2, triode Q1 and Q2, it is described One end of the emitter of triode Q1, resistance R2 and capacitor C2 is connect with DC supply input mouth, and the one of the resistance R4 End is connect with the other end of resistance R3, and collector, resistance R2 and the resistance R4 of the triode Q2 and the other end of capacitor C2 are equal It is connect with the base stage of triode Q1, one end of the collector of the triode Q1, resistance R1 and capacitor C1 is with triode Q2's Base stage connection, the emitter of the other end and triode Q2 of the resistance R1 and capacitor C1 are connect with the other end of resistance R8.
CN201821147138.4U 2018-07-19 2018-07-19 Output overload protection circuit for low-voltage dc power supply system with self-locking function Active CN208337138U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201821147138.4U CN208337138U (en) 2018-07-19 2018-07-19 Output overload protection circuit for low-voltage dc power supply system with self-locking function

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201821147138.4U CN208337138U (en) 2018-07-19 2018-07-19 Output overload protection circuit for low-voltage dc power supply system with self-locking function

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110324034A (en) * 2019-07-04 2019-10-11 东莞市卓品电子科技有限公司 A kind of DC power supply output-controlling device
CN113839368A (en) * 2021-08-19 2021-12-24 惠州Tcl云创科技有限公司 Load protection circuit and power supply equipment

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110324034A (en) * 2019-07-04 2019-10-11 东莞市卓品电子科技有限公司 A kind of DC power supply output-controlling device
CN110324034B (en) * 2019-07-04 2023-04-18 东莞市卓品电子科技有限公司 DC power supply output control device
CN113839368A (en) * 2021-08-19 2021-12-24 惠州Tcl云创科技有限公司 Load protection circuit and power supply equipment

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