CN208753973U

CN208753973U - A kind of low level triggering latching circuit

Info

Publication number: CN208753973U
Application number: CN201821327326.5U
Authority: CN
Inventors: 刘富兴; 宋建峰; 程志勇
Original assignee: Mornsun Guangzhou Science and Technology Ltd
Current assignee: Mornsun Guangzhou Science and Technology Ltd
Priority date: 2018-08-17
Filing date: 2018-08-17
Publication date: 2019-04-16
Anticipated expiration: 2028-08-17

Abstract

The utility model provides a kind of low level triggering latching circuit, is mainly used in Switching Power Supply, the latching circuit in control circuit, it can be achieved that low level triggering and self-locking；When the exception such as over-voltage, excess temperature occurs for external output end voltage, outside exports detection unit and sends a low level single pulse signal to the triggering end of low level triggering latching circuit, so that the control terminal of low level triggering latching circuit is persistently kept low level, by the controller shutdown outside control terminal control, and achieve the purpose that self-locking.The utility model can be applied not only to output over-voltage locking protection, be equally applicable for the circuit that excess temperature locking protection etc. needs low level to trigger and need to keep.

Description

A kind of low level triggering latching circuit

Technical field

The utility model relates to the control fields such as Switching Power Supply, driving, especially control terminals, and low level to be needed to trigger and protect The circuit held.

Background technique

With social progress and the reach of science, the high reliability of product is big important as improve product competitiveness one Factor generally comprises input, output protection mechanism at this stage in Switching Power Supply.Importation such as inputs overvoltage, electricity is owed in input Pressure protection, the protection mechanisms such as output par, c such as output over-voltage, overcurrent, short circuit.

Currently, output over-voltage protection mechanism is generally divided into three kinds: the first is output voltage clamper protected mode, even if Obtain makes false voltage be maintained at comparatively safe level when output over-voltage failure occurs；Second is hiccup protections mode, i.e., Shutdown output voltage when above-mentioned failure occurs, and for a period of time, then starting detection failure again again whether there is, until therefore Barrier disappears；The third is to turn off output voltage mode, that is, occurs directly to turn off output voltage when output over-voltage failure, until Recovery is restarted when trouble shooting.

Obviously, the equipment that the first clamper protected mode is only applicable to equipment wide input voltage range, and use the protection The small-power switching power-supply of the generally low-voltage output of mode.The fatal defects of the protected mode are that output over-voltage occurs When failure, one side power supply overpower time length itself will greatly shorten power source life, and another aspect electrical equipment continues in height It works under voltage rating, considerably increases damage risk, and the not noticeable failure of this kind of protected mode occurs, and cannot send out in time Now repair；The second way enhances predictability, and can operate in the slightly larger equipment of power, but its disadvantage also it is obvious that Hiccup protections mode makes the continuous switching on and shutting down of equipment, injures particularly with electrical equipments such as transient power demand height, inductive loads It is very big；The third protected mode applies less, the only built-in protected mode of a small number of power-supply controller of electric, but the protection side at present Formula is immature, and the situation of Chang Fasheng relay protective scheme confusion, range is also narrow, product adjustable for some output voltage ranges It provides no advantage against.

Utility model content

In view of the above-mentioned problems, the utility model provides a kind of low level triggering latching circuit, which be can be applied not only to Output over-voltage locking protection is equally applicable for the circuit that excess temperature locking protection etc. needs low level to trigger and need to keep.

By taking the locking protection of Switching Power Supply output over-voltage as an example, which passes through when there is output over-voltage failure Comparing detection unit and triggering holding unit makes power-supply controller of electric continue shutdown output, reaches the protection side of output voltage shutdown Simultaneously as the triggering holding unit is external unit chiasma interference problem is not present with IC internal logic, therefore widen in formula Protection scope, while ensure that the validity of its protection.

To achieve the above object, the utility model takes following basic technical scheme: one kind be mainly used in Switching Power Supply, Latching circuit in control circuit is, it can be achieved that low level triggering and self-locking；Including resistance R1, triode Q1, triode Q2, a touching Originator, a control terminal and a stable power-supplying end, the supply voltage of stable power-supplying end stable connection are defeated outside triggering end connection Detection unit out, control terminal are connected to external controller, control the enabled and disability of peripheral control unit；One end of resistance R1 connects It is connected to stable power-supplying end, the emitter of the other end connecting triode Q1 of resistance R1, the base stage of triode Q1 and triode Q2's Collector is connected and is connected respectively with control terminal and triggering end, and the collector of triode Q1 is connected with triode Q2 base stage, three poles The emitter of pipe Q2 is grounded.

Preferably, on the basis of basic technical scheme, low level described in the utility model triggers latching circuit, also wraps Resistance R2 and resistance R3 are included, resistance R2 is connected between the base stage and triggering end of triode Q1, and resistance R3 is connected to triode Q1 Collector and triode Q2 base stage between.

Alternatively, further including zener diode Z, the anode connection three of zener diode Z on the basis of basic technical scheme The base stage of pole pipe Q2, the collector of the cathode connected to the transistor Q1 of zener diode Z.

Alternatively, further including resistance R6 on the basis of basic technical scheme, resistance R6 is connected to the collector and ground of Q1 Between.

Utility model works principle is as follows:

When the exception such as over-voltage, excess temperature occurs for external output end voltage, outside output detection unit sends a low level Single pulse signal all drags down control terminal and PNP pipe base stage to triggering end, so that PNP pipe is connected, at this time at stable power-supplying end Under aid, NPN triode is by saturation conduction, so that control terminal is persistently kept low level, achievees the purpose that self-locking.It is supplied when stablizing Under electric end after electricity, control terminal is just released, and at this time if there is the triggering of low level pulse again, repeats the above logic.

Compared with prior art, the utility model has the following beneficial effects:

1) the utility model provides a kind of low level triggering latching circuit, when control terminal has " self- recoverage " formula logic, Triggering locking can be carried out to control terminal by the utility model circuit, to have the function that lasting holding.

2) the utility model, which can solve some integrated control units, has relay protective scheme confusion, passes through peripheral circuit Control terminal is continued to lock, and is separated inside control unit, so that it is mixed to solve relay protective scheme existing for integrated control unit Random problem.

Detailed description of the invention

Fig. 1 is the utility model first embodiment circuit diagram；

Fig. 2 be the utility model second embodiment circuit diagram apply output over-voltage lock protection work-based logic show It is intended to；

Fig. 3 is that the utility model second embodiment circuit diagram is applied in excess temperature locking protection work-based logic schematic diagram；

Fig. 4 is the utility model 3rd embodiment circuit diagram figure；

Fig. 5 is the utility model fourth embodiment circuit diagram figure.

Specific embodiment

First embodiment

Referring to Fig. 1, what the utility model was proposed a kind of is mainly used in Switching Power Supply, the self-locking electricity in control circuit Road includes resistance R1, a NPN triode Q2, a PNP triode Q1, a triggering end, a control terminal and a stable power-supplying It holds, the supply voltage of stable power-supplying end stable connection, the output detection unit outside triggering end connection, when output detection unit inspection When having measured output abnormality, low level being fed back to by triggering end and triggers latching circuit, control terminal is connected to external controller, Control the enabled and disability of peripheral control unit；Wherein one end of resistance R1 is connected to stable power-supplying end, and the other end of resistance R1 connects Connect the emitter of PNP triode Q1, the base stage of PNP triode Q1 and the collector of NPN triode Q2 be connected and respectively with control End is connected with triggering end, and the collector of PNP triode Q1 is connected with NPN triode Q2 base stage, and the emitter of NPN triode Q2 connects Ground.

The working principle of the utility model is as follows: when the exception such as over-voltage, excess temperature occurs for external output end voltage, triggering end A low level pulse is received, control terminal and PNP pipe Q1 base stage are all dragged down, so that PNP pipe Q1 is connected, is stablizing confession at this time Under the aid at electric end, NPN triode Q2 is by saturation conduction, so that control terminal is persistently kept low level, achievees the purpose that self-locking. After electricity under stable power-supplying end, control terminal is just released, and at this time if there is the triggering of low level pulse again, repeats above patrol Volume.

Second embodiment

On the basis of first embodiment, resistance R2 and resistance R3 are increased, resistance R2 is connected to the base stage and triggering of Q1 Between end, resistance R3 is connected between the collector of Q1 and the base stage of Q2.Resistance R1 and R3 form current limliting and bleeder circuit, prevent Because the conducting of Q1, Q2 are clamped stable power-supplying end VCC, to prevent Q1, Q2 transient state overpower from damaging；R2 also rises in circuit Metering function, to limit the electric current for flowing through OC and Q2.

The working principle of the utility model is as follows:

Fig. 2 is that utility model second embodiment circuit diagram is applied in output over-voltage locking protection work-based logic signal Figure, when overvoltage occurs in output end vo, voltage-stabiliser tube Z1 is breakdown, has larger current to flow through Optocoupler detection device at this time, passes through The conversion of electrical-optical-electrical, optocoupler output base stage detect photoelectron, so that optocoupler output is connected, by control terminal EN pin electricity Horizontal drawing is low, shutdown controller driving, output voltage shutdown.Meanwhile PNP triode Q1 emitter junction positively biased is connected, so that tri- pole NPN Pipe Q2 emitter junction and collector junction positively biased, triode Q2 saturation conduction, control terminal EN is persistently locked, to realize self-locking mesh 's.

Fig. 3 is that the utility model second embodiment circuit diagram is applied in excess temperature locking protection work-based logic schematic diagram, When temperature is more than setting value, NTC thermistor resistance decrease, Q3 base potential is reduced, so that PNP triode Q3 is connected, Control terminal EN is pulled low, shutdown controller driving, output voltage shutdown.Meanwhile PNP triode Q1 emitter junction positively biased is connected, and makes NPN triode Q2 emitter junction and collector junction positively biased are obtained, triode Q2 saturation conduction, control terminal EN is persistently locked, to realize Self-locking purpose.

3rd embodiment

On the basis of first embodiment, for the circuit that some pairs of recovery times require, the utility model is to first Embodiment has made some improvements.The base of the anode connection Q2 of zener diode a Z, Z is sealed between Q1 collector and Q2 base stage Pole, the collector of the cathode connection Q1 of Z, latching circuit release current potential and resetting time, tool when electricity under stable power-supplying end is adjusted Body running principle is identical with the first embodiment, and details are not described herein.

Fourth embodiment

Resistance R6 is increased on the basis of first embodiment, R6 is connected between the collector of Q1 and ground.

Increase R6 effect also for adjust stable power-supplying end under electricity when low level triggering latching circuit release current potential and Resetting time.

It should be pointed out that above-mentioned preferred embodiment is not construed as limitations of the present invention, this technology is led For the those of ordinary skill in domain, without departing from the spirit and scope of the utility model, several improvement and profit can also be made Decorations, these improvements and modifications also should be regarded as the protection scope of the utility model, and the protection scope of the utility model should be with right It is required that subject to limited range.

Claims

1. a kind of low level triggers latching circuit, it is characterised in that: including resistance R1, triode Q1, triode Q2, a triggering End, a control terminal and a stable power-supplying end, the supply voltage of stable power-supplying end stable connection, the output outside triggering end connection Detection unit, control terminal are connected to external controller, control the enabled and disability of peripheral control unit；One end of resistance R1 connects To stable power-supplying end, the emitter of the other end connecting triode Q1 of resistance R1, the base stage of triode Q1 and the collection of triode Q2 Electrode is connected and is connected respectively with control terminal and triggering end, and the collector of triode Q1 is connected with triode Q2 base stage, triode The emitter of Q2 is grounded.

2. low level according to claim 1 triggers latching circuit, it is characterised in that: it further include resistance R2 and resistance R3, Resistance R2 is connected between the base stage and triggering end of triode Q1, and resistance R3 is connected to the collector and triode Q2 of triode Q1 Base stage between.

3. low level according to claim 1 triggers latching circuit, it is characterised in that: further include zener diode Z, pressure stabilizing The base stage of the anode connecting triode Q2 of diode Z, the collector of the cathode connected to the transistor Q1 of zener diode Z.

4. low level according to claim 1 triggers latching circuit, it is characterised in that: further include resistance R6, resistance R6 connects It connects between the collector and ground of triode Q1.