CN209057109U - A kind of protection circuit and Switching Power Supply - Google Patents

Abstract

The utility model relates to a kind of protection circuit and Switching Power Supplies, including controlling chip, thermal resistor, zener diode, three end adjustable shunt reference sources, triode Q1, triode Q2 and triode Q3, thermal resistor respectively with reference voltage chip, the cathode of zener diode, the reference end of three end adjustable shunt reference sources is connected with fan cathode, the anode of zener diode is connect with the base stage of triode Q2, the collector of triode Q2 is connect with voltage output end, voltage output end is also connect with the base stage of triode Q1, the collector of triode Q1 is connect with reference voltage chip, the anode of three end adjustable shunt reference sources is connect with fan cathode, the cathode of three end adjustable shunt reference sources is connect with the base stage of triode Q3, the emitter of triode Q3 is connect with voltage output end, the current collection of triode Q3 Pole is connect with fan anode.The utility model can control fan movement according to temperature change, to guarantee the service life of Switching Power Supply.

Description

A kind of protection circuit and Switching Power Supply

Technical field

The utility model relates to the technical field of Switching Power Supply, especially a kind of protection circuit and including the protection circuit Switching Power Supply.

Background technique

Component fever is more severe when existing high power switching power supply works, and need to generally be dropped using fan Temperature processing guarantees that each component temperature control is in reasonable range in Switching Power Supply.Usually, Switching Power Supply one is powered, wind Fan begins to work, and since fan works long hours, the lubricating oil that uses in shaft and shaft aging and will slowly dry up, wind Fan performance will reduce and break down, to influence the service life of Switching Power Supply.Moreover, when large power supply connection is lighter When load, in zone of reasonableness, fan similarly works each component temperature of Switching Power Supply, causes Switching Power Supply energy Waste also influences the service life of Switching Power Supply.

Utility model content

For overcome the deficiencies in the prior art, one of the purpose of this utility model is to provide a kind of protection circuit, another mesh Be to provide it is a kind of with it is described protection circuit Switching Power Supply, can according to temperature change control fan movement, to guarantee The service life of Switching Power Supply.

The technical scheme adopted by the utility model to solve the technical problem is as follows:

A kind of protection circuit, including control chip U1, the thermal resistor NTC, pressure stabilizing for fixed frequency pulse width modulated Diode ZD1, three end adjustable shunt reference source U2, triode Q1, triode Q2 and triode Q3, the thermal resistor NTC First end with control chip U1 connect, the second end of the thermal resistor NTC respectively with the cathode of zener diode ZD1, The reference end of three end adjustable shunt reference source U2 is connected with fan cathode, the anode and triode Q2 of the zener diode ZD1 Base stage connection, the emitter ground connection of the triode Q2, the collector of the triode Q2 connect with voltage output end Vout, The voltage output end Vout is also connect with the base stage of triode Q1, the emitter ground connection of the triode Q1, the triode The collector of Q1 is connect with control chip U1, and the anode of the three ends adjustable shunt reference source U2 is connect with fan cathode, described The cathode of three end adjustable shunt reference source U2 is connect with the base stage of triode Q3, and the emitter and voltage of the triode Q3 is defeated Outlet Vout connection, the collector of the triode Q3 are connect with fan anode.

It further, further include diode D3, the anode of the diode D3 is connect with fan anode, the diode D3's Cathode is connect with voltage output end Vout.

It further, further include capacitor C1, the capacitor C1 uses electrolytic capacitor, anode and the control core of the capacitor C1 Piece U1 connection, the cathode ground connection of the capacitor C1.

It further, further include capacitor C2, the capacitor C2 uses electrolytic capacitor, and the anode of the capacitor C2 is through a resistance R1 is connect with control chip U1, the cathode ground connection of the capacitor C2.

It further, further include that the anode of diode D1 and resistance R4, the diode D1 and the collector of triode Q1 connect It connects, the cathode of the diode D1 is connect with one end of resistance R4, and the other end of the resistance R4 is grounded through a resistance R5.

It further, further include that the anode of diode D2 and resistance R10, the diode D2 and the collector of triode Q3 connect It connects, the cathode of the diode D2 is connect with one end of resistance R10, and the other end of the resistance R10 is grounded through a resistance R8.

Further, the control chip U1 uses reference voltage chip.

A kind of Switching Power Supply, including the protection circuit.

The beneficial effects of the utility model are: fan does not work when Switching Power Supply is powered on；Work as Switching Power Supply After a period of work, Switching Power Supply internal component generates heat, and when temperature reaches setting value, fan is started to work；When switch electricity Source there are when abnormal high temperature (such as power supply be placed on compare do temperature in the environment of), Switching Power Supply stops working, and fan also stops Work, etc. after temperature lower, Switching Power Supply is started to work again；When Switching Power Supply connects lighter load the case where Under, Switching Power Supply internal component also in the reasonable scope when, fan does not need work.The utility model not only can effective protection The working life of Switching Power Supply, and unusual condition can be avoided the occurrence of at high temperature, for example is damaged under component high temperature, electrolysis electricity Hold high temperature explosion etc..

Detailed description of the invention

Specific embodiment of the present utility model is further described with reference to the accompanying drawing:

Fig. 1 is the circuit diagram for protecting circuit.

Specific embodiment

In order to make those skilled in the art better understand the scheme of the utility model, practical to this below in conjunction with attached drawing Technical solution in new embodiment is clearly and completely described, it is clear that described embodiment is only the utility model The embodiment of a part, instead of all the embodiments.Based on the embodiments of the present invention, those of ordinary skill in the art The model of the utility model protection all should belong in the every other embodiment obtained without creative efforts It encloses.

Referring to Fig.1, a kind of protection circuit, including control chip U1, the thermal resistor for fixed frequency pulse width modulated NTC, zener diode ZD1, three end adjustable shunt reference source U2, triode Q1, triode Q2 and triode Q3, the temperature-sensitive electricity Hinder device NTC first end with control chip U1 connect, the second end of the thermal resistor NTC respectively with zener diode ZD1 Cathode, R7 one end be connected, the reference end of three end adjustable shunt reference source U2 is connected with fan cathode, the pressure stabilizing two The anode of pole pipe ZD1 is connect through R6 with the base stage of triode Q2, the emitter ground connection of the triode Q2, the triode Q2 Collector connect with voltage output end Vout, the voltage output end Vout is also connect with the base stage of triode Q1, described three The emitter of pole pipe Q1 is grounded, and the collector of the triode Q1 is connect with control chip U1, the three ends adjustable shunt base The anode of quasi- source U2 is connect with fan cathode, and the cathode of the three ends adjustable shunt reference source U2 and the base stage of triode Q3 connect It connects, the emitter of the triode Q3 is connect with voltage output end Vout, and the collector and fan anode of the triode Q3 connects It connects.

The protection circuit further includes diode D3, and the anode of the diode D3 is connect with fan anode, two pole The cathode of pipe D3 is connect with voltage output end Vout, and the moment that the diode D3 is used to prevent fan from opening or closing generates punching Hit voltage.

The protection circuit further includes capacitor C1, and the capacitor C1 uses electrolytic capacitor, anode and the control of the capacitor C1 The U1 connection of coremaking piece, the cathode ground connection of the capacitor C1；The protection circuit further includes capacitor C2, and the capacitor C2 is using electrolysis The anode of capacitor, the capacitor C2 is connect through a resistance R1 with control chip U1, the cathode ground connection of the capacitor C2, the electricity Hold C1 and capacitor C2 for filtering.

The protection circuit further includes the anode of diode D1 and resistance R4, the diode D1 and the current collection of triode Q1 Pole connection, the cathode of the diode D1 are connect with one end of resistance R4, and the other end of the resistance R4 is grounded through a resistance R5, The diode D1 and resistance R4 is for protecting triode Q1.

The protection circuit further includes the anode of diode D2 and resistance R10, the diode D2 and the collection of triode Q3 Electrode connection, the cathode of the diode D2 are connect with one end of resistance R10, and the other end of the resistance R10 is through a resistance R8 Ground connection, the diode D2 and resistance R10 are for protecting triode Q3.

The triode Q1 and triode Q2 uses NPN type triode, and the range of amplification factor is 120-240.Described three Pole pipe Q3 uses PNP type triode, and the range of amplification factor is 140-240.Controlled chip U1 uses the base of model TL494 Quasi- voltage chips.The three ends adjustable shunt reference source U2 uses the three end adjustable shunt reference sources of model TL431.Above-mentioned Component model or parameter can be adjusted according to the actual situation.

A kind of Switching Power Supply, including the protection circuit.

When Switching Power Supply is powered on, the component inside Switching Power Supply is in non-febrile state, at this time thermal resistor NTC is in maximum resistance state of value, and electric current flows through resistance R7, resistance R8 through thermal resistor NTC and is formed into a loop；At this point, voltage V3 is more small, and the reference voltage 2.5V less than three end adjustable shunt reference source U2, three end adjustable shunt reference source U2 do not work； Voltage V0 is not enough to puncture zener diode ZD1；It controls chip U1 to start to work, voltage V1314 is 5V, i.e. control chip U1's Reference voltage, voltage output end Vout are supplied to one driving voltage V2 of base stage of triode Q1 by resistance R3, and electric current is from electricity Resistance R1 flows through the collector of triode Q1, again passes through emitter, forms the normal work circuit of control chip U1；Triode Q2, The base stage of triode Q3 does not have voltage, therefore cannot work；Voltage output end Vout cannot provide electricity to fan by triode Q3 Pressure, therefore fan does not work.In the case where Switching Power Supply does not work or is to be in lower temperature or is that connection gently loads, Electric signal is above-mentioned flow direction, and fan does not work.

When Switching Power Supply after a period of work, internal component temperature slowly increases, thermal resistor NTC resistance value be in line Property become smaller, increase at this point, voltage V3 is opposite, when more than the reference voltage 2.5V of three end adjustable shunt reference source U2, adjustable point It flows a reference source U2 to start to work, electric current is formed into a loop with arriving again followed by resistance R11, resistance R9, adjustable shunt reference source U2； Base stage one driving voltage V4, triode Q3 conducting of the voltage output end Vout to triode Q3, voltage output end Vout output Electric current anode, the cathode of fan are flowed through through triode Q3, form the performance loop of fan, fan works normally, and gives switch electricity Component inside source radiates.

When Switching Power Supply is under abnormal high temperature state, the resistance value of thermal resistor NTC is smaller and smaller, and voltage V0 is more next Higher, when voltage V0 is higher than the breakdown voltage of zener diode ZD1, electric current flows through two pole of pressure stabilizing by thermal resistor NTC Pipe ZD1, resistance R6, resistance R5 forming circuit；One part of current flows to emitter forming circuit, three poles through the base stage of triode Q2 Pipe Q2 conducting, one part of current are grounded by resistance R3, triode Q2, at this point, voltage V2 is essentially 0, i.e. triode Q1 cut-off Work, control chip U1 are in protection, i.e., off position, Switching Power Supply end work simultaneously.

In conclusion above embodiments are only to illustrate the technical solution of the utility model, rather than its limitations；Although ginseng The utility model is described in detail according to previous embodiment, those skilled in the art should understand that；It is still It can modify the technical solutions described in the foregoing embodiments, or equally be replaced to being wherein no lack of technical characteristic It changes, and these are modified or replaceed, the utility model embodiment technical solution that it does not separate the essence of the corresponding technical solution Spirit and scope.

Claims (8)

1. a kind of protection circuit, it is characterised in that: including control chip U1, the thermal resistor for fixed frequency pulse width modulated NTC, zener diode ZD1, three end adjustable shunt reference source U2, triode Q1, triode Q2 and triode Q3, the temperature-sensitive electricity Hinder device NTC first end with control chip U1 connect, the second end of the thermal resistor NTC respectively with zener diode ZD1 Cathode, three end adjustable shunt reference source U2 reference end connected with fan cathode, the anode and three of the zener diode ZD1 The base stage of pole pipe Q2 connects, the emitter ground connection of the triode Q2, the collector and voltage output end of the triode Q2 Vout connection, the voltage output end Vout are also connect with the base stage of triode Q1, the emitter ground connection of the triode Q1, institute The collector for stating triode Q1 is connect with control chip U1, and the anode and fan cathode of the three ends adjustable shunt reference source U2 connects Connect, the cathode of the three ends adjustable shunt reference source U2 is connect with the base stage of triode Q3, the emitter of the triode Q3 with Voltage output end Vout connection, the collector of the triode Q3 are connect with fan anode.

2. protection circuit according to claim 1, it is characterised in that: it further include diode D3, the sun of the diode D3 Pole is connect with fan anode, and the cathode of the diode D3 is connect with voltage output end Vout.

3. protection circuit according to claim 1, it is characterised in that: further include capacitor C1, the capacitor C1 is using electrolysis The anode of capacitor, the capacitor C1 is connect with control chip U1, the cathode ground connection of the capacitor C1.

4. protection circuit according to claim 1, it is characterised in that: further include capacitor C2, the capacitor C2 is using electrolysis The anode of capacitor, the capacitor C2 is connect through a resistance R1 with control chip U1, the cathode ground connection of the capacitor C2.

5. protection circuit according to claim 1, it is characterised in that: further include diode D1 and resistance R4, two pole The anode of pipe D1 is connect with the collector of triode Q1, and the cathode of the diode D1 is connect with one end of resistance R4, the electricity The other end of resistance R4 is grounded through a resistance R5.

6. protection circuit according to claim 1, it is characterised in that: further include diode D2 and resistance R10, two pole The anode of pipe D2 is connect with the collector of triode Q3, and the cathode of the diode D2 is connect with one end of resistance R10, the electricity The other end of resistance R10 is grounded through a resistance R8.

7. protection circuit according to claim 1, it is characterised in that: the control chip U1 uses reference voltage chip.

8. a kind of Switching Power Supply, it is characterised in that: including protection circuit as claimed in claim 1 to 7.