CN205231714U - Switching power supply protection circuit and switching power supply - Google Patents
Switching power supply protection circuit and switching power supply Download PDFInfo
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- CN205231714U CN205231714U CN201521010537.2U CN201521010537U CN205231714U CN 205231714 U CN205231714 U CN 205231714U CN 201521010537 U CN201521010537 U CN 201521010537U CN 205231714 U CN205231714 U CN 205231714U
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Abstract
The utility model discloses a switching power supply protection circuit and switching power supply, is used for detecting external power source input voltage and controls during above a presupposition voltage value at external power source input voltage the transformer that this switching power supply protection circuit is connected including the power input end that is used for importing external power source, with the power input end, the power management chip that driving transformer worked input over - voltage detection circuit that protection device opened, be used for detecting transformer output voltage and control when transformer output voltage surpasses the 2nd presupposition voltage value output over - voltage detection circuit that protection device opened, be used for detecting transformer output return circuit intermediate -current and surpass at transformer output return circuit intermediate -current and firstly control when presetting the current value the output that protection device opened overflows detection circuitry and is used for the protection device of supply interruption management chip's when opening working power supply with the protection switch power. The utility model discloses technical scheme has the lower advantage of cost.
Description
Technical field
The utility model relates to switch power technology field, particularly a kind of protective circuit of switch power source and Switching Power Supply.
Background technology
Switching Power Supply is high with its efficiency, take the advantages such as volume is little, output voltage precision is high and be widely used in various power electronic equipment.Switching Power Supply is mainly carried out power conversion by power management chip and auxiliary circuit control transformer thereof and realizes Power convert output.Wherein, power management chip is mainly used in the power management work such as conversion, information gathering controlling electric energy; further, general power management chip also has overvoltage, overcurrent protection function, so that protect the late-class circuits such as transformer when input power overcurrent, overvoltage.But, this possess overvoltage, overcurrent protection function power management chip comparatively complicated compared to common power management chip technique, and price is more expensive, makes the hardware cost of Switching Power Supply higher.
Utility model content
Main purpose of the present utility model is to provide a kind of protective circuit of switch power source, is intended to the circuit cost reducing Switching Power Supply.
For achieving the above object, the utility model proposes a kind of protective circuit of switch power source, this protective circuit of switch power source comprises the power input for inputting external power source, the transformer be connected with described power input and drives the power management chip of described transformer work, and described protective circuit of switch power source also comprises protective device, input over-voltage detection circuit, output overvoltage testing circuit and output overcurrent testing circuit; Wherein, the output of described input over-voltage detection circuit, described output overvoltage testing circuit and described output overcurrent testing circuit is all connected with the controlled end of protective device; The input of described protective device is connected with described power input, and the test side of described input over-voltage detection circuit is connected with described power input, and described output overvoltage testing circuit is connected with the output of described transformer; The input of described output overcurrent testing circuit is connected with the output of described transformer; Wherein,
Described input over-voltage detection circuit, for detecting described external power source input voltage and when outside power input voltage is more than the first preset voltage value, controls described protective device and open;
Described output overvoltage testing circuit, for detecting described transformer output voltage and when transformer output voltage is more than the second preset voltage value, controls described protective device and open; Described over-current detection circuit, for detect electric current in described transformer output loop and in described transformer output loop, electric current is more than the first pre-set current value time, control described protective device open;
Described protective device, for when opening, cuts off the working power of described power management chip with protection switch power supply.
Preferably, described transformer comprises elementary auxiliary winding, and test side and the described primary of described output overvoltage testing circuit assist the first end of winding to be connected; Input and the described primary of described output overcurrent testing circuit assist the second end of winding to be connected.
Preferably, described protective device comprises thyristor, the first resistance, the second resistance and the first diode; The input of described thyristor is connected with external power source through described first resistance, the output head grounding of described thyristor, and the controlled end of described thyristor is the controlled end of described protective device; The negative electrode of described first diode is connected with the input of described thyristor, and the anode of described first diode is connected with the power end of described power management chip through described second resistance.
Preferably, described input over-voltage detection circuit comprises the first switching tube, second switch pipe, the 3rd resistance, the 4th resistance, the 5th resistance, the second diode, the first voltage-stabiliser tube and the first electric capacity; The first end ground connection of described first electric capacity, the second end of described first electric capacity is connected with the anode of described second diode; The minus earth of described first voltage-stabiliser tube, anode being connected with the controlled end of described first switching tube through described 3rd resistance of described first voltage-stabiliser tube; The output of described first switching tube is connected with the anode of described second diode, and the input of described first switching tube is connected with the controlled end of described second switch pipe by described 4th resistance; The input of described second switch pipe is connected with the power end of described power management chip, and the output of described second switch pipe is connected with the controlled end of described thyristor by described 5th resistance.
Preferably, described protective circuit of switch power source also comprises the 6th resistance and the 3rd diode; The first end of described 6th resistance is connected with the negative electrode of described second diode, and the second end of described six resistance is connected with the anode of described 3rd diode; The negative electrode of described 3rd diode is connected with the power end of described power management chip.
Preferably, described output overvoltage testing circuit comprises the second voltage-stabiliser tube, the 7th resistance, the 8th resistance, the 9th resistance and the second electric capacity; The anode of described second voltage-stabiliser tube is connected with the controlled end of described thyristor by described 7th resistance, and the negative electrode of described second voltage-stabiliser tube is connected with the first end of described second electric capacity; Second end ground connection of described second electric capacity; The first end of described 8th resistance is connected with the negative electrode of described second voltage-stabiliser tube, the second end ground connection of described 8th resistance; The first end of described 9th resistance is connected with the first end of described 8th resistance, and the second end of described 9th resistance assists the first end of winding to be connected with described primary; Described primary assists the second end ground connection of winding.
Preferably, described over-current detection circuit comprises the 3rd voltage-stabiliser tube, the 4th diode, the tenth resistance, the 11 resistance, the 12 resistance, the 3rd electric capacity and feedback optocoupler; The first end of described tenth resistance is connected with the controlled end of described thyristor, and the second end of described tenth resistance is connected with the first end of described 3rd electric capacity; Second end ground connection of described 3rd electric capacity; The first end of described 11 resistance is connected with the second end of described tenth resistance, the second end ground connection of described 11 resistance; The first end of described 12 resistance is connected with the second end of described tenth resistance, and the second end of described 12 resistance is connected with the anode of described 3rd voltage-stabiliser tube; The negative electrode of described 3rd voltage-stabiliser tube is connected with the negative electrode of described 4th diode; The anode of described 4th diode is connected with the feedback end of described power management chip; The execution input of described feedback optocoupler is connected with the feedback end of described power management chip, the execution output head grounding of described feedback optocoupler.
Preferably, described protective circuit of switch power source also comprises the 4th electric capacity, the 5th electric capacity and the 13 resistance; The first end of described 4th electric capacity is connected with the feedback end of described power management chip, the second end ground connection of described 4th electric capacity; The first end of described 5th electric capacity is connected with the power end of described power management chip, the second end ground connection of described 5th electric capacity; The first end of described 13 resistance is connected with described external power source, and the second end of described 13 resistance is connected with the power end of described power management chip.
The utility model also proposes a kind of Switching Power Supply, this Switching Power Supply comprises protective circuit of switch power source as above, and this protective circuit of switch power source comprises the power input for inputting external power source, the transformer be connected with described power input, the power management chip driving described transformer work, protective device, input over-voltage detection circuit, output overvoltage testing circuit and output overcurrent testing circuit; The output of described input over-voltage detection circuit, described output overvoltage testing circuit and described output overcurrent testing circuit is connected with the controlled end of protective device respectively; The input access external power source of described protective device, the input access external power source of described input over-voltage detection circuit, described output overvoltage testing circuit is connected with the output of described transformer; The input of described output overcurrent testing circuit is connected with the output of described transformer; Wherein, described input over-voltage detection circuit, for detecting described external power source input voltage and when outside power input voltage is more than the first preset voltage value, controls described protective device and open; Described output overvoltage testing circuit, for detecting described transformer output voltage and when transformer output voltage is more than the second preset voltage value, controls described protective device and open; Described over-current detection circuit, for detect electric current in transformer output loop and in transformer output loop, electric current is more than the first pre-set current value time, control described protective device open; Described protective device, for cutting off the working power of described power management chip with protection switch power supply when opening.
Technical solutions of the utility model detect the whether overvoltage of external power source input voltage by arranging input over-voltage detection circuit; the output detecting transformer by output overvoltage testing circuit whether overvoltage and also detect load current whether overcurrent by over-current detection circuit; and when the above results is for being; the input power of disconnecting transformer, thus realize carrying out overvoltage, overcurrent protection to Switching Power Supply.And adopt outside independent protective circuit of switch power source to coordinate power management chip to realize power management and security operations; namely the power management chip without the need to carrying overvoltage and overcurrent protection function can realize corresponding power supply overvoltage and overcurrent protection function; therefore, this protective circuit of switch power source has lower-cost advantage.
Accompanying drawing explanation
In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is only embodiments more of the present utility model, for those of ordinary skill in the art, under the prerequisite not paying creative work, the structure according to these accompanying drawings can also obtain other accompanying drawing.
Fig. 1 is the circuit block diagram of the utility model protective circuit of switch power source preferred embodiment;
Fig. 2 is the electrical block diagram of the utility model protective circuit of switch power source preferred embodiment.
Drawing reference numeral illustrates:
| Label | Title | Label | Title |
| 10 | Transformer | U1 | Power management chip |
| 20 | Power management chip | U2 | Feedback optocoupler |
| 30 | Protective device | SCR | Thyristor |
| 40 | Input over-voltage detection circuit | Q1 | First switching tube |
| 50 | Output overvoltage testing circuit | Q2 | Second switch pipe |
| 60 | Over-current detection circuit | Q3 | 3rd switching tube |
| R1 | First resistance | C1 | First electric capacity |
| R2 | Second resistance | C2 | Second electric capacity |
| R3 | 3rd resistance | C3 | 3rd electric capacity |
| R4 | 4th resistance | C4 | 4th electric capacity |
| R5 | 5th resistance | C5 | 5th electric capacity |
| R6 | 6th resistance | Z1 | First voltage-stabiliser tube |
| R7 | 7th resistance | Z2 | Second voltage-stabiliser tube |
| R8 | 8th resistance | Z3 | 3rd voltage-stabiliser tube |
| R9 | 9th resistance | D1 | First diode |
| R10 | Tenth resistance | D2 | Second diode 3--> |
| R11 | 11 resistance | D3 | 3rd diode |
| R12 | 12 resistance | D4 | 4th diode |
| R13 | 13 resistance | Rs | First current-limiting resistance |
The realization of the utility model object, functional characteristics and advantage will in conjunction with the embodiments, are described further with reference to accompanying drawing.
Embodiment
Below in conjunction with the accompanying drawing in the utility model embodiment, be clearly and completely described the technical scheme in the utility model embodiment, obviously, described embodiment is only a part of embodiment of the present utility model, instead of whole embodiments.Based on the embodiment in the utility model, those of ordinary skill in the art are not making the every other embodiment obtained under creative work prerequisite, all belong to the scope of the utility model protection.
Need explanation, all directivity instruction (such as up, down, left, right, before and afters in the utility model embodiment ...) only for explaining the relative position relation, motion conditions etc. under a certain particular pose (as shown in drawings) between each parts, if when this particular pose changes, then directionality instruction also correspondingly changes thereupon.
In addition, in the utility model, relate to the description of " first ", " second " etc. only for describing object, and instruction can not be interpreted as or imply its relative importance or the implicit quantity indicating indicated technical characteristic.Thus, be limited with " first ", the feature of " second " can express or impliedly comprise at least one this feature.In addition; technical scheme between each embodiment can be combined with each other; but must be can be embodied as basis with those of ordinary skill in the art; when technical scheme combination occur conflicting maybe cannot realize time will be understood that the combination of this technical scheme does not exist, also not the utility model require protection range within.
The utility model proposes a kind of protective circuit of switch power source.
With reference to Fig. 1, in the utility model embodiment, this protective circuit of switch power source comprise power input, the transformer 10 be connected with described power input for inputting external power source and drive the power management chip 20 of described transformer work, protective device 30, input over-voltage detection circuit 40, output overvoltage testing circuit 50 and output overcurrent testing circuit 60; The output of described input over-voltage detection circuit 40, described output overvoltage testing circuit 50 and described output overcurrent testing circuit 60 is all connected with the controlled end of described protective device 30; The input access external power source of described protective device 30, the input access external power source of described input over-voltage detection circuit 40, described output overvoltage testing circuit 50 is connected with the output of described transformer 10; The input of described output overcurrent testing circuit 60 is connected with the output of described transformer 10.
Described input over-voltage detection circuit 40, for detecting described external power source input voltage and when outside power input voltage is more than the first preset voltage value, controls described protective device 30 and open; Described output overvoltage testing circuit 50, for detecting described transformer 10 output voltage and when transformer 10 output voltage is more than the second preset voltage value, controls described protective device 30 and open; Described over-current detection circuit 60, for detect electric current in transformer 10 output loop and in transformer 10 output loop, electric current is more than the first pre-set current value time, control described protective device 30 and open; Described protective device 30, for when opening, cuts off the working power of described power management chip 20 with protection switch power supply.
It should be noted that, when external power source input overvoltage, input over-voltage detection circuit 40 detects that external input voltage is more than the first preset voltage value (i.e. the overvoltage threshold of input voltage), and control protective unit 30 is opened; When transformer 10 output overvoltage, output overvoltage testing circuit 50 detects that output voltage is more than the second preset voltage value (i.e. transformer output overvoltage threshold value), and control protective unit 30 is opened; When Switching Power Supply overcurrent or overload, over-current detection circuit 60 detects that load current is more than the first pre-set current value (i.e. load current overcurrent threshold value), and control protective unit 30 is opened.When protective device 30 is opened, by external power source access the earth, thus cut off the input power of transformer 10, prevented overvoltage or overcurrent to the damage of Switching Power Supply, thus protect Switching Power Supply.
Technical solutions of the utility model detect the whether overvoltage of external power source input voltage by arranging input over-voltage detection circuit 40; the output detecting transformer 10 by output overvoltage testing circuit 50 whether overvoltage and also detect load current whether overcurrent by current detection circuit 60; and when the above results is for being; the input power of disconnecting transformer 10, thus realize carrying out overvoltage, overcurrent protection to Switching Power Supply.And adopt outside independent protective circuit of switch power source to coordinate power management chip to realize power management and security operations; namely the power management chip without the need to carrying overvoltage and overcurrent protection function can realize corresponding power supply overvoltage and overcurrent protection function; therefore, this protective circuit of switch power source has lower-cost advantage.
Particularly, described transformer T1 (transformer 10 namely in Fig. 1) comprises elementary auxiliary winding, and the test side of described output overvoltage testing circuit 50 is connected with the first end of the elementary auxiliary winding of described transformer T1; The input of described output overcurrent testing circuit 60 is connected with the second end of the elementary auxiliary winding of described transformer T1.
Wherein, the input of described output overcurrent testing circuit 60 and the equal ground connection of the second end of the elementary auxiliary winding of described transformer T1, therefore, the input of described output overcurrent testing circuit 60 and the second end of the elementary auxiliary winding of described transformer T1 are equivalent to direct connection.
It should be noted that, in the present embodiment, by arranging the size that an auxiliary winding detects transformer T1 secondary winding output voltage, electric current transformer T1 is elementary, without the need to voltage, size of current that direct-detection transformer T1 exports, play the effect of signal isolation, thus improve the safety and stability of Switching Power Supply.
External input power is represented with reference to Vin in Fig. 2, Fig. 2.
Particularly, described protective device 30 comprises thyristor SCR, the first resistance R1, the second resistance R2 and the first diode D1; The input of described thyristor SCR is connected with external power source through described first resistance R1, the output head grounding of described thyristor SCR; The negative electrode of described first diode D1 is connected with the input of described thyristor SCR, and the anode of described first diode D1 is connected with the power end VDD of described power management chip U1 (power management chip 20 namely in Fig. 1) through described second resistance R2.
It should be noted that, thyristor can bear larger electric current, and thyristor is half control type device, after gate circuit transistor gate triggers, only needs less electric current can maintain conducting between the anode and negative electrode of thyristor always.Therefore, when Switching Power Supply overvoltage or overcurrent, after thyristor is triggered, guard mode can be maintained always.In the present embodiment, the input of thyristor SCR is the anode of thyristor SCR, and the output of thyristor SCR is the negative electrode of thyristor SCR, and the controlled end of thyristor SCR is the gate pole of thyristor SCR.
After thyristor SCR conducting, the working power of transformer 10 can be shorted to ground, make transformer 10 stop output voltage.
Particularly, described input over-voltage detection circuit 40 comprises the first switching tube Q1, second switch pipe Q2, the 3rd resistance R3, the 4th resistance R4, the 5th resistance R5, the second diode D2, the first voltage-stabiliser tube Z1 and the first electric capacity C1; The first end ground connection of described first electric capacity C1, second end of described first electric capacity C1 is connected with the anode of described second diode D2; The minus earth of described first voltage-stabiliser tube Z1, anode being connected with the controlled end of described first switching tube Q1 through described 3rd resistance R3 of described first voltage-stabiliser tube Z1; The output of described first switching tube Q1 is connected with the anode of described second diode D2, and the input of described first switching tube Q1 is connected with the controlled end of described second switch pipe Q2 by described 4th resistance R4; The input of described second switch pipe Q2 is connected with the power end of described power management chip U1, and the output of described second switch pipe Q2 is connected with the controlled end of described thyristor SCR by described 5th resistance R5.
It should be noted that; when transformer T1 input voltage is excessive; transformer T1 exports also overvoltage; now transformer T1 assists the voltage that winding is responded to also to raise, and raises with the both end voltage of the first electric capacity C1 of the elementary auxiliary winding parallel of transformer T1, when the puncture voltage of electric capacity both end voltage more than the first voltage-stabiliser tube Z1; first switching tube Q1 and second switch pipe Q2 conducting; thyristor gate pole tension reaches cut-in voltage, so turn on thyristors, protective device 30 is opened.
Further, described protective circuit of switch power source 50 also comprises the 6th resistance R6 and the 3rd diode D3; The first end of described 6th resistance R6 is connected with the negative electrode of described second diode D2, and second end of described six resistance R6 is connected with the power end of described power management chip U1.Wherein, the 3rd diode D3 can prevent reverse direction current flow in loop, and the 9th resistance R9 can absorb the reverse spike voltage that transformer T1 assists winding to produce.
Particularly, described output overvoltage testing circuit 50 comprises the second voltage-stabiliser tube Z2, the 7th resistance R7, the 8th resistance R8, the 9th resistance R9 and the second electric capacity C2; The anode of described second voltage-stabiliser tube Z2 is connected with the controlled end of described thyristor SCR by described 7th resistance R7, and the negative electrode of described second voltage-stabiliser tube Z2 is connected with the first end of described second electric capacity C2; The second end ground connection of described second electric capacity C2; The first end of described 8th resistance R8 is connected with the negative electrode of described second voltage-stabiliser tube Z2, the second end ground connection of described 8th resistance R8; The first end of described 9th resistance R9 is connected with the first end of described 8th resistance R8, and second end of described 9th resistance R9 is connected with the first end of described transformer T1 armature winding.
It should be noted that, when transformer T1 output voltage overvoltage, the voltage that the elementary auxiliary winding of transformer T1 is responded to raises, and therefore the both end voltage of the 7th resistance R7, the 8th resistance R8 raises, and the 7th resistance R7 charges to the second electric capacity C2 simultaneously; When both end voltage more than the second voltage-stabiliser tube Z2 of the both end voltage of the second electric capacity C2, thyristor scr gate pole tension reaches cut-in voltage, so thyristor SCR conducting, protective device 30 is opened.
Particularly, described over-current detection circuit 60 comprises the 3rd voltage-stabiliser tube Z3, the 4th diode D4, the tenth resistance R10, the 11 resistance R11, the 12 resistance R12, feedback optocoupler U2 and the 3rd electric capacity C3; The first end of described tenth resistance R10 is connected with the controlled end of described thyristor SCR, and second end of described tenth resistance R10 is connected with the first end of described 3rd electric capacity C3; The second end ground connection of described 3rd electric capacity C3; The first end of described 11 resistance R11 is connected with second end of described tenth resistance R10, the second end ground connection of described 11 resistance R11; The first end of described 12 resistance R12 is connected with second end of described tenth resistance R10, and second end of described 12 resistance R12 is connected with the anode of described 3rd voltage-stabiliser tube Z3; The negative electrode of described 3rd voltage-stabiliser tube Z3 is connected with the negative electrode of described 4th diode D4, and the anode of described 4th diode D4 is connected with the feedback end FB of described power management chip U1; The execution input of described feedback optocoupler U2 is connected with the feedback end FB of described power management chip 20, the execution output head grounding of described feedback optocoupler U2.
It should be noted that, the control end of described feedback optocoupler U2 is connected for the feedback regulating circuit detecting transformer T1 output current size with outside, the feedback regulating circuit of the band optocoupler that this feedback regulating circuit sampling power technique fields is commonly used, particular circuit configurations is not restricted herein.
Described protective circuit of switch power source 30 also comprises the 3rd switching tube Q3 and the first current-limiting resistance Rs; the described controlled end of the 3rd switching tube Q3 is connected with the drive end DRI of power management chip U1; the input of described 3rd switching tube Q3 is connected with the output of the elementary main winding of described transformer T1, and the output of described 3rd switching tube Q3 is through described first current-limiting resistance Rs ground connection.When power management chip U1 quits work, the 3rd switching tube Q3 is in cut-off state, and transformer T1 stops exporting.
It should be noted that, feedback optocoupler U2 to be used for the current feedback in load circuit to power management chip U1 to regulate transformer T1 output voltage thus to reach the object of adjustment electric current.The actuating station (having the side of photosensitive semiconductor) of feedback optocoupler U2 is connected with the feedback end FB of power management chip U1, when control end (having the side of the light-emitting diode) electric current feeding back optocoupler U2 exceedes the maximum operating currenbt of feedback optocoupler U2, feedback optocoupler U2 can lose efficacy.In Switching Power Supply load when overcurrent or overload, feedback optocoupler U2 quits work, and now the feedback end FB voltage of power management chip U1 raises; When the feedback end FB voltage of power management chip U1 reaches the puncture voltage of the 3rd voltage-stabiliser tube Z3, feedback end FB voltage charges to the 3rd electric capacity C3 through the 11 resistance R11; When the 3rd electric capacity C3 both end voltage reaches gate circuit transistor gate cut-in voltage, protective device 30 is opened.The earth terminal GND ground connection of described power management chip U1, the over-current detection end ISEN of described power management chip U1 is connected with the output of the 3rd switching tube Q3, for the power cutoff managing chip U1 when the 3rd switching tube Q3 output current is excessive.
Further, protective circuit of switch power source 30 also comprises the 4th electric capacity C4 and the 5th electric capacity C5, the 13 resistance R13, the first end of described 4th electric capacity C4 is connected with the feedback end FB of described power management chip U1, the second end ground connection of described 4th electric capacity C4; Wherein, the 13 resistance R13 plays the effect of current limliting; 4th electric capacity C4 and the 5th electric capacity C5 plays the effect of voltage stabilizing.
The utility model by adopting power management chip U1 and the lower-cost protective device of low cost, input over-voltage detection circuit 40, output overvoltage testing circuit 50 and over-current detection circuit 60 and coordinate, achieve a kind of protective circuit of switch power source of low cost.Wherein, protective device, input over-voltage detection circuit 40, output overvoltage testing circuit 50 and over-current detection circuit 60 all adopt the passive electronic component such as resistance, electric capacity, and cost is lower.
The utility model also proposes a kind of Switching Power Supply; this Switching Power Supply comprises protective circuit of switch power source; the concrete structure of this protective circuit of switch power source is with reference to above-described embodiment; because this Switching Power Supply have employed whole technical schemes of above-mentioned all embodiments; therefore all beneficial effects that the technical scheme at least having above-described embodiment is brought, this is no longer going to repeat them.
The foregoing is only preferred embodiment of the present utility model; not thereby the scope of the claims of the present utility model is limited; every under inventive concept of the present utility model; utilize the equivalent structure transformation that the utility model specification and accompanying drawing content are done, or directly/be indirectly used in other relevant technical fields to include in scope of patent protection of the present utility model.
Claims (9)
1. a protective circuit of switch power source, comprise the power input for inputting external power source, the transformer be connected with described power input and drive the power management chip of described transformer work, it is characterized in that, described protective circuit of switch power source also comprises protective device, input over-voltage detection circuit, output overvoltage testing circuit and output overcurrent testing circuit; Wherein, the output of described input over-voltage detection circuit, described output overvoltage testing circuit and described output overcurrent testing circuit is all connected with the controlled end of protective device; The input of described protective device is connected with described power input, and the test side of described input over-voltage detection circuit is connected with described power input, and the test side of described output overvoltage testing circuit is connected with described transformer output; The input of described output overcurrent testing circuit is connected with described transformer output; Wherein,
Described input over-voltage detection circuit, for detecting described external power source input voltage and when outside power input voltage is more than the first preset voltage value, controls described protective device and open;
Described output overvoltage testing circuit, for detecting described transformer output voltage and when transformer output voltage is more than the second preset voltage value, controls described protective device and open;
Described over-current detection circuit, for detect electric current in described transformer output loop and in described transformer output loop, electric current is more than the first pre-set current value time, control described protective device open;
Described protective device, for when opening, cuts off the working power of described power management chip with protection switch power supply.
2. protective circuit of switch power source as claimed in claim 1, it is characterized in that, described transformer comprises elementary auxiliary winding, and test side and the described primary of described output overvoltage testing circuit assist the first end of winding to be connected; Input and the described primary of described output overcurrent testing circuit assist the second end of winding to be connected.
3. protective circuit of switch power source as claimed in claim 1, it is characterized in that, described protective device comprises thyristor, the first resistance, the second resistance and the first diode; The input of described thyristor is connected with external power source through described first resistance, the output head grounding of described thyristor, and the controlled end of described thyristor is the controlled end of described protective device; The negative electrode of described first diode is connected with the input of described thyristor, and the anode of described first diode is connected with the power end of described power management chip through described second resistance.
4. protective circuit of switch power source as claimed in claim 3, it is characterized in that, described input over-voltage detection circuit comprises the first switching tube, second switch pipe, the 3rd resistance, the 4th resistance, the 5th resistance, the second diode, the first voltage-stabiliser tube and the first electric capacity; The first end ground connection of described first electric capacity, the second end of described first electric capacity is connected with the anode of described second diode; The minus earth of described first voltage-stabiliser tube, anode being connected with the controlled end of described first switching tube through described 3rd resistance of described first voltage-stabiliser tube; The output of described first switching tube is connected with the anode of described second diode, and the input of described first switching tube is connected with the controlled end of described second switch pipe by described 4th resistance; The input of described second switch pipe is connected with the power end of described power management chip, and the output of described second switch pipe is connected with the controlled end of described thyristor by described 5th resistance.
5. protective circuit of switch power source as claimed in claim 4, it is characterized in that, described protective circuit of switch power source also comprises the 6th resistance and the 3rd diode; The first end of described 6th resistance is connected with the negative electrode of described second diode, and the second end of described six resistance is connected with the anode of described 3rd diode; The negative electrode of described 3rd diode is connected with the power end of described power management chip.
6. protective circuit of switch power source as claimed in claim 5, it is characterized in that, described output overvoltage testing circuit comprises the second voltage-stabiliser tube, the 7th resistance, the 8th resistance, the 9th resistance and the second electric capacity; The anode of described second voltage-stabiliser tube is connected with the controlled end of described thyristor by described 7th resistance, and the negative electrode of described second voltage-stabiliser tube is connected with the first end of described second electric capacity; Second end ground connection of described second electric capacity; The first end of described 8th resistance is connected with the negative electrode of described second voltage-stabiliser tube, the second end ground connection of described 8th resistance; The first end of described 9th resistance is connected with the first end of described 8th resistance, and the second end of described 9th resistance assists the first end of winding to be connected with described primary; Described primary assists the second end ground connection of winding.
7. protective circuit of switch power source as claimed in claim 6, is characterized in that, described over-current detection circuit comprises the 3rd voltage-stabiliser tube, the 4th diode, the tenth resistance, the 11 resistance, the 12 resistance, the 3rd electric capacity and feedback optocoupler; The first end of described tenth resistance is connected with the controlled end of described thyristor, and the second end of described tenth resistance is connected with the first end of described 3rd electric capacity; Second end ground connection of described 3rd electric capacity; The first end of described 11 resistance is connected with the second end of described tenth resistance, the second end ground connection of described 11 resistance; The first end of described 12 resistance is connected with the second end of described tenth resistance, and the second end of described 12 resistance is connected with the anode of described 3rd voltage-stabiliser tube; The negative electrode of described 3rd voltage-stabiliser tube is connected with the negative electrode of described 4th diode; The anode of described 4th diode is connected with the feedback end of described power management chip; The execution input of described feedback optocoupler is connected with the feedback end of described power management chip, the execution output head grounding of described feedback optocoupler.
8. protective circuit of switch power source as claimed in claim 1, it is characterized in that, described protective circuit of switch power source also comprises the 4th electric capacity, the 5th electric capacity and the 13 resistance; The first end of described 4th electric capacity is connected with the feedback end of described power management chip, the second end ground connection of described 4th electric capacity; The first end of described 5th electric capacity is connected with the power end of described power management chip, the second end ground connection of described 5th electric capacity; The first end of described 13 resistance is connected with described external power source, and the second end of described 13 resistance is connected with the power end of described power management chip.
9. a Switching Power Supply, is characterized in that, described Switching Power Supply comprises the protective circuit of switch power source as described in claim 1-8 any one.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521010537.2U CN205231714U (en) | 2015-11-27 | 2015-11-27 | Switching power supply protection circuit and switching power supply |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521010537.2U CN205231714U (en) | 2015-11-27 | 2015-11-27 | Switching power supply protection circuit and switching power supply |
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| Publication Number | Publication Date |
|---|---|
| CN205231714U true CN205231714U (en) | 2016-05-11 |
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| CN201521010537.2U Expired - Fee Related CN205231714U (en) | 2015-11-27 | 2015-11-27 | Switching power supply protection circuit and switching power supply |
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| CN (1) | CN205231714U (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108020699A (en) * | 2016-11-04 | 2018-05-11 | 翔熙实业股份有限公司 | Automobile circuit detection device |
| WO2019015224A1 (en) * | 2017-07-18 | 2019-01-24 | 深圳市华星光电半导体显示技术有限公司 | Overcurrent protection circuit |
| WO2019205940A1 (en) * | 2018-04-25 | 2019-10-31 | 广东美芝制冷设备有限公司 | Over-voltage protection circuit for switching power supply, switching power supply, and compressor |
| CN110855127A (en) * | 2019-11-27 | 2020-02-28 | 常州格力博有限公司 | Feedback control circuit, charger and switching power supply |
| CN110994548A (en) * | 2019-12-30 | 2020-04-10 | 四川虹美智能科技有限公司 | Protection circuit, power supply device and switching power supply protection method |
| US10637230B2 (en) | 2017-07-18 | 2020-04-28 | Shenzhen China Star Optoelectronics Semiconductor Display Technology Co., Ltd. | Over current protection circuit |
| CN113451994A (en) * | 2021-06-30 | 2021-09-28 | 科华数据股份有限公司 | Optical coupler failure protection circuit and power supply system |
| WO2024032118A1 (en) * | 2022-08-12 | 2024-02-15 | 苏州汇川控制技术有限公司 | Overvoltage protection circuit and method, and power supply system |
-
2015
- 2015-11-27 CN CN201521010537.2U patent/CN205231714U/en not_active Expired - Fee Related
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108020699A (en) * | 2016-11-04 | 2018-05-11 | 翔熙实业股份有限公司 | Automobile circuit detection device |
| WO2019015224A1 (en) * | 2017-07-18 | 2019-01-24 | 深圳市华星光电半导体显示技术有限公司 | Overcurrent protection circuit |
| US10637230B2 (en) | 2017-07-18 | 2020-04-28 | Shenzhen China Star Optoelectronics Semiconductor Display Technology Co., Ltd. | Over current protection circuit |
| WO2019205940A1 (en) * | 2018-04-25 | 2019-10-31 | 广东美芝制冷设备有限公司 | Over-voltage protection circuit for switching power supply, switching power supply, and compressor |
| CN110855127A (en) * | 2019-11-27 | 2020-02-28 | 常州格力博有限公司 | Feedback control circuit, charger and switching power supply |
| CN110994548A (en) * | 2019-12-30 | 2020-04-10 | 四川虹美智能科技有限公司 | Protection circuit, power supply device and switching power supply protection method |
| CN110994548B (en) * | 2019-12-30 | 2021-08-31 | 四川虹美智能科技有限公司 | Protection circuit, power supply device and switching power supply protection method |
| CN113451994A (en) * | 2021-06-30 | 2021-09-28 | 科华数据股份有限公司 | Optical coupler failure protection circuit and power supply system |
| CN113451994B (en) * | 2021-06-30 | 2024-03-15 | 科华数据股份有限公司 | Optical coupler failure protection circuit and power supply system |
| WO2024032118A1 (en) * | 2022-08-12 | 2024-02-15 | 苏州汇川控制技术有限公司 | Overvoltage protection circuit and method, and power supply system |
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