CN206313652U - A kind of overload protection arrangement of Switching Power Supply - Google Patents
A kind of overload protection arrangement of Switching Power Supply Download PDFInfo
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- CN206313652U CN206313652U CN201621434592.9U CN201621434592U CN206313652U CN 206313652 U CN206313652 U CN 206313652U CN 201621434592 U CN201621434592 U CN 201621434592U CN 206313652 U CN206313652 U CN 206313652U
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Abstract
The utility model discloses a kind of overload protection arrangement of Switching Power Supply; including sampling unit, voltage follow unit, first voltage output unit and second voltage output unit; sampling unit connecting valve power supply simultaneously gathers the current signal of Switching Power Supply; sampling unit is connected by voltage follow unit with first voltage output unit; first voltage output unit and second voltage output unit connecting valve power supply, first voltage output unit and second voltage output unit gather the secondary output voltage of Switching Power Supply and to the PWM controller output feedback signal of Switching Power Supply.By the secondary output voltage and current signal that gather Switching Power Supply; judgement is whether Switching Power Supply has overload; overload protection can be carried out to Switching Power Supply in time when finding that Switching Power Supply is overloaded, and the power output of Switching Power Supply can be limited, it is ensured that Switching Power Supply is not damaged by.
Description
Technical field
The utility model is related to switch power technology field, more particularly to a kind of overload protection arrangement of Switching Power Supply.
Background technology
In the prior art, the overload protection mode of Switching Power Supply is relatively simple, is carried by switching power source chip
Overload protection arrangement protected, the over-current protection point of Switching Power Supply, the output of Switching Power Supply are adjusted by adjusting resistance
Once exceeding this over-current protection point, overload protection arrangement will be started, Switching Power Supply is to stop output.This overload protection side
Formula has the following disadvantages：One is when some switching power source chips do not have overload protection function, it is impossible to carry out overload protection, easily
Damage Switching Power Supply；Two is when Switching Power Supply starts overload protection, it is impossible to keeps output, cannot more keep the maximum defeated of permission
Go out power.
Utility model content
In order to overcome the above-mentioned deficiencies of the prior art, the utility model provides a kind of overload protection dress of Switching Power Supply
Put, overload protection can be carried out to Switching Power Supply, and the power output of Switching Power Supply can be limited.
The utility model solve technical scheme that its technical problem used for：A kind of overload protection dress of Switching Power Supply
Put, including sampling unit, voltage follow unit, first voltage output unit and second voltage output unit, the sampling unit
Connecting valve power supply simultaneously gathers the current signal of Switching Power Supply, and the sampling unit is defeated with first voltage by voltage follow unit
Go out unit to be connected, the first voltage output unit and second voltage output unit connecting valve power supply, the first voltage are defeated
Go out the secondary output voltage of unit and second voltage output unit collection Switching Power Supply and exported to the PWM controller of Switching Power Supply
Feedback signal.
Further, the sampling unit includes that the in-phase input end of operational amplifier U4A, the operational amplifier U4A leads to
Cross resistance R55 to be connected with Switching Power Supply, the inverting input of the operational amplifier U4A is grounded by resistance R61, the computing
Adjustable resistance RW3, the output end of the operational amplifier U4A are provided between the inverting input and output end of amplifier U4A
Pass sequentially through the B poles that voltage-stabiliser tube D24 and resistance R56 connects a triode Q9, the E poles ground connection of the triode Q9, three pole
The C poles of pipe Q9 are connected with voltage follow unit.
Further, the voltage follow unit includes a voltage follower U6B, and the voltage follower U6B's is same mutually defeated
Enter end to be connected with sampling unit, the in-phase input end of the voltage follower U6B is also connected by a resistance R54 and resistance R52
By the mu balanced circuit being made up of triode Q8, resistance R47 and voltage-stabiliser tube D22, the output end of the voltage follower U6B is by electricity
Resistance R51, resistance R57 and resistance R58 partial pressures are simultaneously connected with first voltage output unit.
Further, the first voltage output unit includes an operational amplifier U5B, and the operational amplifier U5B's is same
Phase input is connected with voltage follow unit, and the inverting input of the operational amplifier U5B gathers switch electricity by resistance R48
The secondary output voltage in source, the secondary output voltage of Switching Power Supply passes through resistance R48, resistance R59 and resistance R60 partial pressures and connects
Ground, PWM controller output feedback signal from the output end of the operational amplifier U5B to Switching Power Supply, the operational amplifier
The reference voltage of U5B is 2.5V.
Further, the second voltage output unit includes that operational amplifier a U4B's, the operational amplifier U4B is outer
Enclose circuit and set identical with operational amplifier U5B.
Further, the first voltage output unit and second voltage output unit pass through optocoupler unit and Switching Power Supply phase
Even and to the PWM controller output feedback signal of Switching Power Supply.
Further, the optocoupler unit uses PC817 chips.
The beneficial effects of the utility model have：By gathering the secondary output voltage and current signal of Switching Power Supply, judge
It is whether Switching Power Supply has overload, overload protection can be carried out to Switching Power Supply in time when finding that Switching Power Supply is overloaded, and can
Limit the power output of Switching Power Supply.
Brief description of the drawings
Below in conjunction with the accompanying drawings and specific embodiment the utility model is described in further detail, wherein：
Fig. 1 is the circuit theory diagrams of the utility model overload protection arrangement；
Fig. 2 is the primary circuit schematic diagram of the utility model Switching Power Supply；
Fig. 3 is the secondary circuit schematic diagram of the utility model Switching Power Supply.
Specific embodiment
A kind of overload protection arrangement of Switching Power Supply, including sampling unit, voltage follow unit, first voltage output unit
With second voltage output unit, the sampling unit connecting valve power supply simultaneously gathers the current signal of Switching Power Supply, the sampling
Unit is connected by voltage follow unit with first voltage output unit, and the first voltage output unit and second voltage are exported
Unit connecting valve power supply, the secondary output of the first voltage output unit and second voltage output unit collection Switching Power Supply
Voltage and to the PWM controller output feedback signal of Switching Power Supply.The first voltage output unit and second voltage output are single
Unit is connected and to the PWM controller output feedback signal of Switching Power Supply by optocoupler unit with Switching Power Supply.Specifically, the light
Coupling unit uses PC817 chips.
When Switching Power Supply is overloaded, sampling unit gathers the current signal of Switching Power Supply, and current signal is by enhanced processing
After pass to voltage follow unit, the voltage of voltage follow unit output end can produce change, single so as to cause first voltage to export
The reference voltage change of unit, in the present embodiment, i.e. the voltage of A points declines, and second voltage output unit is maked somebody a mere figurehead, only by the
One voltage output unit output voltage.By gathering the secondary output voltage and current signal of Switching Power Supply, judgement is switch electricity
Whether source has overload, can carry out overload protection to Switching Power Supply in time when finding that Switching Power Supply is overloaded, and can limit switch
The power output of power supply.A points are located at the input of first voltage output unit, the i.e. input of operational amplifier U5B.
Referring to Fig. 1, Fig. 1 is the circuit theory diagrams of the utility model overload protection arrangement.The sampling unit includes computing
The in-phase input end of amplifier U4A, the operational amplifier U4A is connected by resistance R55 with Switching Power Supply, the operation amplifier
The inverting input of device U4A is grounded by resistance R61, is set between the inverting input and output end of the operational amplifier U4A
The output end for being equipped with adjustable resistance RW3, the operational amplifier U4A passes sequentially through one or three poles of voltage-stabiliser tube D24 and resistance R56 connections
The B poles of pipe Q9, the E poles ground connection of the triode Q9, the C poles of the triode Q9 are connected with voltage follow unit.The voltage
Following unit includes a voltage follower U6B, and the in-phase input end of the voltage follower U6B is connected with sampling unit, described
The in-phase input end of voltage follower U6B is also connected with by triode Q8, resistance R47 and steady by a resistance R54 and resistance R52
The mu balanced circuit of pressure pipe D22 compositions, the output end of the voltage follower U6B is by resistance R51, resistance R57 and resistance R58 point
Press and be connected with first voltage output unit.The first voltage output unit includes an operational amplifier U5B, and the computing is put
The in-phase input end of big device U5B is connected with voltage follow unit, and the inverting input of the operational amplifier U5B passes through resistance
R48 gathers the secondary output voltage of Switching Power Supply, and the secondary output voltage of Switching Power Supply passes through resistance R48, resistance R59 and resistance
R60 partial pressures are simultaneously grounded, PWM controller output feedback signal from the output end of the operational amplifier U5B to Switching Power Supply, it is described
The reference voltage of operational amplifier U5B is 2.5V.The second voltage output unit includes an operational amplifier U4B, the fortune
The peripheral circuit for calculating amplifier U4B sets identical with operational amplifier U5B.
It is the primary circuit schematic diagram of the utility model Switching Power Supply referring to Fig. 2 and Fig. 3, Fig. 2, Fig. 3 is the utility model
The secondary circuit schematic diagram of Switching Power Supply, wherein VO terminates the secondary output voltage of Switching Power Supply, RS ends sampling switch power supply
Current signal, FB terminates the feedback signal of Switching Power Supply PWM controller.The periphery of operational amplifier U4B and operational amplifier U5B
Circuit is identical, and by taking the operational amplifier U4B of second voltage output unit as an example, resistance R34, resistance R44 and resistance R43 are partial pressure
Resistance, the output voltage for adjusting Switching Power Supply；Accordingly, in first voltage output unit, resistance R48 correspondence R34, electricity
Resistance R59, resistance R60 correspond to resistance R44, resistance R43 respectively.The periphery of operational amplifier U4B is a benchmark, defeated for adjusting
Go out voltage, and operational amplifier U5B replicates a reference value of operational amplifier U4B.But the benchmark of operational amplifier U5B is possible to
Can change, i.e., when the power of switching battery output is beyond rated power, the voltage of datum mark A can decline, once A points
Voltage decline, operational amplifier U4B will be maked somebody a mere figurehead, and now can perform output with operational amplifier U5B.
Current sampling signal enters sampling unit by RS ends and resistance R55, by operational amplifier U4A to detecting
Ultra-weak electronic signal is amplified, and the voltage follow unit of rear end is entered back into by the electric signal after amplification.By adjusting resistance R61
The multiplication factor of amplifier is adjusted with adjustable resistance RW3, that is, adjusts the scope of rated power.
When the output of Switching Power Supply is beyond rated power, the signal that sampling unit is detected is by passing through voltage stabilizing after amplification
Pipe D24 and resistance R56 enters the B poles of triode Q9, and a voltage stabilizing electricity is constituted by triode Q8, resistance R47 and voltage-stabiliser tube D22
Road, the voltage that the E poles of triode Q8 export provides a bias voltage by resistance R52 to the C poles of triode Q9 so that three poles
Pipe Q9 is in magnifying state, and the CE poles internal resistance of triode Q9 changes in amplification region, and the more big then internal resistance of multiplication factor is smaller,
The voltage of B points will be pulled low.Voltage follow unit includes a voltage follower U6B, resistance R51, resistance R57 and resistance R58
Constitute bleeder circuit, it is therefore an objective to ensure that the voltage of A points remains reference voltage 2.5V so that when no overload is used, computing
The parameter of amplifier U5B and operational amplifier U4B is consistent, it is ensured that its output voltage is not sent out during Switching Power Supply normal work
Changing.B points are located at the in-phase input end of voltage follower U6B.
When Switching Power Supply is overloaded, the CE poles internal resistance of triode Q9 will diminish, and B point voltages will also be pulled low, and pass through
The voltage that voltage follower U6B is obtained diminishes, and the voltage of A points can also be pulled low, so as to cause the 2.5V bases of operational amplifier U5B
Quasi- voltage is pulled low, and now operational amplifier U4B is maked somebody a mere figurehead, operational amplifier U5B work.Reference voltage is pulled low, output electricity
Pressure also will step-down, the overload of Switching Power Supply is bigger, and the voltage of Switching Power Supply output also can and then reduce more severe, it is ensured that switch
The rated power of power supply is always held in setting limit value, so that protection switch power supply is not damaged by.
The above, simply better embodiment of the present utility model, but the utility model is not limited to above-mentioned reality
Example is applied, as long as it reaches technique effect of the present utility model with any same or similar means, should all belong to of the present utility model
Protection domain.
Claims (7)
1. a kind of overload protection arrangement of Switching Power Supply, it is characterised in that：Including sampling unit, voltage follow unit, the first electricity
Pressure output unit and second voltage output unit, the sampling unit connecting valve power supply and gather Switching Power Supply electric current letter
Number, the sampling unit is connected by voltage follow unit with first voltage output unit, the first voltage output unit and
Second voltage output unit connecting valve power supply, the first voltage output unit and second voltage output unit collection switch electricity
The secondary output voltage in source and to the PWM controller output feedback signal of Switching Power Supply.
2. the overload protection arrangement of a kind of Switching Power Supply according to claim 1, it is characterised in that：The sampling unit bag
The in-phase input end for including operational amplifier U4A, the operational amplifier U4A is connected by resistance R55 with Switching Power Supply, the fortune
The inverting input for calculating amplifier U4A is grounded by resistance R61, the inverting input and output end of the operational amplifier U4A
Between be provided with adjustable resistance RW3, the operational amplifier U4A output end pass sequentially through voltage-stabiliser tube D24 and resistance R56 connection
The B poles of one triode Q9, the E poles ground connection of the triode Q9, the C poles of the triode Q9 are connected with voltage follow unit.
3. the overload protection arrangement of a kind of Switching Power Supply according to claim 1, it is characterised in that：The voltage follow list
Unit includes a voltage follower U6B, and the in-phase input end of the voltage follower U6B is connected with sampling unit, the voltage with
Also it is connected with by triode Q8, resistance R47 and voltage-stabiliser tube by a resistance R54 and resistance R52 with the in-phase input end of device U6B
The mu balanced circuit of D22 compositions, the output end of the voltage follower U6B passes through resistance R51, resistance R57 and resistance R58 partial pressures simultaneously
It is connected with first voltage output unit.
4. the overload protection arrangement of a kind of Switching Power Supply according to claim 1, it is characterised in that：The first voltage is defeated
Going out unit includes an operational amplifier U5B, and the in-phase input end of the operational amplifier U5B is connected with voltage follow unit, institute
State the secondary output voltage that the inverting input of operational amplifier U5B gathers Switching Power Supply by resistance R48, Switching Power Supply time
Level output voltage by resistance R48, resistance R59 and resistance R60 partial pressures and being grounded, the output end of the operational amplifier U5B to
The PWM controller output feedback signal of Switching Power Supply, the reference voltage of the operational amplifier U5B is 2.5V.
5. the overload protection arrangement of a kind of Switching Power Supply according to claim 4, it is characterised in that：The second voltage is defeated
Go out the phase of peripheral circuit setting of the unit including operational amplifier a U4B, the operational amplifier U4B and operational amplifier U5B
Together.
6. the overload protection arrangement of a kind of Switching Power Supply according to claim 1, it is characterised in that：The first voltage is defeated
Go out unit and second voltage output unit to be connected with Switching Power Supply by optocoupler unit and exported to the PWM controller of Switching Power Supply
Feedback signal.
7. the overload protection arrangement of a kind of Switching Power Supply according to claim 6, it is characterised in that：The optocoupler unit is adopted
Use PC817 chips.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621434592.9U CN206313652U (en) | 2016-12-23 | 2016-12-23 | A kind of overload protection arrangement of Switching Power Supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621434592.9U CN206313652U (en) | 2016-12-23 | 2016-12-23 | A kind of overload protection arrangement of Switching Power Supply |
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| Publication Number | Publication Date |
|---|---|
| CN206313652U true CN206313652U (en) | 2017-07-07 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201621434592.9U Active CN206313652U (en) | 2016-12-23 | 2016-12-23 | A kind of overload protection arrangement of Switching Power Supply |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107482586A (en) * | 2017-08-23 | 2017-12-15 | 苏州麦喆思科电子有限公司 | A kind of overload protecting circuit of Switching Power Supply |
-
2016
- 2016-12-23 CN CN201621434592.9U patent/CN206313652U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107482586A (en) * | 2017-08-23 | 2017-12-15 | 苏州麦喆思科电子有限公司 | A kind of overload protecting circuit of Switching Power Supply |
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