CN204103461U - The undervoltage protection device of Switching Power Supply and there is its Switching Power Supply - Google Patents
The undervoltage protection device of Switching Power Supply and there is its Switching Power Supply Download PDFInfo
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- CN204103461U CN204103461U CN201420440329.5U CN201420440329U CN204103461U CN 204103461 U CN204103461 U CN 204103461U CN 201420440329 U CN201420440329 U CN 201420440329U CN 204103461 U CN204103461 U CN 204103461U
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Abstract
The utility model discloses a kind of undervoltage protection device of Switching Power Supply and have its Switching Power Supply, wherein undervoltage protection device comprises: for the voltage detecting circuit detected the voltage being input to Switching Power Supply; Thyristor, the control end of thyristor is connected with the output of voltage detecting circuit, wherein, voltage detecting circuit detect the voltage of Switching Power Supply be less than first preset protection voltage time thyristor cut-off, voltage detecting circuit detect the voltage of Switching Power Supply be more than or equal to second preset protection voltage time thyristor open-minded, second preset protection voltage is greater than first preset protection voltage; Under-voltage protecting circuit, under-voltage protecting circuit exports the power supply chip of under-voltage protection signal to Switching Power Supply to realize under-voltage protection when thyristor ends.This undervoltage protection device not easily can produce misoperation to the fluctuation among a small circle of voltage, and can carry out under-voltage protection to different electrical voltage systems, range of application is wider.The invention also discloses a kind of Switching Power Supply with above-mentioned undervoltage protection device.
Description
Technical field
The utility model relates to electric and electronic technical field, particularly a kind of undervoltage protection device of Switching Power Supply and a kind of Switching Power Supply with the undervoltage protection device of Switching Power Supply.
Background technology
Automobile operationally, utilizes the controller etc. that battery is automobile to provide voltage usually.When the brownout that battery provides, controller may be caused normally to work, also may produce overcurrent damage components and parts simultaneously, thus, the fail safe of car load cannot be ensured when the brownout that battery provides.In addition, the input voltage of circuit is more and more higher, and the area requirement of operating voltage is increasing, and this proposes a new difficult problem just to circuit design and parts selection.
In correlation technique, the control chip with under-voltage protection function is usually adopted to carry out under-voltage protection to controller and components and parts etc.But, mainly there is following shortcoming in correlation technique: first voltage range is narrower, related chip mostly can only be used for 12V or 24V electrical voltage system, the system of 48V electrical voltage system or compatible three kinds of voltages can not be used for, this is because the design of chip can only be 12V or 24V to the voltage of chip power supply, and can not be 48V; It two is that the fluctuation for voltage easily produces misoperation, thus makes the unstable working condition of circuit.
Summary of the invention
The utility model is intended to solve one of technical problem in correlation technique at least to a certain extent.
For this reason, an object of the present utility model is the undervoltage protection device proposing a kind of Switching Power Supply, and this undervoltage protection device can carry out under-voltage protection to different electrical voltage systems, and easily can not produce misoperation for the fluctuation among a small circle of voltage.
Another object of the present utility model is to propose a kind of Switching Power Supply.
According to the undervoltage protection device of a kind of Switching Power Supply that the utility model proposes, comprising: for the voltage detecting circuit detected the voltage being input to described Switching Power Supply; Thyristor, the control end of described thyristor is connected with the output of described voltage detecting circuit, wherein, described voltage detecting circuit detect the voltage of described Switching Power Supply be less than first preset protection voltage time described thyristor cut-off, described voltage detecting circuit detect the voltage of described Switching Power Supply be more than or equal to second preset protection voltage time described thyristor open-minded, described second preset protection voltage is greater than described first preset protection voltage; Under-voltage protecting circuit, described under-voltage protecting circuit exports the power supply chip of under-voltage protection signal to described Switching Power Supply to realize under-voltage protection when described thyristor cut-off.
According to the undervoltage protection device of the Switching Power Supply that the utility model proposes; by voltage detecting circuit, the voltage being input to Switching Power Supply is detected; voltage detecting circuit detect the voltage of Switching Power Supply be less than first preset protection voltage time thyristor cut-off; voltage detecting circuit detect the voltage of Switching Power Supply be more than or equal to second preset protection voltage time thyristor open-minded, simultaneously under-voltage protecting circuit exports the power supply chip of under-voltage protection signal to Switching Power Supply to realize under-voltage protection when thyristor ends.Thus, this undervoltage protection device can carry out under-voltage protection when the voltage of Switching Power Supply is less than the first default protection voltage to the power supply chip of Switching Power Supply, and until the voltage of Switching Power Supply is greater than the second default protection voltage, the power supply chip of Switching Power Supply is normally worked, thus not easily misoperation is produced for the fluctuation among a small circle of voltage, and, compared with correlation technique, voltage detecting circuit can detect different voltage, not by the impact of chip design, thus this undervoltage protection device can carry out under-voltage protection to different electrical voltage systems, range of application is wider.
According to a kind of Switching Power Supply that the utility model proposes on the other hand, comprising: power supply chip; The undervoltage protection device of described Switching Power Supply.
According to the Switching Power Supply that the utility model proposes; undervoltage protection device can carry out under-voltage protection when the voltage of Switching Power Supply is less than the first default protection voltage to power supply chip; and again make power supply chip normally work until the voltage of Switching Power Supply is greater than the second default protection voltage; thus not easily misoperation is produced for the fluctuation among a small circle of voltage; and; can carry out under-voltage protection to different electrical voltage systems, range of application is wider.
Accompanying drawing explanation
Fig. 1 is the block diagram of the undervoltage protection device of Switching Power Supply according to the utility model embodiment;
Fig. 2 is the circuit theory diagrams of the undervoltage protection device of Switching Power Supply according to the utility model embodiment;
Fig. 3 is the block diagram of the Switching Power Supply according to the utility model embodiment.
Embodiment
Be described below in detail embodiment of the present utility model, the example of described embodiment is shown in the drawings, and wherein same or similar label represents same or similar element or has element that is identical or similar functions from start to finish.Be exemplary below by the embodiment be described with reference to the drawings, be intended to for explaining the utility model, and can not be interpreted as restriction of the present utility model.
Undervoltage protection device and the Switching Power Supply of the Switching Power Supply proposed according to utility model embodiment are described with reference to the accompanying drawings.
Fig. 1 is the block diagram of the undervoltage protection device of Switching Power Supply according to the utility model embodiment.As shown in Figure 1, the undervoltage protection device of this Switching Power Supply comprises: voltage detecting circuit 1, thyristor 2 and under-voltage protecting circuit 3.
Wherein, voltage detecting circuit 1 is for detecting the voltage VCC being input to Switching Power Supply; The control end 20 of thyristor 2 is connected with the output of voltage detecting circuit 1, wherein, detects that the voltage VCC of Switching Power Supply is less than first and presets protection voltage V at voltage detecting circuit 1
tH-time thyristor 2 end, detect that the voltage VCC of Switching Power Supply is more than or equal to second and presets protection voltage V at voltage detecting circuit 1
tH+time thyristor 2 open-minded, second presets protection voltage V
tH+be greater than first and preset protection voltage V
tH-; Under-voltage protecting circuit 3 exports the power supply chip of under-voltage protection signal to Switching Power Supply to realize under-voltage protection when thyristor 2 ends.
That is, protection voltage V is preset when the voltage VCC of Switching Power Supply is less than first
tH-time, the detection voltage that voltage detecting circuit 1 exports will make thyristor 2 end, when thyristor 2 ends, under-voltage protecting circuit 3 exports the power supply chip of under-voltage protection signal such as high level signal to Switching Power Supply, thus under-voltage protection is carried out to the circuit be connected with Switching Power Supply, such as, power supply chip stops the circuit supply for being connected with Switching Power Supply; In the process of carrying out under-voltage protection, voltage detecting circuit 1 continues the voltage VCC of sense switch power supply, until the voltage VCC of Switching Power Supply is more than or equal to second preset protection voltage V
tH+the detection voltage that voltage detecting circuit 1 exports will make thyristor 2 open-minded again; when thyristor 2 is opened; under-voltage protecting circuit 3 exports the power supply chip of normal working signal such as low level signal to Switching Power Supply; power supply chip normally works; such as, power supply chip continues as the circuit supply be connected with Switching Power Supply.
According to a concrete example of the present utility model, thyristor 2 can be three end thyristors, and when the voltage of the control end of thyristor 2 is more than or equal to its internal reference voltage VREF, thyristor 2 is in conducting state; When the voltage of the control end of thyristor 2 is less than its internal reference voltage VREF, thyristor 2 is in cut-off state.Particularly, thyristor 2 can be TL431.
Specifically; the voltage of the control end of thyristor 2 is the detection voltage of the output output of voltage detecting circuit 1; when the power supply chip of Switching Power Supply normally works, if the voltage VCC of Switching Power Supply is under-voltage, if namely the voltage VCC of Switching Power Supply is less than the first default protection voltage V
tH-, then the detection voltage that the output of voltage detecting circuit 1 exports will be less than the threshold voltage of thyristor 2 inside, and thyristor 2 ends, and under-voltage protecting circuit 3 exports under-voltage protection signal to the power supply chip of Switching Power Supply when thyristor 2 ends, realize under-voltage protection; Afterwards, if the voltage VCC of Switching Power Supply recovers normal and voltage VCC is more than or equal to second presets protection voltage V
tH+the detection voltage that then output of voltage detecting circuit 1 exports just can be more than or equal to the threshold voltage of thyristor 2 inside; thyristor 2 is again open-minded, and under-voltage protecting circuit 3 can export the power supply chip of normal working signal to Switching Power Supply again, and power supply chip normally works.
Thus; this undervoltage protection device can carry out under-voltage protection when the voltage of Switching Power Supply is less than the first default protection voltage to the power supply chip of Switching Power Supply; and until the voltage of Switching Power Supply is greater than the second default protection voltage, the power supply chip of Switching Power Supply is normally worked, thus not easily misoperation is produced for the fluctuation among a small circle of voltage.
Particularly, according to an embodiment of the present utility model, as shown in Figure 2, voltage detecting circuit 1 comprises: the first resistance R1 and the second resistance R2.
Wherein, one end of the first resistance R1 is connected with the default power supply 4 of the voltage VCC providing Switching Power Supply; One end of second resistance R2 is connected with the other end of the first resistance R1, the other end ground connection of the second resistance R2, have first node a between first resistance R1 and the second resistance R2, first node a is connected with the control end 20 of thyristor 2, and first node a is the output of voltage detecting circuit 1.
Specifically, when the voltage of the voltage Va of the first node a between the first resistance R1 and the second resistance R2 and the control end 20 of thyristor 2 is more than or equal to the reference voltage V REF of thyristor 2 inside, thyristor 2 is open-minded; When the voltage of the voltage Va of the first node a between the first resistance R1 and the second resistance R2 and the control end 20 of thyristor 2 is less than the reference voltage V REF of thyristor 2 inside, thyristor 2 ends.
Particularly, according to an embodiment of the present utility model, as shown in Figure 2, under-voltage protecting circuit 3 also comprises: the 3rd resistance R3, the first switching tube Q1, second switch pipe Q2, the 3rd switching tube Q3, the 4th switching tube Q4.
Wherein, one end of the 3rd resistance R3 is connected with one end of the second resistance; The first end 101 of the first switching tube Q1 is connected with the other end of the 3rd resistance R3, second end 102 ground connection of the first switching tube Q1, and the 3rd end 103 of the first switching tube Q3 is connected with default power supply 4; The first end 201 of second switch pipe Q2 is connected with the 3rd end 103 of the first switching tube Q1, second end 202 ground connection of second switch pipe Q2; The first end 301 of the 3rd switching tube Q3 is connected with the 3rd end 203 of second switch pipe Q2, second end 302 of the 3rd switching tube Q3 is connected with default power supply 4,3rd end 303 of the 3rd switching tube Q3 is connected with the negative electrode 21 of thyristor 2, wherein, and anode 22 ground connection of thyristor 2; The first end 401 of the 4th switching tube Q4 is connected with default power supply 4; second end 402 ground connection of the 4th switching tube Q4; 3rd end 403 of the 4th switching tube Q4 is connected with the first end 301 of the 3rd switching tube Q3, and the first end 401 of the 4th switching tube Q4 exports under-voltage protection signal when thyristor 2 ends.
According to a specific embodiment of the present utility model, wherein, the first switching tube Q1, second switch pipe Q2, the 4th switching tube Q4 are NPN type triode, and the 3rd switching tube Q3 is PNP type triode.
That is, the collector electrode of the first switching tube Q1 is connected with the other end of the 3rd resistance R3, the grounded emitter of the first switching tube Q1, and the base stage of the first switching tube Q3 is connected with default power supply 4; The collector electrode of second switch pipe Q2 is connected with the base stage of the first switching tube Q1, the grounded emitter of second switch pipe Q2; The collector electrode of the 3rd switching tube Q3 is connected with the base stage of second switch pipe Q2, and the emitter of the 3rd switching tube Q3 is connected with default power supply 4, and the base stage of the 3rd switching tube Q3 is connected with the negative electrode of thyristor 2, wherein, and the plus earth of thyristor 2; The collector electrode of the 4th switching tube Q4 is connected with default power supply 4, the grounded emitter of the 4th switching tube Q4, and the base stage of the 4th switching tube Q4 is connected with the collector electrode of the 3rd switching tube Q3, and the collector electrode of the 4th switching tube Q4 exports under-voltage protection signal when thyristor 2 ends.
Particularly, according to an embodiment of the present utility model, as shown in Figure 2, under-voltage protecting circuit 3 also comprises: the 4th resistance R4 and the 5th resistance R5.
Wherein, the 4th resistance R4 is connected between the 3rd end 103 of the first switching tube Q1 and default power supply 4; 5th resistance R5 is connected between the first end 401 of default power supply 4 and the 4th switching tube Q4.Namely say, one end of the 4th resistance R4 is connected with the base stage of the first switching tube Q1, and the other end of the 4th resistance R4 is connected with default power supply 4; One end of 5th resistance R5 is connected with default power supply 4; the other end of the 5th resistance R5 is connected with the collector electrode of the 4th switching tube Q4; there is between 5th resistance R5 and the 4th switching tube Q4 Section Point protect (namely protecting end); wherein, Section Point protect exports under-voltage protection signal when thyristor 2 ends.
Particularly, according to an embodiment of the present utility model, as shown in Figure 2, under-voltage protecting circuit 3 also comprises: the 6th resistance R6, the 7th resistance R7 and the 8th resistance R8.
Wherein, the 6th resistance R6 is connected between the negative electrode 21 of thyristor 2 and the 3rd end 303 of the 3rd switching tube Q3; 7th resistance R7 is connected between the first end 301 of the 3rd switching tube Q3 and the 3rd end 403 of the 4th switching tube Q4; One end of 8th resistance R8 is connected with the 3rd end 403 of the 4th switching tube Q4, the other end ground connection of the 8th resistance R8.
Namely say, one end of the 6th resistance R6 is connected with the negative electrode of thyristor 2, and the other end of the 6th resistance R6 is connected with the base stage of the 3rd switching tube Q3; One end of 7th resistance R7 is connected with the collector electrode of the 3rd switching tube Q3, and the other end of the 7th resistance R7 is connected with the base stage of the 4th switching tube Q4; One end of 8th resistance R8 is connected with the base stage of the 4th switching tube Q4, the other end ground connection of the 8th resistance R8.
Particularly, according to an embodiment of the present utility model, as shown in Figure 2, the undervoltage protection device of Switching Power Supply also comprises: the 9th resistance R9.9th resistance R9 is connected between default power supply 4 and the negative electrode 21 of thyristor 2.Namely say, one end of the 9th resistance R9 is connected with default power supply 4, and the other end of the 9th resistance R9 is connected with the negative electrode of thyristor 2.
Specifically, when the voltage VCC of Switching Power Supply is normal, the voltage Va of the first node a between the first resistance R1 and the second resistance R2 is more than or equal to the reference voltage V REF of thyristor 2 inside, and thyristor 2 is open-minded, and the negative electrode of thyristor 2 is low level; Thus the voltage between the emitter of the 3rd switching tube Q3 and base stage is greater than the conducting voltage of the 3rd switching tube Q3, the 3rd switching tube Q3 conducting, the current collection very high level of the 3rd switching tube Q3; And then the voltage between the base stage of second switch pipe Q2 and emitter is greater than the conducting voltage of second switch pipe Q2, second switch pipe Q2 conducting, the current collection very low level of second switch pipe Q2; Thus the voltage between the base stage of the first switching tube Q1 and emitter is that the 0, first switching tube Q1 ends; Simultaneously; voltage between the base stage of the 4th switching tube Q4 and emitter is greater than the conducting voltage of the 4th switching tube Q4; 4th switching tube Q4 conducting; the current collection very low level of the 4th switching tube Q4; Section Point protect (namely protecting end) is low level; namely under-voltage protecting circuit 3 output low level signal is to the power supply chip of Switching Power Supply, and power supply chip normally works.Now, the voltage Va of first node a is the voltage that carries out dividing potential drop after of the first resistance R1 and the second resistance R2 to the voltage VCC of Switching Power Supply, namely.Afterwards, if the voltage VCC of Switching Power Supply declines, preset protection voltage V when voltage VCC drops to first
tH-time, the voltage Va of first node a can be made to be less than the reference voltage V REF of thyristor 2 inside, and thyristor 2 ends, and under-voltage protecting circuit 3, by exporting the power supply chip of under-voltage protection signal to Switching Power Supply to realize under-voltage protection, is namely sayed, first presets protection voltage.
That is, when the voltage VCC of Switching Power Supply is less than the first default protection voltage, thyristor 2 ends, and the negative electrode of thyristor 2 is high level; Thus, voltage between the emitter of the 3rd switching tube Q3 and base stage is 0,3rd switching tube Q3 ends, the current collection very low level of the 3rd switching tube Q3, and, voltage between the base stage of second switch pipe Q2 and emitter is also 0, and second switch pipe Q2 ends, the current collection very high level of second switch pipe Q2; Thus the voltage between the base stage of the first switching tube Q1 and emitter is greater than the conducting voltage of the first switching tube Q1, the first switching tube Q1 conducting; Meanwhile, the voltage between the base stage of the 4th switching tube Q4 and emitter is that the 0, four switching tube Q4 ends; the current collection very high level of the 4th switching tube Q4; Section Point protect is high level, and namely under-voltage protecting circuit 3 exports the power supply chip of high level signal to Switching Power Supply, realizes under-voltage protection.Now, the voltage Va of first node a be the first resistance R1 and the second resistance R2 in parallel and the 3rd resistance R3 to the voltage carried out after dividing potential drop of the voltage VCC of Switching Power Supply, namely.Afterwards, if the voltage VCC of Switching Power Supply rises, preset protection voltage V when voltage VCC rises to second
tH+time; the voltage Va of first node a can be made to be more than or equal to the reference voltage V REF of thyristor 2 inside; thyristor 2 is open-minded; Section Point protect is low level; under-voltage protecting circuit 3 will export the power supply chip of normal working signal to Switching Power Supply; power supply chip normally works, and namely says, second presets protection voltage.
That is; when the voltage VCC of Switching Power Supply is more than or equal to the second default protection voltage; thyristor 2 is open-minded; second switch pipe Q2, the 3rd switching tube Q3, the 4th switching tube Q4 conducting; first switching tube Q1 ends; Section Point protect is low level, and namely under-voltage protecting circuit 3 is by output low level signal to the power supply chip of Switching Power Supply, and power supply chip normally works again.
Generally speaking, when the power supply chip of Switching Power Supply normally works, the voltage of first node a, first presets protection voltage.Afterwards, if the voltage VCC of Switching Power Supply declines, need carry out under-voltage protection, the voltage VCC of the reference voltage V REF and Switching Power Supply that are namely less than thyristor 2 inside as the voltage Va of first node a is less than first and presets protection voltage V
tH-time, thyristor 2 ends, and the 3rd switching tube Q3, the 4th switching tube Q4, second switch pipe Q2 end, and the first switching tube Q1 is open-minded, and Section Point protect exports high level signal to the power supply chip of Switching Power Supply, realizes under-voltage protection; Now; in the process of carrying out under-voltage protection; the voltage Va of first node a becomes; second presets protection voltage; afterwards; when the voltage VCC of Switching Power Supply recovers normal; R2//R3 and R1 partial pressure value Va is needed to be greater than the reference voltage V REF of thyristor 2 inside; thyristor 2 is open-minded; 3rd switching tube Q3, the 4th switching tube Q4, Q2 is open-minded for second switch pipe; first switching tube Q1 ends, and Section Point protect output low level signal is to the power supply chip of Switching Power Supply, and power supply chip normally works again.
Thus, the undervoltage protection device of Switching Power Supply achieves hysteresis function, is namely less than V when the voltage VCC of Switching Power Supply falls
tH-time, Section Point protect exports the under-voltage protection signal of high level, is more than or equal to V when VCC goes back up to
tH+(V
tH+>V
tH-) time, the normal working signal of Section Point protect output low level, Switching Power Supply recovers normal operating conditions.Like this, after the voltage VCC increase return difference △ V of Switching Power Supply, Switching Power Supply just can by under-voltage protection recovering state to normal operating conditions, and return difference △ V is second and presets protection voltage V
tH+with first preset protect voltage V
tH-difference, return difference △ V=V
tH+-V
tH->0, like this, the undervoltage protection device of this Switching Power Supply not easily produces misoperation to the fluctuation among a small circle of voltage.It should be noted that, first presets protection voltage V
tH-, second preset protection voltage V
tH+can designed, designed according to demand with return difference △ V, thus this undervoltage protection device can use according to demand flexibly.
In addition, according to embodiment of the present utility model, the voltage VCC being input to Switching Power Supply can be 12V, 24V or 48V.
That is; this undervoltage protection device can be applicable to the electrical voltage system of different electric pressure; such as; can be applicable to the electrical voltage system of 12V, 24V, 48V; and without the need to changing the circuit structure of undervoltage protection device; only need according to specific requirement selector model, the resistance namely only replacing different resistance can bear different voltage.
Below for the electrical voltage system of 24V, describe the undervoltage protection device of the Switching Power Supply of the utility model embodiment in detail.Such as, first resistance R1 can be 20k Ω, second resistance R2 can be 5.5k Ω, 3rd resistance R3 can be 36k Ω, 4th resistance R4 can be 20k Ω, 5th resistance R5 can be 10k Ω, 6th resistance R6 can be 10k Ω, 7th resistance R7 can be 10k Ω, and the 8th resistance R8 can be 10k Ω, and the 9th resistance R9 can be 1k Ω, first switching tube Q1, the 4th switching tube Q4, second switch pipe Q2 can be BC847B, 3rd switching tube Q3 can be BC857B, and thyristor 2 can be TL431, and the reference voltage V REF of its inside is 2.5V.
According to the description of above-described embodiment, first presets protection voltage, and second presets protection voltage.Like this; when normally namely power supply chip normally works the voltage VCC of Switching Power Supply; TL431 is open-minded; the negative electrode output low level of TL431; 3rd switching tube Q3, the 4th switching tube Q4, Q2 is open-minded for second switch pipe, and the first switching tube Q1 ends, and Section Point protect output low level signal is to the power supply chip of Switching Power Supply; power supply chip normally works, and now under-voltage protection point is the first default protection voltage V
tH-=11.4V.When the voltage VCC of Switching Power Supply fall to be less than 11.4V time; TL431 ends; the negative electrode of TL431 exports high level; 3rd switching tube Q3, the 4th switching tube Q4, second switch pipe Q2 end; first switching tube Q1 is open-minded, and Section Point protect exports high level, realizes under-voltage protection; now, under-voltage protection point is the second default protection voltage V
tH+=12.8V.When the voltage VCC of Switching Power Supply need rise to and be more than or equal to 12.8V, the power supply chip of Switching Power Supply recovers normal work.In addition, be V according to the simulation result of above-described embodiment
tH-=11.5V, V
tH+=13V, basically identical with the theoretical value of the theory calculate according to the utility model embodiment.
To sum up; according to the undervoltage protection device of the Switching Power Supply that the utility model proposes; by voltage detecting circuit, the voltage being input to Switching Power Supply is detected; voltage detecting circuit detect the voltage of Switching Power Supply be less than first preset protection voltage time thyristor cut-off; voltage detecting circuit detect the voltage of Switching Power Supply be more than or equal to second preset protection voltage time thyristor open-minded, simultaneously under-voltage protecting circuit exports the power supply chip of under-voltage protection signal to Switching Power Supply to realize under-voltage protection when thyristor ends.Thus, this undervoltage protection device can carry out under-voltage protection when the voltage of Switching Power Supply is less than the first default protection voltage to the power supply chip of Switching Power Supply, and until the voltage of Switching Power Supply is greater than the second default protection voltage, the power supply chip of Switching Power Supply is normally worked, thus not easily misoperation is produced for the fluctuation among a small circle of voltage, and, compared with correlation technique, voltage detecting circuit can detect different voltage, not by the impact of chip design, thus this undervoltage protection device can be applied to different electrical voltage systems to realize under-voltage protection, range of application is wider, and when being applied in different electrical voltage systems, without the need to changing the circuit structure of undervoltage protection device, only need according to specific requirement selector model.In addition, this undervoltage protection device simplicity of design, multiple functional, cost is lower.
Fig. 3 is the block diagram of the Switching Power Supply according to the utility model embodiment.As shown in Figure 3, this Switching Power Supply comprises: the undervoltage protection device 200 of power supply chip 100 and above-mentioned Switching Power Supply.
Wherein, under-voltage protection signal such as high level is exported to power supply chip 100 to realize under-voltage protection when the undervoltage protection device 200 of Switching Power Supply is for being less than the first default protection voltage at the voltage VCC of Switching Power Supply; Further, export normal working signal such as low level when the undervoltage protection device 200 of Switching Power Supply is for being more than or equal to the second default protection voltage at the voltage VCC of Switching Power Supply normally to work to power supply chip 100 to make power supply chip 100.
To sum up; according to the Switching Power Supply that the utility model proposes; undervoltage protection device can carry out under-voltage protection when the voltage of Switching Power Supply is less than the first default protection voltage to power supply chip; and again make power supply chip normally work until the voltage of Switching Power Supply is greater than the second default protection voltage; thus not easily misoperation is produced for the fluctuation among a small circle of voltage; and can carry out under-voltage protection to different electrical voltage systems, range of application is wider.
In description of the present utility model, it will be appreciated that, term " " center ", " longitudinal direction ", " transverse direction ", " length ", " width ", " thickness ", " on ", D score, " front ", " afterwards ", " left side ", " right side ", " vertically ", " level ", " top ", " end " " interior ", " outward ", " clockwise ", " counterclockwise ", " axis ", " radial direction ", orientation or the position relationship of the instruction such as " circumference " are based on orientation shown in the drawings or position relationship, only the utility model and simplified characterization for convenience of description, instead of indicate or imply that the device of indication or element must have specific orientation, with specific azimuth configuration and operation, therefore can not be interpreted as restriction of the present utility model.
In addition, term " first ", " second " only for describing object, and can not be interpreted as instruction or hint relative importance or imply the 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 description of the present utility model, the implication of " multiple " is at least two, such as two, three etc., unless otherwise expressly limited specifically.
In the utility model, unless otherwise clearly defined and limited, the term such as term " installation ", " being connected ", " connection ", " fixing " should be interpreted broadly, and such as, can be fixedly connected with, also can be removably connect, or integral; Can be mechanical connection, also can be electrical connection; Can be directly be connected, also indirectly can be connected by intermediary, can be the connection of two element internals or the interaction relationship of two elements, unless otherwise clear and definite restriction.For the ordinary skill in the art, the concrete meaning of above-mentioned term in the utility model can be understood as the case may be.
In the utility model, unless otherwise clearly defined and limited, fisrt feature second feature " on " or D score can be that the first and second features directly contact, or the first and second features are by intermediary indirect contact.And, fisrt feature second feature " on ", " top " and " above " but fisrt feature directly over second feature or oblique upper, or only represent that fisrt feature level height is higher than second feature.Fisrt feature second feature " under ", " below " and " below " can be fisrt feature immediately below second feature or tiltedly below, or only represent that fisrt feature level height is less than second feature.
In the description of this specification, specific features, structure, material or feature that the description of reference term " embodiment ", " some embodiments ", " example ", " concrete example " or " some examples " etc. means to describe in conjunction with this embodiment or example are contained at least one embodiment of the present utility model or example.In this manual, to the schematic representation of above-mentioned term not must for be identical embodiment or example.And the specific features of description, structure, material or feature can combine in one or more embodiment in office or example in an appropriate manner.In addition, when not conflicting, the feature of the different embodiment described in this specification or example and different embodiment or example can carry out combining and combining by those skilled in the art.
Although illustrate and described embodiment of the present utility model above, be understandable that, above-described embodiment is exemplary, can not be interpreted as restriction of the present utility model, those of ordinary skill in the art can change above-described embodiment, revises, replace and modification in scope of the present utility model.
Claims (9)
1. a undervoltage protection device for Switching Power Supply, is characterized in that, comprising:
For the voltage detecting circuit detected the voltage being input to described Switching Power Supply;
Thyristor, the control end of described thyristor is connected with the output of described voltage detecting circuit, wherein, described voltage detecting circuit detect the voltage of described Switching Power Supply be less than first preset protection voltage time described thyristor cut-off, when described voltage detecting circuit detects that the voltage of described Switching Power Supply is more than or equal to the second default protection voltage, described thyristor is open-minded, and described second presets protection voltage is greater than the described first default protection voltage;
Under-voltage protecting circuit, described under-voltage protecting circuit exports the power supply chip of under-voltage protection signal to described Switching Power Supply to realize under-voltage protection when described thyristor cut-off.
2. the undervoltage protection device of Switching Power Supply as claimed in claim 1, it is characterized in that, described voltage detecting circuit comprises:
First resistance, one end of described first resistance is connected with providing the default power supply of the voltage of described Switching Power Supply;
Second resistance, one end of described second resistance is connected with the other end of described first resistance, the other end ground connection of described second resistance, have first node between described first resistance and described second resistance, described first node is connected with the control end of described thyristor.
3. the undervoltage protection device of Switching Power Supply as claimed in claim 2, it is characterized in that, described under-voltage protecting circuit also comprises:
3rd resistance, one end of described 3rd resistance is connected with one end of described second resistance;
First switching tube, the first end of described first switching tube is connected with the other end of described 3rd resistance, the second end ground connection of described first switching tube, and the 3rd end of described first switching tube is connected with described default power supply;
Second switch pipe, the first end of described second switch pipe is connected with the 3rd end of described first switching tube, the second end ground connection of described second switch pipe;
3rd switching tube, the first end of described 3rd switching tube is connected with the 3rd end of described second switch pipe, and the second end of described 3rd switching tube is connected with described default power supply, and the 3rd end of described 3rd switching tube is connected with the negative electrode of described thyristor, wherein, the plus earth of described thyristor;
4th switching tube; the first end of described 4th switching tube is connected with described default power supply; second end ground connection of described 4th switching tube; 3rd end of described 4th switching tube is connected with the first end of described 3rd switching tube, and the first end of described 4th switching tube exports under-voltage protection signal when described thyristor cut-off.
4. the undervoltage protection device of Switching Power Supply as claimed in claim 3, it is characterized in that, described under-voltage protecting circuit also comprises:
4th resistance, described 4th resistance is connected between the 3rd end of described first switching tube and described default power supply;
5th resistance; described 5th resistance is connected between the first end of described default power supply and described 4th switching tube; have Section Point between described 5th resistance and described 4th switching tube, wherein, described Section Point exports under-voltage protection signal when described thyristor cut-off.
5. the undervoltage protection device of Switching Power Supply as claimed in claim 4, it is characterized in that, described under-voltage protecting circuit also comprises:
6th resistance, described 6th resistance is connected between the negative electrode of described thyristor and the 3rd end of described 3rd switching tube;
7th resistance, between the first end that described 7th resistance is connected to described 3rd switching tube and the 3rd end of the 4th switching tube;
8th resistance, one end of described 8th resistance is connected with the 3rd end of described 4th switching tube, the other end ground connection of described 8th resistance.
6. the undervoltage protection device of Switching Power Supply as claimed in claim 3, is characterized in that, also comprise:
9th resistance, described 9th resistance is connected between described default power supply and the negative electrode of described thyristor.
7. the undervoltage protection device of Switching Power Supply as claimed in claim 3, it is characterized in that, wherein, described first switching tube, described second switch pipe, described 4th switching tube are NPN type triode, and described 3rd switching tube is PNP type triode.
8. the undervoltage protection device of Switching Power Supply as claimed in claim 1, is characterized in that, described in be input to described Switching Power Supply voltage be 12V, 24V or 48V.
9. a Switching Power Supply, is characterized in that, comprising:
Power supply chip; And
The undervoltage protection device of the Switching Power Supply as described in any one of claim 1-8, described undervoltage protection device is electrically connected with described power supply chip.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420440329.5U CN204103461U (en) | 2014-08-05 | 2014-08-05 | The undervoltage protection device of Switching Power Supply and there is its Switching Power Supply |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420440329.5U CN204103461U (en) | 2014-08-05 | 2014-08-05 | The undervoltage protection device of Switching Power Supply and there is its Switching Power Supply |
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| CN204103461U true CN204103461U (en) | 2015-01-14 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201420440329.5U Active CN204103461U (en) | 2014-08-05 | 2014-08-05 | The undervoltage protection device of Switching Power Supply and there is its Switching Power Supply |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108039879A (en) * | 2017-12-28 | 2018-05-15 | 郑州天舜电子技术有限公司 | A kind of intelligent electric power controlling switch circuit |
| CN113708341A (en) * | 2021-09-04 | 2021-11-26 | 广西普德新星电源科技有限公司 | Undervoltage protection circuit |
-
2014
- 2014-08-05 CN CN201420440329.5U patent/CN204103461U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108039879A (en) * | 2017-12-28 | 2018-05-15 | 郑州天舜电子技术有限公司 | A kind of intelligent electric power controlling switch circuit |
| CN113708341A (en) * | 2021-09-04 | 2021-11-26 | 广西普德新星电源科技有限公司 | Undervoltage protection circuit |
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