CN204992533U - Switching power supply protection circuit, protection device and switching power supply - Google Patents
Switching power supply protection circuit, protection device and switching power supply Download PDFInfo
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- CN204992533U CN204992533U CN201520581475.4U CN201520581475U CN204992533U CN 204992533 U CN204992533 U CN 204992533U CN 201520581475 U CN201520581475 U CN 201520581475U CN 204992533 U CN204992533 U CN 204992533U
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Abstract
The utility model discloses a switching power supply protection circuit, protection device and switching power supply. The protection circuit include the overvoltage protection component, with overvoltage protection component connection's an over -current protection component and with overvoltage protection component connection's the 2nd over -current protection component, wherein, the overvoltage protection component connects in parallel between the live wire and zero line of power input end, an over -current protection component with the overvoltage protection component is parallelly connected, the 2nd over -current protection component with the overvoltage protection component is established ties, the 2nd over -current protection component is used for detecting the electric current increase of overvoltage protection component is broken off when just the temperature exceedes the settlement threshold value. The utility model discloses a corresponding switching power supply protection device and the switching power supply of providing still. The utility model provides a technical scheme can more effective protection switch power supply circuit.
Description
Technical field
The utility model belongs to circuit engineering field, is specifically related to a kind of protective circuit of switch power source, protective device and Switching Power Supply.
Background technology
Switching power circuit is operated on off state due to its power transistor, obtains apply widely in Power convert field.For a certain embody rule occasion, the output voltage of usual switching power circuit is a fixing direct voltage, but its input voltage may have certain change.At Switching Power Supply input, generally power voltage surge can be produced.So-called surge, is also surging, exceeds the transient overvoltage of normal voltage exactly, the big current that the short time referring generally to occur in circuit causes as the high voltage " wave ".
In the circuit of prior art, as shown in Figure 1, for the method suppressing surge voltage to adopt be, by common MOV(MetalOxideVaristor, metal oxide piezo-resistance) be attempted by the L(live wire of power input), N(zero line) between, when surge enters power supply, surge voltage is absorbed by piezo-resistance MOV, thus reduces impact.
But the processing method of prior art, while absorption surge voltage, also can bring certain damage to MOV(.After the N task gone round and begun again, add the life problems of MOV itself, the internal electrical of MOV fails to be convened for lack of a quorum constantly aggravation, makes it innerly constantly heat up, and the phenomenon such as finally just may set off an explosion, catch fire.
Therefore, existing switching power circuit guard method imperfection, wish there is safer guard method.
Summary of the invention
Technical problem to be solved in the utility model is to provide a kind of protective circuit of switch power source, protective device and Switching Power Supply, can more protective efficient switch power circuit, ensures user's use safety.
The technical scheme that the utility model provides is as follows:
The utility model provides a kind of protective circuit of switch power source:
The second over-current protecting element that described protective circuit comprises overvoltage protection element, the first over-current protecting element be connected with described overvoltage protection element and is connected with described overvoltage protection element; Wherein,
Described overvoltage protection element is connected in parallel between the live wire of power input and zero line;
Described first over-current protecting element is in parallel with described overvoltage protection element;
Described second over-current protecting element is connected with described overvoltage protection element, described second over-current protecting element for detect described overvoltage protection element electric current increase and temperature exceed setting threshold time disconnect.
Preferred: described overvoltage protection element is piezo-resistance, described first over-current protecting element is the first fuse, and described second over-current protecting element is the second fuse;
Described piezo-resistance is connected in parallel between the live wire of power input and zero line;
Described first fuse is in parallel with described piezo-resistance;
Described second fuse is connected with described piezo-resistance, described second fuse for detect described piezo-resistance electric current increase and temperature exceed setting threshold time disconnect.
Preferred: described second fuse and described piezo-resistance adopt sleeve pipe to entangle.
Preferred: described protective circuit also comprises the rectification circuit for alternating current being converted to Rectified alternating current;
One end of described first fuse is connected with one end of described rectification circuit, and the other end of described first fuse is connected with one end of described piezo-resistance;
The other end of described piezo-resistance is connected with the other end of described rectification circuit.
Preferred: described second fuse is high fusing-off temperature fuse, described piezo-resistance is high-energy metal oxide piezo-resistance.
Preferred: described sleeve pipe is heat-shrinkable T bush.
The utility model also provides a kind of Switching Power Supply protective device, comprises above-mentioned protective circuit of switch power source.
The utility model also provides a kind of Switching Power Supply, comprises above-mentioned protective circuit of switch power source.
Preferred: described Switching Power Supply also comprises the first filter circuit, charging capacitor, PWM controller, metal-oxide-semiconductor, transformer, the second rectification circuit, the second filter circuit;
After the described first filter circuit rectification circuit be used in described protective circuit of switch power source changes the alternating current of described power input into Rectified alternating current, described Rectified alternating current is transformed into smooth direct current electricity;
Described charging capacitor is used for being connected with described first filter circuit, and the smooth direct current electricity utilizing described first filter circuit to export charges;
Described PWM controller is used for being connected with described charging capacitor, reach the starting resistor of PWM controller at the voltage of described charging capacitor after, output pulse width modulation (PWM) signal drives described metal-oxide-semiconductor to realize opening and closing, and makes to become alternating current by the electric current of transformer;
Described metal-oxide-semiconductor is used for being connected with PWM controller and transformer respectively, realizes opening and closing according to the pwm signal that PWM controller exports;
Described second rectification circuit is used for being connected with described transformer, and the alternating current that described transformer exports is become Rectified alternating current;
Described second filter circuit is used for being connected with described second rectification circuit, the Rectified alternating current that described second rectification circuit exports is converted to smooth direct current electricity powering load.
Preferred: described transformer is for generation of alternating current, and the other road alternating current that described transformer produces is powered to described PWM controller by being converted into smooth direct current electricity after rectification, current limliting and filtering process successively.
As can be seen from technique scheme, the protective circuit of switch power source that the utility model provides, by increasing the second over-current protecting element (such as the second fuse), second over-current protecting element is connected with overvoltage protection element (such as piezo-resistance), so when the electric current of overvoltage protection element increases and temperature exceedes setting threshold, this second over-current protecting element will disconnect automatically, thus protect the second over-current protecting element (such as piezo-resistance) and constantly can not to heat up the blast finally caused because of inside, the phenomenon such as to catch fire, thus available protecting switching power circuit, protect the use safety of user.
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, other accompanying drawing can also be obtained according to these accompanying drawings.
Below in conjunction with accompanying drawing, the utility model is described further, in accompanying drawing:
Fig. 1 is prior art switching power circuit protective circuit schematic diagram;
Fig. 2 is the utility model switching power circuit protective circuit schematic diagram;
Fig. 3 is the utility model switching power circuit schematic diagram;
Fig. 4 is the utility model Switching Power Supply protective device structural representation.
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 the utility model part embodiment, instead of whole embodiments.Based on the embodiment in the utility model, those of ordinary skill in the art are not making other embodiments all obtained under creative work prerequisite, all belong to the scope of the utility model protection.
The utility model puies forward a kind of protective circuit of switch power source, protective device and Switching Power Supply, can more protective efficient switch power circuit, protection user use safety.
Below in conjunction with accompanying drawing, introduce content of the present utility model in detail.
Fig. 2 is the utility model switching power circuit protective circuit schematic diagram.As shown in Figure 2, in Switching Power Supply input protective circuit of the present utility model, control circuit is formed primarily of overvoltage protection element, the over-current protecting element be connected with overvoltage protection element and part of its periphery circuit.Overvoltage protection element of the present utility model; can be piezo-resistance but be not limited to this; also can be that other have the element of over-voltage protection function; over-current protecting element of the present utility model; can being fuse (also referred to as fuse) but being not limited to this, also can be that other have the element of excess current protective function.
The fuse that the utility model uses, can be high fusing-off temperature fuse (also referred to as high fusing-off temperature fuse) F, the piezo-resistance that the utility model uses, can be high joule MOV(MetalOxideVaristor, metal oxide piezo-resistance), wherein joule is the unit of energy, and high joule MOV is also referred to as high-energy MOV.
Concrete, on the circuit shown in Fig. 2, it is 5A/250VT=130 DEG C that the utility model adds high fusing-off temperature fuse F2(specifications parameter, represent maximum current 5A, ceiling voltage 250V, maximum temperature 130 DEG C), and fuse F2 and piezo-resistance MOV sleeve pipe are entangled, carry out firm.This sleeve pipe can be heat-shrinkable T bush but be not limited to this, also can be the sleeve pipe of other types.In Fig. 2, piezo-resistance MOV is connected in parallel between the live wire of power input and zero line; Fuse F1 is in parallel with described piezo-resistance; Fuse F2 connects with described piezo-resistance MOV, for detect described piezo-resistance MOV electric current increase and temperature exceed setting threshold time disconnect.D1-D4(diode is also had in Fig. 2) bridge rectifier that forms, for converting alternating current to Rectified alternating current.One end of fuse F1 is connected with one end of bridge rectifier, and the other end of F1 is connected with one end of MOV; The other end of MOV is connected with the other end of bridge rectifier, and MOV also entangles with fuse F2 heat-shrinkable T bush.
Like this, when MOV electric current strengthens, heating is when causing temperature to rise to uniform temperature, and fuse F2 will fuse, thus cut-off loop, ensures that MOV does not blast because of overheated or the potential safety hazard such as to catch fire.And in the protective circuit of prior art, MOV heating is when exceeding uniform temperature, fuse F1 can't disconnect, the potential safety hazard such as MOV therefore cannot be avoided to blast because of overheated or catch fire.So the circuit after the utility model improves, not only to the more effective suppression of wave stream voltage, and makes secure context better be ensured.
Fig. 3 is the utility model switching power circuit schematic diagram.The figure illustrates the structure than more complete switching power circuit.As shown in Figure 3, the workflow of this circuit is:
First, the 100-240V(volt of input) AC alternating current first after these two surge protector component of fuse F1 and MOV1, then be added on D1-D4(diode through the fuse F2 that the utility model increases) on bridge rectifier.When MOV heating causes temperature to rise to uniform temperature threshold value, F2 will fuse, thus cut-off loop, the potential safety hazard such as avoid MOV to blast because of overheated or to catch fire.This uniform temperature threshold value, rule of thumb can carry out value, such as, can be 130 DEG C but be not limited to this, as being 120 DEG C or 140 DEG C etc.
Alternating current, after the diode D1-D4 rectification of rectification circuit, changes Rectified alternating current into, and this Rectified alternating current through the electric capacity C1 of filter circuit, inductance L 1, these three filter element filtering of electric capacity C3, is transformed into smooth direct current electricity again.First this level and smooth direct current is charged to charging capacitor C4 by resistance R10, R11.
When the voltage on electric capacity C4 reaches PWM(PulseWidthModulation, pulse width modulation) controller U1 starting resistor after, PWM controller U1 starts, by 6 pin output pwm signals, through R7, R9 resistor network driven MOS pipe (Metal-Oxide-Semiconductor, metal oxide semiconductor transistor) Q1, realize the opening and closing (ON-OFF) of metal-oxide-semiconductor, making by the electric current of transformer T1 is alternating current, this alternating current produces the magnetic field of alternation in inside transformer, alternating current can be produced after secondary coil senses alternating magnetic field, Rectified alternating current is converted to through diode D7 or D8 rectification shape, again through electric capacity C8, C9 filtering, convert smooth direct current electricity to export, powering load.
Another road, auxiliary the coil-induced of winding also can produce alternating current after alternating magnetic field, after diode D6 rectification, resistance R5 current limliting, electric capacity C4 filtering, converts smooth direct current electricity to, powers to PWM controller U1.
In addition, R16, R18, R15, C7, R12, R13, PC1, C5 in figure are combined as sampling voltage stabilizing circuit, and the error signal of this electric circuit inspection outputs to the 2nd pin of U1, thus the switching frequency of control PWM and duty ratio, realize the stable of output voltage.
The too high protection of OCP(electric current of circuit in Fig. 3) realization of function protected by these elements of R1, R2, Cx, R4, C2.When current is excessive, R1 overtension on R2, this voltage signal, after Cx, R4, C2 filtering, is added on the 4th pin of U1, thus control U1 stops output pwm signal.
In Fig. 3 circuit D5, R3, R6, C6 be combined as peak absorbing circuit, prevent the peak voltage of the D pole of Q1 too high and damage metal-oxide-semiconductor.
Fig. 4 is the utility model Switching Power Supply protective device structural representation.As shown in Figure 4, Switching Power Supply protective device 400 comprises above-mentioned protective circuit of switch power source 401, and the specific descriptions of protective circuit of switch power source 401, see describing above, repeat no more herein.
In sum, the protective circuit of switch power source that the utility model provides, by increasing the second over-current protecting element (such as the second fuse), second over-current protecting element is connected with overvoltage protection element (such as piezo-resistance), so when the electric current of overvoltage protection element increases and temperature exceedes setting threshold, this second over-current protecting element will disconnect automatically, thus protect the second over-current protecting element and constantly can not to heat up the blast finally caused because of inside, the phenomenon such as to catch fire, thus available protecting switching power circuit, protect the use safety of user.
Above to the technical scheme that the utility model embodiment provides, be described in detail, apply specific case herein to set forth principle of the present utility model and execution mode, the explanation of above embodiment just understands method of the present utility model and core concept thereof for helping; Meanwhile, for one of ordinary skill in the art, according to thought of the present utility model, all will change in specific embodiments and applications, in sum, this description should not be construed as restriction of the present utility model.
Claims (10)
1. a protective circuit of switch power source, is characterized in that:
The second over-current protecting element that described protective circuit comprises overvoltage protection element, the first over-current protecting element be connected with described overvoltage protection element and is connected with described overvoltage protection element; Wherein,
Described overvoltage protection element is connected in parallel between the live wire of power input and zero line;
Described first over-current protecting element is in parallel with described overvoltage protection element;
Described second over-current protecting element is connected with described overvoltage protection element, described second over-current protecting element for detect described overvoltage protection element electric current increase and temperature exceed setting threshold time disconnect.
2. protective circuit of switch power source according to claim 1, is characterized in that:
Described overvoltage protection element is piezo-resistance, and described first over-current protecting element is the first fuse, and described second over-current protecting element is the second fuse;
Described piezo-resistance is connected in parallel between the live wire of power input and zero line;
Described first fuse is in parallel with described piezo-resistance;
Described second fuse is connected with described piezo-resistance, described second fuse for detect described piezo-resistance electric current increase and temperature exceed setting threshold time disconnect.
3. protective circuit of switch power source according to claim 2, is characterized in that:
Described second fuse and described piezo-resistance adopt sleeve pipe to entangle.
4. the protective circuit of switch power source according to Claims 2 or 3, is characterized in that:
Described protective circuit also comprises the rectification circuit for alternating current being converted to Rectified alternating current;
One end of described first fuse is connected with one end of described rectification circuit, and the other end of described first fuse is connected with one end of described piezo-resistance;
The other end of described piezo-resistance is connected with the other end of described rectification circuit.
5. the protective circuit of switch power source according to Claims 2 or 3, is characterized in that:
Described second fuse is high fusing-off temperature fuse, and described piezo-resistance is high-energy metal oxide piezo-resistance.
6. protective circuit of switch power source according to claim 3, is characterized in that:
Described sleeve pipe is heat-shrinkable T bush.
7. a Switching Power Supply protective device, is characterized in that, comprises the protective circuit of switch power source described in any one of the claims 1 to 6.
8. a Switching Power Supply, is characterized in that, comprises the protective circuit of switch power source described in any one of the claims 1 to 6.
9. Switching Power Supply according to claim 8, is characterized in that:
Described Switching Power Supply also comprises the first filter circuit, charging capacitor, pulse width modulation (PWM) controller, metal-oxide semiconductor (MOS) crystal metal-oxide-semiconductor, transformer, the second rectification circuit, the second filter circuit;
After the described first filter circuit rectification circuit be used in described protective circuit of switch power source changes the alternating current of described power input into Rectified alternating current, described Rectified alternating current is transformed into smooth direct current electricity;
Described charging capacitor is used for being connected with described first filter circuit, and the smooth direct current electricity utilizing described first filter circuit to export charges;
Described PWM controller is used for being connected with described charging capacitor, reach the starting resistor of PWM controller at the voltage of described charging capacitor after, output pulse width modulation (PWM) signal drives described metal-oxide-semiconductor to realize opening and closing, and makes to become alternating current by the electric current of transformer;
Described metal-oxide-semiconductor is used for being connected with PWM controller and transformer respectively, realizes opening and closing according to the pwm signal that PWM controller exports;
Described second rectification circuit is used for being connected with described transformer, and the alternating current that described transformer exports is become Rectified alternating current;
Described second filter circuit is used for being connected with described second rectification circuit, the Rectified alternating current that described second rectification circuit exports is converted to smooth direct current electricity powering load.
10. Switching Power Supply according to claim 9, is characterized in that:
Described transformer is for generation of alternating current, and the other road alternating current that described transformer produces is powered to described PWM controller by being converted into smooth direct current electricity after rectification, current limliting and filtering process successively.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520581475.4U CN204992533U (en) | 2015-08-05 | 2015-08-05 | Switching power supply protection circuit, protection device and switching power supply |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520581475.4U CN204992533U (en) | 2015-08-05 | 2015-08-05 | Switching power supply protection circuit, protection device and switching power supply |
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| CN204992533U true CN204992533U (en) | 2016-01-20 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106451350A (en) * | 2015-08-05 | 2017-02-22 | 惠州市忠邦电子有限公司 | Switching power supply protection circuit and device and switching power supply |
| CN111854071A (en) * | 2020-06-09 | 2020-10-30 | 海信（山东）空调有限公司 | Switch input circuit and air conditioner |
-
2015
- 2015-08-05 CN CN201520581475.4U patent/CN204992533U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106451350A (en) * | 2015-08-05 | 2017-02-22 | 惠州市忠邦电子有限公司 | Switching power supply protection circuit and device and switching power supply |
| CN111854071A (en) * | 2020-06-09 | 2020-10-30 | 海信（山东）空调有限公司 | Switch input circuit and air conditioner |
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