CN103701100A - Switching power supply and over-voltage protection circuit thereof - Google Patents
Switching power supply and over-voltage protection circuit thereof Download PDFInfo
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- CN103701100A CN103701100A CN201210374624.0A CN201210374624A CN103701100A CN 103701100 A CN103701100 A CN 103701100A CN 201210374624 A CN201210374624 A CN 201210374624A CN 103701100 A CN103701100 A CN 103701100A
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Abstract
The invention relates to a switching power supply and an over-voltage protection circuit of the switching power supply. The over-voltage protection circuit comprises a varistor RV, a zero sequence current transformer T1, a potentiometer RP1, a bidirectional thyristor VS and a fuse F1, wherein the zero sequence current transformer comprises a first primary coil L1, a second primary coil L2 and a second coil L3, a first electrode of the bidirectional thyristor VS is connected with the first end of a commercial power after being connected with the fuse F1 in series, a second electrode is connected with the second end of the commercial power, and a control pole is connected with a sliding contact end of the potentiometer RP1; L1 is connected between the first electrode and the first input end of a rectifier-filter circuit, L2 is connected between the second electrode and the second input end of the rectifier-filter circuit, and L3 is connected between the second electrode and a first fixed end of the potentiometer RP1; a second fixed end of the potentiometer is connected with a second electrode; the varistor RV is connected between the second electrode and the first input end of the rectifier-filter circuit. The over-voltage protection circuit can cut off the circuit when voltage continuously exceeds standards.
Description
Technical field
The present invention relates to over-voltage protection technology, relate in particular to a kind of switch power over-voltage protection circuit.
Background technology
Switching Power Supply is to utilize modern power electronics technology, and the time ratio that control switch pipe turns on and off maintains a kind of power supply of regulated output voltage, is widely used in every field.
In comparatively complicated, the severe situation of some power environment conditions, as unstable in line voltage, 220V and 380V are difficult for the occasion of resolution etc., easily cause the internal component of Switching Power Supply to damage because bearing too high voltage.For protective circuit components and parts, conventionally use in the prior art a kind of transient state (transition) voltage to suppress diode TVS protection is provided, as shown in Figure 1, show a kind of schematic diagram of common Off-line SMPS importation.TVR1 in Fig. 1 is a kind of over-voltage protection element; make transient state (transition) voltage suppress diode TVS; under the applied in reverse condition of regulation; when bearing a high-octane instantaneous overvoltage pulse; its working impedance can be down to very low conduction value immediately; allow large electric current to pass through, and voltage clamping is arrived to predeterminated level, thereby effectively protect the precision components in electronic circuit to avoid damaging.But this element is generally used for preventing overvoltage moment, the short time of surge one class, and for lasting overvoltage, it has just been not suitable for, and in sustained overvoltage situation, TVS diode can generate heat serious until burn, and will lose protective effect; Or in another situation, input voltage has surpassed the rated value of circuit design but has not reached in the puncture voltage situation of TVS, and TVS does not provide protection yet.
Summary of the invention
The technical problem to be solved in the present invention is; the above-mentioned defect that can not protect circuit element in sustained overvoltage situation for prior art; a kind of Switching Power Supply and overvoltage crowbar thereof are provided; when the too high and sustained overvoltage of Switching Power Supply input terminal voltage; automatically cut off path, other elements in protective circuit exempt from destruction.
The technical solution adopted for the present invention to solve the technical problems is: a kind of switch power over-voltage protection circuit is provided, wherein, described switch power over-voltage protection circuit is connected between civil power input and current rectifying and wave filtering circuit, and described switch power over-voltage protection circuit comprises piezo-resistance, zero sequence current mutual inductor, potentiometer, bidirectional thyristor and fuse; Described zero sequence current mutual inductor comprises the first primary coil, the second primary coil and secondary coil; Wherein, the first electrode of described bidirectional thyristor is connected and is connected the first end of civil power after described fuse, and the second electrode connects the second end of civil power, controls the sliding contact end that the utmost point connects described potentiometer; Described the first primary coil is connected between first electrode and the first input end of current rectifying and wave filtering circuit of described bidirectional thyristor, described the second primary coil is connected between the second electrode of described bidirectional thyristor and the second input of current rectifying and wave filtering circuit, and described secondary coil is connected between the first stiff end of described potentiometer and the second electrode of described bidirectional thyristor; The second stiff end of described potentiometer connects the second electrode of described bidirectional thyristor; Described piezo-resistance is connected between the first input end of current rectifying and wave filtering circuit and the second electrode of described bidirectional thyristor.
In switch power over-voltage protection circuit of the present invention, the rated current of described bidirectional thyristor is greater than the blowout current of described fuse.
In switch power over-voltage protection circuit of the present invention, the withstand voltage 300V that is greater than of described bidirectional thyristor.
In switch power over-voltage protection circuit of the present invention, the nominal value of described piezo-resistance is selected based on input voltage range.
The present invention also provides a kind of Switching Power Supply, and described Switching Power Supply comprises EMI filter circuit, current rectifying and wave filtering circuit and above-mentioned switch power over-voltage protection circuit, and described switch power over-voltage protection circuit is connected between civil power input and current rectifying and wave filtering circuit.
Implement technical scheme of the present invention, there is following technique effect: when the too high and sustained overvoltage of Switching Power Supply input terminal voltage, circuit will disconnect automatically, and other elements in protective circuit exempt from destruction.
Accompanying drawing explanation
Below in conjunction with drawings and Examples, the invention will be further described, in accompanying drawing:
Fig. 1 is the circuit diagram of a kind of Off-line SMPS of the prior art;
Fig. 2 is the circuit diagram of switch power over-voltage protection circuit according to an embodiment of the invention;
Fig. 3 is the circuit diagram of Switching Power Supply according to an embodiment of the invention.
Embodiment
Fig. 2 is the circuit diagram of switch power over-voltage protection circuit according to an embodiment of the invention.This switch power over-voltage protection circuit is connected between civil power input and current rectifying and wave filtering circuit.As shown in Figure 2, this switch power over-voltage protection circuit comprises piezo-resistance RV, zero sequence current mutual inductor T1, potentiometer RP1, bidirectional thyristor VS and fuse F1.Zero sequence current mutual inductor T1 comprises the first primary coil L1, the second primary coil L2 and secondary coil L3.Wherein, connect the first end of civil power after the first electrode series connection fuse F1 of bidirectional thyristor VS, the second electrode connects the second end of civil power, controls the sliding contact end that the utmost point connects potentiometer RP1; The first primary coil L1 is connected between the first electrode and the first input end of current rectifying and wave filtering circuit of described bidirectional thyristor VS, the second primary coil L2 is connected between the second electrode of bidirectional thyristor VS and the second input of current rectifying and wave filtering circuit, and secondary coil L3 is connected between the first stiff end of potentiometer RP1 and the second electrode of described bidirectional thyristor VS; The second stiff end of potentiometer RP1 connects the second electrode of bidirectional thyristor VS; Piezo-resistance RV is connected between the first input end of current rectifying and wave filtering circuit and the second electrode of bidirectional thyristor VS.In an embodiment of the present invention, the first end of civil power is civil power live wire, and the second end of civil power is civil power zero line, or the first end of civil power is civil power zero line, and the second end of civil power is civil power live wire.In addition, in an embodiment of the present invention, the first end that connects civil power after the first electrode series connection fuse F1 of bidirectional thyristor VS, the second electrode directly connects the second end of civil power, yet, those skilled in the art it should be understood that the first electrode of bidirectional thyristor VS also can directly connect the first end of civil power, and after the second electrode series connection fuse F1, connects the second end of civil power.In addition, those skilled in the art it should be understood that and also can adopt two resistance to replace the potentiometer RP1 in example of the present invention.
In the present invention, in Switching Power Supply, increase by an overvoltage crowbar, be used to provide over-voltage protecting function.The operation principle of switch power over-voltage protection circuit is specific as follows: when 220V civil power is normal, the resistance approach infinity of piezo-resistance RV, the size of current of primary coil L1, L2 by zero sequence current mutual inductor T1 equates, opposite direction, the vector sum of these two electric currents is zero, in the secondary coil L3 of zero sequence current mutual inductor T1, no current flows through, and bidirectional thyristor VS can not get triggering signal and in cut-off state; When supply voltage is too high; piezo-resistance RV disruptive discharge; destroyed the poised state of primary circuit; in secondary coil L3, there is induction Voltage-output; the signal being detected by potentiometer RP1 just can trigger bidirectional thyristor VS saturation conduction; cause that to flow through fuse F1(be fuse) current surge and it is fused very soon, thereby reach the object of overvoltage protection.In circuit, the rated current of bidirectional thyristor VS should be greater than the blowout current of fuse F1, and it is withstand voltage should be greater than 300V; Can be that piezo-resistance RV selects corresponding nominal value according to input voltage range, the resistance of piezo-resistance RV have determined overvoltage protection operation voltage threshold values.
Fig. 3 is the circuit diagram of Switching Power Supply according to an embodiment of the invention.As shown in Figure 3, this Switching Power Supply comprises EMI filter circuit 100, switch power over-voltage protection circuit 200 and current rectifying and wave filtering circuit 300.Wherein:
Switch power over-voltage protection circuit 200 is connected between civil power input and current rectifying and wave filtering circuit 300, and it comprises piezo-resistance RV, zero sequence current mutual inductor T1, potentiometer RP1, bidirectional thyristor VS and fuse F1.Zero sequence current mutual inductor T1 comprises the first primary coil L1, the second primary coil L2 and secondary coil L3.Wherein, connect the first end of civil power after the first electrode series connection fuse F1 of bidirectional thyristor VS, the second electrode connects the second end of civil power, controls the sliding contact end that the utmost point connects potentiometer RP1; The first primary coil L1 is connected between the first electrode and the first input end of current rectifying and wave filtering circuit of described bidirectional thyristor VS, the second primary coil L2 is connected between the second electrode of bidirectional thyristor VS and the second input of current rectifying and wave filtering circuit, and secondary coil L3 is connected between the first stiff end of potentiometer RP1 and the second electrode of described bidirectional thyristor VS; The second stiff end of potentiometer RP1 connects the second electrode of bidirectional thyristor VS; Piezo-resistance RV is connected between the first input end of current rectifying and wave filtering circuit and the second electrode of bidirectional thyristor VS.
Current rectifying and wave filtering circuit 300 comprises rectifier bridge, thermistor NTC1, inductance L 4, capacitor C 2, capacitor C 3 and the capacitor C 29 that diode D1-D4 forms.The output of current rectifying and wave filtering circuit 300 connects load.
In an embodiment of the present invention, primary coil L1, the L2 of zero sequence current mutual inductor T1 can be used as common mode inductance.When input voltage is too high; such as input voltage should meet 220V but meet 380V; now piezo-resistance RV is breakdown; the secondary coil L3 of zero sequence current mutual inductor T1 has induced voltage, by RP1 potentiometer dividing potential drop, stimulates bidirectional thyristor VS conducting, approximate short circuit between live wire and zero line; moment has large electric current to flow through fuse F1; fuse F1 is fused, and has cut off circuit, has protected other elements in circuit to exempt from infringement.
In the present invention, thereby stimulate thyristor conducting to make fuse blows to cut off circuit by piezo-resistance is breakdown when there is overvoltage, reach the object of protective circuit element.No matter implement the present invention, be the in the situation that of transient overvoltage or sustained overvoltage, can realize the object of protective circuit element.
Although the present invention describes by specific embodiment, it will be appreciated by those skilled in the art that, without departing from the present invention, can also carry out various conversion and be equal to alternative the present invention.In addition, for particular condition or material, can make various modifications to the present invention, and not depart from the scope of the present invention.Therefore, the present invention is not limited to disclosed specific embodiment, and should comprise the whole execution modes that fall within the scope of the claims in the present invention.
Claims (5)
1. a switch power over-voltage protection circuit, it is characterized in that, described switch power over-voltage protection circuit is connected between civil power input and current rectifying and wave filtering circuit, and described switch power over-voltage protection circuit comprises piezo-resistance (RV), zero sequence current mutual inductor (T1), potentiometer (RP1), bidirectional thyristor (VS) and fuse (F1); Described zero sequence current mutual inductor (T1) comprises the first primary coil (L1), the second primary coil (L2) and secondary coil (L3); Wherein, the first electrode of described bidirectional thyristor (VS) is connected and is connected the first end of civil power after described fuse (F1), and the second electrode connects the second end of civil power, controls the sliding contact end that the utmost point connects described potentiometer (RP1); Described the first primary coil (L1) is connected between first electrode and the first input end of current rectifying and wave filtering circuit of described bidirectional thyristor (VS), described the second primary coil (L2) is connected between the second electrode of described bidirectional thyristor (VS) and the second input of current rectifying and wave filtering circuit, and described secondary coil (L3) is connected between the first stiff end of described potentiometer (RP1) and the second electrode of described bidirectional thyristor (VS); The second stiff end of described potentiometer (RP1) connects the second electrode of described bidirectional thyristor (VS); Described piezo-resistance (RV) is connected between the first input end of current rectifying and wave filtering circuit and the second electrode of described bidirectional thyristor (VS).
2. switch power over-voltage protection circuit according to claim 1, is characterized in that, the rated current of described bidirectional thyristor (VS) is greater than the blowout current of described fuse (F1).
3. switch power over-voltage protection circuit according to claim 1, is characterized in that, the withstand voltage 300V that is greater than of described bidirectional thyristor (VS).
4. switch power over-voltage protection circuit according to claim 1, is characterized in that, the nominal value of described piezo-resistance (RV) is selected based on input voltage range.
5. a Switching Power Supply; it is characterized in that; described Switching Power Supply comprises EMI filter circuit, current rectifying and wave filtering circuit and the switch power over-voltage protection circuit as described in claim 1-4 any one, and described switch power over-voltage protection circuit is connected between civil power input and current rectifying and wave filtering circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210374624.0A CN103701100A (en) | 2012-09-27 | 2012-09-27 | Switching power supply and over-voltage protection circuit thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210374624.0A CN103701100A (en) | 2012-09-27 | 2012-09-27 | Switching power supply and over-voltage protection circuit thereof |
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| CN103701100A true CN103701100A (en) | 2014-04-02 |
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| CN201210374624.0A Pending CN103701100A (en) | 2012-09-27 | 2012-09-27 | Switching power supply and over-voltage protection circuit thereof |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104917166A (en) * | 2015-05-26 | 2015-09-16 | 谈宁 | Wiring board circuit structure |
| CN105071370A (en) * | 2015-07-21 | 2015-11-18 | 重庆市亚东亚集团变压器有限公司 | Quick self-triggering damping resistor protection device |
| CN107432204A (en) * | 2017-06-19 | 2017-12-05 | 汤在英 | A kind of ecological greening wall for being capable of water processed based on Internet of Things |
-
2012
- 2012-09-27 CN CN201210374624.0A patent/CN103701100A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104917166A (en) * | 2015-05-26 | 2015-09-16 | 谈宁 | Wiring board circuit structure |
| CN105071370A (en) * | 2015-07-21 | 2015-11-18 | 重庆市亚东亚集团变压器有限公司 | Quick self-triggering damping resistor protection device |
| CN107432204A (en) * | 2017-06-19 | 2017-12-05 | 汤在英 | A kind of ecological greening wall for being capable of water processed based on Internet of Things |
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Application publication date: 20140402 |