CN1479424A - Inputting overvoltage protection circuit and electric device with the protection circuit - Google Patents

Abstract

To surely cut off a circuit without relying on the performance or reliability of an overvoltage protection element if an input overvoltage is generated in a power supply line. An inrush current prevention circuit 25 is interposed in at least one of AC line L1 and L2, and a detection circuit 24 detects voltages of the AC lines L1 and L2. If a detected voltage exceeds a prescribed value, a switch circuit 26 is turned on to transmit the excess to the inrush current prevention circuit 25 by a phototriac coupler 41 of a transmission circuit 27. In the inrush current prevention circuit 25, a resistor 43 with a temperature fuse and a triac 42 which is a semiconductor switch element are connected in parallel. The triac 42 is normally conductive, and when information that the switch circuit 26 is turned on is transmitted by the transmission circuit 27, it is opened. It makes a current to flow the resistor 43 with temperature fuse, and a power feeding circuit is disconnected when the temperature fuse is blown off.

Description

Input excess voltage protection and electric device with this protective circuit

Technical field

The present invention relates to be arranged on from exchange power supply on the power supply circuits of load device or load circuit power supply, be used for when external surge or input overvoltage take place, cutting off power supply circuits, prevent the input excess voltage protection that load device or load circuit destroy and in power supply circuits, comprise the switching mode pressurizer etc. of this input excess voltage protection.

Background technology

Always, the AC load device of multipurpose switch type pressurizer, the DC load device that uses this switching mode pressurizer, heater etc., converter etc. are from the load device or the load circuit (these are called electric device) of the ac power supply of commercial frequency.And, on this ac power circuit, be provided with protective circuit usually, be used to protect these electric devices to avoid the input overvoltage that causes because of external surge etc.

So-called external surge refers to the abnormal voltage that is created in the power line internal induction by thunderbolt etc., the acyclic transient voltage that the short time sharply raises.If this external surge input starts from the power supply circuits of AC power, then become the electric abrasion of load device, the reason of initial failure.In addition, when the contact of contacts such as the switch of static or other device or relay surge taking place also, return input source, influences other device.

And so-called input overvoltage refers to excessive alternating voltage and is applied on the electric device and the state that continues, and prolongs the very danger of reason that burnings (spreading) damaged because of becoming the circuit element that constitutes electric device.

For example Japanese, by change the shape of socket and attaching plug on AC100V power supply and AC230V power supply, the possibility of the feasible AC230V that by mistake powers on the device that uses 100V is very low.But during the manufacturing before attaching plug is installed, have and take place because the possibility that overvoltage causes accident takes place to import the misconnection AC power.

So-called input excess voltage protection refers to and cuts off circuit prevent plant failure, also prevent that destruction owing to electric device from causing the circuit of accident simultaneously when so external surge and overvoltage take place.

Represent the example of existing switching mode pressurizer at Figure 20 with power supply circuits.These power supply circuits are made up of following: two power line L1, L2 with 2 AC input terminal IN101, IN102 being connected with AC power; The excess voltage protection that constitutes by elementary fuse 101 and rheostat 102; Noise filter 103; Rectification, the smoothing circuit and the inrush current of inserting its primary side that is situated between that are made of diode bridge 104 and level and smooth electricity consumption container C 101 prevent that circuit 105 from forming, and the direct current that comes from dc output end OUT101, OUT102 is outputed to not shown switching mode pressurizer.

Noise filter 103 is the filters that are made of common mode choke coil and norm choke coil, X capacitor or Y capacitor, make from AC input terminal IN101, IN102 input, disturb and the common formula that produces between power line L1, L2 and ground is disturbed and reduced in the normality that produces between AC power cord L1, L2.

Diode bridge 104 full-wave rectifications are passed through in interchange through noise filter 103, by the smoothing capacitor C101 smoothing as aluminium electrolytic capacitor, if there is not load, then become direct voltage substantially.Export this direct current to the switching mode pressurizer from the sub-OUT101 of dc output end, OUT102.Between diode bridge 104 and level and smooth electricity consumption container C 101, be provided with active filter circuit, also usually exist according to making voltage between the sub-OUT101 of dc output end, the OUT102 be controlled and reduce the situation of input current high frequency distortion near the mode of constant voltage.

No matter the common input overcurrent protection that produces such as the device load that causes for which kind of reason or the unusual or misoperation of circuit; elementary fuse is set on these power supply circuits usually; yet in order to avoid its border because unusual overvoltage or overcurrent; surpass the withstand voltage of element; make element form breakage or catch fire a class state; in order constantly to stop power supply as soon as possible, as the protective circuit slotting elementary fuse (main fuse) 101 that on a side power line L1, is situated between.Think that as above-mentioned reason unusual or misoperation dewfall, high-intensity magnetic field, dust, foreign matter sneak into, impact that hanging of causing split, heat environment such as (high temperature) causes circuit element short circuit or open circuit, and load self short circuit and so on etc.

Connect rheostat 102 between power line L1, L2 after being close to elementary fuse 101, so that when at this moment returning the surge voltage of input and can not fully remove by noise filter 103, as its absorb with and move, unlikelyly give the electric device harmful effect of powering jointly.

Elementary fuse 101 is the over-current protecting elements that fuse when flowing through big electric current, and rheostat 102 is to follow added voltage rising between terminal, the resistor of resistance value minimizing non-linearly.

And, because during the overvoltage between power line L1, L2 more than the proof voltage (the surge amount of bearing) of input rheostat 102, rheostat 102 is subjected to voltage and destroys, make short circuit between power line L1, the L2, flow through excessive electric current in the elementary fuse 101 and fuse, so these power supply circuits cut off, and stop by this power supply circuits powered switch type pressurizer safety.

Inrush current prevents that circuit 105 from being the circuit that restriction flows to the inrush current in rectification, the smoothing circuit.So-called inrush current is after not shown mains switch has just been connected, the excessive initial current that flows through till the smoothing capacitor C101 charging with big capacitance is over.If this initial current is excessive, then worry to constitute each diode or smoothing capacitor 101 scaling loss of diode bridge 104, elementary fuse 101 fusing.Except bridge voltage is produced harmful effect, can cause that also the instantaneous of power supply stops.

Therefore, on the input side of diode bridge 104, be situated between to insert the inrush current that constitutes by the resistance 106 of band Thermal Cutoffs or power type thermal resistance, TRIAC, silicon controlled rectifier and prevent circuit 105, reduce the inrush current size.

In main various countries except China; the existing excess voltage protection of number spare's report in a year by constituting by rheostat 102 and elementary fuse 101; because of external surge or the input overvoltage move; rheostat 102 be voltage breakage (short circuit) thus elementary fuse 101 fusing; cut-out stops fully to the power supply of switching mode pressurizer.That is, in the main various countries except China, this excess voltage protection is being brought into play function effectively.

This excess voltage protection is not limited to the power supply circuits to the switching mode pressurizer, is not arranged on the power supply circuits or the rectifier smoothing circuit of other DC load, and is arranged on also being effective on the power supply circuits of AC electric.Even to the AC electric; what especially need excess voltage protection (inrush current prevents circuit) is; in load is under the situation of the lamp of Halogen lamp LED or discharge tube etc. or fixed heater even load; power supply begins that resistance value was little originally; in case temperature rises; it is big that resistance value becomes, cross greatly up to inrush current flow through, till the stable temperature control, the situation that has the input overcurrent to flow through.

When in power supply, adding overvoltage, in other words, when on as the Halogen lamp LED of load or discharge tube, applying this voltage, become overvoltage or overcurrent condition, produce instantaneous the stopping or flickering voltage of power supply, worry the load breakage.This also might produce fire owing to because energy is excessive.

But; poor in power status; the problem of the burning damage accident and the accident of smoldering even its problem is to use the devices such as switching mode pressurizer of the power supply circuits that are equipped with such excess voltage protection, also might take place in the frequent Chinese market that takes place of input overvoltage.

Figure 21 represents the distribution system of China.The distribution system of China be the single-phase three-wire formula (1 3W, AC220V), by supply with the both sides of AC110V and AC220V from 3 supply lines of the transformer 111 that is provided with at electric post etc.Power line from the secondary coil mid point of transformer 111 is center line (neutral line) N of ground connection, and 2 power lines bringing in from its secondary coil two are live wire (pressure-wire) L101, the L102 that add alternating voltage.Also thinner than live wire L101, L102 at Chinese center line N, impedance uprises.

And, at this Figure 21, be connected making alive V1 in the load 113 between center line N and the live wire L101, be connected making alive V2 in the load 114 between center line and the live wire 102, be connected making alive V3 in the load 112 between live wire L101 and the L102.Under the normal power supply state, V1 and V2 are AC110V, and V3 is AC220V (being the effective value of 2 phase times).

The waveform example of voltage V3 when Figure 22 represents this state.If take the impedance balance of load shown in Figure 21 113 and 114, then the electric current that flows through in the center line N is roughly 0A.And the mid point of voltage waveform is 0V (earthing potential), and positive negative wave is impartial, and its peak height value is

Volt.

, when load 113 and 114 impedance balance difference, in center line N, flow through big electric current.

At this moment, in China, center line phase shortage accident owing to this thermal fatigue breaks in the junction of the circuit breaker of twisted wire welding, and takes place in center line heating that impedance is high repeatedly.

If produce the center line phase shortage like this, then the AC wave shape mid point forms instability, and under the unequal situation of the impedance of load 113 and 114, voltage V1, V2 are unequal, become bias voltage waveform.In view of the above, voltage V3 forms the waveform that misplaces to the plus or minus side from the mid point of original AC0V according to the mode shown in V3 ' among Figure 22.Therefore, if for example stagger in positive side, then the peak height value of positive side becomes greatly

Like that, the peak height value of minus side diminish for Like that.If it is stagger, then opposite with it at minus side.If the mid point of its interchange changes, then as shown in figure 23, become the mid point of original relatively AC0V and the waveform that changes.Therefore, become and in load 112, add periodic overvoltage repeatedly.

Like this, the input power status extreme difference of China, the input overvoltage frequently takes place.In addition, think and will continue from now on to improve, yet, with in Japan or the source impedance in Europe opposite less than 1 Ω especially big because Chinese source impedance be number+Ω, so owing to the mains voltage variations of source impedance generation is also big.

Therefore; even to the input overvoltage; through the power supply circuits of existing excess voltage protection as shown in Figure 20 are set; switching mode pressurizer even load device is given in power supply; often can not produce according to design load yet and stop like that safely; that might follow that rheostat 102 catches fire prolongs the burning accident, or catches fire or smolder, prolongs accidents such as burning as the smoothing capacitor C101 of aluminium electrolytic capacitor.

; during rheostat 102 variation; can make elementary fuse 101 broken strings reliably; if the surge capacity that makes rheostat 102 is more than the amount of bearing of elementary fuse 101; then because the moment before rheostat 102 or smoothing capacitor C101 destruction more early; because of the amount of bearing that surpasses elementary fuse breaks, so can prevent this class accident.

, the capacity of elementary fuse is exported the input current of size and power factor (PF) efficient by devices such as depending on the switching mode pressurizer and is determined.In view of the above, the capacity of elementary fuse is 8A when for example making AC100V, in order to prevent accident, is necessary rheostatic surge capacity is set in more than the capacity 8A of elementary fuse.

In addition, but this rheostat is necessary to select to have the element that about 2 times of alternating voltage clamper absorbs the surge capacity of external surge voltage.Because the external surge energy by generations such as thunder or input surges is indefinite, uptake determines by empirical value.

, rheostat surge capacity and overall dimension are ratio substantially, and surge rheostatic profile capacious is also big.In view of the above, for example the elementary fuse of surge Capacity Ratio capacity 8A is also big, and the rheostat size of this elementary fuse that can fuse is: there is the so-called miniaturization issues that hinders devices such as switching mode pressurizer in diameter more than about 10mm.

In addition, now, the digitlization by various devices makes the gradually big outputization of electric device of switching mode pressurizer etc.Accompany therewith, also be necessary to make the capacity of elementary fuse 101 or the capacity of rheostat 102 to strengthen., having the fusible capacity sells poorly greater than the rheostat of the surge capacity of the elementary fuse of 8A.

Therefore, using capacity to show in do input overvoltage result of experiment on the rheostatic input excess voltage protection of the Φ of elementary fuse more than the 8A and aforementioned profile about 10 sizes: rheostat must prolong burning before elementary fuse broken string.

Promptly; when the big output of switching mode pressurizer even load device; the limit is arranged utilizing on the input excess voltage protection only depend on existing elementary fuse and rheostat etc., existence can not prevent from above-mentionedly to prolong the burning accident or prolong the problem of burning damaged accident reliably.

; as existing input excess voltage protection; for example the spy opens that the 2001-339844 communique is described to replace rheostat 102 with Zener diode overvoltage protections such as (voltage stabilizing didoes) with element like that; when the input overvoltage, make overvoltage protection, make blowout with element short circuit breakage (puncture).

This overvoltage protection element, for example and smoothing capacitor C101 be connected in parallel between diode bridge shown in Figure 20 104 and level and smooth electricity consumption container C 101, between this overvoltage protection is with element and diode bridge 104, be situated between and insert fuse.And, between the output point of smoothing capacitor C101 and diode bridge 104, connect diode.

At such input excess voltage protection; if the input overvoltage protection above overvoltage of component breakdown voltage; then overvoltage protection element short circuit, breakage; the electric charge that makes smoothing capacitor C101 go up savings flows through by diode and fuse; by its discharging current blown fuse, cut off power supply circuits.

Propose with voltage stabilizing didoe, silicon varistor, the combination of avalanche diode or silicon controlled rectifier and voltage stabilizing didoe etc. are as this overvoltage protection element.

, the shortcoming of voltage stabilizing didoe and silicon varistor is that high withstand voltage element is few, and reactivity is also poor.Exist because of the situation of short-circuit mode (connection mode) breakage with because of the damaged situation of open circuit mode (open mode) about avalanche diode; because when open circuit mode is damaged, can not bring into play function, so its shortcoming is to carry out circuitry cuts reliably as overvoltage protection element.

That is: input excess voltage protection as noted above is except the reactivity difference, because action is fluctuateed about institute, so there is the shortcoming of the poor reliability of circuitry cuts with element characteristic by overvoltage protection.

Summary of the invention

The present invention does in view of these problems; purpose is: even under the environmental condition poor in for example power status, that the input overvoltage frequently takes place; when external surge or input overvoltage take place; also cut off power supply circuits reliably; safety stops load device or load circuit (electric device); the generation that can prevent the burning damage accident of circuit element early or emit burning accident etc.; simultaneously, the cut-out of these power supply circuits does not rely on performance or the reliability of overvoltage protections such as rheostat or fuse or voltage stabilizing didoe with element.

The present invention has many power lines that are connected with AC power; be arranged on by these many power lines and power to the input excess voltage protection on the power supply circuits of load device or load circuit; in order to achieve the above object; at least 1 slotting inrush current that is situated between at above-mentioned many each power lines prevents circuit; simultaneously, the testing circuit of detection about the voltage of above-mentioned many each power lines is set; the switching circuit that when the voltage that is detected by this testing circuit surpasses setting, carries out switch motion; the on/off state of this switching circuit is sent to the transmission circuit that above-mentioned inrush current prevents circuit.

And, above-mentioned inrush current prevents that circuit is connected in parallel to the resistance and the thyristor of band Thermal Cutoffs, this thyristor conducting at ordinary times, when the voltage that is detected by above-mentioned testing circuit surpasses setting, on/off state according to the said switching circuit that transmits by above-mentioned transmission circuit, above-mentioned thyristor disconnects, and flows through electric current in the resistance of above-mentioned band Thermal Cutoffs, cuts off power supply circuits by the fusing of this band Thermal Cutoffs.

The testing circuit of each power line voltage that above-mentioned testing circuit also can be the testing circuit that detects arbitrary voltage of above-mentioned many power lines, detect above-mentioned many power lines or detect arbitrary circuit of the testing circuit of above-mentioned many power supply voltages between lines.

At these input excess voltage protections; be inserted with above-mentioned inrush current in above-mentioned many power line intermediaries and prevent that this inrush current of the power line of circuit from preventing that the input side place of circuit from be situated between inserting elementary fuse, prevent between the outlet side of circuit and the other power line rheostat to be set in the inrush current of this power line.

Constitute said switching circuit by Zener diode, also can be with the zener voltage of this Zener diode as above-mentioned voltage setting.

This invention also is provided at the electric device of the switching mode pressurizers etc. that comprise these input excess voltage protections on the power supply circuits.

Description of drawings

Fig. 1 is the circuit diagram that is provided with the power supply circuits of the input excess voltage protection of representing embodiment of the present invention 1.

Fig. 2 is the circuit diagram of the different examples of presentation graphs 1 testing circuit.

Fig. 3 is the circuit diagram that the power supply circuits that are illustrated in Fig. 1 are provided with the situation example of active filter.

Fig. 4 is the circuit diagram of the more specifically circuit example of expression power supply circuits identical, shown in Figure 1 and DC/DC converter.

Fig. 5 be the expression embodiment of the present invention 2, with the same circuit diagram of Fig. 4.

Fig. 6 be the expression embodiment of the present invention 3, with Fig. 4 and the same circuit diagram of Fig. 5.

Fig. 7 be the expression embodiment of the present invention 4, with the same circuit diagram of Fig. 4 to Fig. 6.

Fig. 8 be the expression embodiment of the present invention 5, with the same circuit diagram of Fig. 4 to Fig. 7.

Fig. 9 be the expression embodiment of the present invention 6, with the same circuit diagram of Fig. 4 to Fig. 8.

Figure 10 be the expression embodiment of the present invention 7, with the same circuit diagram of Fig. 4 to Fig. 6.

Figure 11 is the circuit diagram to the power supply circuits of the AC load device of the input excess voltage protection that is provided with embodiment of the present invention 8.

Figure 12 be the expression embodiment of the present invention 9, with the same circuit diagram of Figure 11.

Figure 13 be the expression embodiment of the present invention 10, with Fig. 1 and the same circuit diagram of Figure 12.

Figure 14 be the expression embodiment of the present invention 11, with the same circuit diagram of Figure 11.

Figure 15 be the expression embodiment of the present invention 12, with Figure 11 and the same circuit diagram of Figure 14.

Figure 16 be the expression embodiment of the present invention 13, with the same circuit diagram of Fig. 5.

Figure 17 be the expression embodiment of the present invention 14, with the same circuit diagram of Fig. 8.

Figure 18 be the expression embodiment of the present invention 15, with the same circuit diagram of Fig. 8.

Figure 19 be the expression embodiment of the present invention 16, with the same circuit diagram of Fig. 9.

Figure 20 is the circuit diagram that expression is provided with power supply circuits one example of existing input excess voltage protection.

Figure 21 is the key diagram of the distribution system example of expression China.

Figure 22 is the oscillogram of AC wave shape of the voltage V3 of expression Figure 21.

Figure 23 is the oscillogram of mid point fluctuation situation of the voltage V3 of expression Figure 21.

Embodiment

Below according to the description of drawings embodiments of the present invention.

(execution mode 1: Fig. 1～Fig. 3)

Fig. 1 is the circuit diagram that is provided with the power supply circuits that the DC/DC converter of input excess voltage protection of expression embodiment of the present invention 1 uses.

These power supply circuits are same with the conventional example of Figure 20 explanation on following: have 2 power line AC line L1, L2, these two power lines have 2 AC input terminal IN1, IN2 that are connected with AC power by attaching plug is inserted the commercial ac power supply socket.Below in explanation during these power supply circuits, to being called " input side " with the approaching side of AC input terminal IN1, the IN2 of AC line L1, L2, opposition side (with as the approaching side of the diode bridge 4 of load) is called " outlet side " for easy.The part 2 of surrounding with chain-dotted line is the AC part that transmission exchanges, and its outer part is the transmission DC or the DC/AC part of direct current (pulsating current) substantially.

Series connection Jie inserts the elementary fuse 21 as the current protection element on the input side of AC line L1.Then between 2 AC line L1 of its outlet side and L2, connect rheostat 22, on its outlet side, be arranged in parallel noise filter 23.

On the AC line L1 of the outlet side of noise filter 23, inrush current is set and prevents circuit 25, this inrush current prevents that the outlet side of circuit 25 is connected with an AC input terminal 4a of the diode bridge 4 that carries out full-wave rectification, and the AC line L2 of the outlet side of noise filter 23 is connected with another AC input terminal 4b of diode bridge 4.

The DC line L3 of power line and L4 are connected on DC lead-out terminal 4c, the 4d of this diode bridge 4.In addition, between DC line L3, L4, connect smoothing capacitor C1, DC/DC converter 3 is connected with the sub-OUT1 of dc output end, the OTU2 that are provided with on DC line L3, the L4 of the outlet side of this smoothing capacitor C1 as aluminium electrolytic capacitor.

On the other hand, AC line L1 and L2 are connected with the testing circuit 24 of the magnitude of voltage that detects this AC line L1 and L2 separately in the outlet side of aforesaid noise filter 23 branch separately.On the outlet side of this testing circuit 24, thereby the switching circuit 26 of the magnitude of voltage of the magnitude of voltage of the AC line L1 that judgement detects by testing circuit 24 and AC line L2 or little on/off bigger than predetermined value is set and the state of this on/off is sent to the transmission circuit 27 that inrush current prevents circuit 25.Be provided with accessory power supply 28 in parallel with switching circuit 26 and as the accessory power supply electricity consumption container C 2 of aluminium electrolytic capacitor.

This power supply circuits from the interchange of AC input terminal IN1, IN2 input by the noise filter 23 as AC line filter suppress normalities disturb, altogether after the formula interference etc., by diode bridge 4 rectifications, C1 is level and smooth by smoothing capacitor, be transformed to direct current (pulsating current) substantially, this cardinal principle direct current is supplied with DC/DC converter 3.DC/DC converter 3 is the known circuits that the cardinal principle direct current of input are transformed to the direct current of low pressure or high pressure by oscillating circuit and switching circuit and transformer and rectification circuit etc.

Also can replace this DC/DC converter 3 and be replaced by the DC/AC converter.At this moment, be transformed to the known circuits that exchanges of low pressure or high pressure by transformer and rectification circuit.

About noise filter 23 and diode bridge 4 and level and smooth electricity consumption container C 1, because be identical, so detailed with the noise filter 103 of aforesaid existing switching mode pressurizer and diode bridge 104 and level and smooth electricity consumption container C 101.

Input excess voltage protection at these power supply circuits is made of following: by elementary fuse 21 and rheostat 22 same protective circuits that constitute and existing; With prevent the new protective circuit that circuit 25 constitutes by testing circuit 24, switching circuit 26, transmission circuit 27, inrush current.

For the protective circuit that constitutes by elementary fuse 21 and rheostat 22 because be identical by the elementary fuse 101 of the conventional example of Figure 20 explanation and the protective circuit that rheostat 102 produces, omit its explanation.

Below describe new protective circuit in detail.

Testing circuit 24 by: with anode be connected to AC line L1 and L2 go up, with the diode D1 and the D2 of the shared connection of negative electrode; The resistance R 1 that is connected with this shared tie point; The resistance R 2 of connecting with this resistance value R1; Constitute with the resistance R 3 of connecting with resistance R 2.Resistance R 1 and R2 also can make 1 resistance.In addition, resistance R 3 is bleeder resistances, has also passablely, omits and also can.

In addition, shown in Fig. 2 (A), (B), resistance R 1 is divided into resistance R 1a, R1b, also can be connected on cathode side or the anode-side of diode D1, D2 separately.As long as can detect the voltage of AC line L1 and L2.

And, switching circuit 26 is connected the two ends of resistance R 3.Switching circuit 26 is compared the both end voltage of resistance R 3 and default predetermined voltage, when the both end voltage of resistance R 3 hour becomes OFF, becomes ON when big than scheduled voltage.With detailed formation and the above-mentioned predetermined value aftermentioned of other figure to switching circuit 26.

Transmission circuit 27 is by the diode D3 that anode is connected resistance R 2 and R3 tie point; The resistance R 6 that one end is connected with its negative electrode; With anode is connected with its other end, constitute as LED (light-emitting diode) 41a of the light-emitting component of the light TRIAC coupler 41 of signal transmission component.The negative electrode of this LED41a is connected the ground connection side tie point of the switching circuit 26 that is connected with the DC lead-out terminal 4d of resistance R 3 and diode bridge 4.In addition, accessory power supply 28 and accessory power supply electricity consumption container C 2 are connected in parallel with the series circuit of this resistance R 6 and LED41a.

So-called light TRIAC coupler 41 is with as the LED41a of light-emitting component with as the light TRIAC 41b combination of light receiving element and be configured in the semiconductor element of the centre of a cover, if flow through electric current in the LED41a this current signal linear transformation be light signal and the transmission, 41b receives this light signal by the light TRIAC, once more the return current signal.That is, it is the high withstand voltage signal transmission component that limit transmission signal, limit can make complete electric insulation between output.

The light TRIAC 41b of this light TRIAC coupler 41 is loaded into inrush current to be prevented in the circuit 25.

Inrush current prevent circuit 25 by: prevent resistance 43 as being connected in series in inrush current on the AC line L1 with the band Thermal Cutoffs of element; TRIAC 42 as the thyristor that is connected in parallel with it; Be connected the resistance R 4 between an one terminal T1 and the gate terminal G; And be connected series circuit between the gate terminal G of TRIAC 42 and another terminal T2, light TRIAC 41b and resistance R 5.

TRIAC 42 is to have above-mentioned three terminals (element use in G) interchange control for T1, T2, is by being added in the thyristor that voltage on the gate terminal G makes short circuit between terminal T1 and T2 or opening.Not during making alive, be nonconducting state (OFF state) between terminal T1 and T2 on gate terminal G, a making alive on gate terminal G then becomes conducting state (ON state) between terminal T1 and T2.In addition, when being between the terminal T1 of conducting state and the T2 no potential difference and not having electric current and flow through, return nonconducting state between terminal T1 and T2.

Secondly, the action of this input excess voltage protection is described.From diode D1 and each self-rectifying of D2 by testing circuit 24 of the alternating voltage of AC input terminal IN1, IN2 input AC line L1, L2, detect, by resistance R 1 and R2 and resistance R 3 dividing potential drops.

, when dropping into power supply, TRIAC 42 is in the OFF state, because smoothing capacitor C1 is uncharged, so the resistance 43 by the band Thermal Cutoffs flows through inrush current, flow through the electric current of this smoothing capacitor C1 by resistance 43 restrictions of band Thermal Cutoffs.If capacitor C1 charges, then export the cardinal principle direct current of its normal voltage.DC/DC converter 3 action, associated therewith, accessory power supply 28 output dc voltages.

On the other hand, at the alternating voltage of input when not comprising superpotential normal value, because the voltage that takes place between resistance R 3 two ends of testing circuit 24 is in switching circuit below the predefined predetermined value, so switching circuit 26 becomes off-state.In view of the above, electric current flows to the LED41a of light TRIAC coupler 41 from accessory power supply 28 through the resistance R 6 of transmission circuit 27, makes LED41a luminous.

So, TRIAC 41b receives its light signal, and conducting is because flow through electric current in inrush current prevents the resistance R 4 of circuit 25, so TRIAC 42 is making alive on gate terminal G, make to be conducting (ON) state between terminal T1 and the T2.Therefore the electric current that flows to diode bridge 4 from AC line L1 flows by TRIAC 42, does not have electric current to flow through in the resistance 43 of being with Thermal Cutoffs.

Thereafter, input comprises superpotential unusual alternating voltage on AC line L1, at least one side of L2, the voltage difference at resistance R 3 two ends than switching circuit 26 in predefined scheduled voltage when big, switching circuit 26 conductings, because short circuit between the anode of the LED41a of transmission circuit 27 and negative electrode, so in LED41a, there is not electric current to flow through, not luminous.

In view of the above, TRIAC 41b as the light receiving element of light TRIAC coupler 41 disconnects, in resistance R 4, there is not electric current to flow through, owing to do not have making alive on the gate terminal G of TRIAC 42, so become non-conduction (OFF) state between the terminal T1 of TRIAC 42 and T2.If do like this, then in the resistance 43 of band Thermal Cutoffs, flow through electric current, the temperature of the resistance 43 of band Thermal Cutoffs rises, and makes Thermal Cutoffs fusing.This operate time is owing to begin to change expense only several seconds from the input overvoltage, so before rheostat 22 or smoothing capacitor C1 did not reach destruction, power supply circuits can be cut off safely.

Because in fact the voltage that adds between the terminal T1 of TRIAC 42 and T2 is AC wave shape, waveform at its each each half-wave rises or the decline initial stage, on gate terminal G, add trigger voltage, TRIAC 42 becomes connection (ON) state, thereafter, added alternating voltage waveform is till zero crossing, keep on-state always, though when zero crossing, instantaneous disconnection (OFF) state that becomes, but thereafter at next half-wave, add trigger voltage at once on gate terminal G, TRIAC repeats to be in connection (ON) state again.Therefore, as if TRIAC 42 continues to be in connection (ON) state.

, if TRIAC 41b disconnects, after then TRIAC becomes disconnection (OFF) when the alternating voltage waveform zero crossing, owing on gate terminal G, do not add trigger voltage, so keep disconnection (OFF) state.

Like this; at power supply circuits as shown in Figure 1; if the input excess voltage protection detects the input overvoltage; then cut off circuit apace; stop to diode bridge 4 and smoothing capacitor C1 power supply as load circuit; because make DC/DC converter 3 (in fact owing to be not to be direct current but pulsating current completely as load device; so be also referred to as the AC+DC/DC converter) stop fully; so be not subjected to about the fluctuation as rheostat 22 characteristics of importing overvoltage protection element or reliability, the accident that can prevent reliably takes place.

Therefore, rheostat 22 and unnecessary use have the large-scale element of sufficient surge capacity (than the also big surge capacity of the capacity of elementary fuse 21) to the input overvoltage as existing mode, have the element that a clamper absorbs as the surge capacity of external surges such as the thunder of short time aperiodicity transient voltage or input surge and get final product because use, so overall dimension is less, can select the cheap product of extensively peddling.

Do not adding under the superpotential standing state, from AC input terminal IN1, IN2 interchange to AC line L1, L2 input, can't help resistance 43 decay with Thermal Cutoffs, the TRIAC 42 by short circuit is added on the diode bridge 4, so the utilization ratio of electric power does not reduce.

In present embodiment; to the example of direct current to the power supply circuits of DC/DC converter power supply is illustrated; yet this input excess voltage protection is not limited to this; also go for interchange is offered the power supply circuits of following load: other switching mode pressurizer (AC/DC converter; DC/AC converter: high-voltage lamp pressurizer; the AC/AC converter) or active filter, series voltage regulator etc. beyond DC load; interchange is superimposed upon on the direct current and the load of usefulness, opposite to it DC stacked load or the AC load of on exchanging, using.Also can only power with the AC part 2 of Fig. 1 when AC load is given in power supply gets final product, and diode bridge 4 and smoothing capacitor C1 do not want.

When being provided with source filter, for example as shown in Figure 3, be arranged between diode bridge 4 and the level and smooth electricity consumption container C 1.This active filter shown in Figure 35 by lead-out terminal 4c that is connected in series in diode bridge 4 and capacitor C1+choke coil 51, diode D1 (anode is connected with choke coil 51, negative electrode is connected with capacitor C1) and switch element 52 between the side terminal constitute.This switch element 52 will drain and be connected with the tie point of choke coil 51 with diode D1, the connecting line of source electrode with the side terminal of another lead-out terminal 4c that is connected diode bridge 4 and capacitor C1 is connected, on grid, adds from the control signal of control circuit 6.Therefore, by control signal, control the filtering characteristic of this active filter 5 from control circuit 6.Supply with this control circuit 6 from the direct voltage of accessory power supply 28 through diode D6.

The purpose of this active filter 5 is for the power factor (PF) rising that suppresses to import and the high-frequency current of input current, takes booster type peak clipper mode.Control by 6 pairs of switch elements 52 of control circuit with input voltage waveform control input current and according to become surmount be predetermined output voltage the input voltage maximum (if 100V then is

) the substantially voltage stabilizing control of mode of setting voltage.

About the circuit description aspect, be arranged on the AC line L1 though inrush current prevents circuit 25, yet be not limited thereto, can be arranged on also that AC line L2 goes up, DC line L3 goes up, on the DC line L4.

In addition, though voltage that will produce on resistance R 3 two ends of testing circuit 24 and the predetermined voltage of setting on switching circuit 26 are in advance compared, yet be not limited to this, also can omit resistance R 3, to be compared by diode D1 or D2 magnitude of voltage that detects and the magnitude of voltage of directly stipulating, be made switching circuit 26 actions.

The logic of the on/off of switching circuit 26 (ON/OFF) also can be opposite.Main points are when needing only the input overvoltage, and inrush current prevents that the TRIAC 42 of circuit 25 from getting final product for disconnecting (OFF).

(the example of circuit more specifically of execution mode 1: Fig. 4)

Secondly, the execution mode 1 that the invention described above is described by Fig. 4 circuit example more specifically.Fig. 4 will be provided with the power supply circuits of this input excess voltage protection with the circuit diagram of representing as the switching mode pressurizer of load device.

In this example, expression is as the physical circuit example of DC/DC converter 3 and the switching circuit 26 and the noise filter 23 of switching mode pressurizer shown in Figure 1.At Fig. 4,, omit its explanation to the additional prosign of the part corresponding with Fig. 1.In order to see accompanying drawing easily, represent that the chain-dotted line of AC part 2 shown in Figure 1 has omitted diagram.

Switching circuit 26 shown in Figure 4 be connected second resistance R 8 between the tie point of the resistance R 2 of first resistance R 7, the other end that is connected this first resistance R 7 and testing circuit on the base stage of transistor 44 and R3 by transistor 44, with an end and be connected the other end of same first resistance R 7 and the tie point of resistance R 3 and the sub-OUT2 of dc output end between the 3rd resistance R 9 constitute.And the collector electrode of transistor 44 is connected with the anode of the LED41a of the light TRIAC coupler 41 of transmission circuit 27, and the emitter of transistor 44 is connected with negative electrode.

And the base stage one emission voltage across poles VBE when transistor 44 conductings is different according to temperature, is roughly about 0.7V.Make the resistance value of resistance R 1, R2 and second resistance R 8 and the 3rd resistance R 9 be respectively R1, R2, R8, R9, make that input voltage is that (the peak height value is Vin ), then when not having resistance R 3, the base current I of transistor 44 _BAnd the assigned voltage value is obtained by following formula. $I_B=\left(\mathrm{Vin}\sqrt{2}\right)/(\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="A0315007700381.png,A0315007700531.png"\; state="\{\{state\}\}">R</figure-callout>}1+\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="A0315007700381.png,A0315007700471.png"\; state="\{\{state\}\}">R</figure-callout>}2+R8+R9)$

Voltage between resistance R 8 and the R9 also is subjected to the influence of capacitor C2, yet because when permanent, the voltage between terminals of capacitor C2 is only done certain certain variation, ignores so its influence can be given.

When considering resistance R 3, the R8+R9 in the following formula also can use

1/{ (1/R3))+1/ (R8+R9)) replace.

If the voltage that detects by testing circuit 24 is at this more than assigned voltage value, then transistor 44 conductings, electric current flows to emitter from collector electrode.In view of the above, as described above, owing on the LED41a of the light TRIAC coupler 41 of transmission circuit 27, do not have electric current to flow through, not luminous, so inrush current prevents the light TRIAC 41b of circuit 25 and disconnects, TRIAC 42 is opened, and flows through electric current in the resistance 43 of band Thermal Cutoffs.In view of the above, the temperature of the resistance 43 of band Thermal Cutoffs rises, Thermal Cutoffs fusing, and power supply circuits are opened.

On the other hand, the DC load (comprising rectification circuit) 33 that DC/DC converter 3 is provided with by transformer 31, in the primary side of this transformer 31, the primary side of open close transformer 3l and primary side make the switching circuit that voltage inducts (for 26 differences of switch road, be called " voltage is inducted and use switching circuit ") 34, the control circuit 35 of the signal of this switching circuit 34 of output control and be arranged on clamper type buffer circuit 32 formations of primary side and the surge voltage peak value that produce when being suppressed at switching circuit 34 on/off of transformer 31.Resistance R 1, the R2 of the aforesaid testing circuit 24 of starting resistance dual-purpose of DC/DC converter 3, (or R3).Induct with the details aftermentioned of switching circuit 34 and buffer circuit 32 about voltage.

Transformer 31 has the primary coil 31a as magnet exciting coil, the secondary level that is used to obtain to export is enclosed 31b and is used to obtain 3 coils of accessory power supply with the ancillary coil 31c of output.And the end of its primary winding 31a is connected with the sub-OUT1 of the dc output end of aforesaid power supply circuits, and the other end is inducted through voltage and is connected with the sub-OUT2 of the dc output end of power supply circuits with switching circuit 34, simultaneously, connects buffer circuit 32 on its two ends.Connect the DC load 33 that comprises rectifier smoothing circuit at the two ends of secondary coil 3lb, connect the accessory power supply 28 that constitutes by rectification circuit etc. at the two ends of ancillary coil 31c.Accessory power supply electricity consumption container C 2 is to make from the voltage smoothing of accessory power supply 28 supplies and stable capacitor capacious, is connected in parallel with it and removes the little capacitor C3 of capacity that disturbs usefulness.Supply with transmission circuit 27 and control circuit 35 respectively from the voltage of this accessory power supply 28.

This control circuit 35 is inducted with voltage with common wire L6 through holding wire L5 and is connected with switching circuit 34, and common wire L6 also is connected with the sub-OUT2 of dc output end, testing circuit 24 and switching circuit 26 bus with transmission circuit 27 and accessory power supply.The oscillating circuit that produces rectangular wave pulse signal is set in this control circuit 35 and modulates the pulse width modulation circuit etc. of this pulse duration, the pulse signal is outputed between holding wire L5 and the common wire L6 from lead-out terminal PS.In addition, on this control circuit 35, connect voltage stabilizing and monitor the light receiving element 37b that uses optical coupler 37.

Voltage is inducted and is comprised N-channel MOS type FET36 as thyristor with switching circuit 34, its drain electrode (D) is connected with the primary coil 31a of transformer 31, its source electrode (S) is connected with the common wire that is connected with sub-OUT2 of dc output end and control circuit 35 etc.The grid of its FET36 (G) is connected with holding wire L5 from control circuit 35 through resistance R 10, is connected resistance R 11 between its grid line and source electrode, and the series circuit of resistance R 12 and buffering electricity consumption container C 4 is connected between drain electrode and source electrode.

And from control circuit 35 output rectangular pulse signals to holding wire L5 and the common wire L6, by it being added between the gate-source of FET36, between the period of change ground on/off source drain of FET36 according to its level H/L.

In view of the above, because the drain current of this FET36, i.e. the discontinuous current that flows through in the primary coil 31a of transformer 31 is so the alternating voltage of inducting in secondary coil 31b.It is supplied with DC load 33, be transformed to direct current, supply with real DC load circuit by inner rectifier smoothing circuit.Detect this direct voltage, monitor by voltage stabilizing to feed back to control circuit 35, carry out FEEDBACK CONTROL, this aftermentioned with optical coupler 37.

The series circuit of resistance R 12 and buffering electricity consumption container C 4 forms the damp type buffer circuit.This buffer circuit prevents the excessive rising (surge voltage) of the drain source voltage across poles when FET36 disconnects, and it is a protective circuit of avoiding FET36 to destroy.Especially because the rising of surge voltage is slowly carried out, the damp type buffer circuit also has the effect of low noiseization.

On the other hand, the buffer circuit 32 that connects between the two ends of the primary coil 31a of transformer 31 is clamper type buffer circuits, it constitutes by the parallel circuits of buffering electricity consumption container C 5 and resistance 13 with the diode that negative electrode is connected an one points of common connection, another of the points of common connection of this capacitor C5 and resistance R 13 is connected on the end of primary coil 31a of transformer 31, the anode of diode D4 is connected on the other end of primary winding 31a.

These buffer circuits play does to suppress surge voltage peak voltage effect.This clamping level is set according to the resistance of resistance R 13.

When being used to depend on the power connection of DC/DC converter of these power supply circuits, resistance R 1, R2, R3 play a part starting resistance, because by these resistance and diode D1 or D2 and diode D3, the power supply terminal Vcc of direct current starting resistor supply control circuit 35, so control circuit 35 begins action, output pulse signal is inducted with the FET36 on/off of switching circuit 34 voltage.In view of the above, this DC/DC converter 3 starts, and produces alternating voltage in the secondary coil 31b of transformer 31 and ancillary coil 31c.

This ancillary coil 31c and accessory power supply 28 and capacitor C2 constitute the power circuit that control circuit 35 and aforesaid transmission circuit 27 operating stablies are used after DC/DC converter 3 starts.If rated current voltage supply control circuit 35 and transmission circuit 27, then diode D3 reverse bias becomes non-conduction from this accessory power supply 28.In view of the above, the resistance R 1 of testing circuit 24, R2, R3 are cut off from the power line of control circuit 35 and transmission circuit 27.

The voltage stabilizing that is connected with control circuit 35 monitors that the light-emitting component with optical coupler 37 omits diagram, yet for example be connected with the output circuit of rectifier smoothing circuit in the DC load 33, luminous with brightness according to its output voltage, receive this light by light receiving element 37b, make its resistance change, feed back to control circuit 35.In view of the above, control circuit 35 makes the pulse width variations of the pulse signal of output by the modulation of pulsewidth degree, change the duty ratio of the on/off time of switching circuit 34, the alternating voltage that control produces by transformer 31, output variation or load change make output voltage stabilizationization relatively, can be with the voltage stabilizing supply load.

Perhaps in the DC load, produce abnormal voltage, it is luminous that voltage stabilizing is monitored with the light-emitting component of optical coupler 37, and light receiving element 37 receives this light, when being in conducting state, the output of stop pulse signal also can make the action of DC/DC converter 3 stop.

The concrete configuration example of also representing noise filter 23 at Fig. 2.This noise filter 23 is by having respectively the common mode choke coil 45 that is inserted in 2 coils on AC line L1 and the L2 of being situated between, being connected the X capacitor C6 between AC line L1 and L2 and constituting at the Y capacitor C7 and the C8 that are connected respectively between the AC of outlet side line L1 and L2 and the framework ground connection FG at its input side.And be to absorb normality by X capacitor C6 to disturb, absorb the AC line filter that the formula of being total to is disturbed by Y capacitor C7 and C8.

, noise filter 23 is not limited thereto, and also can use the AC line filter of any kind.For example, use compound choke coil to replace common mode choke coil 45, also can omit X capacitor C6 and Y capacitor C7, C8 and only use common mode choke coil 45.Also such filter circuits is set as noise filter with multistage.

(execution mode 2: Fig. 5)

Secondly, embodiments of the present invention 2 are described.Fig. 5 be the power supply circuits that will be provided with this input excess voltage protection with represent as the switching mode pressurizer of load circuit, with the same circuit of Fig. 2.This execution mode and above-mentioned execution mode shown in Figure 41 major part are common, at the additional prosign of its common ground, omit these explanations.At Fig. 5, omit the dashdotted diagram of expression DC/DC converter 3 parts shown in Figure 4.

Difference at this execution mode shown in Figure 5 and execution mode shown in Figure 4 is: use and append the transformer 31 that drives with 4 coils of coil 31d, the transformer 31 that replaces the DC/DC converter, when preventing that with inrush current circuit 55 and transmission circuit 57 and the inrush current of Fig. 4 from preventing that circuit 25 and transmission circuit 27 are different in a measure, the link position of rheostat 22 is different.

Transmission circuit 57 shown in Figure 5 is identical with transmission circuit 27 shown in Figure 4, constitutes by diode D3 and resistance R 6 with as the LED41a of the light-emitting component of light TRIAC coupler 41.At this transmission circuit 57, series resistance R6 and LED41a between the collector emitter of transistor 44 are connected between the output line of accessory power supply 28.

Therefore, this transmission circuit 57, when transistor 44 off-states of switching circuit 26, promptly on arbitrary line of AC line L1, L2, import and do not comprise under the situation of superpotential normal alternating voltage, on the LED41a of light TRIAC coupler 41, do not flow through electric current, so LED41a is not luminous.

On the other hand, at least one side's input at AC line L1, L2 comprises superpotential unusual alternating voltage, if the transistor 44 of switching circuit 26 becomes conducting state, then because flow through electric current in the series circuit between the collector emitter of the resistor R 6 that between the output line of accessory power supply 28, connects and LED41a and transistor 44, so LED41a is luminous.

That is, the LED41a of transmission circuit 57 is non-luminous when normal power supply, and is luminous when overvoltage takes place, and carries out the action opposite with the transmission circuit 27 of Fig. 4.

Inrush current shown in Figure 5 prevents that circuit 55 from comprising and prevents the resistance 43 of the band Thermal Cutoffs that circuit 25 similarly is connected and TRIAC 42 and detection resistance R4 with inrush current shown in Figure 4 and as the light TRIAC 41b of the light receiving element of light TRIAC coupler 41.Inrush current is not set to be prevented from resistance R 5 in the circuit 25 from directly to connect the end of light TRIAC 41b and the terminal T2 of TRIAC 42.And the driving that makes transformer 31 uses the end of coil 31d to be connected with the tie point of resistance R 4 with the other end of light TRIAC 41b with the gate terminal G of TRIAC 42 through resistance R 15, make this driving be connected connection resistance R 14 between this two tie point with the tie point (the tie point 4a of diode bridge 4) of the terminal T2 of the end of the resistance 43 of the other end of coil 31d and band Thermal Cutoffs and light TRIAC 41b and TRIAC 42.

Therefore, prevent on the circuit 55 in this inrush current, because from energized on these power supply circuits, till startup of DC/DC converter and operate as normal, drive with enough alternating voltages of not inducting in the coil 31d, in view of the above, because on the G of TRIAC 42 terminal, do not add enough trigger voltages, so TRIAC 42 keeps the former state of nonconducting state.Therefore, the resistance 43 by the band Thermal Cutoffs flows through alternating current in the diode bridge 4, by its rectification output, makes capacitor C1 charging.Prevent that with inrush current shown in Figure 4 the function of circuit 25 is identical on the inrush current this point that when the resistance 43 by the band Thermal Cutoffs is suppressed at it and starts, produces.

Thereafter, capacitor C1 charging, export with direct voltage substantially, control circuit 35 adds by the resistance R 1 of testing circuit 24, the starting resistor that R2, R3 produce by diode D3 and moves, if pass through output pulse signal, with the situation of aforementioned embodiments the DC/DC converter is started, when then inducting alternating voltage in the level coil 31b secondarily, the alternating voltage of also inducting at ancillary coil 31c and in driving with coil 31d.

And, arbitrary alternating voltage at AC line L1, L2 does not comprise under the superpotential normal condition, the magnitude of voltage that testing circuit 24 detects is also littler than the setting voltage value of switching circuit 26, then because transistor 44 becomes off-state, the LED41a of the light TRIAC coupler 41 of transmission circuit 57 is not luminous, so light TRIAC 41b disconnects.Therefore, the voltage that produces in coil 31d in the driving of transformer 31 adds as trigger voltage on the G of TRIAC 42 terminal, so at each half-wave initial stage of AC wave shape, TRIAC 42 becomes connection (ON) state, in diode bridge 4, flow through alternating current between terminal T1, the T2 by this TRIAC 42, in the resistance 43 of band Thermal Cutoffs, almost completely do not flow through electric current.Therefore, the resistance 43 of band Thermal Cutoffs can be because of overheated fusing-off temperature fuse.

; input comprises superpotential unusual alternating voltage on AC line L1, at least one side of L2; if the setting voltage value that magnitude of voltage surpasses switching circuit 26 that detects by testing circuit 24; then because transistor 44 conductings; the LED41a of the light TRIAC coupler 41 of transmission circuit 57 is luminous, light TRIAC 41b conducting.So, because on the terminal G of TRIAC 42, do not add trigger voltage, so TRIAC 42 is in disconnection (OFF) state.Therefore, flow through electric current in the resistance 43 of band Thermal Cutoffs, its temperature rises, and power supply circuits are cut off in Thermal Cutoffs fusing.

,, not between fuse 21 and noise filter 23, but on the rectification outlet side of diode bridge 4, be connected in parallel at rheostat 22 on these power supply circuits with smoothing capacitor C1.

To aforementioned embodiments with stated similarly, inrush current prevents that the position of circuit 55 also can be arranged on arbitrary line of AC line L1 and L2, DC line L3 and L4, not shown center line.Rheostat 22 also can be arranged on outlet side and the input side either side that inrush current prevents circuit 55, even under the situation that either side is provided with, testing circuit 24, switching circuit 26, transmission circuit 57 and inrush current prevent that the action of circuit 55 from also being identical.

Rheostat 22 is being arranged under the situation of input side that inrush current prevents circuit 55; when input comprises superpotential unusual alternating voltage; (detecting circuit 24 detects overvoltage in the action of input excess voltage protection; switching circuit 26 conversions; by the transmission signals that produces by light TRIAC coupler 41; TRIAC 42 becomes disconnection (OFF) state; till resistance 43 fusing of band Thermal Cutoffs); on rheostat 22, continue to add overvoltage; as previously shown; because do not need several seconds the operate time that needs till these power supply circuits cut off yet, so rheostat 22 is not damaged.

On the other hand, shown in this execution mode, when on inrush current prevents the outlet side of circuit 55 rheostat 22 being set, the voltage drop that produces owing to the resistance 43 that has because of the band Thermal Cutoffs is so the overvoltage that adds on the rheostat 22 compared with the above case diminishes.In addition, even surpassing varistor voltage, overvoltage rheostat 22 punctures owing to be with the resistance 43 restriction electric currents of Thermal Cutoffs, can be surpassed permissive waste and before catching fire, are with the resistance 43 of Thermal Cutoffs promptly to be fused at rheostat 22.That is,, then can prevent the destruction of rheostat 22 more reliably if prevent from inrush current on the outlet side of circuit 55 rheostat 22 to be set.

; when on inrush current prevents the outlet side of circuit 55, rheostat 22 being set; when external surges such as thunder and input surge take place; because testing circuit 24 detects the voltage that comprises external surge; so switching circuit 26 is because of external surge conducting; inrush current prevents that the TRIAC 42 of circuit 55 from becoming disconnection (OFF) state, and the resistance 43 of band Thermal Cutoffs might fuse.Therefore, be necessary to be careful the configuration that rheostat 22 and inrush current prevent circuit 55 when more low-yield (low-voltage) at external surge, so that the resistance 43 of band Thermal Cutoffs does not fuse.With respect to resulting from the surge voltage of thunder, resistance 43 fusing of band Thermal Cutoffs get final product when 6kV is above.

On the other hand, when inrush current prevents that the input side of circuit 55 is provided with rheostat 22, rheostat 22 is earlier to external surge clamper, restriction, because testing circuit 24 detects this magnitude of voltage after restricted, so switching circuit 26 can be because of external surge conducting, the resistance 43 of band Thermal Cutoffs does not fuse yet.Therefore there is no need to be careful the configuration that rheostat 22 and inrush current prevent circuit 55.

Promptly, no matter prevent that in inrush current the input side of circuit 55 or outlet side are provided with rheostat,, can prevent the generation of accident because two sides can both cut off circuit reliably, so consider to be provided with the environment of device such as switching mode pressurizer etc., suitably select it to get final product in which side.

For example, when worrying the very high-tension input overvoltage of input, the scheme that prevents to be provided with on the outlet side of circuit 55 rheostat 22 in inrush current is good.In the time might producing external surge continually, the scheme that prevents to be provided with on the input side of circuit 55 rheostat 22 in inrush current is good.

(execution mode 3: Fig. 6)

Secondly, embodiments of the present invention 3 are illustrated.Fig. 6 be be provided with the input excess voltage protection power supply circuits with represent as the switching mode pressurizer of load device, with Fig. 4 and the same circuit diagram of Fig. 5.This execution mode major part is common with above-mentioned execution mode shown in Figure 52, and additional prosign omits its explanation on its common ground.Promptly in Fig. 6, also omit the dashdotted diagram of the part of expression DC/DC converter 3 shown in Figure 4.

Be with the difference of execution mode shown in Figure 5 at this execution mode shown in Figure 6: testing circuit 54 and switching circuit 56 and transmission circuit 67 are respectively different with transmission circuit 57 with testing circuit 24 and the switching circuit 26 of Fig. 5, with testing circuit starting resistor supply circuit to control circuit 35 is set differently, and the link position of rheostat 22 also is different.

The testing circuit 54 of present embodiment is the formation that is omitted in the resistance R 3 in Fig. 1, Fig. 4 and the testing circuit 24 shown in Figure 5.

56 of switching circuits are made of Zener diode ZD5, and its negative electrode is connected a terminal that is not connected with resistance R 1 as the resistance R 2 of the output of testing circuit 54, and anode is connected on the transmission circuit 67.

67 of this transmission circuits are made of the LED41a as the light-emitting component of light TRIAC coupler 41, and its anode is connected with the anode of Zener diode ZD5, and negative electrode is connected with the DC line L4 of the outlet side of diode bridge 4.

That is, the Zener diode ZD5 of the resistance R 1 of testing circuit 54 and R2 and switching circuit 56 and the LED41a of transmission circuit 67 all connect, in addition, and diode D1, the D2 of Zener diode ZD5 reverse bias connection detection circuit 54 and the LED41a of transmission circuit 67.

On the input excess voltage protection of these power supply circuits, testing circuit 54 detects the voltage of AC line L3 and L4, adds its corresponding voltage on the negative electrode of Zener diode ZD5, adds counter voltage on Zener diode ZD5.So the assigned voltage value that makes switching circuit 56 on/off becomes the Zener voltage of Zener diode ZD5.

And, when input does not comprise superpotential normal voltage on AC line L1 and L2, because the output voltage of testing circuit 54 (detecting voltage) is littler than the Zener voltage of Zener diode ZD5, so the Zener diode ZD5 of switching circuit 56 becomes off-state, because on the LED41a of transmission circuit 67, do not have electric current to flow through, so not luminous.

; if input comprises superpotential abnormal voltage on AC line L1, at least one side of L2; then the output voltage of testing circuit 54 (detecting voltage) becomes bigger than the Zener voltage of Zener diode ZD5; then because the Zener diode ZD5 of switching circuit 56 becomes conducting state; flow through Zener current, so the LED41a of transmission circuit 67 is luminous.So, with the situation of aforesaid execution mode 2 similarly, the inrush current of light TRIAC coupler 41 prevents that the light TRIAC 41b in the circuit 55 from becoming conducting state, because TRIAC 42 becomes disconnection (OFF) state, so flow through electric current in the resistance 43 of band Thermal Cutoffs, temperature rises, its Thermal Cutoffs fusing, and power supply circuits cut off.

Preestablish the resistance R 1 of this testing circuit 54, the resistance value of R2, so that at the voltage of AC line L1, L2 just often, the Zener voltage of the detection voltage ratio Zener diode ZD5 of testing circuit 54 is little.And, can be set in advance in to cut off power supply circuits when how many inputs lies prostrate above overvoltage by adjusting this resistance R 1, the resistance value of R2 and the Zener voltage of Zener diode ZD5.Because this testing circuit 54 did not have electric current to flow through, reduce power consumption in resistance R 1, R2 before it detects the Zener voltage of voltage above the Zener diode ZD5 of switching circuit 56.

The resistance value of these resistance R 1, R2 and Zener diode ZD5 and LED41a also can change the order of connection.Even for example fall on the mountain peak, position of Zener diode ZD5 and LED41a, its action also is identical certainly.

At this execution mode, resistance R 1, the R2 with testing circuit 54 is not used in the starting resistance of DC/DC converter, the series circuit of resistance R 16 and R17 is connected between the power supply terminal Vcc of the DC line L3 of outlet side of diode bridge 4 and control circuit 35 with resistance as starting in addition.Under shared situation, for example also can be from the negative electrode of Zener diode ZD5, on the resistance of voltage adjustment usefulness or diode or its are connected power supply terminal Vcc at control circuit 35.

Be provided with and start with resistance R16 and R17, DC/DC converter behind the power connection (also can be the AC/DC converter, other switching mode pressurizers such as AC/AC converter) start, give control circuit 35 from supplying with direct voltage from the DC line L3 of the outlet side of diode bridge 4 between accessory power supply 28 is till exporting normal voltage, be used for the pulsing signal.

At this execution mode, identical with Fig. 1 and execution mode 1 shown in Figure 4, between AC line L1, the L2 between fuse 21 and the noise filter 23, connect rheostat 22.

(execution mode 4,5: Fig. 7, Fig. 8)

Secondly, embodiments of the present invention 4 and execution mode 5 are illustrated.Fig. 7 and Fig. 8 are respectively the circuit same with Fig. 4～Fig. 6 of embodiments of the present invention 4 and execution mode 5.

These execution modes almost execution mode shown in Figure 63 with above-mentioned are identical, have only changed to start being connected with the series circuit of resistance R16 and R17.

That is,, between the power supply terminal Vcc of the AC line L2 of the interchange input side of diode bridge 4 and control circuit 35, connect the DC/DC converter and start series circuit (also can be 1 resistance) with resistance R16 and R17 at execution mode shown in Figure 74.Alternating voltage with AC line L2 when starting is added on the control circuit 35.In order to prevent the discharge of capacitor C2, preferably diode and this startup are connected in series with resistance R16, R17, even shown in this example, there is not diode, because R16, R17 are high resistance (for example 20k Ω～100k Ω), so fully start.

At execution mode shown in Figure 85, between the power supply terminal Vcc of the tie point of diode D1, the D2 of testing circuit 54 and resistance R 1 and control circuit 35, be connected the DC/DC converter and start series circuit, will be respectively when starting be added on the control circuit by diode D1, the D2 cardinal principle direct voltage after to the ac voltage rectifier of AC line L1, L2 with resistance R16, R17.

Also bring into play function equally by these each execution modes with the power supply circuits and the DC/DC converter of aforementioned embodiments 1～3.

(execution mode 6: Fig. 9)

Secondly, embodiments of the present invention 6 are illustrated.Fig. 9 is the circuit diagram identical with Fig. 4～Fig. 8 of embodiment of the present invention 6.

This execution mode 6 and execution mode shown in Figure 7 40 minutes are identical, however 3 identical coil transformers 31 of the transformer use of DC/DC converter and Fig. 1 and execution mode shown in Figure 41.And, the inrush current that inrush current prevents that circuit 65 from replacing execution mode 4 shown in Figure 7 is set prevents circuit 55, be connected the series circuit of the LED46a of resistance R 18 and light TRIAC coupler 46 between the lead-out terminal of accessory power supply 28 with capacitor C2 in parallel.

And, inrush current prevents that circuit 65 from constituting, the inrush current that part has changed execution mode 1 prevents circuit 25, omit its resistance R 5, the light TRIAC 41b that between the gate terminal G of TRIAC 42 and terminal T2, is directly connecting light TRIAC coupler 41, simultaneously, the light TRIAC 46b that is connected resistance R 19 and newly-installed smooth TRIAC coupler 46 with it in parallel.

According to this execution mode 6, the DC/DC converter starts, the alternating voltage of in boost line Figure 31 of transformer 31 c, inducting, till the direct voltage of regulation is added on the control circuit 35 from accessory power supply 28, the LED46a of light TRIAC coupler 46 is not luminous, inrush current prevents that the light TRIAC 46b in the circuit 65 is in off-state, so on the gate terminal G of TRIAC 42, do not add trigger voltage, because TRIAC 42 becomes disconnection (OFF) state, so in diode bridge 4, flow through alternating current by the resistance 43 of band Thermal Cutoffs.

; if the DC/DC converter starts; direct voltage from accessory power supply 28 output regulations; then because in the LED46a of light TRIAC coupler 46, flow through electric current; luminous; so the light TRIAC 46b that is provided with in inrush current prevents circuit 65 becomes conducting state; because in resistor R 19, flow through electric current; so triode ac switch open and the gate terminal G of element 42 on add trigger voltage, TRIAC 42 becomes connection (ON) state.Therefore, in diode bridge 4, flow through alternating current by this TRIAC 42 thereafter, in the resistance 43 of band Thermal Cutoffs, almost do not have electric current to flow through.

It is identical with the situation of execution mode shown in Figure 54 importing the input overvoltage protection action that comprises superpotential abnormal voltage in AC line L1 or L2.

At this execution mode, also between the power supply terminal Vcc of the input side AC of diode bridge 4 line L2 and control circuit 35, connect the DC/DC converter and start the series circuit of using resistance R16 and R17.Also can accumulate 1 with resistance R16 and R17 in this case, discharge in order to prevent capacitor C2 starting, also can be to this resistance R 16, the R17 slotting diode that in series is situated between.

But be not limited thereto, execution mode 3 as shown in Figure 6 is such, one end that also can on the AC line L3 of the outlet side of diode bridge 4, connect resistance R 16, execution mode 5 as shown in Figure 8 is such, also the points of common connection of the cathode side of the diode D1 of an end of resistance R 16 and testing circuit 54 and D2 can be connected.

Prevent that in inrush current the input side of circuit 65 is provided with rheostat 22, yet be not limited thereto, also can as Fig. 3 illustrates, prevent that in inrush current the outlet side of circuit 65 is provided with rheostat 22.

On AC line L1, this inrush current is set and prevents circuit 65, yet be not limited to this, can be arranged on also that AC line L2 goes up, on DC line L3 or the L4 (center line :) as the datum line of power ground.

(execution mode 7: Figure 10)

Secondly, embodiments of the present invention 7 are illustrated.Figure 10 is the circuit diagram same with Fig. 4～Fig. 9 of embodiments of the present invention 7.

This execution mode 7 and aforementioned execution mode shown in Figure 9 60 minutes are identical, but inrush current is prevented that circuit 75 is arranged on the DC line L4 of the rectification outlet side of diode bridge 4 (center line: as the datum line of power ground).Replace light TRIAC coupler 41 as transmission circuit, the transistor 47 according to the State Control on/off of the Zener diode ZD5 of switching circuit 56 is set, connecting difference on resistance R 20 these aspects between its Base-Emitter.

The inrush current of this execution mode 7 prevents that circuit 75 is provided with the light TRIAC 41b that inrush current that transistor 47 replaces execution mode 6 shown in Figure 9 prevents the light TRIAC coupler 41 of circuit 65, its collector electrode is connected on the gate terminal G of TRIAC 42, and emitter is connected on the terminal T2 (resistance 43 of band Thermal Cutoffs and the tie point of level and smooth electricity consumption container C 1) of TRIAC 42.Connect resistance R 20 between the Base-Emitter of this transistor 47, base stage directly is connected on the anode of Zener diode ZD5 of switching circuit 56.

So, when inrush current being set on center line preventing circuit 75, because the insulation of TRIAC 42 and switching circuit 56 is unnecessary, so unnecessary making in transmission circuit as from Fig. 4 to execution mode shown in Figure 9 with light TRIAC coupler can directly connect.

In present embodiment, the alternating voltage of importing on AC line L1, L2 is when not comprising superpotential normal voltage, identical with the situation of aforementioned embodiments 6, because do not have electric current to flow through in the Zener diode ZD5 of switching circuit 56, transistor 47 becomes off-state.

Start up to the DC/DC converter, the rectified current that is produced by diode electrode 4 is by the resistance 43 of band Thermal Cutoffs, flows to smoothing capacitor C1 and to its charging.The DC/DC converter starts, if direct voltage from accessory power supply 28 output regulations, when then it offers control circuit 35, the LED46a of light TRIAC coupler 46 is luminous, prevent that in inrush current the light TRIAC 46b that is provided with on the circuit 75 from receiving this light, become conducting state, because by in resistance R 19, flowing through electric current, on the gate terminal G of TRIAC 42, add trigger voltage, so TRIAC 42 becomes connection (ON) state, in the resistor 43 of band Thermal Cutoffs, there is not electric current to flow through.Preferably in starting, in series be situated between in this case and insert diode with resistance R16, R17.

; if input comprises superpotential unusual alternating voltage at least one side of AC line L1, L2; then in the Zener diode ZD5 of switching circuit 56, flow through Zener current; in the transistor 47 that inrush current prevents to be provided with on the circuit 75, flow through base current and conducting; because make conducting between collector emitter, so the gate terminal G of TRIAC 42 and terminal T2 become idiostatic.Therefore, TRIAC 42 becomes disconnection (OFF) state, flows through electric current in the resistor 43 of band Thermal Cutoffs, and temperature rises, and power supply circuits are cut off in its Thermal Cutoffs fusing.

(execution mode 8: Figure 11)

Aforementioned each execution mode 1～7 to as load device, is illustrated the situation example that connects or be wholely set as a kind of DC/DC converter of switching mode pressurizer.Following the execution mode that connects as load device or be wholely set AC load device situation is illustrated.This AC load device also can be a kind of AC/AC converter as the switching mode pressurizer.

Figure 11 is to being provided with the circuit diagram according to the power supply circuits of the AC load device of the input excess voltage protection of this execution mode 8.At this Figure 11, with the additional prosign of the equal part of Fig. 1～Figure 10, omit its explanation.

The power supply circuits of this execution mode 8, the diode bridge 4 of removing execution mode for example shown in Figure 63 is provided with the sub-OUT3 of ac output end, OUT4 with level and smooth capacitor C 1, connect AC load device 40 there, become induct formation after removing with switching circuit 34 and control circuit 35 etc. of the transformer 31, buffer circuit 32, the voltage that constitute the DC/DC converter.

The series connection restriction electric current primary coil 39a of choke coil 39 on AC load device 40.On this choke coil 39, secondary coil 39b is set, replaces the drive coil 31d of the transformer 31 of Fig. 4, the voltage of this secondary coil 39b internal induction is used to drive inrush current prevents circuit 85 with this.Inrush current prevents that other formation of circuit 85 and function from being to prevent that with inrush current shown in Figure 6 circuit 55 is identical.

And, after the Alternating Current Power Supply of AC load device 40 begun, a little time before only voltage is inducted in the secondary coil 39b of choke coil 39, because inrush current prevents that the TRIAC 42 of circuit 85 from becoming disconnection (OFF) state, so alternating current flows to AC load device 40 by the resistance 43 of being with Thermal Cutoffs.

The LED41a of the light TRIAC coupler 41 of general transmission circuit 67 does not light, because light TRIAC 41b becomes off-state, if so produce voltage in the secondary coil 39b of choke coil 39, then add trigger voltage on inrush current prevents the gate terminal G of TRIAC 42 of circuit 85, TRIAC 42 becomes connection (ON) state.Therefore, power supply flows for the interchange of AC load device 40 by TRIAC 42, because do not have electric current to flow through in the resistance 43 of band Thermal Cutoffs, so Thermal Cutoffs does not fuse.

If input comprises superpotential abnormal voltage on AC line L1, at least one side of L2, then flow through Zener current in the Zener diode ZD5 of switching circuit 56.In view of the above, the LED41a of the light TRIAC coupler 41 of formation transmission circuit 67 is luminous, because the light TRIAC 41b in inrush current prevents circuit 85 becomes conducting state, so TRIAC 42 becomes disconnection (OFF) state, in the resistance 43 of band Thermal Cutoffs, flow through electric current, because its temperature rises, power supply circuits are cut off in Thermal Cutoffs fusing.

, also can omit Zener diode ZD5.At this moment flow through in the LED41a of light TRIAC coupler 41 according to the electric current of the resistance value of input voltage and resistance R 1, R2 (also can be 1 resistance) usually, make it luminous, yet because electric current is little, its luminous quantity is few, light TRIAC 41 does not become conducting state, add trigger voltage on the gate terminal G of TRIAC 42, TRIAC 42 becomes connection (ON) state.If be input as overvoltage, there then have enough electric currents to flow through in LED41a to be also luminous, because light TRIAC 41b is in conducting state fully, on the gate terminal G of TRIAC 42, do not add trigger voltage, so TRIAC becomes disconnection (OFF) state.Therefore, flow through electric current in the resistance 43 of band Thermal Cutoffs, because its temperature rises, power supply circuits are cut off in the fusing of Thermal Cutoffs.

When AC load device 40 is not held voltage and is inducted the switching circuit of usefulness, accessory power supply 28 and accessory power supply electricity consumption container C 2, and preventing that in dc output end and inrush current the startup that connects between the AC line L1 of outlet side of circuit 85 from not wanting with the series circuit of resistance R16, R17, the cathode side of the LED41a of light TRIAC coupler 41 is connected with reference potential (power ground line) in the circuit and gets final product.

; AC load device 40 is lighted the situation of lamp or uninterrupted power supply (ups) Unity etc. for switching mode pressurizer, AC stabilized power supply (AVR), the high frequency of AC/AC converter or AC/DC converter one class; same with the situation of aforementioned each execution mode; the control circuit that generation is used to make this voltage to induct with the pulse signal of switching circuit action is necessary, is used for that the alternating voltage at the ancillary coil internal induction of transformer carried out rectification and the accessory power supply 28 (transformer or control circuit omit diagram) of the supply voltage of this control circuit is provided.During till starting,, be provided with the power supply circuits of forming with resistance R16, R17 by starting (control circuit and supply lines thereof omit diagram) for the power supply voltage supplying control circuit to this switching mode pressurizer.

(execution mode 9: Figure 12)

Secondly, embodiments of the present invention 9 are illustrated.From then on Shuo Ming experiment method 9-12 gives the AC load device with Alternating Current Power Supply, simultaneously, only detects 1 voltage in the many AC lines and imports the mode of overvoltage protection and be provided with the input excess voltage protection according to testing circuit.

Figure 12 is the figure same with Fig. 1 of this execution mode 9 of expression, with the equal part of Fig. 1 on additional prosign, omit its explanation.

The power supply circuits of the execution mode 9 that this Figure 12 represents are removed the diode bridge 4 of the execution mode 1 that Fig. 1 represents and level and smooth electricity consumption container C 2 and the sub-OUT3 of ac output end, OUT4 are set, and connect AC load device 40 there and replace DC/DC converters 3.Also these power supply circuits and AC load device 40 can be set to one, this point is identical with each execution mode so far.

The testing circuit 64 of this execution mode is a formation of having omitted the diode D1 that is connected with the AC line L1 of testing circuit 24 shown in Figure 1, and resistance R 1, the R2 (or R3) of diode D2 that it is connected with the outlet side of the noise filter 23 of a side AC line L2 by anode and order series connection on the negative electrode of this diode D2 constitute.This overvoltage detection resistance R1, R2 (or R3) is under the situation of switching mode pressurizer at AC load device 40, but also dual-purpose starts starting resistance with power supply as supplying with it, is identical with the situation of each execution mode so far.

At this three testing circuit 64, diode D2 detects the voltage of AC line L2, by series resistance and resistance R 3 dividing potential drops of resistance R 1 and R2, and the voltage at output R3 two ends.Omit this resistance R 3, the voltage that detects by diode D2 also can be added on the switching circuit 26 by resistance R 1 and R2.

Accessory power supply 28, at AC load device 40 is under the situation of switching mode pressurizer, with execution mode 1 shown in Figure 4 similarly, the circuit that produces direct voltage in the ancillary coil of transformer so long as the alternating voltage that will induct carries out rectification gets final product, if not, so long as AC line L1, at least one side's of L2 alternating voltage is carried out rectification and the circuit of output dc voltage gets final product.

The input overvoltage protection action of this execution mode; except following; with the situation of execution mode 1 is identical: when only input comprises superpotential abnormal voltage on AC line L2; make TRIAC 42 be in off-state, in the resistance 43 of band Thermal Cutoffs, flow through electric current and make the fusing of this Thermal Cutoffs.

(example at Figure 12 is AC line L2 to the situation of the input excess voltage protection of this execution mode 9 owing to only detect in the power line 1; yet also can on other AC line L1, carry out) voltage; so compare with detecting whole AC line voltage condition, the detection time of cost is long.Even like that, its detection time also has only about hundreds of milliseconds.Therefore; because the operate time of input excess voltage protection, (comprising superpotential abnormal voltage from input begins till resistor 43 fusing of band Thermal Cutoffs) do not spend the several seconds yet; so can the fast shut-off power supply circuits before rheostat 22 destroys, can prevent accident reliably.

Can reduce component count by constituting in this wise.

(execution mode 10: Figure 13)

Then, embodiments of the present invention 10 are illustrated.Figure 13 be the expression embodiments of the present invention 10 with Fig. 1 and the same circuit diagram of Figure 12.At this Figure 13, to the equal additional prosign of part of Fig. 1 and Figure 12 because switching circuit 26 is identical with the switching circuit 26 of execution mode shown in Figure 41, omit its explanation.

This execution mode 10 and execution mode 9 shown in Figure 12 are relatively only preventing inrush current circuit 25 is situated between the elementary fuse 21 of ratio that is inserted in AC line L1 and rheostat 22 also near different on the AC input terminal IN1 side this point.Therefore, its input over-voltage protection function is also identical with execution mode 9, yet can prevent more reliably because the rheostat that abnormal voltage produces destroys.

(execution mode 11,12: Figure 14, Figure 15)

Secondly, embodiments of the present invention 11,12 are illustrated.Figure 12 and Figure 15 are respectively the circuit diagrams identical with Figure 11 of expression embodiments of the present invention 11,12.At this Figure 14 and Figure 15, to adding prosign, because switching circuit 26 and transmission circuit 57 are identical with the switching circuit 26 and the transmission circuit 57 of execution mode shown in Figure 52, so omit its explanation with the equal part of Figure 11.

Testing circuit 74 at this execution mode 11,12 is the diode D2 that omitted testing circuit shown in Figure 13 64.Like this, enough big even overvoltage detects the resistance of the resistance R 1 of usefulness and R2, under the situation that not have problem of moving (depending on the capacity of load or input voltage range etc.), also can omit diode.

And the execution mode of representing at Figure 14 11 is connected an end of the resistance R 1 of this testing circuit 74 on the outlet side of noise filter 23 of AC line L2.The execution mode of representing at Figure 15 12 is connected an end of the resistance R 1 of this testing circuit 74 input side of the noise filter 23 of AC line L1.

Switching circuit 26 and transmission circuit 57 at these execution modes are similarly to move with execution mode shown in Figure 52, and inrush current prevents that circuit 85 from being similarly to move with execution mode shown in Figure 11 8.

At these execution modes, prevent that in inrush current the outlet side of circuit 85 is provided with rheostat 22, yet be not limited to this, also can prevent that the input side of circuit 85 is provided with rheostat 22 in inrush current.

(execution mode 13: Figure 16)

Secondly, embodiments of the present invention 13 are illustrated.Figure 16 is the circuit same with Fig. 5 of expression embodiment of the present invention 13.This execution mode 13 almost is identical with execution mode shown in Figure 52, is that the power supply circuits as the DC/DC converter of DC load are given in power supply.

In present embodiment, only be following with execution mode 2 differences shown in Figure 5: testing circuit 74 has omitted diode D1, the D2 of testing circuit shown in Figure 5 24, only connects an end of resistance R 1 at the outlet side of the noise filter 23 of AC line L1.

So, if similarly import AC line L1 comprising superpotential abnormal voltage with aforementioned embodiments 11,12 situations, then detect it and make inrush current prevent circuit 55 actions, the Thermal Cutoffs fusing of the resistance 43 of band Thermal Cutoffs can be cut off power supply circuits.Owing to be identical with execution mode shown in Figure 32 explanation, so omit the details of this action.

Resistance R 1 one ends of testing circuit 74 are connected on the AC line L2, also can detect abnormal voltage.

In addition, prevent that in inrush current the input side of circuit 55 is provided with rheostat 22, yet be not limited thereto, also can prevent that the outlet side of circuit 55 is provided with rheostat 22 in inrush current.

(execution mode 14,15: Figure 17, Figure 18)

Secondly, embodiments of the present invention 14 and 15 are illustrated.Figure 17 and Figure 18 are respectively the circuit diagrams same with Fig. 8 of expression embodiments of the present invention 14 and 15.On these figure, to the equal part of Fig. 8 on additional prosign, omit its explanation.

At execution mode shown in Figure 17 14, the points different with execution mode shown in Figure 85 only are: testing circuit 84 and be connected in series between the AC line L1 and L2 of noise filter 23 outlet sides as the Zener diode ZD5 of switching circuit 56 and the LED41a that constitutes the light TRIAC coupler 41 of transmission circuit 67.And the anode of diode D1 is connected with AC line L1, the negative electrode of the LED41a of light TRIAC coupler 41 is connected with AC line L2.

The input overvoltage protection action of present embodiment is as follows: detect voltage between AC line L1 and the L2; if it surpasses the Zener voltage as the Zener diode ZD5 of switching circuit 56; then this Zener diode ZD5 becomes connection (ON) state; flow through Zener current; in the LED41a upper reaches overcurrent of the light TRIAC coupler 41 that constitutes transmission circuit 67, luminous.In view of the above, light triacs 41b in inrush current prevents circuit 55 becomes conducting state, make TRIAC 42 become disconnection (OFF) state, in the resistance 43 of band Thermal Cutoffs, flow through electric current, cut off power supply circuits by the fusing of its Thermal Cutoffs.

Execution mode 15 shown in Figure 180 uses the testing circuit 94 of the diode D1 of the testing circuit 84 that has omitted execution mode shown in Figure 17 14, be connected in series as the Zener diode ZD5 of switching circuit 56 and the LED41a of the light TRIAC coupler 41 that constitutes transmission circuit 67, one end of resistance R 1 is connected with AC line L2, the negative electrode of the LED41a of light TRIAC coupler 41 is connected with AC line L1.

At this moment input overvoltage protection action also is same with the situation of above-mentioned execution mode 14.

(execution mode 16: Figure 19)

Secondly, embodiments of the present invention 16 are illustrated.Figure 19 is the circuit diagram same with 9 figure of expression embodiment of the present invention 16.At this Figure 19, to the additional prosign of the equal part of Fig. 9, omit its explanation.

At this execution mode 16, only be as follows with execution mode 6 differences shown in Figure 9: as the testing circuit testing circuit 94 of diode that used the omission identical with above-mentioned execution mode 15, be connected in series as the Zener diode ZD5 of switching circuit 56 and the LED41a of the light TRIAC coupler 41 that constitutes transmission circuit 67, one end of resistance R 1 is connected with AC line L2, the negative electrode of the LED41a of light TRIAC coupler 41 is connected with AC line L1.

Even according to this execution mode 16, also can be same with aforementioned embodiments 14 and 15, can detect it when between AC line L1, L2, producing abnormal voltage, cut off power supply circuits.In addition, same with execution mode 6 shown in Figure 9, light TRIAC coupler 46 is set, be used in the time before the DC/DC converter as load device starts inrush current being prevented that the TRIAC 42 of circuit 65 from keeping off-state, the inrush current when restriction starts reliably (relying on the resistance 43 of band Thermal Cutoffs).

(supplementary notes)

More than, in execution mode 1-16,, be divided into and be provided with input power supply circuits of excess voltage protection and load device or load circuit and be illustrated for the convenience that illustrates, they can certainly be included in the electric device integratedly.

Therefore, the present invention not only relates to the input excess voltage protection, also relates to the switching mode pressurizer or other the various electric settings (also comprising circuit) that comprise it in power supply circuits.

Input excess voltage protection of the present invention and constitute is not limited to shown in each execution mode, and in addition, the element that uses in its circuit is not subjected to above-mentioned restriction yet.

, prevent that as inrush current the inrush current of circuit from preventing element, because the resistance of band Thermal Cutoffs can cut off circuit reliably, and marked down buying, so be only.

Though as the transfer element of transmission circuit so that with light TRIAC coupler is example, yet is not limited thereto, even with optical coupler and transistor, also can reach same effect with transformer.

Though as overvoltage protection element to use rheostatic example illustration in addition; yet be not limited thereto, also can use the replacement rheostats such as combination of Zener diode (voltage stabilizing didoe), silicon varistor, avalanche diode, silicon controlled rectifier and Zener diode.

Switching circuit 26 also is not limited in the respective embodiments described above the circuit that uses, also can multistage ground transistor circuit, or with digital IC (NAND circuit).

Also can change the combination that many cases were represented in execution mode testing circuit, inrush current prevent circuit, switching circuit, transmission circuit, constitute the input excess voltage protection.In addition, in combination separately, have or not the diode that in testing circuit, is provided with, as the starting resistance resistor whether dual-purpose is provided with on testing circuit, the link position that can select its resistor according to the specification or the environmental condition of load device, the position that inrush current prevents circuit, rheostatic position etc. are set under the starting resistance situation in other approach.

Transmission circuit 27 and inrush current at the execution mode 1 of Figure 1 and Figure 2 prevent that circuit 25 from using because of combination.Reason is that transmission circuit 27 and inrush current prevent circuit 25 because prevent the circuit opposite action with other transmission circuit and inrush current separately, so if only folk prescription uses, then cut off circuit when input does not comprise superpotential normal alternating voltage.

And, the power supply circuits of the respective embodiments described above are to being illustrated as the switching mode pressurizer of the DC/DC converter of load device or load circuit etc. or the routine power of AC load device power supply, yet be not limited thereto, can be suitable for the device of essential interchange or direct voltage fully.For example also can in heater or converter etc., use.

In the respective embodiments described above, be illustrated being suitable for routine power of the present invention in the power supply circuits that exchange at the single-phase two-wire system of input, yet be not limited thereto, also go for importing single-phase 3 line formulas with 3 above power lines or 33 line formulas or 3 power supply circuits of the interchange of 4 line formulas mutually mutually.At this moment, at least 1 of each power line is carried out overvoltage detect, also can carry out between two power lines arbitrarily, if detect voltage between whole power lines or the per 2 whole power lines then better.

Just as described above; if be suitable for input excess voltage protection of the present invention; when then input comprises superpotential abnormal voltage on the power line of power supply circuits; detect it immediately; be sent to inrush current and prevent circuit; the fusing inrush current prevents the Thermal Cutoffs of circuit; cut off power supply; so be not subjected to protect load device (electric device) reliably about the characteristic or reliability institute of the overvoltage of rheostat, elementary fuse, Zener diode (voltage stabilizing didoe) etc. or over-current protecting element.

; owing to begin till cutting off power supply circuits, not change the expense several seconds from the input overvoltage; because before other overvoltage or over-current protecting element destruction, can promptly cut off circuit; even so, also can prevent generations such as the burning damage accident of the protection component shown in above-mentioned or the accident of smoldering power status variation for example, the frequent generation under the such environmental condition of input overvoltage.

In addition, should cut off the overvoltage value of power supply circuits, so can or its set point of suitable change such as environment be set according to the kind of the electric device that uses because can preestablish by the operating voltage of switching circuit.

Claims (7)

1. an input excess voltage protection has many power lines that are connected with AC power, is arranged on by these many power lines to power on the power supply circuits to load device or load circuit, it is characterized by:

The slotting inrush current that is situated between at least 1 in described many power lines prevents circuit, simultaneously, detection is set to be carried out the switching circuit of switch motion and prevents the transmission circuit of circuit for the on/off state transfer of this switching circuit described inrush current about the testing circuit of described many power line voltages, when the voltage that is detected by this testing circuit surpasses setting

Described inrush current prevents that circuit and the resistance and the thyristor of band Thermal Cutoffs are connected in parallel, this thyristor conducting at ordinary times, when the voltage that is detected by described testing circuit surpasses described setting, on/off state according to the described switching circuit that transmits by described transmission circuit, described thyristor disconnects, in the resistance of band Thermal Cutoffs, flow through electric current, utilize the fusing of this band Thermal Cutoffs and cut off described power supply circuits.

2. input excess voltage protection according to claim 1 is characterized by:

Described testing circuit is the testing circuit that detects the voltage of arbitrary power line in the described many power lines.

3. input excess voltage protection according to claim 1 is characterized by:

Described testing circuit is the testing circuit of the voltage of each root power line in detecting described many.

4. input excess voltage protection according to claim 1 is characterized by:

Described testing circuit is the testing circuit that detects voltage between the described many power lines.

5. require each described input excess voltage protection of 1～4 according to claim, it is characterized by:

Be inserted with described inrush current in described many power line intermediaries and prevent that this inrush current of the power line of circuit from preventing that the input side of circuit from be situated between inserting elementary fuse, prevent to be provided with rheostat between the outlet side of circuit and other power line in this inrush current of this power line.

6. require each described input excess voltage protection of 1～4 according to claim, it is characterized by:

Described switching circuit is a Zener diode, and described voltage setting is the zener voltage of this Zener diode.

7. an electric device has each the described input excess voltage protection as claim 1～4 in power supply circuits.

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