CN1122966A - Power supply apparatus having high power-factor and low distortion-factor characteristics - Google Patents

Abstract

A rectifier device can commutate the input voltage of the AC power supply. The first and second switch device is arranged between a pair of output terminals of the rectifier device and can alternatively break-over/cut-off. The series-wound circuit of the first capacitor and inductor is arranged between the two ends of one of the first and the second switch device, to operate the output frequency of the rectifier device smoothly. The second capacitor forms a resonance circuit with the inductor together according to the break-over/cut-off operation of first and second switch. The capacitance of the second capacitor is less than the capacitance of the first capacitor.

Description

Supply unit with High Power Factor and low distortion coefficient feature

The present invention relates to a kind of supply unit, it has improved the input factor of AC power, has reduced the input current distortion, has suppressed harmonic component, relates in particular to a kind of supply unit that is applicable to lighting apparatus for discharge lamp and lighting device.

Device with disclosed layout on Japanese patent application KOKA1 publication number 5-174986 is a kind of known such conventional discharge lamps lamp device that belongs to.

In this lighting apparatus for discharge lamp that in Japanese patent application KOKA1 publication number 5-174986, is disclosed, the one semi-bridge type inverter circuit with switch element of two serial connections is connected on the full-wave rectifier, voltage to industrial AC power carries out rectification, and a series circuit with load circuit of inductance and block capacitor is connected on the switch element in the inverter circuit.

To describe this lighting apparatus for discharge lamp that in Japanese patent application KOKA1 publication number 5-174986, is disclosed as prior art 1 below.

In the prior art, as shown in figure 50, coil 273 and capacitor 274 are disposed in the input side that is used for the output voltage of industrial AC power 271 is carried out the full-wave rectifier 272 of rectification.A time constant is set at the outlet side that the interior capacitor 275 of a certain scope is arranged in full-wave rectifier 272.One have two the serial connection switch elements 276 and 277 semi-bridge type inverter circuit 278 be connected on the capacitor between the full-wave rectifier 272 275 with the form that is connected in parallel.Inductance 279, the series circuit of discharge lamp 280 and block capacitor 281 are connected on the switch element 277 of inverter circuit 278.

The effect of the prior art 1 is not described in detail in detail here.Yet its effect can be from weighing along with obtaining the description to purpose and sequential chart etc.

Frequency in 275 pairs of AC power 271 of capacitor of the outlet side of full-wave rectifier 272 is carried out smooth operation, makes it a certain degree.Simultaneously, coil on the input side of full-wave rectifier 272 273 and capacitor 274 produce resonance potential.This resonance potential synchronously produces with the switch periods with the switch element 276 of semi-bridge type inverter circuit 278.At the turn-on cycle of switch element 276, power supply earlier offers inverter circuit 278 from capacitor 275, but because the capacity of capacitor 275 be set to less, so there is voltage drop to produce.After this, electric current flow to inverter circuit 278 from industrial AC power 271.When switch element 276 ended, interior stream electric current cutout produced above-mentioned resonance potential.If the circuit constant that is limited by coil 273 and capacitor 274 is arranged in the preset range, the voltage on capacitor 275 two ends that this resonance potential is higher than have smoothing effect.Therefore, because resonance potential is as power supply, so electric current flows into capacitor 275.Under this operational circumstances, even during the lower cycle of input ac voltage, also there is input current to flow, thereby realizes high input power factor, reduced the input current distortion.

Device at Japanese patent application KOKA1 publication number: 2-75200 (hereinafter being referred to as prior art 2) is another kind of known conventional apparatus.

Shown in Figure 51, this device comprises a pair of switching device 285 and 286 that is arranged between rectifier 284 outputs, in order to accept through the output of a high frequency cut off device 283 from AC power 282.Provide the diode 287 and 288 of reverse current to be parallel-connected on switching device 285 and 286.Two series capacitors 289 and 290 are parallel-connected on switching device 285 and 286.The capacity of capacitor 290 is configured to greater than another capacitor 289.Diode 291 is parallel-connected on the less relatively capacitor of capacitance 289.The series circuit of inductor 292 and discharge lamp 293 is connected between the node of the node of pair of switches element 285 and 286 and capacitor 289 and 290.In addition, capacitor 294 is connected between the discharge lamp 293 filament two ends.

According to prior art 2, at the turn-on cycle of switching device 285, make electric current by switching device 285 with offer inductor 292 and discharge lamp 293 with the output of rectifier 284, and capacitor 290 chargings bigger to capacity.Switching device 285 by and another switching device 286 conductings between during, provide electric current with the energy that are stored in the inductor 292 to capacitor 290 and diode 288.When switching device 286 conductings, the electric charge on the capacitor 290 discharges by switching device 286, inductor 292 and discharge lamp 293.Next section switching device 286 by and another switching device 285 conductings between during, provide electric current with the energy that are stored in the inductor 292 to capacity less capacitor 289 and diode 287.

In this mode, high-frequency ac current flows through in discharge lamp 293.And in switching device 285 turn-on cycles, electric current makes input current near sinusoidal wave to bigger capacitor 290 chargings of capacity.

Yet, in prior art 1, as if be difficult to carry out sufficient smooth operation; Perhaps reduce the input current distortion fully.This is because near the electric current that flows into inverter circuits 278 from AC power 271 near the zero cross point of AC power 271 is zero, and is perhaps very little, and can not obtain high resonance potential.More particularly,, but near the zero cross point of AC power 271, electric current can not be provided, for above-mentioned reasons, high resonance potential can not be obtained if capacitor 275 will carry out sufficient smooth operation.During this period, alternating voltage 271 can not provide input current.Therefore, can not reduce the input AC distortion fully.If the voltage of capacitor 275 reduces in the time of near the zero cross point of AC power 271, can not obtain enough smooth voltages.As mentioned above, in prior art 1, if circuit constant is arranged to reduce the input current distortion, can not level and smooth fully input voltage.Therefore, the fluctuation of lamp current has increased, and luminous efficiency is reduced, and has perhaps increased the fluctuation of light.

In addition, according to prior art 1, when resonance potential produces, at the alternating current source high-frequency ripple voltage appears.Thereby, except inductor 273 and capacitor 274, also need a special filter to reduce ripple voltage.

According to prior art 2, at the output voltage of rectifier 284 be between the peak period (the pulsation output voltage of rectifier 284 be zero or near zero during), input current can not be provided.During this period, the electric charge on the capacitor 290 that capacity is bigger discharges.Therefore, during this period, the discharging current that capacitor 29 only arranged is with based on this discharging current and be stored in the regenerative current that the energy on the inductor 292 produces and flow through diode 291.The generation of this phenomenon is that underlying cause causes.Therefore, in this cycle, the voltage on capacitor 289 and 290 the series circuit is greater than the output voltage of rectifier 284.As mentioned above, according to prior art 2, in some cycle, industrial power 282 (rectifier 284) can not provide input current, and the result can not fully reduce the input current distortion.

The present invention is exactly for addressing the above problem, and its objective is provides a kind of new for improved supply unit, and it improves input power factor by input voltage smoothly being reduced the fluctuation of output current, and reduces the harmonic wave in the input current.

Another object of the present invention provides a kind of supply unit, and it is controlled resonance potential reliably with a simple relatively structure, as make the peak value of resonance potential constant on above-mentioned basis through improving supply unit.

A further object of the present invention provides a kind of supply unit, and except that above-mentioned effect, it can also reduce the input current distortion reliably.

According to a first aspect of the invention, the output voltage that supply unit comprises AC power carries out the rectifying device that not level and smooth direct voltage is also exported in rectification, the a pair of output that is serially connected in rectifying device each other and with the switching device of the frequency alternate conduction that is higher than rectifying device output/end, be connected between the first switching device two ends and the output frequency of rectifying device is carried out first capacitor of smooth operation and the series circuit of inductor, operate second capacitor of generation resonance and the output circuit that acquisition is exported based on the high frequency of the resonance of inductor and the generation of second capacitor with inductor according to the conduction and cut-off of pair of switches device.

According to the present invention, for instance, can field-effect transistors as switching device.In this case, can reverse current be passed through with its parasitic diode that must comprise of structure because of field effect transistor.On the other hand, switching device also can mainly be made of the switch element that does not comprise parasitic diode between the collector and emitter, as uses bipolar transistor.In this case, the opposite diode that is connected in parallel between collector and emitter with its conducting direction.Yet if because of the structure of transistorized base circuit will connect a diode between emitter and the base stage, this diode can be used to reverse current is flow through.

In addition, in the present invention, according to top description, switching device is an alternate conduction/end.Yet, a switching device from the conducting state to the cut-off state and another switching device from the cut-off state to the conducting state during, might exist, perhaps may not exist two switching devices all to be in the cycle of cut-off state.The right switching frequency of switching device should be higher than the output frequency of rectifying device, and situation is that better greater than 20KHz or higher, this is higher than audio frequency greater than several kilo hertzs or higher preferably.

In the present invention, " serial connection form " or " and connecing form " mean with or mediate without another electronic unit and to connect a given electronic unit.

In addition, second capacitor that forms resonant circuit with inductor can be arranged on the optional position, as long as can form resonant circuit.For example, second capacitor can be connected on the series circuit of second switch device and inductor with the form of serial connection, perhaps can be connected between the output of rectifying device.On the other hand, can part or all of second capacitor be connected to output of rectifying device and switching device between.

And, in the present invention, can be with the inductor of any kind, as long as it can produce resonance with second capacitor.For example, can use similar devices such as choke, transformer.(above-mentioned description is equally applicable to following various aspects of the present invention.)

According to a second aspect of the invention, the output voltage that supply unit comprises AC power carries out rectification and exports the not rectifying device of smooth dc voltage, a pair of be serially connected in each other between the rectifying device output and with the switching device of the output frequency alternate conduction that is higher than rectifying device/end, relative capacity is bigger, and be parallel-connected to first capacitor on the switching device, be inserted in inductor between a switching device and first capacitor and capacity less than first capacitor, form second capacitor of resonant circuit with another switching device and inductor during the cycle at the second switch break-over of device.

According to a third aspect of the invention we, first or second aspect described in supply unit further comprise switch controlling device, be used for making the first and second switching device conduction and cut-off, and can change the turn-on cycle rate of switching device with the frequency of substantial constant.

According to a forth aspect of the invention, first or the supply unit of second aspect further comprise the switching device control device, be used for making the first and second switching device conduction and cut-off with the frequency of substantial constant, and can change the turn-on cycle rate of switching device, this switch controlling device is when the peak value of the voltage of the every half period of AC power output is big, shorten the turn-on cycle of another switching device, when peak value hour, then prolong turn-on cycle.

In the present invention, can be continuously according to peak value or progressively change the turn-on cycle of another switching device.

According to a fifth aspect of the invention, first or the supply unit of second aspect further comprise the switch controlling device of the conduction and cut-off frequency that can change first and second switching devices.

According to a sixth aspect of the invention, in the supply unit aspect the 5th, during less, make first and second switching devices, when peak value raises, then with higher relatively frequency conduction and cut-off with relatively low frequency conduction and cut-off corresponding to the peak value of the output voltage of rectifying device.

According to a seventh aspect of the invention, in the supply unit one of aspect the 5th or the 6th, second capacitor is parallel-connected on another switching device and the inductor.

According to an eighth aspect of the invention, in the supply unit one of aspect first to the 6th, second capacitor is arranged between the output of rectifying device.

According to a ninth aspect of the invention, in the supply unit one of aspect first to the 6th, second capacitor be arranged at least one output of rectifying device and switching device between, have a diode to be parallel-connected on second capacitor, its polarity is identical with the output polarity of rectification dress.

In the present invention, second capacitor can be made of two or more capacitors, these capacitors can be separately positioned on the positive output end of rectifying device and negative output terminal and switching device between.Between the output of rectifying device, need the element of an energy by resonance current.For this element, the capacitor that passes through high frequency waves of common usefulness, but also can use professional component.

According to the tenth aspect of the invention, in the supply unit aspect the 5th or the 6th, in output circuit, be provided with the impedance circuit that an impedance reduces along with the rising of frequency.

According to an eleventh aspect of the invention, in the supply unit one of aspect first to the tenth, between the output of inductor, be provided with output circuit to power supply to load, the elementary winding of transformer is connected in the load with the serial connection form, by the output of transformer secondary output winding first and second switching devices is carried out drive controlling.

According to a twelfth aspect of the invention, the supply unit of one of first to the tenth formula aspect further comprises a discharge lamp as load.

According to a thirteenth aspect of the invention, in the supply unit aspect the 12, during discharge lamp being carried out start-up operation predetermined in, the turn-on cycle of second switch device is arranged to greater than the turn-on cycle in during discharge tube lighting.

According to a fourteenth aspect of the invention, in the supply unit in aspect first to the 13rd, discharge lamp is installed at least on light fixture as load.

According to a fifteenth aspect of the invention, a kind of supply unit is provided, it comprises carries out the rectifying device that not level and smooth direct voltage is also exported in rectification to alternating voltage, connection is one another in series, with the output frequency alternate conduction that is higher than rectifying device/by first and second switching devices that commutate with output to rectifying device, be parallel-connected to first capacitor on first switching device, the output of rectifying device to this first capacitor charging with output to rectifying device is carried out smooth operation at the second switch break-over of device during cycle by the second switch device, when the first switching device turn-on cycle, discharge electric charge by first switching device, be inserted between the node and first capacitor between first and second switching devices, and can pass through the inductor of the charging current of first capacitor, according to first and second switching devices lead can/produce second capacitor of resonance by operation with inductor, discharge according to first capacitor, and the control unit of the resonance potential value that produces with the control inductor and second capacitor of the discharge current value that in first switching device, the flows turn-on cycle of controlling first switching device and the output circuit that on the basis of the resonance that inductor and second capacitor produce, obtains high frequency output.

According to a sixteenth aspect of the invention, a kind of supply unit is provided, it comprises the rectifying device that is connected on the AC power, be serially connected in each other between the pair of output of rectifying device and with first and second switching devices of the output frequency conduction and cut-off that is higher than rectifying device, first capacitor that capacity is bigger and the series circuit of inductor, this series circuit is parallel-connected on first switching device, capacity is less and be arranged to form second capacitor of resonance according to the operation of the conduction and cut-off of first and second switching devices with inductor, have the control unit of turn-on cycle current sensing means and control first switching device according to the detection signal of this current sensing means that is used to detect the electric current that flows in first switching device and produce the output circuit that obtains high frequency output on the basis of resonance at inductor and second capacitor.

In the present invention, first capacitor also carries out smooth operation to the output frequency of rectifying device.In addition, second capacitor is arranged to form resonant circuit with inductor.In this case, similar to the 19th aspect, second capacitor can be arranged on any position, as long as can form resonant circuit.

According to a seventeenth aspect of the invention, in the supply unit aspect the 15 or 16, control unit is controlled the turn-on cycle of first switching device, so that the peak value of first capacitor discharging current that discharge and that flow in first switching device becomes a predetermined value.

The tenth eight aspect according to the present invention, in the supply unit aspect the 15 or the 16, control unit is controlled the turn-on cycle of first switching device, makes first capacitor become predetermined value by the integrated value of the discharging current of inductor and the release of first switching device.

In the present invention, the discharge current value of first capacitor rises according to the definite slope of the impedance of first capacitor, inductor and load.Therefore, the integrated value of discharging current is controlled to a predetermined value, can control the current value in first switching device between the off period.In the present invention, can be with being used as that as saturating current transformer integrated value is controlled to device on the predetermined value.This control can be in conducting state by making first switching device, carries out till saturating current transformer is saturated.Yet this device also can be made of current sensing means and being used for carries out integration to the output of current sensing means integrating gear.In other words, can detect the time period that discharging current is crossed first switching device.

According to a nineteenth aspect of the invention, in the supply unit aspect the 15, control unit is controlled the turn-on cycle of first switching device, and the initial value that makes the resonance current that flows through the second switch device is a predetermined value.

According to a twentieth aspect of the invention, in the supply unit one of aspect the 17 to 19, control device changes the predetermined value of the current value of determining the first switching device turn-on cycle according to the magnitude of voltage on first and second switching devices.

According to a twenty-first aspect of the invention, in the supply unit one of aspect the 15 to 19, control unit ends it after one period scheduled time there being an electric current to flow through the second switch device.

According to a twenty-second aspect of the invention, in the supply unit one of aspect the 15 to 19, control unit makes the second switch device cut one section preset time after the resonance current peak value that inductor and second capacitor produce partly flows into the second switch device.

According to a twenty-third aspect of the invention, in the supply unit one of aspect the 15 to 19, control unit at least one electric current in the input and output electric current flows into rectifying device ends the second switch device after one period scheduled time.

In aspect the of the present invention the 21 to 23, can detect " one section preset time " by the integrated value of detection time or electric current.In addition, can wait according to the output voltage of the output voltage of alternating voltage, rectifier, output circuit and change this scheduled time.

According to a twenty-fourth aspect of the invention, in the supply unit one of aspect the 15 to 19, control unit is according to the turn-on cycle corresponding to the voltage control second switch device at the first capacitor two ends.

In this case, " according to the voltage corresponding to the first capacitor two ends " means not only and can directly also can control according to the voltage at the first capacitor two ends indirectly according to the voltage at the first capacitor two ends, as the voltage according to the first and second capacitor two ends.

According to the twenty-fifth aspect of the invention, in the supply unit one of aspect the 15 to the 19, control unit is according to the turn-on cycle of ac voltage control second switch device.

According to the twenty-sixth aspect, in the supply unit one of aspect the 15 to the 19, control unit is according to the turn-on cycle of the output control second switch device of output circuit.

In the present invention, " output of output circuit " mean power output, voltage or electric current.In addition, if discharge lamp is connected as load, then can be with power, modulating voltage or the lamp current of this discharge lamp.

The 27 aspect of the present invention, the supply unit of one of the 15 to 26 aspect further comprises the discharge lamp as load.

According to a twenty-eighth aspect of the invention, the supply unit of the 27 aspect is arranged to a lighting apparatus for discharge lamp, and wherein, discharge lamp is installed on the lighting as load.

According to the twenty-ninth aspect, a kind of supply unit is provided, the circuit that it comprises first and second switch elements that are connected in series with the outlet side of rectifying device, is made up of bigger smoothing capacity device of capacity and the inductance device that links to each other with a load, this circuit is connected with one of first and second switch elements, and capacity is less than the smoothing capacity device, form the resonant capacitance device of resonator system with inductance device.

According to first or the supply unit of second aspect in, by first capacitor carrying out smoothly to rectifying device without level and smooth direct voltage.In addition, utilize the effect of the resonance potential of the resonant circuit generation that forms by second capacitor and inductor, the voltage of first capacitor be provided be lower than switching device to transition period rectifying device rectification obtain without level and smooth voltage.This operation has been arranged, though the voltage peak of AC power (through rectification without level and smooth direct voltage) also can guarantee to have input current between lowstand, thereby improve input power factor, reduce the input current distortion, reduce input current harmonics.

In addition, in the supply unit according to the third aspect, first and second switching devices are with the frequency conduction and cut-off of substantial constant, and can change the turn-on cycle rate of these switching devices.By changing turn-on cycle, can change resonance amplitude, thereby can change output voltage.And because the switching frequency substantial constant, so compare with the device that switching frequency raises, the rising of its switching loss can be suppressed.

In addition, in supply unit, can change the turn-on cycle rate of first and second switching devices according to fourth aspect.When the peak value of the voltage of the every half period of AC power output is big, shorten the turn-on cycle of another switching device, vice versa.As in the fourth aspect, change on-state rate and can regulate output voltage.And, use the way of the turn-on cycle that changes a switching device according to the peak value that the voltage of the every half period of AC power is exported, can obtain enough level and smooth output voltage.

In according to the supply unit aspect the 5th and the 6th, change switching frequency and can change the absolute turn-on cycle of another switching device, and as above-mentioned, can change output.

In according to the supply unit aspect the 7th, because second capacitor is parallel-connected on another switching device and the inductor, so can be with simple structure realization above-mentioned purpose.

In supply unit,,, can realize above-mentioned purpose with simple structure therefore with the same according to the device of the 7th aspect because second capacitor is connected between the output of rectifying device according to eight aspect.

In according to the supply unit aspect the 9th and since second capacitor be connected rectifying device and switching device between, so, may realize above-mentioned purpose with simple structure to similar according to the device of eight aspect.

In according to the supply unit aspect the tenth, output circuit comprises the impedance circuit that impedance raises and reduces with frequency.Therefore,, realize that the impedance of the circuit of reduction distortion still can keep less, can obtain enough resonance currents even improved frequency of oscillation.

In supply unit, because driving transformer makes the first and second switching device failures of oscillations when load is removed, so can prevent to put on the increase of voltage on first and second switching devices according to the tenth one side.

In according to the supply unit aspect the 12 as lighting apparatus for discharge lamp since discharge lamp as load, so the fluctuation that can reduce to export improves luminous efficiency, thereby reduce light beats.

According to aspect the 13 as in the supply unit of lighting apparatus for discharge lamp, because the turn-on cycle of another switching device during predetermined discharge lamp start-up operation is provided with less than the turn-on cycle during lamp is bright, so filament is being carried out starting discharge lamp after the sufficient preheating.Therefore, can prevent the discharge lamp shortening in useful life.

According to aspect the 14 as in the supply unit of lighting device because lighting apparatus for discharge lamp is installed on the light fixture, improved luminous efficiency, reduced the fluctuation of lamp current, thereby reduced light beats.

According to the 15 and sixteenth supply unit in, the output of rectifying device is charged to first capacitor, and keeps through level and smooth direct voltage, it is worth less than the peak value without level and smooth direct voltage.In addition, the resonant circuit that is formed by second capacitor and inductor produces resonance potential according to the conversion of first and second switching devices.This resonance potential forms such one-period, and in this cycle, the load voltage of seeing from rectifying device all is lower than without level and smooth direct voltage on the whole cycle without level and smooth direct voltage basically.For this mode of operation, even also can guarantee to obtain input current (charging current flows) from AC power when low in first capacitor without the peak value of level and smooth direct voltage, thereby improve input power factor, reduce the input current distortion, reduce the harmonic wave in the input current.The turn-on cycle that discharge current value that discharge according to first capacitor in addition, and that flow in first switching device is controlled first switching device is controlled resonance potential.For example, the turn-on cycle of first switching device of control decision resonance potential amplitude makes the peak value of the electric current that flows in first switching device become predetermined value.For this mode of operation, described as reference Figure 23 A and 23B, can be controlled at the resonance potential value on one constant.Therefore, can control and be added to switching device, prevent the breakdown switch device last magnitude of voltage, thereby the switching device that can use breakdown potential to force down.

And, by changing the predetermined value of determining turn-on cycle, can change output voltage values arbitrarily, the magnitude of voltage that makes change is a constant.

In according to the supply unit aspect the 17, make the peak value of the electric current that flows in first switching device become a predetermined value owing to can control the turn-on cycle of first switching device, so can obtain as the 15 effect identical with the supply unit of 16 aspects.

In the supply unit according to the tenth eight aspect, the turn-on cycle of controlling first switching device makes the integrated value of discharging current become a predetermined value.For this mode of operation, can obtain identical with the supply unit of the 17 aspect basically effect.

In according to the supply unit aspect the 19, control the turn-on cycle of first switching device, make the initial value of the resonance current that flows in the second switch device become a predetermined value.Therefore, can make the current constant of the definite resonance potential that flows into resonant circuit in this case equally, so that the resonance potential value is controlled on the constant.In the present invention, be to control according to the discharge current value that flow through first switching device in the past, therefore, control has a delay.Yet, if being compiled weak point, this delay is for example high frequency waves cycle, can not produce practical problem.

In according to the supply unit aspect the 20, change the current value that determines the first switching device turn-on cycle that flows through first switching device according to the magnitude of voltage on first and second switching devices.For example, change detected voltage or with this detected current ratio reference signal.For this working method, can make the voltage constant on first and second switching devices.

In supply unit,, flow to first capacitor from rectifying device after an electric current flows into its interior one period scheduled time so can guarantee a charging current because the second switch device just ends according to the 20 one side.Therefore, can reduce the input current distortion.

In according to the supply unit aspect the 22, owing to after the peak value of resonance current partly flows through, make the second switch device by one period scheduled time, so after peak value partly flows through, there is a charging current to flow into one period scheduled time of first capacitor reliably from rectifying device.Therefore, can obtain and the 20 on the one hand the identical effect of supply unit.

In according to the supply unit aspect the 23, because the I/O electric current flows into one section preset time of rectifying device, so can obtain the effect identical with the supply unit of the 21 and 22 aspects.

In according to the supply unit aspect the 24,,, control the charge volume of first capacitor also according to turn-on cycle corresponding to the magnitude of voltage control second switch device of the voltage on first capacitor except the 15 working method in aspect 19.Therefore, can make voltage constant on first capacitor.For this working method,, and make the voltage that is added in the load also constant even mains voltage variations also can make the voltage constant on first capacitor.

In according to the supply unit aspect the 25, because according to the turn-on cycle of AC supply voltage control second switch device, so can make voltage constant on first capacitor by the charge volume of controlling first capacitor.For this working method,, and make the voltage that is added in the load also constant even mains voltage variations also can make the voltage constant on first capacitor.

In according to the supply unit aspect the 26, control the charge volume of first capacitor by turn-on cycle, thereby make the voltage constant on first capacitor according to the output control second switch device of output circuit.For this working method,, and can make the voltage that is added in the load also constant even load variations also can make the voltage constant on first capacitor.

According to aspect the 27 as in the supply unit of lighting apparatus for discharge lamp, discharge lamp as load.Therefore, except the effect of supply unit, also reduce output pulsation, improved illumination effect, reduced light beats.

According to the 20 eight aspect as in the supply unit of lighting device because discharge lamp deivce is arranged in the device body,, reduced light beats so improved luminous efficiency.

In according to the supply unit aspect the 29, the high frequency voltage that the resonator system that is made of resonant capacitance device and inductance device produces becomes the alternating voltage by the rectifying device rectification.For this working method, rectifier output voltage equals input voltage, even in the lower cycle of alternating voltage input voltage is arranged also with assurance, thereby reduces the distortion of input current, reduces harmonic components.

Other purpose of the present invention and advantage will propose in the following description, and a part will become along with explanation obviously, perhaps can learn by putting into practice the present invention.Purpose of the present invention and advantage can be passed through media means and comprehensive method, particularly by what claims proposed, go to understand and obtain.

Accompanying drawing combines with specification, and constitutes the part of specification, and it illustrates preferred embodiment of the present invention, with general description that provides above and the detailed description to preferred embodiment given below, is used to separate release principle of the present invention.

Fig. 1 is the circuit diagram of the present invention the 1st embodiment;

Fig. 2 is the perspective view that the present invention is applied to lighting device;

Fig. 3 A to 3C is the waveform sequential chart of voltage of the electric current on each parts of explanation effect embodiment illustrated in fig. 1;

Fig. 4 is the circuit diagram of the present invention the 2nd embodiment;

Fig. 5 is the curve chart of the switching device turn-on cycle among Fig. 4;

Fig. 6 A to 6E is the equivalent circuit diagram that operation embodiment illustrated in fig. 4 is shown;

Fig. 7 is under the situation that the turn-on cycle of second switch device is provided with short, and the waveform sequential chart of voltage and current on each component of the effect of embodiment shown in Figure 4 is described;

Fig. 8 is under the situation that the turn-on cycle of second switch device is provided with long, and the waveform sequential chart of voltage and current on each component of the effect of embodiment shown in Figure 4 is described;

Fig. 9 is under the situation that is provided with the turn-on cycle of second switch device longlyer, and the waveform sequential chart of voltage and current on each component of the effect of embodiment shown in Figure 4 is described;

Figure 10 is the circuit diagram of the present invention the 3rd embodiment;

Figure 11 is the circuit diagram of the present invention the 4th embodiment;

Figure 12 is a curve chart of explaining Figure 11 embodiment effect;

Figure 13 is the circuit diagram of the present invention the 5th embodiment;

Figure 14 is a sequential chart of explaining the present invention the 6th embodiment;

Figure 15 is the circuit diagram of the present invention the 7th embodiment;

Figure 16 is the circuit diagram of the present invention the 8th embodiment;

Figure 17 is the circuit diagram of the present invention the 9th embodiment;

Figure 18 is the circuit diagram of the present invention the 10th embodiment;

Figure 19 is the circuit diagram of the present invention the 11st embodiment;

Figure 20 is the circuit diagram of the present invention the 12nd embodiment;

Figure 21 A to 21E is the level circuitry figure of the operation of explanation embodiment shown in Figure 20;

Figure 22 A and 22B are explanation sequential charts embodiment illustrated in fig. 20;

Figure 23 A and 23B are explanation sequential charts embodiment illustrated in fig. 20;

Figure 24 A to 24C is an explanation sequential chart embodiment illustrated in fig. 20;

Figure 25 A to 25C is an explanation sequential chart embodiment illustrated in fig. 25;

Figure 26 is the circuit diagram of the present invention the 13rd embodiment;

Figure 27 is the circuit diagram of the present invention the 14th embodiment;

Figure 28 schematically illustrates the perspective view that the present invention is applied to lighting device;

Figure 29 is the circuit diagram of the present invention the 15th embodiment;

Figure 30 A to 30C is under the short situation of the turn-on cycle of the second switch device in Figure 29, shows the sequential chart of the waveform of voltage on second capacitor and the electric current in each switching device;

Figure 31 A to 31C is under the bigger situation of the turn-on cycle of the second switch device in Figure 29, shows the sequential chart of the waveform of the electric current in voltage on second capacitor and each switching device;

Figure 32 is the sequential chart of the voltage between the rectifying device output that illustrates among Figure 29;

Figure 33 is the sequential chart that load current among Figure 29 is shown;

Figure 34 is the circuit diagram of the present invention the 16th embodiment;

Figure 35 is the circuit diagram of the present invention the 17th embodiment;

Figure 36 is under the voltage between the output of rectifying device becomes condition with higher, the current waveform sequential chart in the second switch device;

Figure 37 is under the situation that the voltage between the output of rectifying device becomes lower, the current waveform sequential chart in the second switch device;

Figure 38 A to 38E is the curve chart that result of the test is shown, particularly the curve chart that changes with mains voltage variations of each output;

Figure 39 is the circuit diagram of the present invention the 18th embodiment;

Figure 40 is the circuit diagram of the present invention the 19th embodiment;

Figure 41 is the circuit diagram of the present invention the 20th embodiment;

Figure 42 is the circuit diagram of the present invention the 21st embodiment;

Figure 43 is the circuit diagram of the present invention the 22nd embodiment;

Figure 44 is the circuit diagram of the present invention the 23rd embodiment;

Figure 45 is the interior current waveform sequential chart of second switch device among Figure 44;

Figure 46 is the circuit diagram of the present invention the 24th embodiment;

Figure 47 A to 47C is the current waveform sequential chart in first and second switching devices among Figure 46;

Figure 48 is that explanation is the perspective view that is applied to lighting device through improved supply unit of the present invention;

Figure 49 is the circuit diagram of major part structure that is applied to the supply unit of DC load circuit;

Figure 50 is the circuit diagram of prior art 1;

Figure 51 is the circuit diagram of prior art 2.

In the 1st embodiment, supply unit of the present invention is applied to lighting apparatus for discharge lamp, describes the 1st embodiment and lighting device below with reference to Fig. 1 to Fig. 3.

As shown in Figure 2, lamp socket 12 is fixed to the two ends of light fixture 11, forms reflecting surface on the lower surface of light fixture 11.Load promptly is installed between the lamp socket 12 as the fluorescent lamp FL of discharge lamp.Discharge lamp ballast circuit 16 as shown in Figure 1 is set in light fixture 11.

The filter circuit 21 that is made of coil L1 and capacitor C1 is connected on the industrial AC power E of discharge lamp ballast circuit 16.Being connected on the filter circuit 21 as the whole device 22 of the all-wave of speed-sensitive switch rectifying device such as diode bridge etc.The first and second switch element Q1 and Q2 constitute semi-bridge type inverter circuit 23, and are connected in series between the output of full-wave rectifier 22.Backflow diode D1 and D2 are parallel-connected on the first and second switch element Q1 and the Q2.

Leakage magnetic type isolating transformer Tr as inductance device ₁Elementary winding Tr _1aSeries circuit and the first switch element Q1 as the smmothing capacitor C2 of smoothing capacity device bigger with capacity are connected in parallel, formation circuit 24.Notice that smmothing capacitor C2 plays smoothing effect to the supply frequency of industrial AC power E.

Filament FL1 and the FL2 of fluorescent lamp FL are connected to isolating transformer Tr ₁Secondary winding Tr _1bOn.Filament is carried out pre-warmed capacitor C3 to be connected between filament FL1 and the FL2.

The less resonant capacitor C4 as the resonant capacitance device of capacity passes through isolating transformer Tr ₁Elementary winding Tr _1aBe connected to second switch element Q2.Notice that the Capacity Ratio smmothing capacitor C2 of resonant capacitor C4 is much smaller, it and isolating transformer Tr ₁Inductance together in order to produce a waveform, its frequency is the switching frequency of the first and second switch element Q1 and Q2.

The working condition of Fig. 1 embodiment is described below.

At first, remove noise in the voltage of industrial AC power E by filter circuit 21.Then, in full-wave rectifier 22, this voltage is carried out full-wave rectification.The first and second switch element Q1 and Q2 be with the high frequency alternation switch of the frequency that is higher than AC power, with at isolating transformer Tr ₁Secondary winding Tr _1bOn induce high-frequency ac voltage, thereby high frequency is lighted fluorescent lamp FL.In addition, resonant capacitor C4 and isolating transformer Tr ₁Elementary winding produce resonance, when the alternating voltage corresponding to full-wave rectifier 22 rectifications is low level, provide the electric current of power-factor improvement, thereby reduce distortion.

Say that more specifically when the first switch element Q1 conducting, electric current flows through smmothing capacitor C2, the first switch element Q1, isolating transformer Tr ₁Elementary winding Tr _1aClosed circuit with smmothing capacitor C2 formation.Therefore, to isolating transformer Tr ₁Elementary winding Tr _1aCharging.

Then, when the first switch element Q1 ends, isolating transformer Tr ₁Elementary winding Tr _1aOn electric charge by resonant capacitor C4, diode D2 and isolating transformer Tr ₁Elementary winding Tr _1aThe closed circuit that forms discharges.At this moment, the voltage of resonant capacitor C4 is because resonant capacitor C4 and isolating transformer Tr ₁Elementary winding Tr _1aResonance effect and raise.

When second switch element Q2 conducting, electric current is at resonant capacitor C4, isolating transformer Tr ₁Elementary winding Tr _1aFlow in the closed circuit that second switch element Q2 and resonant capacitor C4 form.Therefore, to isolating transformer Tr ₁Elementary winding Tr _1aCharging.Voltage on the resonant capacitor C4 descends at this moment.

Voltage on resonant capacitor C4 descends, and the voltage on resonant capacitor C4 and the smmothing capacitor C2 becomes when equating with input voltage electric current electric current full-wave rectifier 22.Therefore, full-wave rectifier 22, smmothing capacitor C2, isolating transformer Tr have been improved ₁Elementary winding Tr _1a, second switch element Q2 and full-wave rectifier 22 be formed with the power factor of the electric current that flows in the closed circuit, thereby reduced distortion.

When second switch element Q2 ends, be stored in isolating transformer Tr ₁Elementary winding Tr _1aInterior energy is by diode D1, smmothing capacitor C2 and isolating transformer Tr ₁Elementary winding Tr _1aThe closed circuit that forms discharges.Therefore, charged into energy to smmothing capacitor C2.

When usefulness embodiment as shown in Figure 1 implements, can obtain electric current and voltage shown in Fig. 3 A to 3B.Fig. 3 A shows input current Iin; Fig. 3 B shows the output voltage V 22 of full-wave rectifier 22; Fig. 3 C shows the voltage of fluorescent lamp FL.That is, can reduce output ripple.

In addition, by isolating transformer Tr ₁Elementary winding Tr _1aWith second switch element Q2, when operating, power connection can reduce to flow to the starting current of smmothing capacitor C2.

And, even smoothing capacity C2 exchanged with being connected each other of resonant capacitor C4, also can obtain aforesaid effect.

An alternative embodiment of the invention is described with reference to the accompanying drawings.

Now the 2nd embodiment of the present invention is described referring to Fig. 4 to Fig. 9.Referring to Fig. 4, as, the filter circuit that is made of choke 2 and capacitor 3 is connected on the industrial AC power 1.Be connected on this filter circuit by the full-wave rectifier that constitutes as diode bridge etc. as engagement positions 4.Rectifying device 4 (diode bridge) is by constituting as the speed-sensitive switch diode.First and second switching devices 5 and 6 are connected in series between the pair of output of rectifying device 4.In this embodiment, these switching devices 5 and 6 are made of field-effect transistor, parasitic diode as the diode by reverse current.

Bigger elementary winding 7-1 and capacity as the leakage magnetic type isolating transformer of inductor 7, be connected on the switching device as the series circuit of the smmothing capacitor of first capacitor 8, as being connected in the present embodiment on first switching device 5.Notice that the supply frequency of 8 pairs of industrial AC power 1 of first capacitor plays smooth effect.

In this embodiment, on the two ends of inductor 7, form output circuit.That is, the secondary winding 7-2 of inductor 7 is used as output circuit., for example a fluorescent lamp 9 is connected on the second winding 7-2 as load with a discharge lamp.Being used for that filament is carried out pre-warmed capacitor 10 is connected between the filament of fluorescent lamp 9.In this embodiment, also the leakage inductance of inductor 7 current-limiting inductance of doing fluorescent lamp 9.

In the present embodiment, what capacity was less is parallel-connected to another switching device as the resonant capacitor of second capacitor 11 elementary group of 7-1 by inductor 7, promptly on the second switch device 6.Attention: Capacity Ratio first capacitor 8 of second capacitor 11 is much smaller, is used for producing a waveform with the inductance of inductor 7, and its frequency is the switching frequency of first and second switching devices 5 and 6.

And in this embodiment, switch control unit 12 is configured to the conduction and cut-off operation of switching device 5 and 6 is controlled.Switch control unit 12 makes switching device 5 and 6 conduction and cut-off with the frequency of substantial constant.In addition, (output voltage of rectifying device 4 changes the turn-on cycle of switching device 6 to the relation that switch control unit 12 can be as shown in Figure 5 according to the peak value of the output voltage of AC power 1.More particularly, when the peak value (output voltage of rectifying device 4) of the output voltage of AC power 1 was big, switch control unit 12 shortened turn-on cycles, and vice versa.Therefore, the turn-on cycle of first switching device 5 and the 6 opposite changes of second switch device.And, in this embodiment, can also change the turn-on cycle of second switch device 6 according to external signal.More particularly, switch controlling device 12 is by being used to detect the testing circuit 12-1 of input voltage and being used for constituting according to the oscillating circuit 12-2 of the detected voltage change of testing circuit 12-1 turn-on cycle.For oscillating circuit 12-2, can make as integrated circuit as PWM controller (as: TL494 that Texas Instruments produces).Switch control unit 12 also comprises external control signal importation 12-3.

Effect of the present invention is described below.The whole working condition of this device is now described briefly.At first, remove the noise of industrial AC power 1 voltage by filter circuit.Then, in rectifying device 4, voltage is carried out full-wave rectification.Simultaneously, first and second switching devices 5 and 6 induce high-frequency ac voltage on the secondary winding 7-2 of inductor 7, thereby high frequency are lighted fluorescent lamp 9 to be higher than the frequency alternation switch of supply frequency.In addition, second capacitor 11 and inductor 7 produce resonance potential.Even the effect of this resonance potential is the electric current that hour also can provide power factor to change at the peak value of the voltage of rectifying device 4 rectifications, thereby reduces distortion.

Describe the working condition of circuit in detail below with reference to Fig. 6 A to Fig. 9.Attention: Fig. 6 A to 6E only schematically shows rendering circuit and operates needed major part.Reference number same among Fig. 6 A to 6E is represented identical parts with the reference number among Fig. 4.Fig. 7 to Fig. 9 shows the voltage and current waveform of each parts.With reference to Fig. 7 to Fig. 9, reference symbol V represents voltage, and I represents electric current, corresponding parts among each postfix notation Fig. 4 (yet, the gate source voltage of " VGS5 " expression first switching device 5 among Fig. 7,8 and 9, the gate source voltage of " VGS6 " expression second switch device 6).

At first described AC power peak value (not level and smooth direct voltage) the bigger cycle with reference to Fig. 6 A to 6E and Fig. 7.In the bigger cycle, switch control unit 12 is provided with turn-on cycle shortlyer according to detected voltage control second switch device at peak value.

In the period (a) (" (a) " among Fig. 6 A and Fig. 7) owing to formed the closed-loop path of first capacitor 8, first switching device 5 and inductor 7, so the electric charge that is stored in first capacitor 8 discharges by this closed circuit, electric current I 5 and I8 flow as shown in Figure 7.

Period (b) (" (b) " among Fig. 6 B and Fig. 7), first switching device 5 ends, the parasitic diode conducting of second switch device 6.Therefore, the inductor 7 and second capacitor 11 produce series resonance, and resonance current I6 and I11 flow as shown in Figure 7.For this running, as shown in Figure 7 resonance potential V11 and V7 appear on second capacitor 11 and inductor 7.In addition, resonance potential V4 occurs on rectifying device 4, it equals the voltage sum on second capacitor 11 and first capacitor 8.

In period (c) (" (c) " among Fig. 6 c and Fig. 7), 6 conductings of second switch device, the polarity inversion of resonance current.Therefore, resonance current I6 and I11 with Fig. 6 B in flow to mutually that negative side flows.Because the resistive component of resonant circuit is less, resonance potential V7 in the time of in the period (b) and (c) and V11 become and are higher than through the rectified wave ripple voltage.Be that resonance potential raises.

Period (d) (" (d) " among Fig. 6 D and Fig. 7), resonance potential descends, and the voltage on second capacitor 11 and first capacitor 8 also is tending towards descending.Therefore, electric current I 4, I8 and I6 flow through first capacitor 8, inductor 7 and second switch device 6 from rectifying device 4 as shown in Figure 7.

Period (e) (" (e) " among Fig. 6 E and Fig. 7), second switch device 6 ends, the parasitic diode conducting of first switching device 5, so, as shown in Figure 7, because of being stored in the reason of the energy in the inductor 7, electric current I 5 and I8 are flowed in first switching device 5 and first capacitor 8.After this, be returned to the state of period (a).

The peak value of describing AC supply voltage below with reference to Fig. 8 cycle hour.In this cycle, switch control unit 12 detects voltage, and controls, and makes the turn-on cycle of second switch device 6 become longer.In this case, the working condition of circuit is identical with the situation shown in Fig. 6 A to Fig. 6 E basically.Fig. 8 shows the voltage and current waveform on each parts.It should be noted that under situation shown in Figure 8 the amplitude of resonance potential V4 and V11 and peak value are all greater than situation shown in Figure 7.This be because turn-on cycle long, the period (b) prolonged relative with (c).Also because at the peak value of smooth dc voltage not in the less cycle, the charging voltage on second capacitor 11 is according to the peak value step-down, and therefore the electric current that flows into second capacitor 11 in the period (b) is that initial resonance current increases.Therefore, when the peak value step-down of smooth dc voltage not, voltage can rise De Genggao, and the lowest point of not level and smooth direct voltage also can raise.As mentioned above, in circuit shown in Figure 4, come the turn-on cycle of control switch device 5 and 6 according to relation shown in Figure 5.Owing to this reason, in the less cycle, the turn-on cycle of first switching device 5 is shorter at peak value.For this layout,, disconnect the electric current that flows into switching device 5 in the less stage of current value.This makes the initial resonance current value when the period (b) diminish.Therefore, as mentioned above,, the lowest point magnitude of voltage is increased egregiously even resonance potential raises because of the relation of the voltage that fills on second capacitor 11.

When experimentizing with embodiment shown in Figure 4, the waveform of the input current Iin of AC power 1 as shown in Figure 3A.As mentioned above, this explanation is all flowed in the whole cycle at the direct voltage without level and smooth of rectifying device 4 at the electric current of rectifying device 4 during the period (d).Therefore, should be understood that this electric current has improved input power factor, helps to reduce the input current distortion.In addition, Fig. 3 B shows the waveform of the voltage V4 between the output of rectifying device 4, and Fig. 3 C shows the waveform of the electric current in the fluorescent lamp 9.That is, should be understood that and to reduce output ripple.

If the turn-on cycle with external signal control second switch device 6 then can change output voltage.More particularly, if be provided with the turn-on cycle of second switch device 6 longlyer, then output voltage uprises, and vice versa.Therefore, the same with present embodiment, when discharge lamp when the load, can at random make lamp deepening/light.Fig. 9 shows further the contract voltage and current waveform of each parts when knowing of turn-on cycle.

By inductor 7 is connected in series with first capacitor 8, and make second switch device 6 conduction and cut-off, then can reduce when energized is operated, to flow into the electric current of first capacitor 8 with high frequency.

Even change the link position of first and second capacitors 8 and 11 they are exchanged each other, also can obtain aforesaid effect.In this case, also will be the switching device reversal connection of control turn-on cycle.

Figure 10 is the circuit diagram of the present invention the 3rd embodiment.In the present embodiment, the isolating transformer that does not have additional leakage inductance as inductor 7 ', inductor 15 is connected with elementary winding 7 '-1 of this isolating transformer.Therefore identical parts in the identical reference number presentation graphs 4, have omitted the explanation to them among Figure 10.Notice that switching device 5 and 6 illustrates with the form of simplifying.In the present embodiment, inductor 15 is as the current-limiting impedance of fluorescent lamp 9.

Understand easily,, can obtain the effect identical as the embodiment of Fig. 4 for layout as shown in figure 10.Thereby, omitted description to these effects.

Figure 11 is the circuit diagram of the present invention the 4th embodiment.In the present embodiment, the impedance circuit that is made of coil 16 and capacitor 17 is connected in parallel with elementary winding 7-1 as the isolating transformer of the inductor among Fig. 4 embodiment 7.Note, as shown in figure 12, the characteristic impedance of this impedance circuit minimum when frequency f 1.

In the present embodiment, the frequency of oscillation when lighting fully with fluorescent lamp 9 is compared, and making fluorescent lamp 9 deepenings/frequency of oscillation rising of (in the scope of " f1 " left side of Figure 12) inverter circuit when lighting, is reducing output.When frequency of oscillation raise, the turn-on cycle of second switch device 6 shortened.Therefore, be appreciated that from the description of reference Fig. 8 and Fig. 9 output has reduced.

In this case, owing to the rising along with frequency, the characteristic impedance of impedance circuit will descend, and be connected in parallel so impedance circuit changes over inductor 7 from open-circuit condition.If the constant of impedance circuit is arranged to when impedance circuit and inductor 7 are in parallel, the resonance frequency of resonant circuit improves, and then can guarantee such one-period (seeing " (b) " among Fig. 7 and Fig. 8), in this cycle, after resonance, there is electric current from rectifying device 4, to flow out.Therefore, can eliminate electric current and arrhea the period, in the whole cycle, can both reduce distortion from complete ignition period to deepening/ignition period.

Figure 13 is the circuit diagram of the present invention the 5th embodiment.In the present embodiment, constitute in the embodiment shown in fig. 4 first switching device by bipolar transistor 5 '-1 that is connected in parallel with each other and diode 5 '-2, as first switching device 5 ', constitute the second switch device by bipolar transistor 6 '-1 that is connected in parallel with each other and diode 6 '-2, as second switch device 6 '.The elementary winding 8 of driving transformer 18 is connected between the secondary winding 7-2 of fluorescent lamp 9 and isolating transformer as inductor 7.The secondary winding 18-2 of driving transformer 18 be connected first switching device 5 ' the base stage and emitter of bipolar transistor 5 '-1 between.Time group winding 18-3 of driving transformer 18 be connected second switch device 6 ' the base stage and emitter of bipolar transistor 6 '-1 between.For this layout, base current be provided for each switching device 5 ' and 6 '.

In the present embodiment, when taking off fluorescent lamp 9 and make open circuit, no current flows in the elementary winding 18-1 of driving transformer 18 is so the secondary winding 18-2 of driving transformer 18 and 18-3 go up no-output.Therefore, switching device 5 ' and 6 ' interior no base current flow, stop as the circuit oscillation of inverter circuit.

Because the vibration of inverter circuit can stop when taking off fluorescent lamp 9, thus with in addition the situation of when non-loaded, also carrying out switch compare, can reduce to be added to first and second switch elements 5 ' and 6 ' voltage.When no-load condition, the resistive component of impedance circuit is substantially zero.The kurtosis of resonant circuit is bigger when this state, and resonance potential is also higher.Therefore,, continue over a long time a vibration if when no-load condition, then switching device 5 ' and 6 ' on will add bigger resonance potential, cause switching device 5 ' and 6 ' damage or puncture.

If first and second switching devices 5 ' and 6 ' constitute by field-effect transistor, then the output of each secondary winding is offered on the path of corresponding grid source.Therefore, in this case, also can obtain and identical as mentioned above effect.

Figure 14 is the sequential chart of the 6th embodiment of the present invention.In the present embodiment, use the circuit arrangement of embodiment as shown in Figure 4.(when the voltage of representing with " (a) " among Figure 14 was low, inverter vibrated with predetermined frequency f 0, and when this frequency, input current becomes one by the indicated predetermined value of Figure 14 (b) when industrial AC power 1.When the voltage of industrial AC power 1 is higher, carry out the FM modulation, frequency is brought up on the frequency of dotted line indication.For this working method, the turn-on cycle of second switch device is configured to be shorter than the turn-on cycle under the situation of frequency f 0, has reduced the output voltage of inverter circuit, thereby fluorescent lamp 9 is arranged on the deepening state.

In this mode, when the output voltage of rectifying device 4 hangs down,, and impose a condition in advance fixed-frequency, elimination electric current under this frequency arrheas the period, thereby the electric current of power-factor improvement is provided.For this working method, can keep high power factor, reduce distortion.

Resonance effect between the electric capacity of the inductance of inductor 7 and second capacitor 11 has determined to be superimposed upon the waveform of the high-frequency ripple electric current on the alternating voltage, and can not be separately by 5 controls of first switching device.That is, must be arranged such period in the turn-on cycle of second switch device 6, in this period, the voltage of first capacitor 8 and second capacitor 11 is lower than the input voltage of rectifying device 4.This operation can be finished reliably.

Can also be applied to control shown in Figure 14 among the embodiment except that Fig. 4 embodiment.

Figure 15 is the circuit diagram of the 7th embodiment of the present invention.In this embodiment, similar to embodiment shown in Figure 13, mainly by bipolar transistor constitute in embodiment illustrated in fig. 4 first and second switching devices as first and second switching devices 5 ' and 6 ', the 3rd capacitor 19 that capacity is bigger and as the 4th less capacitor 21 of the series circuit of impedor coil 20 and capacity back replacement first capacitor 8 that is connected in parallel to each other.

The 3rd capacitor 19 needs bigger capacity to come stored energy, carries out smooth operation.Therefore, use electrolytic capacitor as the 3rd capacitor 19.But, if in this electrolytic capacitor, flow through the electric current that big ripple is arranged, useful life that then can shortening capatcitor.Therefore, in the present embodiment, flow into capacitor 19 be used for stoping high-frequency current to pass through capacitor 21 as impedor coil 20.

Therefore, in the present embodiment, by the series circuit of the 3rd capacitor 19 and coil 20 low frequency component is carried out smoothly, and the high-frequency ripple electric current is offered the 4th capacitor 21, to reduce the high-frequency ripple electric current that flows into the 3rd capacitor 19.

Mainly provide power supply to inverter circuit by the 4th capacitor 21.When the voltage on the 4th capacitor 21 descends, charge to the 4th capacitor 21 by the 3rd capacitor 19.

Figure 16 is the circuit diagram of the present invention the 8th embodiment.In this embodiment, second capacitor among Fig. 4 embodiment is improved.More particularly, by capacitor 22 and 23 and the series circuit formed as the switch element 24 of capacitor modifier constitute second capacitor.

When fluorescent lamp 9 being preheated and starts, make switch element 24 conductings, capacitor 23 is parallel on the capacitor 22, to increase the capacitance after synthesizing.For this operation, preheating/during start-up period, reduced resonance frequency, to prevent overvoltage, suppress the input current distortion.

Figure 17 is the circuit diagram of the present invention the 9th embodiment.In this embodiment, with connecting a diode 25 and replacing switch element 24 in embodiment illustrated in fig. 16 as the field-effect transistor 26 of capacitor modifier.

In this case, when field-effect transistor 26 ends, can not be to capacitor 23 chargings.When field-effect transistor 26 conductings, can be to capacitor 23 chargings.Note that what capacitor 23 always can discharge by diode 25.In this method, when only using capacitor 22, capacity reduces, and when using the parallel circuits of capacitor 22 and 23, increases easily, thereby has changed capacitance.

Embodiment shown in Figure 17 works in the mode identical with embodiment shown in Figure 16, and can obtain identical effect.

Figure 18 is the circuit diagram of the present invention the 10th embodiment.In this embodiment, resonant capacitor 22 among Figure 17 embodiment and capacitor 23 are connected in series.

In this case, when field-effect transistor 26 ends, can not be to capacitor 23 chargings.When 26 conductings of field effect pipe, can be to capacitor 23 chargings.Notice that capacitor 23 always can discharge by diode 25.In this mode, when only using capacitor 22, capacity reduces, and when using the parallel circuits of resonant capacitor 22 and capacitor 23, capacity increases, thereby can change capacity in fact.

Present embodiment can be worked in Figure 16 mode the same with embodiment shown in Figure 180, and can obtain the effect identical with it.

Figure 19 is the circuit diagram of the 11st embodiment of the present invention.Present embodiment comprises short-circuit detecting circuit 27b, be used for detecting short circuit phenomenon according to the output of the voltage detecting circuit 27a of the voltage of in the embodiment shown in fig. 4 detection first capacitor 8, and drive circuit 28, be used for controlling the vibration of first and second switching devices 5 and 6 according to the working condition of short-circuit detecting circuit 27b.

When the voltage of first capacitor 8 rises to a predetermined value or when higher, short-circuit detecting circuit 27b determines that this is that fluorescent lamp 9 is removed, and makes first and second switching devices 5 and 6 failures of oscillations by drive circuit 28, thereby stops the vibration of inverter circuit.

In this mode, when being removed, fluorescent lamp 9, prevented from overvoltage is added on first and second switching devices 5 and 6 by making the inverter circuit failure of oscillations.

Voltage detecting circuit 27a can also detect the lamp current in the fluorescent lamp 9.When lamp current arrives predetermined value or when higher, for example the electric current in the elementary winding 7-1 of inductor 7 is to a predetermined value or more hour, voltage detecting circuit 27a can determine that fluorescent lamp 9 is to be removed.

In addition, short-circuit detecting circuit 27b also can detect the modulating voltage of fluorescent lamp 9.When modulating voltage arrives a predetermined value, when perhaps higher, short-circuit detecting circuit 27b can determine that fluorescent lamp 9 is to be removed.

Figure 20 is the circuit diagram of the present invention the 12nd embodiment.In the present embodiment, between the output of the rectifying device 4 among the embodiment of second capacitor 11 ' be connected Fig. 4.

The effect of present embodiment is described with reference to Figure 21 A to 21E below.Figure 21 A to 21E is corresponding to Fig. 6 A to 6E and Fig. 7.At period (a) (Figure 21 A), electric current flows to switching device 5 ' and the elementary winding 7-1 of inductor 7 from first capacitor 8.

At period (b) (Figure 21 B), the elementary winding 7-1 of inductor 7, first capacitor 8, second capacitor 11 ', the elementary winding 7-1 of parasitic diode 6 '-2 and inductor 7 forms closed circuit.In this period, the inductor 7 and second inductor 11 ' generation series resonance.Since the capacity setting of first capacitor 8 become greatly greater than second capacitor 11 ' capacity, so in this case, condition of resonance mainly by the inductance of inductor 7 and second capacitor 11 ' capacity determine.

At period (c) (Figure 21 C), when the 6 ' conducting of switching device device, and the polarity of resonance current is conversely the time, and resonance current flows with the direction opposite with the period (b).

At period (d), cause is in the reason of the resonance of period (c), when second capacitor 11 ' on voltage when dropping to the output voltage that is lower than rectifying device 4 gradually, there is electric current to flow to the elementary winding 7-1 of first capacitor 8, inductor 7 and the circuit of second switch device 6 ' formation, to 8 chargings of first capacitor from rectifying device 4.At this moment, as mentioned above since the capacity of first capacitor 8 greatly greater than second capacitor 11 ' capacity because two condenser impedances relation, almost do not have electric current flow into second capacitor 11 '.

At period (e) (Figure 21 D), because of storing energy on the inductor 7, so there is electric current to flow into parasitic diode 5 '-2 and first capacitor 8.After this, get back to the period state of (a).

As mentioned above, the 12nd embodiment works in the mode identical with Fig. 4 embodiment, can reduce distortion, and can obtain identical effect.

According to experiment, shown in Figure 22 B, to compare with the input voltage vin shown in Figure 22 A, the distortion of input current Iin has reduced, and compares with the input voltage vin of Figure 23 A, and the fluctuation of the lamp current IL shown in Figure 23 B is also little.

In addition, second switch device 6 ' drain-source voltage VDS and identical with shown in Figure 24 A of the waveform of leakage current ID.In the high period of the output voltage of rectifying device 4 (b), the waveform of voltage VDS and electric current I D identical with shown in Figure 24 B.In the low period of the output voltage of rectifying device 4 (c), the waveform of voltage VDS and electric current I D identical with shown in Figure 24 C.

In addition, the waveform of the output voltage V 4 of rectifying device 4 and output current I4 is shown in Figure 25 A.In the lower period of the voltage of industrial AC power 1 (b), the waveform of voltage V4 and electric current I 4 is shown in Figure 25 B.When higher period (c) of the output voltage of rectifying device (c), the waveform of voltage V4 and electric current I 4 is shown in Figure 25 C.

Figure 26 is the circuit diagram of the present invention the 13rd embodiment.In the present embodiment, first capacitor 8 ' be connected to second switch device 6 ' side of Figure 20 embodiment.

When the 5 ' conducting of first switching device, have electric current flow through rectifying device 4, first switching device 5 ', the elementary winding 7-1 of inductor 7, first capacitor 8 ' and closed circuit of forming of rectifying device 4, therefore, to first capacitor 8 ' charging.The current flowing of one power-factor improvement is arranged this moment.

When first switching device 5 ' by the time, have electric current flow through first capacitor 8 ', diode 6 '-2, the elementary winding 7-1 of inductor 7 and the closed circuit of first capacitor 8 ' formation.

When the 6 ' conducting of second switch device, have electric current flow through first capacitor 8 ', the elementary winding 7-1 of inductor 7, second switch device 6 ' and the closed circuit of first capacitor 8 ' formation.

When second switch device 6 ' by the time, have regenerative current flow through the elementary winding 7-1, diode 6 '-2, second capacitor 11 of inductor 7 ', first capacitor 8 ' and the closed circuit that forms of the elementary winding 7-1 of inductor 7.Therefore, second capacitor 11 ' on voltage raise.When the 5 ' conducting of first switching device, second capacitor 11 ' on voltage drop to the output voltage that equals rectifying device 4.

As mentioned above, the 13rd embodiment works in the mode identical with the embodiment of Figure 20, and can reduce distortion, obtains identical effect.

Figure 27 is the circuit diagram of the present invention the 14th embodiment.Present embodiment is similar to embodiment shown in Figure 26.But in the present embodiment, a capacitor 11_ as the output of rectifying device 4 and second capacitor 11 between pair of switches device 5 and 6 ' part or all.With the be connected in parallel identical diode 27 of output polarity of a direction and rectifying device 4 of capacitor 11_.In the present embodiment, when resonance effect was formed by capacitor 11_ basically, second capacitor 11 was used to pass through high frequency waves.In addition, can move with the resonance that the combination of capacitor 11_ and 11 ' is scheduled to.And, these capacitors can be parallel-connected to any one second capacitor bank in the switching device, the resonance action of being scheduled to by three capacitors.

In this embodiment, can between the positive-negative output end of rectifying device 4 and switching device are to 5 and 6, two or more capacitors 11_ be set.

Figure 28 shows the situation that the present invention is applied to lighting device.Referring to Figure 28, reference number 261 expression lightings, it is directly mounted on the ceiling.The lighting apparatus for discharge lamp that is made of the supply unit according to the 2nd to 14 embodiment is set in the light fixture 261.Notice that lighting apparatus for discharge lamp must not be arranged in the light fixture 261, can be arranged on light fixture 261 outsides yet.In addition, though the lighting device in the present embodiment belongs to that class that is directly installed on the ceiling, also can adopt another kind of means.

The present invention is not limited to the foregoing description.As, for rectifying device 4, can replace the high speed rectifying device with the low speed rectifying device, can be connected to high speed diode the outlet side of this low speed rectifying device.In addition, the foregoing description also can suitably make up each other.As, can change the running of each derailing switch conduction and cut-off frequency and the running of change turn-on cycle rate.

The the 15th to 24 embodiment that the 1st to 14 embodiment supply unit is further improved is described below.

The above-mentioned viewpoint of consideration is described below ground instance is improved the several embodiment that obtain.

Referring now to Figure 29 the 15th embodiment of the present invention is described.The industrial AC power of reference number 101 expressions.The filter circuit 105 that is made of likes such as common mode choke coil 102, choking-winding 103, capacitors 104 is connected on this AC power 101.Rectifying device 106 as full-wave rectifier is connected on the filter circuit 105.This rectifying device is by constituting as the diode with speed-sensitive switch characteristic.In addition, first and second switching devices 107 and 108 are connected in series between the output of rectifying device 106.

The series circuit as the smmothing capacitor of first capacitor 110 bigger as the elementary winding 109-1 of the leakage magnetic type isolating transformer of inductor 109 and capacity is parallel-connected on first switching device 107.The output frequency of 110 pairs of rectifying devices 106 of first capacitor is smoothing effect.

In the present embodiment, form output circuit at inductor 109 two ends.That is, the secondary winding 109-2 of inductor 109 is used as output circuit., for example a fluorescent lamp is connected on the secondary winding 109-2 as load with a discharge lamp 111.Filament is carried out pre-warmed capacitor 112 to be connected between the filament of discharge lamp 111.In the present embodiment, also the current-limiting impedance of the leakage inductance of inductor 109 as discharge lamp 111.

What capacity was less is parallel-connected on the second switch device 108 as the resonant capacitor of the second capacitor 113 elementary winding 109-1 by inductor 109.The capacity of second capacitor 113 is little more than the capacity of first capacitor 110.The inductance of second capacitor 113 and inductor 109 is with the switching frequency resonance of switching device 107 and 108.

The control unit of reference number 114 expression control switch devices 107 and 108 conduction and cut-off operations.Control unit 114 makes switching device to 107 and 108 frequency alternate conduction with substantial constant/end, and the turn-on cycle of control switch device 107, and making the current peaks that flow in the switching device 107 is predetermined value.In the present embodiment, control unit comprise the checkout gear 114-1 that is used for electric currents in the sense switch device 107, the period (a) shown in Figure 31 A to the output of checkout gear 114-1 carry out rectification with the device 114-2 of output current, be used for comparator 114-4 that the value of the output of rectifying device 114-2 and derived reference signal 114-3 is compared and the oscillation device 114-5 that exports pick-off signals according to the output of comparator 114-4 to switching device 107.In the present embodiment, the buffer that oscillation device 114-5 comprises the trigger 114-7 of the output of oscillator 114-6, reception oscillator 114-4 and comparator 114-4, receive the Q of trigger 114-7 and Q output respectively is to 114-8a and 114-8b, and is inserted in switching device 107 on the high-pressure side and the spacer assembly 114-9 such as transformer or optical coupler between the buffer 114-8a.

In the present embodiment, can change output frequency or the turn-on cycle of oscillation device 114-5 according to external control signal.In this case, for example, can change the output frequency of oscillator 114-6.Notice that oscillation device 114-5 can be made of the integrated circuit as critical piece.Oscillation device 114-5 is not limited to a kind of in the present embodiment, can also do various variations.

The effect of present embodiment is described below with reference to Figure 30 A to 33.In Figure 30 A to Figure 31 C, Figure 30 A and 31A show the voltage on second capacitor 113; Figure 30 B and Figure 31 B show the electric current in first switching device 107; Figure 30 C and 31C show the electric current in the second switch device 108.Figure 30 A to 30C is corresponding to higher relatively period of smooth dc voltage not.Figure 31 A to 31C is corresponding to the lower period of this voltage.Referring to Figure 30 A to 31C, time shaft t expands corresponding to switching frequency.Figure 38 and 39 shows voltage between the output of rectifying device 106 and the lamp current in the discharge lamp 111 respectively.Referring to Figure 38 and 39, time shaft t is corresponding to the frequency of alternating current source 101.

The basic operation situation of present embodiment is identical with second embodiment shown in Figure 5.In the present embodiment, when the peak value of the electric current that discharges by switching device 107 when first capacitor 110 reached predetermined value, when promptly reaching the value (the level A in Figure 30 B and the 31B) of derived reference signal 114-3, oscillation device ended switching device 107.For this operation, the closed circuit that the parasitic diode of inductor 109, second capacitor 113 and second switch device 108 forms produces resonance, and when 108 conductings of second switch device, resonance current is reverse.In this case, be controlled on the predetermined value owing to before resonance takes place, flow through the peak value of the electric current of switching device 107, so the peak value of resonance potential also is a constant.Because so the voltage constant on first capacitor 110 shown in figure 32, does not change and analogue if supply voltage is sent out, then the voltage of rectifying device 106 also keeps constant.Therefore, owing to the voltage constant that is added on switching device 107 and 108, so switching device 107 and 108 can be not breakdown owing to overload.In addition, as shown in figure 33, lamp current contains low frequency (incoming frequency of rectifying device) ripple hardly.Notice that in this case the same with as shown in Figure 3 situation, it is sinusoidal wave that input current waveform belongs to.

At the peak value of the output voltage (not level and smooth direct voltage) of rectifying device 106 in the less cycle (Figure 31 A to 31C), the ON time of first switching device 107 is shorter than at this peak than the ON time in the large period, so the turn-on cycle of second switch device 108 correspondingly prolongs.

Figure 34 is the circuit diagram of the present invention the 16th embodiment.The reference number identical with Figure 29 represented identical parts among Figure 34, and (being equally applicable to the following example) just omitted in the description of these reference numbers.The difference of present embodiment and Figure 29 embodiment is control unit 161.Control unit 161 comprises the current sensing means 161-1 that detects electric currents in the second switch device 108 and according to the rectifying device 161-2 of the detection signal export resonance electric current initial value of current sensing means 161-1.Shown in Fig. 6 B, rectifying device 161-2 carries out the electric current that rectification output is flowed when the period (b).Control unit 161 also comprises a time-delay mechanism 161-3, and it keeps the output of rectifying device 161-2 and in one or several cycle after keeping operation, during first switching device 107 is regularly connected, carries out output function.Control unit 161 further comprises the comparison means 161-5 of value comparison of the output of a time-delay mechanism 161-3 and reference signal 161-4 and the oscillation device 161-6 that first switching device 107 is ended according to the output of comparison means 161-5.Oscillation device 161-6 can be as shown in figure 29 a kind of.

In the present embodiment, detect the peak value of the discharging current that flows through in first switching device 107, its initial value as the resonant circuit that flows through second switch device 108.Shown in Fig. 6 A to 6E, these values equate.Therefore, as shown in scheming, according to the control operation among the embodiment shown in Figure 29, make one or several cycle of control lag, but can obtain and identical effect embodiment illustrated in fig. 29 equally the peak value of the discharging current that flows through second switch device 108.

Figure 35 is the circuit diagram of the present invention the 17th embodiment.Present embodiment also is different with control unit 171 embodiment illustrated in fig. 29.More particularly, except the parts that the control unit 114 of Figure 29 comprises, control unit 171 also comprise between the output that is used to detect rectifying device 106 voltage promptly the voltage check device 117-1 of voltage between first and second capacitors 110 and 113, be used to take out the detection signal of voltage check device 171-1 and by as the device 171-2 with this signal delay a period of time such as integrated circuit, and the comparator 171-4 that is used for the value comparison of the output of handle assembly 171-2 and derived reference signal 171-3.Device 171-2 can adapt to the frequency variation of the low-frequency voltage of rectifying device 106 output frequencies no better than.Oscillation device 114-5 shortens the turn-on cycle of second switch device 10 according to the signal of comparator 171-4 when output voltage increases, and prolongs the turn-on cycle of second switch device 108 when output voltage reduces.Therefore, in the present embodiment, can change the switching frequency of first and second switching devices 107 and 108.

The effect of present embodiment is described below with reference to Figure 36 and 37.

Figure 36 and 37 illustrates the electric current in the second switch device 108.Figure 36 shows the electric current under the voltage condition with higher between the output of rectifying device 106.Figure 37 shows the electric current under the lower situation of this voltage.Control unit 171 utilizes the effect of voltage check device 171-1, and the voltage between the output of rectifying device 106 shortens the turn-on cycle of second switch device 108 when promptly the voltage between first and second capacitors 110 and 113 two ends begins to have low-frequency voltage to increase.Therefore, shortened the charge cycle of first capacitor 110, charge volume is reduced.For this reason, the low-frequency voltage in the voltage between first and second capacitors 110 and 113 reduces.In contrast, when the voltage between the output of rectifying device 106 when promptly the low-frequency voltage in the voltage between first and second capacitors 110 and 113 reduces, the turn-on cycle of second switch device 108 is prolonged.Therefore, prolonged charge cycle, charge volume is increased first capacitor 110.

Thereby, when the voltage between rectifying device 106 outputs when promptly the voltage between first and second capacitors 110 and 113 begins to change owing to the variation of the variation of the voltage of AC power 110, load and similar variation, control unit 171 is worked in the above described manner, voltage control on a steady state value.

Figure 38 A to 38E shows the result of the test of present embodiment.Figure 38 A shows the voltage on first capacitor 110; Figure 38 B shows the voltage at rectifying device 106 two ends; Fig. 3 C shows the distortion factor of input current; Figure 38 D shows lamp power; Figure 38 E illustrates the turn-on cycle of second switch device 108.Abscissa is represented the voltage (V) of AC power.

Be experimental condition below:

AC power 101:200V (effective value), 50Hz

Discharge lamp 111:40W fluorescent lamp * 2

(FLR40SW/M/36 that Toshiba light fixture company produces)

First and second switching devices 107 and 108 switching frequency: about 35KHz

The first capacitor 110:220 μ F

The second capacitor 113:16.6 μ F

As among Figure 38 A to 38E as can be seen, even increase/reduce with respect to the voltage on rated voltage 200V first capacitor 110, the peak value of the electric current in first switching device 107 always is set on the predetermined value, and according to the turn-on cycle (Figure 38 E) of the voltage control second switch device 108 at rectifying device 106 two ends.For this operation, can remain on the voltage at rectifying device 106 two ends (Figure 38 B) on the substantially invariable voltage 560V.Therefore also can remain on lamp power (Figure 38 D) on the substantially invariable power 60W.In addition, can be maintained at about the distortion factor of input current (Figure 38 C) is on 6.5% the constant substantially value.From rising to relation when being higher than rated voltage, the voltage of the AC power 101 shown in Figure 38 A and the 38E is appreciated that the turn-on cycle of second switch device 108 has shortened, to reduce the voltage of first capacitor 110.

Figure 39 is the circuit diagram of the present invention the 18th embodiment.In the present embodiment, except operation embodiment illustrated in fig. 29, also change the predetermined value that determines first switching device, 107 turn-on cycles according to the voltage between rectifying device 106 outputs.More particularly, control unit 411 comprises the voltage check device 411-2 of the voltage between the output that is used to detect rectifying device 106 and the detection signal of voltage check device 411-1 is carried out rectification, and output has the output device 411-1 of the composite signal of scheduled time constant.Change the output of rectifying device 114-2 according to the output of output device 411-1.More particularly, when the detection signal of voltage check device 411-1 begins to raise, just change the output of rectifying device 114-2.Therefore, in this case, it is quite short that the turn-on cycle of first switching device 107 just becomes, and resonance potential changes.In addition, when the detection signal of voltage check device 411-1 begins to raise, carry out opposite operation.For this operation, can make the voltage constant of the output of rectifying device 106.

Figure 40 is the circuit diagram of the present invention the 19th embodiment.In the present embodiment, the parallel circuits of bipolar transistor and diode as first and second switching devices 107 ' and 108 '.In addition, saturating current transformer 422 device as the peak value of the electric current that detects first switching device 107 ' interior.Promptly the input winding 422-1 of saturating current transformer 422 is connected in series on the input winding 109-1 of inductor 109.Its output winding 422-2 and 422-3 be separately positioned on switching device 107 ' and 108 ' base stage and emitter between.Do not illustrate in the drawings though regulate the parallel circuits of impedance by being used to of constituting as capacitor and diode, if necessary, can be concatenated into them respectively on output winding 422-2 and the 422-3, can be parallel-connected to discharge circuit on this capacitor.

In the present embodiment, be used to detect on the rectifying device 106 voltage promptly first and second capacitors 110 constitute by rectifier 423-1, smmothing capacitor 423-2 and bleeder circuit 423-3 with 113 mutually alive voltage check device 423.This embodiment further comprises the error amplifier 425 of the value of the output that receives bleeder circuit 423-3 and reference source 424, according to the branch pressure voltage device 426 and the transistor 427 of the output signal output of error amplifier 425.Base current by the output control transistor 427 of bleeder circuit 426 changes its conductance.In this mode, transistor 427 is worked in the mode identical with variable resistance, with control switch device 108 ' turn-on cycle.

In the present embodiment, when switching device 107 ' when interior value of current flowing arrived a predetermined value, current transformer 422 was saturated.Because switching device 107 ' and interior mobile electric current increases with the resistance of voltage on first capacitor 110 and inductor 109 basically, coincides so can be in advance the 422 saturated times of saturating current transformer be arranged to the time that peak value with the mobile electric current of switching device 107 ' interior arrives predetermined value.When current transformer 422 is saturated, switching device 107 ' end, and switching device 108 ' conducting.In addition, when current transformer 422 because of switching device 108 ' when interior mobile electric current is saturated, switching device 108 ' end, and switching device 107 ' conducting.Then, repeat this operation.Therefore, in the cycle of amplifying without the peak value of level and smooth direct voltage of rectifying device 106, first capacitor 110 and second switch device 108 ' interior value of current flowing is bigger.As a result, current transformer is comparatively fast saturated, therefore, switching device 108 ' turn-on cycle be provided with shortlyer.In contrast, at the peak value without level and smooth direct voltage of rectifying device 106 in the less cycle, switching device 108 ' turn-on cycle be provided with longlyer.For this operation, according to relation shown in Figure 30 control first and second switching devices 107 ' and 108 ' turn-on cycle.If because of outside surge voltage effect has overcurrent flows, then current transformer 422 is saturated fast when conducting is operated, makes second switch device 108 ' end, thereby prevent that overcurrent from continuing to flow.

Simultaneously, detect the magnitude of voltage at rectifying devices 106 two ends, according to conductance based on the error signal oxide-semiconductor control transistors 427 of predetermined value by voltage check device 423.Just specifically, as when the voltage at rectifying device 106 two ends reduces because of the variation of the variation of supply voltage or load, reduce the conductance of transistor 427.When the conductance of transistor 427 reduces, its resistance value increases, prolonged second switch device 108 ' turn-on cycle.For this operation, also prolonged charging interval, so that the voltage at first capacitor, 110 two ends to be provided to first capacitor 110.

Thereby, in the present embodiment, can make resonance potential constant, also can make the voltage constant at first and second capacitors 110 and 113 two ends.Therefore, can prevent because of mains voltage variations, load variations etc. similar former thereby cause the change in voltage at first capacitor, 110 two ends.

In the example according to present embodiment not, though because smooth effect, the voltage of first capacitor 110 is also almost constant for switching frequency, and this voltage will change along with analogue such as mains voltage variations.For this reason, if for example mains voltage variations and rising, the voltage of first capacitor 110 will be constant at the voltage constant that is higher than predetermined value.If supply voltage reduces, the voltage of capacitor 112 will be lower than on the voltage of predetermined value invariable.When this voltage is invariable on high voltage, on switching device, will add too high voltage.When this voltage is invariable on low-voltage, then can not provide predetermined bearing power.

In the present embodiment, can omit the device that is used to detect and control rectifying device both end voltage value.

Figure 41 is the circuit diagram of the present invention the 20th embodiment.Figure 41 only shows the major part of present embodiment, and remainder has omitted.Notice that the structure of abridged part can be identical with embodiment shown in Figure 40.In the present embodiment, the device 431 of the device of the output voltage (input voltage of rectifying device 106) that detects AC power 101 as control switch device 108 ' turn-on cycle.In order to detect the output voltage of AC power 101, rectifier 431-1 and 431-2 are connected to the output of AC power 101, and the output of rectifier 431-1 and 431-2 is input to time constant circuit 431-3.The output of time constant circuit 431-3 be input to Figure 40 in identical error amplifier 425.Similar to the error amplifier of Figure 40, error amplifier 425 is made comparisons the value of the output of time constant circuit 431-3 and derived reference signal 424, and control Driver Circuit 426 and transistor 427.

Therefore, in the present embodiment,, also can make output voltage constant even the output voltage of AC power changes.

Figure 42 is the circuit diagram of the present invention the 21st embodiment.In the present embodiment, when the output current that detects rectifying device 106 flows one period scheduled time, second switch device 108 is ended.More particularly, current sensing means 411, time-delay mechanism 442, derived reference signal 443 and comparator 444 are set in addition and control oscillation device 114-5.Owing to, can easily understand the effect of present embodiment, so omitted description to effect according to above description.Though do not illustrate among the figure, can be with making resonance potential constant with the same control device shown in Figure 29,34 or 39.

Figure 43 is the circuit diagram of the present invention the 22nd embodiment.In the present embodiment, according to offering as the power control switching device of the fluorescent lamp 111 of load to 107 and 108 turn-on cycle.More particularly, current sensing means 451 and voltage check device 452 are set, by the control device 153 control oscillation device 114-5 of the detection output that receives these checkout gears.In the present embodiment, equally can be with making resonance potential constant with Figure 29,34 or 39 identical control device.

Owing to can from foregoing description, easily understand the effect of present embodiment, therefore omit description to effect.In the present embodiment, can be only come the control switch device to 107 and 108 turn-on cycle according to lamp current or modulating voltage.In addition, also can only control the turn-on cycle of one of them switching device.And, can change switching frequency.

Figure 44 is the circuit diagram of the present invention the 23rd embodiment.Figure 44 has only shown the major part of present embodiment, has omitted remaining part.In the present embodiment, the annexation between first and second capacitors 110 and 113 is conversely on the vertical direction for Figure 29.Therefore, first and second derailing switches 107 and 108 annexation are also opposite.In addition, in the present embodiment, flow to first switching device by inductor 109 after 107 1 periods scheduled times at the discharging current of first capacitor 110, first switching device 107 ends.More particularly, present embodiment comprises that current sensing means 461, is in order to detect detected value that current sensing means 461 obtains whether by zero cross point and the comparison means 462 that rises and be used for detecting the timing device 463 that detected value is controlled oscillation device 114-5 after by zero cross point at comparison means 462.

The effect of present embodiment is described with reference to Figure 45.Figure 45 illustrates the electric current that flows in first switching device 107.The zero crossing time t1 that comparison means 462 detects among Figure 45.Timing device 463 ends first switching device 107 after zero crossing time t1.Therefore, as from foregoing description, seeing, make resonance potential keep constant.

In the present embodiment, after the electric current that flows in the parasitic diode of first switching device 107 stops to flow, can make first switching device 107 by one period scheduled time.In this case, if first switching device 107 is a field-effect transistor, then can not use circuit shown in Figure 44 with changing.If first switching device 107 is a bipolar transistor, the time point in the time of then can detecting the electric current that flows in the cross-couplings diode and stop to flow.

Figure 46 is the circuit diagram of the present invention the 24th embodiment.In the present embodiment, second switch device 108 ends after 108 1 sections preset times of electric current inflow second switch device are arranged.More particularly, present embodiment comprises the current sensing means 481 that is used to detect the electric currents that flow in the second switch device 108, is used for detected value to current sensing means 481 and carries out the integrating gear 482 of integration and the comparison means 483 that the output of integrating gear 482 and reference value are made comparisons.Control oscillation device 114-5 by the output of comparison means 483.Note, for instance, signal that frequency is constant of vibration dress 114-5 output.

The effect of present embodiment is described with reference to Figure 47 A to 37C.Figure 47 A shows the electric current that flows in the second switch device 108; Figure 47 B shows the electric current that flows in first switching device 107; Figure 47 C shows the output current of rectifying device 106.For example, if when comparison means 483 is arranged in integrated value and arrives the dash area zone of the current waveform shown in Figure 47 A, output signal is ended second switch device 108, and then shown in Figure 47 C, rectifying device 106 can provide electric current reliably.That is, after peak value appearred in resonance current, rectifying device 106 can provide electric current.For this operation, can realize high input power factor, reduce the input current distortion, obtain constant output voltage.

Figure 48 is the perspective view that the present invention is applied to lighting device.Reference number 201 expressions belong to the lighting that directly is installed to type on the ceiling.Discharge powder 111 is installed on the light fixture 201.Supply unit as one of the 15th to 24 embodiment is being set as lighting apparatus for discharge lamp in the light fixture 201.Notice that lighting apparatus for discharge lamp might not need to be arranged in the light fixture 201, it can be arranged on light fixture 201 outsides.Directly be installed to type on the ceiling though the lighting device of present embodiment belongs to, also can use another kind of type.

Improvement of the present invention is not limited to the foregoing description.For example can replace the high speed rectifying device, can be connected to high speed diode the outlet side of this low rectifying device with the low speed rectifying device.In addition, can also suitably make up mutually the foregoing description.

Figure 49 shows the structure of the major part of the supply unit that is applied to DC load circuit 551.

In this structure, DC load circuit 551 is connected to transformer 7 by rectification circuit 550 " the secondary winding side on, the elementary winding of transformer be connected to above-mentioned first and second switching devices 5 ' and 6 ' node and the node of above-mentioned first and second capacitors 8 and 11 on.

Ordinary electronic equipment and circuit that this DC load circuit 551 comprises ohmic load and needs DC power supply.

Therefore, as mentioned above,, can obtain following effect according to the present invention.

According to of the present invention first or second aspect, because rectifying device can provide input current whole basically on the not smooth dc voltage cycle of rectification, so can obtain level and smooth output, and the waveform of input current that can make AC power reduces distortion to sinusoidal wave similar.

According to the 3rd aspect of the present invention,, regulate output voltage by changing the turn-on cycle of one of switching device, can change the energy that is stored in the inductor.In addition, because the switching frequency substantial constant, so, can not increase switching loss even produce situation about improving as switching frequency yet.

According to the 4th aspect of the present invention,, can regulate output voltage with the identical method in the present invention the 3rd aspect by changing the right turn-on cycle rate of switching device.In addition, the turn-on cycle that changes switching device by the peak value according to the output of the voltage of the every half period of AC power can obtain enough smooth output voltages.

According to the of the present invention the 5th and the 6th aspect, by changing switching frequency, can change the absolute turn-on cycle of another switching device, can change output voltage too.

According to the 7th aspect of the present invention, because the form of second capacitor with parallel connection is connected on another switching device and the inductance, so can realize simple layout.

According to the 8th aspect of the present invention, because second capacitor is connected between the output of rectifying device, similar with the 7th aspect of the present invention, can realize simple layout.

According to the 9th aspect of the present invention and since second capacitor be connected rectifying device and switching device between, similar with the 7th aspect of the present invention, can realize simple layout.

According to the 10th aspect of the present invention, output circuit comprises the impedance circuit that impedance raises and reduces with frequency.Therefore, even frequency of oscillation raises, the impedance that reaches the circuit that reduces the distortion purpose still can keep less, so can obtain enough little resonance current.

According to the 11st aspect of the present invention, because when load was removed, driving transformer made the first and second switching device failures of oscillations, can prevent to be added to the increase of voltage on first and second switching devices.

According to the 12nd aspect of the present invention, can reduce output pulsation, improve luminous efficiency, thereby reduce light beats.

According to the 13rd aspect of the present invention, owing in the predetermined period of discharge lamp start-up operation, be arranged to be shorter than the connection cycle of lamp the admittance cycle of another switching device, so after abundant preheating, just start discharge lamp to filament.Therefore, can prevent the discharge lamp shortening in useful life.

According to the 14th aspect of the present invention, improved luminous efficiency, reduce the fluctuation of lamp current, thereby reduced light beats.

According to the of the present invention the 15th and 16 aspects because rectifying device can provide input current whole basically on the not smooth dc voltage cycle of rectification, so the waveform of input current that can make AC power with sinusoidal wave similar, the reduction distortion.In addition, owing to directly control the interior electric current of first switching device of decision resonance potential amplitude,, perhaps be steady state value so can be controlled at resonance potential on the arbitrary value.

In according to the supply unit aspect the of the present invention the 17th, make the peak value of the electric current that flows in first switching device become a predetermined value because the turn-on cycle of first switching device is controlled to, so can make resonance potential constant.This operation has prevented that too high voltage is added on the switching device and makes its puncture.And it is unnecessary that this operation also uses the switching device with high-breakdown-voltage to become, and therefore, prevented the increase of cost.

In according to the supply unit aspect the of the present invention the 18th, because the integrated value of electric current mobile in first switching device is controlled on the predetermined value, so can obtain identical with the 17th aspect basically effect.

In according to the supply unit aspect the of the present invention the 19th, because the initial value of resonance current mobile in first switching device is controlled on the predetermined value, so can obtain identical with the 17th aspect basically effect.

In according to the supply unit aspect the of the present invention the 20th, change the electric current predetermined value that determines the first switching device turn-on cycle according to the magnitude of voltage on first and second switching devices.Therefore, regardless of the variation of supply voltage, the similar variations such as variation of load, the voltage on first and second switching devices can be accomplished invariable.

In according to the supply unit aspect the of the present invention the 21st, owing to after one period scheduled time the second switch device is ended there being electric current to flow through the second switch device, so can provide charging current to first capacitor reliably.Therefore, can improve power factor, reduce the input current distortion.

In according to the supply unit aspect the of the present invention the 22nd, owing to after the peak value of resonance current flows, make the second switch device end one period scheduled time, so can provide charging current to first capacitor reliably.Therefore, can obtain the effect identical with the 21st aspect.

In the supply unit aspect the 23rd according to the present invention, owing in rectifying device, have the I/O electric current to flow through one period scheduled time, so can obtain and the identical effect in the 21st and 22 aspects.

In according to the supply unit aspect the of the present invention the 24th, because according to the turn-on cycle of controlling the second switch device corresponding to the magnitude of voltage of the voltage on first capacitor, so can make the voltage constant on first capacitor by the charge volume of control first capacitor.For this mode of operation,, and can make the voltage that is added in the load also invariable even mains voltage variations also can make the voltage constant on first capacitor.

In according to the supply unit aspect the of the present invention the 25th, owing to control the turn-on cycle of second switch device, so the charge volume by control first capacitor can make the voltage constant on first capacitor according to AC supply voltage.For this mode of operation,, and can make the voltage that is added in the load also invariable even mains voltage variations also can make the voltage constant on first capacitor.

In according to the supply unit aspect the of the present invention the 26th, owing to control the turn-on cycle of second switch device according to the output of output circuit, so can make the power invariability that offers load.

According to the 27th aspect of the present invention, for the present invention is applied in the lighting apparatus for discharge lamp, the load of discharge lamp as this supply unit.Therefore, further reduced output pulsation,, reduced light beats to improve luminous efficiency.

According to the 28th aspect of the present invention,, the lighting apparatus for discharge lamp of the 21st aspect is arranged in the device body for the present invention is applied in the lighting device.Therefore, improve luminous efficiency, reduced the distortion of lamp current, reduced light beats.

In according to the supply unit aspect the of the present invention the 29th, in the alternating voltage of rectifying device rectification, form the high frequency voltage that the resonator system by resonant capacitance device and inductance device produces.For this operation, it makes rectifier output voltage equal input voltage, even guaranteed that input current is also arranged when alternating voltage is low, thereby reduces the input current distortion, reduces the input current harmonics component.

For person skilled in the art, can obtain other advantage and improvement very soon.Therefore, the present invention is in its far-ranging various aspects, is not subjected to the restriction of these concrete detailed rules and regulations of illustrating and describing herein.Thereby, under the scope that does not break away from essence of the present invention that claims and its equivalents limited and general inventive concept, can produce various follow-on supply units.

Claims (18)

1. supply unit comprises:

Rectifying device is used for the input voltage of AC power is carried out rectification, and exports not level and smooth direct voltage on pair of output;

Be one another in series the output that is connected described rectifying device between first and second switching devices, they alternately switch on and off the output voltage of described rectifying device with the frequency that is higher than output voltage frequency;

Being one another in series is connected first capacitor and inductor series circuit between the described first switching device two ends, and it carries out smoothly the output voltage frequency of described rectifying device;

Second capacitor is used for the conduction and cut-off operation generation resonance of described inductor according to first and second switching devices; And

Output circuit is used for obtaining high frequency output based on the resonance of described inductor and the generation of described second capacitor.

2. supply unit comprises:

One rectifying device is used for alternating voltage is carried out rectification, and output is without level and smooth direct voltage;

First and second switching devices that are one another in series and connect, they are with the frequency alternate conduction of the output frequency that is higher than described rectifying device/end, so that the output of described rectifying device conversion;

One parallel connection is connected to first capacitor on first switching device, at described second switch break-over of device during the cycle, the output of described rectifying device is charged to described first capacitor by described second switch device, described first capacitor carries out smooth operation to the output frequency of described rectifying device, in the described first switching device turn-on cycle, described first capacitor discharges electric charge by described first switching device;

One is plugged on the node of described first and second switching devices and the inductor between described first capacitor, and it is by the charging and discharging currents of described first capacitor;

One second capacitor, be used for according to described first and second switching devices lead love/by the operation producing resonance with described inductor;

One control unit, the discharging current that is used for discharging according to described first capacitor and flow in described first switching device is controlled the turn-on cycle of described first switching device, to control the resonance potential value that described inductor and described second capacitor produce; And

One output circuit is used for obtaining high frequency output based on the resonance of described inductor and the generation of described second capacitor.

3. device as claimed in claim 1 or 2 is characterized in that further comprising switch controlling device, is used to make described first and second switching devices with constant basically frequency conduction and cut-off, and can change the turn-on cycle rate of described switching device.

4. as claim 1 or described device, it is characterized in that, further comprise switch controlling device, be used to make described first and second switching devices to end with substantially invariable frequency conducting, and can change the turn-on cycle rate of described first and second switching devices, described switch controlling device shortens the turn-on cycle of described second switch device when the electric output peak value of the every half period of described AC power is big, when this peak value hour, prolong this turn-on cycle.

5. device as claimed in claim 1 or 2 is characterized in that, further comprises the switch controlling device that can change the described first and second switching device conduction and cut-off frequencies.

6. device as claimed in claim 5, it is characterized in that described first and second switching devices are in the cycle less corresponding to the peak value of the output voltage of described rectifying device, with lower frequency conduction and cut-off, when this peak value increases, with higher frequency conduction and cut-off.

7. device as claimed in claim 1 or 2 is characterized in that, described second capacitor is parallel-connected on described second switch device and the described inductor.

8. device as claimed in claim 1 or 2 is characterized in that, described second capacitor is arranged between the output of described rectifying device.

9. device as claimed in claim 1 or 2, it is characterized in that, described output circuit is coupled on the described inductor, the elementary winding of a transformer is connected in series in load, power to the load by described output circuit, described first and second switching devices are carried out drive controlling by the output of described Secondary winding of transformer.

10. device as claimed in claim 1 or 2 is characterized in that, further comprises the discharge lamp as load that is arranged in the described output circuit.

11. device as claimed in claim 10 is characterized in that, described discharge lamp is installed on the lighting.

12. device as claimed in claim 2 is characterized in that, described control unit is controlled the turn-on cycle of described first switching device, and making discharging current that first capacitor discharges and that flow in described first switching device is a predetermined value.

13. device as claimed in claim 2 is characterized in that, described control unit is controlled the turn-on cycle of described first switching device, and making described first capacitor is a predetermined value by the discharging current that described inductor and described first switching device discharge.

14. device as claimed in claim 2 is characterized in that, described control unit changes the predetermined value of the current value of the described first switching device turn-on cycle of decision according to the magnitude of voltage on described first and second switching devices.

15., it is characterized in that described control unit flows into described rectifying device at one of input and output electric current at least ends described second switch device after one period scheduled time as claim 2,12,13 or 14 described devices.

16., it is characterized in that described control unit is according to the turn-on cycle of controlling described second switch device corresponding to the magnitude of voltage of the voltage on described first capacitor as claim 2,12,13 or 14 described devices.

17., it is characterized in that described control unit is controlled the turn-on cycle of described second switch device according to ac voltage as claim 2,12,13 or 14 described devices.

18., it is characterized in that described control unit is controlled the turn-on cycle of described second switch device according to the output of described output circuit as claim 2,12,13 or 14 described devices.

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