CN104869687A - Power supply device and lighting device - Google Patents
Power supply device and lighting device Download PDFInfo
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- CN104869687A CN104869687A CN201410440556.2A CN201410440556A CN104869687A CN 104869687 A CN104869687 A CN 104869687A CN 201410440556 A CN201410440556 A CN 201410440556A CN 104869687 A CN104869687 A CN 104869687A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
Abstract
The present invention provides a power supply device and a lighting device which can restrain the noise generation without needing to add the elements. A second power supply device 20 of the present invention operates in a current discontinuous mode, and reduces the voltage value of a voltage outputted from a first power supply device 13 to a light source 30, and the second power supply device 20 is at least equipped with an inductor 23, a switch element 24 for supplying the energy from the first power supply device 13 to the inductor 23 by a conduction operation, and supplying the energy from the first power supply device 13 to the inductor by the cut-off operation, and releasing the energy accumulated in the inductor; a control part 14 for controlling the switch element 24. The control part controls the switch element to be cut off from being conducted, during the free vibration period of a current flowing through the inductor, and during the period that the polarity of the current flowing through the inductor is switched one time to three times, the switch element is controlled to be conducted from being cut off.
Description
Technical field
Embodiments of the present invention relate to a kind of supply unit and lighting device.
Background technology
When utilizing step-down switching-converter driving LED (Light Emitting Diode, light-emitting diode) even load, dc-dc converter operates with electric current discontinuous mode sometimes.When dc-dc converter is operated with electric current discontinuous mode, putting aside after the energy of inductor is released, also producing the polarity switching free vibration repeatedly flowing through the electric current of inductor.When flowing through the polarity switching of the electric current of inductor, electrical noise can be produced.In order to the generation of restraint speckle, need to set up the noise counter plan such as inductor or capacitor element, become the main cause of larger-scale unit or cost increase.
Patent documentation 1: Japanese Unexamined Patent Publication 2013-229234 publication
Summary of the invention
The technical problem to be solved in the present invention is also can the generation of restraint speckle without the need to setting up element.
Supply unit involved by present embodiment operates with electric current discontinuous mode, and the voltage step-down exported from other supply unit is supplied to load, and this supply unit at least possesses: inductor; Switch element, by being operating as conducting, by the Power supply from other supply unit described to described inductor, by being operating as disconnection, cut off energy from other supply unit described to the supply of described inductor, and savings is released in the energy of described inductor; Control part, control described switch element, described control part is after controlling to be off from conducting by described switch element, during the free vibration of electric current flowing through described inductor, to during before switching 3 times after the polarity of the electric current flowing through described inductor switches 1 time, perform and described switch element is controlled to control for the ON time of conducting from disconnection.
According to the present invention, the generation without the need to setting up element and restraint speckle can be expected.
Accompanying drawing explanation
Fig. 1 is the stereogram of an example of the lighting device represented involved by execution mode.
Fig. 2 is the figure of the example representing the substrate being equipped with electric component.
Fig. 3 is the figure of an example of the circuit structure representing lighting device.
Fig. 4 is the figure of an example in control time for illustration of switch element.
Fig. 5 is the figure for illustration of example switch element being controlled the time for conducting from disconnection.
Fig. 6 is the figure for illustration of example switch element being controlled the time for conducting from disconnection.
Fig. 7 be pulse duration when utilizing PWM (Pulse Width Modulation, pulse width modulation) Signal-controlled switch element and by switch element from disconnect be controlled to conducting time between the figure of relation.
Fig. 8 be pulse spacing when utilizing PFM (Pulse Frequency Modulation, pulse frequency modulated) Signal-controlled switch element and by switch element from disconnect be controlled to conducting time between the figure of relation.
In figure: 13-the 1st supply unit, 14-control device, 20-the 2nd supply unit, 21-diode, 22-capacitor, 23-inductor, 24-switch element, 25-resistance, 30-light source, 31-light-emitting component.
Embodiment
Supply unit involved by execution mode described below operates with electric current discontinuous mode, and the voltage step-down exported from other supply unit is supplied to load, and this supply unit at least possesses: inductor; Switch element, by being operating as conducting, by the Power supply from other supply unit to inductor, by being operating as disconnection, cutting off energy from other supply unit to the supply of inductor, and savings is released in the energy of inductor; Control part, control switch element, control part is after controlling to be off from conducting by described switch element, during the free vibration of electric current flowing through described inductor, to during before switching 3 times after the polarity of the electric current flowing through described inductor switches 1 time, perform and switch element is controlled from disconnecting the ON time being controlled to conducting.According to this supply unit, the generation without the need to setting up element and restraint speckle can be expected.
And, in supply unit involved by execution mode described below, switch element conducting and disconnection according to the pwm signal supplied from control part, control part, when the pulse duration of pwm signal is more than predetermined length, performs the pwm signal of the duty ratio that described ON time controls to switch element supply.The pulse duration of pwm signal is larger, and the amplitude flowing through the electric current of inductor during free vibration is larger, and the noise produced during free vibration also increases.Therefore, when the pulse duration of pwm signal is more than predetermined length, controls by performing ON time, the noise effectively suppressing to produce during free vibration can be expected.
And, in supply unit involved by execution mode described below, control part is when being less than the pwm signal of predetermined length to switch element supply pulse duration, by switch element from conducting control be off after, during the free vibration of electric current flowing through inductor, after the polarity of the electric current flowing through inductor switches more than 3 times, switch element is controlled as conducting from disconnection.The pulse duration of pwm signal is less, and the amplitude flowing through the electric current of inductor during free vibration is less, and the noise produced during free vibration also reduces.Therefore, when the pulse duration of pwm signal is less, controls even if do not perform ON time, also can not produce excessive noise.Control by not performing ON time when the pulse duration of pwm signal is less, can expect to make the process of control part become simple and reduce process load.
And, in supply unit involved by execution mode described below, switch element conducting and disconnection according to the PFM signal supplied from control part, control part, when the frequency of PFM signal is more than predetermined value, performs the PFM signal of the pulse duration that ON time controls to switch element supply.During free vibration, inductor current switch polarity is while decay.But, if the duty ratio of PFM signal is higher, then produce the amplitude of the inductor current during more free vibration larger during, the noise produced also increases.Therefore, when the duty ratio of PFM signal is more than predetermined value, controls by performing ON time, the noise effectively suppressing to produce during free vibration can be expected.
And in the supply unit involved by execution mode described below, load can be semiconductor light-emitting elements.
And the lighting device involved by execution mode described below possesses described supply unit, apparatus main body, load, load is that the voltage that supplies according to supply unit and electric current carry out luminous light source.
And the lighting device involved by execution mode described below possesses: the 1st supply unit, multiple light source, comprises the light-emitting component of more than 1 respectively, multiple 2nd supply unit, operates with electric current discontinuous mode respectively, and the voltage step-down exported from the 1st supply unit is supplied to each light source, control device, controls multiple 2nd supply unit respectively, and multiple 2nd supply unit at least possesses respectively: inductor, switch element, by being operating as conducting, by the Power supply from the 1st supply unit to inductor, by being operating as disconnection, cut off energy from the 1st supply unit to the supply of inductor, and savings is released in the energy of inductor, control device is at least any one supply unit of multiple 2nd supply unit, after the switch element possessed by the 2nd supply unit controls to be off from conducting, during the free vibration of electric current flowing through inductor, to during before switching 3 times after the polarity of the electric current flowing through described inductor switches 1 time, perform and switch element is controlled from disconnecting the ON time being controlled to conducting.According to this lighting device, the generation without the need to setting up element and restraint speckle can be expected.
And, in lighting device involved by execution mode described below, the light source that load current is larger than other light source is there is in multiple light source, control device performs ON time to following 2nd supply unit and controls, and the 2nd supply unit will be supplied to the load current light source larger than other light source after the output voltage step-down from the 1st supply unit.Thereby, it is possible to expect the noisiness of the 2nd supply unit that restraint speckle generation is larger effectively.
Below, with reference to accompanying drawing, the supply unit involved by execution mode and lighting device are described.In addition, in embodiments, to the structure mark same-sign with identical function, and repeat specification is omitted.And the supply unit illustrated in execution mode below and lighting device just illustrate, are not intended to limit the present invention.And execution mode below can carry out appropriately combined in reconcilable scope.
(the 1st execution mode)
[structure of lighting device 1]
Fig. 1 is the stereogram of an example of the lighting device 1 represented involved by execution mode.Lighting device 1 is such as ceiling light, possesses the lampshade 11 of whole lower surface of apparatus main body 10, cladding system main body 10.The lower surface of apparatus main body 10 is provided with substrate, and this substrate is configured with the light source with multiple light-emitting component.Light source is such as divided into 6 groups, can control separately lighting and light-off for every 1 group, and light modulation.
Being provided with the rear side of substrate of light source, be connected with the substrate be equipped with for the electric component to light source power supply by cable etc.Light source is luminous according to the electric power supplied via cable.Lampshade 11 is formed by the resin material etc. with light transmission, makes the light transmission from light source injection.Lampshade 11 can be such as transparent, also can have light diffusing.
Lighting device 1 is arranged at ceiling, has the connector be such as electrically connected with roughly cylindric ceiling rose.Lighting device 1 by making connector chimeric with ceiling rose to make lampshade 11 state down be fixed on ceiling.The power line of the commercial ac power source introduced from ceiling inboard is connected with at ceiling rose.
Fig. 2 is the figure of the example representing the substrate 12 being equipped with electric component.The central authorities of substrate 12 are provided with the opening for configuring the connector chimeric with ceiling rose.Substrate 12 is arranged in lighting device 1 in the mode be centered around around the connector chimeric with ceiling rose.
As shown in Figure 2, the 1st supply unit 13 that to be such as provided with the voltage transitions of commercial ac power source be on the substrate 12 direct voltage, the direct voltage that the 1st supply unit 13 is changed is converted to hope voltage and be supplied to multiple 2nd supply unit 20-1 ~ 6 of light source and control the electric component of control device 14 etc. of the 2nd supply unit 20-1 ~ 6 respectively.In addition, in the following description, be called " the 2nd supply unit 20 " when not distinguishing the 2nd supply unit 20-1 ~ 6 and be referred to as.
In the present embodiment, such as 6 the 2nd supply units 20 are provided with on the substrate 12.Each the 2nd supply unit 20 is provided with one for being such as divided into each light source of 6 groups, and to corresponding light source supply direct voltage.
1st supply unit 13 accepts commercial ac power source via connector from ceiling rose, and is direct voltage by the voltage transitions of accepted commercial ac power source.The voltage that the voltage transitions being converted to direct current by the 1st supply unit 13 becomes to wish by each the 2nd supply unit 20, and via cable, the direct voltage after conversion is supplied to corresponding light source.The light-emitting component comprised in each light source is luminous according to the electric current based on supplied direct voltage.
[circuit structure of lighting device 1]
Fig. 3 is the figure of an example of the circuit structure representing lighting device 1.Under the state that lighting device 1 is fixed on ceiling, the input terminal of the 1st supply unit 13 is connected with commercial ac power source 15 via connector, ceiling rose and switch 16.And the lead-out terminal of the 1st supply unit 13 is connected with the 2nd supply unit 20-1 ~ 6 respectively.2nd supply unit 20-1 ~ 6 are connected with any one of light source 30-1 ~ 6 respectively.In addition, in the following description, be called " light source 30 " when not distinguishing light source 30-1 ~ 6 and be referred to as.
Each the 2nd supply unit 20 has: diode 21, capacitor 22, inductor 23, switch element 24, resistance 25.In the present embodiment, switch element 24 is such as MOSFET (MetalOxide Semiconductor Field Effect Transistor, mos field effect transistor).In addition, as other examples, switch element 24 also can be bipolar transistor or junction field effect transistor.
The negative electrode of diode 21 is connected to the node between the lead-out terminal of the 1st supply unit 13 and light source 30.The anode of diode 21 is connected to the node between inductor 23 and switch element 24.One end of capacitor 22 is connected to the node between the lead-out terminal of the 1st supply unit 13 and light source 30, and the other end is connected to the node between inductor 23 and light source 30.
One end of inductor 23 is connected with light source 30, and the other end is connected with the drain terminal of switch element 24.The drain terminal of switch element 24 is connected with the other end of inductor 23, and gate terminal is connected with control device 14, and source terminal is via resistance 25 ground connection.
Each light source 30 has the multiple light-emitting components 31 be connected in series.One end of each light source 30 is connected with one end of the lead-out terminal of the 1st supply unit 13, the negative electrode of diode 21 and capacitor 22.The other end of each light source 30 is connected with one end of inductor 23.
Light-emitting component 31 in present embodiment for utilize from the 2nd supply unit 20 supply electric current and action load one example.And in the present embodiment, light-emitting component 31 is such as the semiconductor light-emitting elements such as LED.And, as other examples, light-emitting component 31 also can be Organic Light Emitting Diode (Organic Light Emitting Diode), inorganic EL (Inorganic ElectroLuminescence) light-emitting component or other field emission light-emitting component etc.
When switch 16 closes, the voltage transitions of the commercial ac power source 15 accepted via switch 16 is direct voltage by the 1st supply unit 13, and is supplied to each the 2nd supply unit 20.The voltage step-down that supplies from the 1st supply unit 13 to the direct voltage of hope, and is supplied to corresponding light source 30 by each the 2nd supply unit 20.
The control signal of the conducting of control switch element 24 and disconnection action is supplied to each the 2nd supply unit 20 by control device 14.Specifically, control device 14 is by the voltage V between supplying gate pole-source electrode to the switch element 24 of each the 2nd supply unit 20
gScontrol as high-caliber control signal, thus switch element 24 is controlled as conducting, make the current direction light source 30 from the 1st supply unit 13 and inductor 23.
By switch element 24 is controlled, for conducting, to flow through the electric current I of inductor 23 from disconnection
lincrease, energy savings is in inductor 23.At this, the electric current I of inductor 23 will be flow through from light source 30 towards switch element 24 direction
ldirection be defined as positive direction.
Then, control device 14 is by the voltage V between supplying gate pole-source electrode to the switch element 24 of each the 2nd supply unit 20
gScontrol as low-level control signal, thus switch element 24 is controlled to be off, cut off the electric current supply from the 1st supply unit 13 towards light source 30 and inductor 23.By being controlled to be off from conducting by switch element 24, flow through the electric current I of inductor 23 with positive direction
lbe supplied to light source 30 via diode 21, flow through the electric current I of inductor 23
lreduce, the energy put aside in inductor 23 is released.
So, each the 2nd supply unit 20, by carrying out the control signal of self-control device 14, makes switch element 24 conducting and disconnection, carries out work thus as buck circuit.In addition, control device 14 makes each the 2nd supply unit 20 operate with electric current discontinuous mode.
[control time]
At this, the time of the control signal supplied from control device 14 to each switch element 24 is described in detail.Fig. 4 is the figure of an example in the control time of switch element 24 for illustration of each the 2nd supply unit 20.As T during Fig. 4
oNshown in, the voltage V between the gate pole-source electrode of switch element 24
gSwhen becoming high level by carrying out the control signal of self-control device 14, switch element 24 becomes conducting, flows through the electric current I of inductor 23 with positive direction
lincrease, energy is put aside in inductor 23.
Then, as T during Fig. 4
oFFshown in, the voltage V between the gate pole-source electrode of switch element 24
gSwhen becoming low-level by carrying out the control signal of self-control device 14, switch element 24 becomes disconnection, flows through the electric current I of inductor 23 with positive direction
lreduce and become 0, the energy put aside in inductor 23 is released.Then, as shown in Figure 4, the electric current I flowing through inductor 23 is produced
lpolarity (electric current I
ldirection) switch free vibration repeatedly.
In the present embodiment, control device 14 is flowing through the electric current I of inductor 23 from generation
lfree vibration start after a predetermined time after T, the voltage V between the gate pole-source electrode again making switch element 24 to switch element 24 supply
gSbecome high-caliber control signal, make switch element 24 conducting.
Fig. 5 is the figure for illustration of example switch element 24 being controlled the time for conducting from disconnection.As shown in Figure 5, the voltage V between the gate pole-source electrode of switch element 24
gSwhen becoming low-level by carrying out the control signal of self-control device 14, switch element 24 becomes disconnection, flows through the electric current I of inductor 23 with positive direction
lreduce.Then, at moment t
1electric current I
lbecome 0, begin to flow through the electric current I of inductor 23
lfree vibration.
Flow through the electric current I of inductor 23
lwith moment t
1for (electric current I after transfer point polarity inversion
ldirection become in the other direction after), at moment t
2again 0 is become.Then, the electric current I of inductor 23 is flow through
lwith moment t
2for transfer point polarity is again reversed and return original polarity (positive direction).Then, if switch element 24 not conducting, then the electric current I of inductor 23 is flow through
lat moment t
3again 0 is become, with moment t
3for transfer point polarity is reversed again.Then, if switch element 24 not conducting, then the electric current I of inductor 23 is flow through
lrepeatedly carry out the reversion of polarity, decay simultaneously.
So, when switch element 24 becomes disconnection from conducting, the electric current I of inductor 23 is flow through
lpolarity at moment t
1carry out the 1st time reversion and at moment t
2carry out the 2nd reversion, if switch element 24 not conducting, then at moment t
3carry out the 3rd reversion.
In the present embodiment, control device 14 performs following ON time and controls: when T after a predetermined time, switch element 24 is controlled as conducting from disconnection, this scheduled time T at switch element 24 from the electric current I flowing through inductor 23 after conducting becomes disconnection with positive direction
lbecome the moment t of 0
1start to generation current I
lthe moment t of the 3rd polarity inversion
3till during T
0within.
In addition, because control device 14 is in ON time controls, at period T
0within switch element 24 is controlled as conducting from disconnection, therefore, such as shown in Figure 6, can from the electric current I flowing through inductor 23 with positive direction
lbecome the moment t of 0
1start through generation current I
lthe 2nd polarity inversion before moment of scheduled time T ', switch element 24 is controlled as conducting from disconnection.
At this, flow through the electric current I of inductor 23
lpolarity inversion time, produce high-frequency noise.Therefore, in the electric current I flowing through inductor 23
lfree vibration during, electric current I
leach polarity inversion all produce high-frequency noise.Each the 2nd supply unit 20 can be made with continuous current mode running, but from the view point of easily designing, in the present embodiment, make each the 2nd supply unit 20 using the running of electric current discontinuous mode as prerequisite.Therefore, the electric current I to flowing through inductor 23 is needed
lduring setting free vibration.
At this, if switch element 24 is controlled for conducting, then to flow through the electric current I of inductor 23 with positive direction from disconnection
lstart to increase.If that is, switch element 24 just become conducting before stream have the electric current I of positive direction
l, then become conducting by switch element 24 from disconnection, flow through the electric current I of inductor 23 with positive direction
lstart to increase.On the other hand, if switch element 24 just become conducting before stream have the rightabout electric current I with positive direction
l, then conducting is become by switch element 24 from disconnection, to flow through the electric current I of inductor 23 in the other direction
lreduce, electric current I
lpolarity inversion, the electric current I flow through with positive direction
lstart to increase.
Such as, therefore, as shown in Figure 6, if from the electric current I flowing through inductor 23 with positive direction
lbecome the moment t of 0
1start the moment t to generation the 2nd polarity inversion
2till during, switch element 24 is controlled as conducting from disconnection, then to flow through the electric current I of inductor 23 in the other direction
lreduce and after polarity inversion, the electric current I flow through with positive direction
lstart to increase.Its result, switch element 24 is off from ON transitions and till again changing conducting into during, flow through the electric current I of inductor 23
lpolarity reverse altogether 2 times.
And, such as, as shown in Figure 5, if from generation current I
lthe moment t of the 2nd polarity inversion
2start the moment t to generation the 3rd polarity inversion
3till during, switch element 24 is controlled as conducting, then due to electric current I from disconnection
lto positive direction flowing, therefore conducting and generation current I can not be changed because of switch element 24 into from disconnection
lpolarity inversion.Therefore, switch element 24 is off from ON transitions and till again changing conducting into during, flow through the electric current I of inductor 23
lpolarity reverse altogether 2 times.
To this, if at generation current I
lthe moment t of the 3rd polarity inversion
3after, switch element 24 is controlled for conducting, then to flow through the electric current I of inductor 23 with positive direction from disconnection
lincrease, its result produces the electric current I of more than 4 times
lpolarity inversion.Therefore, with from electric current I
lbecome the moment t of 0
1start to generation current I
lthe moment t of the 3rd polarity inversion
3till during by switch element 24 from disconnection control compare for during conducting, electric current I
lpolarity inversion number of times increase, the noise of generation increases.
So, the control device 14 in present embodiment is by from the electric current I flowing through inductor 23 with positive direction
lbecome the moment t of 0
1start to generation current I
lthe moment t of the 3rd polarity inversion
3till during, switch element 24 is controlled as conducting from disconnection, can enable the 2nd supply unit 20 with while the running of electric current discontinuous mode by produced noise suppressed for lower.Lighting device 1 in present embodiment is by controlling switch element 24 from disconnecting the time controlled as conducting, can be lower by produced noise suppressed, therefore without the need to arranging the noise counter plan such as inductor or capacitor element, can miniaturization of the apparatus or cost reduction.
[relation between duty ratio and ON time]
Pwm signal is supplied to each switch element 24 as control signal by control device 14.By controlling the duty ratio being supplied to the pwm signal of switch element 24, the electric current being supplied to light source 30 from the 2nd supply unit 20 can be controlled, the light quantity of light source 30 can be controlled.At this, in electric current discontinuous mode, the pulse duration (during high level) of pwm signal is longer, flows through the electric current I of inductor 23
lmaximum larger.
Fig. 7 controls to be the figure of the relation between the time of conducting from disconnecting for illustration of pulse duration when utilizing pwm signal control switch element 24 with by switch element 24.In Fig. 7, (a) represents the electric current I when pwm signal of the pulse duration of more than predetermined length (such as design on maximum) being supplied to switch element 24
lchange.Electric current I when (b) represents that pwm signal pulse duration being less than predetermined length is supplied to switch element 24 in Fig. 7
lchange.In Fig. 7, (c) represents electric current I when pwm signal shorter to (b) in pulse width ratio Fig. 7 being supplied to switch element 24
lchange.
As shown in (a) ~ (c) in Fig. 7, in the pwm signal of fixed frequency, pulse duration is wider, and (that is, duty ratio is (such as with pulse spacing T
10between ratio) higher), flow through the electric current I of inductor 23
lmaximum larger.Such as, due to the pulse width T of the pwm signal in Fig. 7 shown in (a)
11than the pulse width T of the pwm signal in Fig. 7 shown in (c)
15greatly, the therefore electric current I shown in (a) in Fig. 7
lmaximum than the electric current I in Fig. 7 shown in (c)
lmaximum large.
And, electric current I
lmaximum larger, flow through the electric current I of inductor 23 in during free vibration
lamplitude larger, the noise that produces during free vibration increases.Such as, due to the electric current I in Fig. 7 shown in (a)
lmaximum than the electric current I in Fig. 7 shown in (c)
lmaximum large, the therefore free vibration period T of (a) in Fig. 7
12middle electric current I
lamplitude ratio Fig. 7 in the free vibration period T of (c)
16middle electric current I
lamplitude large.Therefore, when control signal control switch element 24 by the pulse duration in Fig. 7 shown in (a), if lengthen electric current I
lfree vibration during, then compared with during control signal control switch element 24 by the pulse duration in Fig. 7 shown in (c), the noise produced becomes large.
Therefore, control device 14 when the pulse duration of pwm signal is more than predetermined length (such as, the maximum in design), when namely the light quantity of light source 30 is predetermined above light quantity, preferably from electric current I
lbecome the moment t of 0
1t during starting to generation the 3rd polarity inversion
0by switch element 24, the ON time controlled as conducting controls in interior execution.
In other words, control device 14, when the pulse duration of pwm signal is more than predetermined length, preferably supplies the pwm signal performing the duty ratio that ON time controls to switch element 24.Thereby, it is possible to will the electric current I of inductor 23 be flow through
lthe noise suppressed produced during free vibration is for lower.
In addition, during free vibration, flow through the electric current I of inductor 23
lvibration period depend on the circuit constant such as inductance, the parasitic capacitance of switch element 24, the stray capacitance of substrate distribution of inductor 23.Therefore, due to the deviation of these constants, electric current I
lvibration period produce deviation, the electric current I during free vibration
lthe moment t of the 1st polarity inversion
1start the moment t to the 3rd polarity inversion
3till during sometimes also can produce deviation.Therefore, in ON time controls, preferably by switch element 24 from disconnect the time being converted to conducting be designed to free vibration during electric current I
lthe moment t of the 2nd polarity inversion
2near.
Thus, even if there is deviation in the circuit constant of substrate or element, also can in the electric current I during free vibration
lthe moment t of the 1st polarity inversion
1start the moment t to the 3rd polarity inversion
3till during in switch element 24 is controlled as conducting from disconnection.
In addition, in order to reduce the electric current being supplied to light source 30, need the duty ratio reducing pwm signal.But as shown in (a) in Fig. 7, the duty ratio that control device 14 adjusts pwm signal controls to perform ON time when pulse duration is more than predetermined length.Therefore, if reduce the duty ratio of pwm signal, then, such as shown in (c) in (b) in Fig. 7 or Fig. 7, the electric current I of inductor 23 is being flow through
lfree vibration during, electric current I
lpolarity inversion more than 3 times after switch element 24 is controlled as conducting and do not carry out ON time control from disconnection.
At this, in the pwm signal of fixed frequency, if reduce duty ratio, then pulse duration shortens.If the pulse duration of pwm signal shortens, then flow through the electric current I of inductor 23 in during free vibration
lamplitude diminish, the noise therefore produced during free vibration also diminishes.Therefore, such as, as shown in (b) or (c) in Fig. 7, the pulse width T of pwm signal
13or T
15when being less than predetermined length, at free vibration period T
14or T
16the noise produced also can not be excessive.Therefore, even if in the electric current I flowing through inductor 23
lcontrol as conducting by switch element 24 from disconnection after carrying out more than 3 times reversions, the noise produced by lighting device 1 entirety also can not be excessive.
So, the control device 14 in present embodiment, when the pulse duration of pwm signal is less than predetermined length, does not carry out ON time control.Thereby, it is possible to expectation simplifies the process performed by control device 14 and alleviates process load.
Above, execution mode is illustrated.
As mentioned above, lighting device 1 according to the present embodiment, just can the generation of restraint speckle without the need to setting up element.
[variation]
In addition, the present invention is not only limited to above-mentioned execution mode, can carry out various distortion in the scope of its aim.
Such as, in the above-described embodiment, control device 14 performs ON time to all 2nd supply units 20 and controls, but the present invention is not only limited to this, can control at least any one the execution ON time in multiple 2nd supply unit 20.
Such as, as shown in Figure 3, lighting device 1 has 6 light sources 30, but can there is the light source that the electric current (can be called load current) obtaining desired light quantity and necessity is greater than other light source 30 in 6 light sources 30.Control device 14 can perform ON time to the 2nd supply unit 20 and control, and the 2nd supply unit 20 is the 2nd supply unit 20 that the light source 30 that the electric current of necessity is greater than other light source 30 is powered to acquisition desired light quantity.
Thus, compared with performing when ON time controls with to all 2nd supply units 20, the control time of switch element 24 can be disperseed, therefore, it is possible to avoid the increase of the switching noise caused because of the control time overlap of switch element 24.
And in the above-described embodiment, control device 14 utilizes conducting and the disconnection of the pwm signal control switch element 24 of fixed frequency, but the present invention is not only limited to this.Such as, as alternate manner, control device 14 can utilize conducting and the disconnection of the PFM Signal-controlled switch element 24 of fixed pulse width.Fig. 8 controls to be the figure of the relation between the time of conducting from disconnecting for illustration of pulse spacing when utilizing PFM Signal-controlled switch element with by switch element.
In Fig. 8, (a) represents to be the PFM signal of more than predetermined value (maximum such as, in design) electric current I when being supplied to switch element 24 by frequency
lchange.Electric current I when (b) represents that PFM signal frequency being less than predetermined value is supplied to switch element 24 in Fig. 8
lchange.When utilizing the conducting of the PFM Signal-controlled switch element 24 of fixed pulse width and disconnecting, as shown in (a) in Fig. 8, control device 14 supplies the frequency of more than predetermined value to switch element 24, and (such as, the pulse spacing is scheduled time T
21) the middle pulse width T performing ON time and control
20pFM signal.And as shown in (b) in Fig. 8, control device 14 supplies to switch element 24 frequency being less than predetermined value, and (such as, the pulse spacing is scheduled time T
22) in do not perform ON time control pulse width T
20pFM signal.Thereby, it is possible to reduce the noise produced from lighting device 1.
Above, some execution modes of the present invention are illustrated, but these execution modes just illustrate, do not limit the intention of invention scope.These new execution modes can be implemented in other various mode, without departing from the spirit and scope of the present invention, can carry out various omission, displacement, change.These execution modes or its distortion all belong in scope of the present invention or aim, and are also contained in the invention and equivalent scope thereof recorded in technical scheme.
Claims (5)
1. a supply unit, operates with electric current discontinuous mode, and the voltage step-down exported from other supply unit is supplied to load, and the feature of this supply unit is:
At least possess: inductor;
Switch element, by being operating as conducting, by the Power supply from other supply unit described to described inductor, by being operating as disconnection, cut off energy from other supply unit described to the supply of described inductor, and savings is released in the energy of described inductor;
Control part, controls described switch element,
Described control part is after controlling to be off from conducting by described switch element, during the free vibration of electric current flowing through described inductor, to during before switching 3 times after switching 1 time from the polarity of the electric current flowing through described inductor, perform and described switch element is controlled to control for the ON time of conducting from disconnection.
2. supply unit according to claim 1, is characterized in that:
Conducting and the disconnection according to the pulse width modulation (PWM) signal supplied from described control part of described switch element,
Described control part, when the pulse duration of described pwm signal is more than predetermined length, performs the pwm signal of the duty ratio that described ON time controls to described switch element supply.
3. supply unit according to claim 2, is characterized in that:
Described control part is when being less than the pwm signal of described predetermined length to described switch element supply pulse duration, by described switch element from conducting control be off after, during the free vibration of electric current flowing through described inductor, after the polarity of the electric current flowing through described inductor switches more than 3 times, described switch element is controlled to conducting from disconnection.
4. supply unit according to claim 1, is characterized in that:
Conducting and the disconnection according to the pulse frequency modulated PFM signal supplied from described control part of described switch element,
Described control part, when the frequency of described PFM signal is more than predetermined value, performs the PFM signal of the pulse duration that described ON time controls to described switch element supply.
5. a lighting device, is characterized in that:
Possess: the supply unit described in any one of Claims 1-4;
Be equipped with the apparatus main body of described supply unit;
Described load,
Described load is according to the voltage supplied from described supply unit and electric current and the light source of luminescence.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2014034452A JP6273896B2 (en) | 2014-02-25 | 2014-02-25 | Power supply device and lighting device |
| JP2014-034452 | 2014-02-25 |
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| Publication Number | Publication Date |
|---|---|
| CN104869687A true CN104869687A (en) | 2015-08-26 |
| CN104869687B CN104869687B (en) | 2018-12-07 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201410440556.2A Active CN104869687B (en) | 2014-02-25 | 2014-09-01 | Power supply device and lighting device |
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| JP (1) | JP6273896B2 (en) |
| CN (1) | CN104869687B (en) |
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| CN111182676B (en) | 2018-11-08 | 2021-07-09 | 台达电子企业管理（上海）有限公司 | Dimming circuit and dimming control method |
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|---|---|---|---|---|
| US20030141857A1 (en) * | 2002-01-31 | 2003-07-31 | Canon Kabushiki Kaisha | Current determination circuit, and image printing apparatus having current determination circuit |
| US20080024104A1 (en) * | 2006-07-25 | 2008-01-31 | Fuji Electric Device Technology Co., Ltd. | DC-DC converter |
| JP2008109761A (en) * | 2006-10-24 | 2008-05-08 | Fuji Electric Device Technology Co Ltd | Operation mode determination circuit of dc-dc converter |
| JP2011010450A (en) * | 2009-06-25 | 2011-01-13 | Fujitsu Semiconductor Ltd | Semiconductor integrated circuit and power supply apparatus |
| JP2011193549A (en) * | 2010-03-11 | 2011-09-29 | Toyota Motor Corp | Failure detector of chopper circuit |
| JP2013110062A (en) * | 2011-11-24 | 2013-06-06 | Panasonic Corp | Led driving device, illuminating device and illumination apparatus |
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- 2014-09-01 CN CN201410440556.2A patent/CN104869687B/en active Active
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|---|---|---|---|---|
| US20030141857A1 (en) * | 2002-01-31 | 2003-07-31 | Canon Kabushiki Kaisha | Current determination circuit, and image printing apparatus having current determination circuit |
| US20080024104A1 (en) * | 2006-07-25 | 2008-01-31 | Fuji Electric Device Technology Co., Ltd. | DC-DC converter |
| JP2008109761A (en) * | 2006-10-24 | 2008-05-08 | Fuji Electric Device Technology Co Ltd | Operation mode determination circuit of dc-dc converter |
| JP2011010450A (en) * | 2009-06-25 | 2011-01-13 | Fujitsu Semiconductor Ltd | Semiconductor integrated circuit and power supply apparatus |
| JP2011193549A (en) * | 2010-03-11 | 2011-09-29 | Toyota Motor Corp | Failure detector of chopper circuit |
| JP2013110062A (en) * | 2011-11-24 | 2013-06-06 | Panasonic Corp | Led driving device, illuminating device and illumination apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2015159695A (en) | 2015-09-03 |
| JP6273896B2 (en) | 2018-02-07 |
| CN104869687B (en) | 2018-12-07 |
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