CN102651927A - Power supply circuit - Google Patents
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- CN102651927A CN102651927A CN201110045829XA CN201110045829A CN102651927A CN 102651927 A CN102651927 A CN 102651927A CN 201110045829X A CN201110045829X A CN 201110045829XA CN 201110045829 A CN201110045829 A CN 201110045829A CN 102651927 A CN102651927 A CN 102651927A
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Abstract
The invention provides a power supply circuit which is capable of reducing undesirable single flicker of a lamp caused by unscheduled malfunction of double-direction controllable silicon of a light modulator with smaller power loss. In a power supply circuit (10) with a supply circuit (21) that rectifies and reduces an alternating current voltage Vi input by the light modulator (14) from a commercial alternating current power supply (12) in a phase control manner to supply power to the lamp (16), a line filter (22) arranged on a primary side of the supply circuit (21) comprises a noise-proof capacitor (40) installed in parallel to the supply circuit (21) and a stabilized resistor (42) installed above at least one of a pair of power supply lines (44) installed on a primary side of the noise-proof capacitor (40). Inductance L of a coil (50) of the light modulator (14), a capacitance value C of the noise-proof capacitor (40) and a resistance value R of the stabilized resistor (42) meet the condition that R2 is greater than or equal to 4*L/C.
Description
Technical field
The present invention relates to possess the power circuit of the line filter that is used to reduce the switching noise that the reduction voltage circuit by on-off mode produces.
Background technology
Compare with incandescent lamp bulb in the past, have the light-emitting diode (below, be called " LED ") of low and life-span of consumed power such strong point such as long; Raising along with the environmental consciousness of demander; As one of strategy of Saving Energy, its scope of application is expanded hastily, and; As the substitute of incandescent lamp bulb, want to use the such demand of LED also increasing.
But; Because LED will (for example be lower than commercial voltage; 60Hz, 100V) " direct current " voltage under carry out work; So when using commercial voltage to light LED, this commercialization voltage is carried out step-down, rectification (=be transformed to direct voltage) or rectification, step-down and is necessary to the power circuit of LED power supply.
As such power circuit, exploitation has and will carry out rectification from the alternating voltage of commercial ac power source earlier and be transformed to direct voltage, with switching circuit this direct voltage is carried out step-down then and is supplied to the circuit (for example, patent documentation 1) of LED.
The power circuit 1 that patent documentation 1 is put down in writing; As shown in Figure 4, by the rectifier smoothing circuit 4 with diode bridge 4a and smoothing capacitor 4b, it is level and smooth that the alternating voltage Vi that supplies with, imports via the dimmer 3 of the phase control mode that uses bidirectional triode thyristor (TRIAC) 3a from commercial AC power 2 is carried out rectification; Then; After being depressured to predetermined voltage by the buck circuit that has used switch element 5, offer LED6 (in patent documentation 1, a plurality of LED are connected in series with positive direction).
In addition; If the switch element that in buck circuit 5, uses action, then from this switch element generation switching noise (high-frequency noise), so in power circuit 1; As countermeasure, protection against noise has been installed with capacitor 7 in the primary side of rectifier smoothing circuit 4 to this switching noise.
In addition; The dimmer 3 of phase control mode changes the angle of flow of AC power through the grid of control bidirectional triode thyristor 3a; Thereby become the input that makes to power circuit 10 and change the light modulation of carrying out lamp, in addition, in this dimmer 3; As countermeasure, be provided with filter circuit (noise prevention circuit) 3b that has made up coil 3c and capacitor 3d to high-frequency noise.
According to this power circuit 1; Can be after will being transformed to direct voltage from the alternating voltage Vi that commercial AC power 2 is exported via dimmer 3 by rectifier smoothing circuit 4; By buck circuit 5 it is depressured to the voltage corresponding with LED6, and LED6 is lighted through it being offered LED6.
But as stated, it is low that LED6 and incandescent lamp bulb are in the past compared consumed power; So, for example, if the phase control mode dimmer 3 that uses existing incandescent lamp bulb load to use; Then when this LED6 lights, the current value of bidirectional triode thyristor 3a that flows to dimmer 3 is too small, so can not in the whole half period from the alternating voltage Vin of commercial ac power source 2, keep the on-state of this bidirectional triode thyristor 3a; LED6 is stably lighted, have the problem that " flicker " takes place.
In order to tackle such problem, in power circuit 1,, with capacitor 7 impedance 8 (mainly using resistance) has been installed parallelly connectedly with respect to protection against noise in the primary side of rectifier smoothing circuit 4.
Patent documentation 1: TOHKEMY 2004-296205 communique
Summary of the invention
Through such installation impedance 8;, LED6 in impedance 8, also flows through by-pass current when lighting; Therefore the some light current of LED6 and by-pass current add up to the bidirectional triode thyristor 3a of the current direction dimmer 3 that forms; Can avoid with " current value is too small " is the such problem of on-state reason, that can not in the whole half period of alternating voltage Vin, keep bidirectional triode thyristor 3a, but still can't avoid " because ' transient ' ' oscillating current ' of bringing thereby cause and the bidirectional triode thyristor 3a undesirable flicker (flicker of the single-shot property that takes place in a flash aperiodically, flash of light is such) that action produces that makes a mistake aperiodically ".
Specify, in power circuit 1, the coil 3c that has with the filter circuit 3b of commercial ac power source 2, dimmer 3, protection against noise form L-RC parallel connection alternating current circuit (with reference to Fig. 5) with capacitor 7 and impedance 8.Form under the situation of such L-RC parallel connection alternating current, when bidirectional triode thyristor 3a is on-state, as stated, in this bidirectional triode thyristor 3a, except lighting the LED point light current of LED6, the also overlapping electric current that flows through this L-RC parallel connection alternating current circuit.
In L-RC parallel connection alternating current circuit,, flow through " oscillating current " that the current value of this circuit vibrates significantly during extremely short sometimes owing to become " transient " that the timing of connection produces at bidirectional triode thyristor 3a." oscillating current " takes place in the L-RC parallel connection alternating current circuit; And shown in Fig. 6 (c); When bidirectional triode thyristor 3a became the current value I in that and then flows to dimmer 3 after connecting and descends sharp, bidirectional triode thyristor 3a can not keep on-state and become shutoff (malfunction), arrives the ensuing half period; With take place aperiodically can not be to the situation (so-called " no waveform ") of power circuit 1 supply power (promptly; Even sharply descend and moment becomes under the negative situation at current value I in, existing bidirectional triode thyristor 3a keeps the situation of on-state, and the situation that becomes shutoff is also arranged).Because in the half period that such " no waveform " takes place; The average current value of supplying with to LED6 descend significantly (almost vanishing); The illumination of the light that radiates from LED6 also reduces widely, and such illumination reduces as the undesirable flicker of the such single-shot property of flash of light and perceived by the people.
In addition, the amplitude of " oscillating current " that " transient " brought is big more, and the frequency that bidirectional triode thyristor 3a carries out malfunction is high more, and the frequency of " no waveform " is also high more, and " flicker " also increases thereupon.
The inductance L [H] of use coil 3c, protection against noise are with the capacitance C [F] of capacitor 7 and the resistance value R of impedance 8
PWhether [Ω] can judge owing to " oscillating current " takes place " transient ".
Promptly, based on the theory of transient, if above-mentioned physical quantity satisfies R
P 2≤L/4C then is judged to be this L-RC parallel connection alternating current circuit and is " non-vibration property " (promptly, do not take place " oscillating current "), otherwise, as if satisfying R
P 2＞L/4C judges that then this L-RC parallel connection alternating current circuit is " vibratility " (promptly, " oscillating current " taking place).
As the object lesson of practicality, the inductance L of establishing coil 3c is 100 μ H, protection against noise when using the capacitance C of capacitor 7 to be 0.1 μ F, and the value of L/4C is 250.250 square root is about 15.8, so at this moment, if the resistance value R of impedance 8
P≤15 [Ω], then L-RC parallel connection alternating current circuit is " a non-vibration property ".
But, at the resistance value R of impedance 8
PBe under the situation of 15 [Ω], if the alternating voltage Vin that establishes from commercial ac power source is 100V, when then the angle of flow of dimmer 3 was maximum, the power loss of impedance 8 became greatly, for 667W (in addition, by power loss=Vin
2/ R
PCalculate and get).That is it is unpractical, using impedance 8 in order to prevent " oscillating current " that brings in " transient " that the moment that bidirectional triode thyristor 3a connects produces.Therefore, in power circuit 1 in the past, can't tackle the LED6 that " oscillating current " that " transient " bring cause undesirable " flicker of single-shot property ".
The present invention develops in view of such problem of technology in the past.Therefore; Major subjects of the present invention is; Providing a kind of can lose with less power, eliminates the power circuit of undesirable " flicker of single-shot property " (" flicker " do not taken place or significantly reduce its frequency) of the lamp that " oscillating current " that " transient " that timing that bidirectional triode thyristor in the dimmer of phase control mode becomes connection takes place bring cause.
This power circuit 10 is characterised in that to possess:
Be arranged on the line filter 22 of the primary side of said power supply circuits 21,
Wherein, said line filter 22 has:
Between a pair of supply line 44 that said power supply circuits 21 and said commercial ac power source 12 is electrically connected, the protection against noise that is in parallel installed with said power supply circuits 21 is with capacitor 40; And
In the primary side of said protection against noise with capacitor 40, the stabilisation resistance of at least one side of said a pair of supply line 44, installing 42,
If the inductance of the said coil 50 in the said filter circuit 48 of said dimmer 14 is said protection against noise in L [H], the said line filter 22 during with the capacitance C [F] of capacitor 40, the resistance value R of said stabilisation resistance 42 [Ω] satisfies formula 1,
Said formula 1 is represented as follows:
R
2≥4×L/C。
The line filter 22 of the power circuit 10 among the present invention; Between a pair of supply line 44, have protection against noise that power supply circuits 21 are in parallel installed with capacitor 40, have the stabilisation resistance 42 at least one side who is installed in a pair of supply line 44 with the primary side of capacitor 40 in this protection against noise.Through such stabilisation resistance 42 is set, can be reduced in undesirable " flicker of single-shot property " of the lamp 16 that " oscillating current " that " transient " that timing that bidirectional triode thyristor 46 in the dimmer 14 of phase control mode becomes connection takes place down bring cause.Below, its reason is described.
In the power circuit 10 of the present invention; Protection against noise by the coil 50 in the dimmer 14 of commercial ac power source 12, phase control mode, line filter 22 forms series LC R alternating current circuit (with reference to Fig. 1 and Fig. 2) with capacitor 40 and stabilisation resistance 42; When bidirectional triode thyristor 46 is connected; In the bidirectional triode thyristor 46, the lamp point light current that lamp 16 is lighted is overlapping with the electric current that flows through this series LC R alternating current circuit.
In the electric current that flows to this series LC R alternating current circuit; Also sometimes because above-mentioned " transient "; Flow through " oscillating current " that the current value of this circuit vibrates significantly during extremely short; Whether take place about " oscillating current ", can use the inductance L [H] of coil 50, protection against noise to judge with the capacitance C [F] of capacitor 40 and the resistance value R [Ω] of stabilisation resistance 42.
That is, satisfy R in above-mentioned physical quantity
2During>=4 * L/C, judge that this series LC R alternating current circuit is that " non-vibration property " (that is " oscillating current ", do not take place) is (wherein, at R
2Be called " critical " state during=4 * L/C.)。And, " oscillating current " in this case, not only do not take place, and the peak value of inrush current reduces also self.
Otherwise, satisfying R
2During＜4 * L/C, judge that this series LC R alternating current circuit is " vibratility ", when " oscillating current " took place, the peak value of the inrush current also situation than " non-vibration property " was high.
For example, be made as 100 μ H, protection against noise when being made as 0.1 μ F with the capacitance C of capacitor 40 in the inductance L with coil 50, the value of 4 * L/C becomes 4,000.4,000 square root is 63.2, so at this moment, if the resistance value R of stabilisation resistance 42 >=64 [Ω], then series LC R alternating current circuit is " a non-vibration property ".
Otherwise the resistance value R of stabilisation resistance 42 (certainly, also comprises the situation (R=0) that does not have stabilisation resistance 42) under the situation below 63 [Ω], and series LC R alternating current circuit is " vibratility ".
Fig. 3 shows and is being provided with the stabilisation resistance 42 (R of appropriate resistance value R
2During>=4 * L/C) situation under waveform, Fig. 6 show be not provided with stabilisation resistance 42 (that is, under R=0) the situation or the resistance value R of this stabilisation resistance 42 satisfy R
2Waveform under the situation of＜4 * L/C.In addition, the both with 90 ° of the angles of flow by phase control.
Under the situation that appropriate stabilisation resistance 42 is not set (with reference to Fig. 6); Flow through the electric current of series LC R alternating current circuit; The danger of " oscillating current " that generation " transient " brings is arranged; When the electric current that flows to this series LC R alternating current circuit vibrates significantly (, when " oscillating current " takes place), shown in Fig. 6 (c); Sometimes the timing bidirectional triode thyristor 46 that descends sharp at the current value I in that flows to dimmer 14 can't keep on-state and become shutoff (malfunction), till the ensuing half period not to power circuit 10 supply powers (promptly so-called " no waveform ")." no waveform " so for example takes place (promptly with 1 minute 1 time degree aperiodically; Even sharply descend and moment becomes under the negative situation at current value I in; Existing bidirectional triode thyristor 46 is kept the situation of on-state; The situation that becomes shutoff is also arranged), but because in that take place should be in the half period of " no waveform ", the average current value of supplying with to lamp 16 descend significantly (almost vanishing); Thereby the illumination of the light that radiates from lamp 16 also reduces widely, and this illumination reduces as the undesirable flicker of the such single-shot property of flash of light and perceived by the people.In addition, the amplitude of " oscillating current " is big more, and the frequency that bidirectional triode thyristor 46 carries out malfunction is high more, and the frequency of " no waveform " is also high more, and " flicker " also increases thereupon.
Under the situation of the stabilisation resistance 42 that appropriate resistance value R is arranged (Fig. 3); " oscillating current " do not take place; Become the current value I in that flows to dimmer 14 after connecting and can sharply not descend being right after bidirectional triode thyristor 46; But stable, " no waveform " do not take place, so do not have the problem of " flicker of single-shot property " of above-mentioned that kind.In addition, the peak value self of inrush current that becomes the timing of connection at bidirectional triode thyristor 46 also reduces, so the noise terminal voltage that reaches supply line 44 is step-down also.
In addition; The power loss that causes about stabilisation resistance 42; Under the situation of the power circuit 10 that is used to make the lamp about 5W for example to light; It is following (promptly that input current Iin is roughly 0.1 [A]; If establish efficiency eta=70% of lamp power P o=5W, alternating voltage Vin=100V, power supply; Input power factor PF=80%; The input current of power circuit 10
then), resistance value R is that the power loss in the stabilisation resistance 42 of 63 [Ω] is below the 0.63W, can not become the rank of loss energy-saving effect.
According to power circuit of the present invention, just can eliminate owing to the undesirable single-shot property flicker that takes place of malfunction aperiodically of the bidirectional triode thyristor in the dimmer of phase control mode with less power loss.
Description of drawings
Fig. 1 is the figure that power circuit of the present invention is shown.
Fig. 2 is the figure that the model of series LC R alternating current circuit is shown.
Fig. 3 is the figure that the waveform under the situation of the stabilisation resistance that is provided with appropriate resistance value is shown.
Fig. 4 illustrates the figure of the power circuit of technology in the past.
Fig. 5 is the figure that model in the technology in the past, L-RC parallel connection alternating current circuit is shown.
Fig. 6 is the figure that the resistance value of the stabilisation resistance waveform when incorrect is shown.
Description of reference numerals
10: power circuit; 12: commercial ac power source; 14: dimmer; 16: lamp; 18: rectification circuit; 20: reduction voltage circuit; 21: power supply circuits; 22: line filter; 24: diode; 26: full bridge circuit; 28: smoothing capacitor; 30: switch is used FET; 32: high speed diode; 34: current limliting is used inductor; The 35:FET switch portion; 36: current detecting is used resistance; The 38:PWM circuit; 40: capacitor is used in protection against noise; 42: stabilisation resistance; 44: supply line; 46: bidirectional triode thyristor; 48: filter circuit; 50: coil; 52: capacitor.
Embodiment
Below, use description of drawings to use power circuit 10 of the present invention.Fig. 1 is the figure that the power circuit 10 of present embodiment is shown.
In addition; In the present embodiment, used the lamp 16 that two LED are connected in series on positive direction, but lamp 16 is not limited thereto certainly; For example; As the Halogen lamp LED of lighting with the direct voltage of 12V etc., so long as the light source of lighting with the voltage that commercial ac voltage is carried out the rectification step-down, then its kind is unrestricted with a number average.
Smoothing capacitor 28 establishes as required, make the direct voltage of the pulsating current of supplying with from full bridge circuit 26 more level and smooth and with the capacitor of line filter 22 cooperations reduction switching noise; As its kind; For example, can serviceability temperature characteristic good film capacitor etc.
This reduction voltage circuit 20; With electric current detection resistance 36 the point light current of lamp 16 is detected as read-out voltage (current detecting is with the read-out voltage=light current * current detecting of resistance 36 resistance value with resistance 36); According to making FET switch portion 35 carry out switch motion from the pulse width signal of pwm circuit 38 outputs accordingly with this read-out voltage; And thus to carrying out pulse width control, the steady state point light current to be provided to lamp 16 from the some light current of FET switch portion 35 outputs.
Protection against noise is in 44 of a pair of supply lines that power supply circuits 21 and commercial ac power source 12 are electrically connected, is the primary side of power supply circuits 21 with capacitor 40, the capacitor that power supply circuits 21 are in parallel installed with.Protection against noise can be selected type arbitrarily with capacitor 40 used capacitors; But it is to get final product with above-mentioned smoothing capacitor 28 same little electric capacity that the electric capacity of capacitor 40 is used in the protection against noise of present embodiment, so preferred serviceability temperature characteristic good film capacitor etc.
Dimmer 14 (dimmer 14 is not the key element that constitutes power circuit 10) has been to use the dimmer of the phase control mode of bidirectional triode thyristor 46; Through the phase angle of connecting by this bidirectional triode thyristor 46 of phase control signal control (scratch start phase angle); Make the mean variation that supplies to the electric current of lamp 16 via power circuit 10, lamp 16 is carried out brightness adjustment control.In addition, in dimmer 14, as to the countermeasure of high-frequency noise and be provided with filter circuit (noise prevention circuit) 48, this filter circuit 48 has coil 50 that bidirectional triode thyristor 46 is connected in series and the capacitor 52 that this coil 50 is connected in parallel.
As typical case, it is the element of 100 μ H that the coil of filter circuit 48 50 is used inductance L, and it is the element of 0.1 μ F that capacitor 52 is used capacitance C.The resonance frequency f of filter circuit 48
xCan be with f
x=1/ (2 π * (L * C)
1/2) represent (that is, if general filter circuit then has fx
), through reducing than this resonance frequency f
xThe high-frequency noise of high frequency field can make the noise terminal voltage reduce to below horizontal by electrical appliance safety law regulation.
If via 14 pairs of such power circuits 10 of dimmer the alternating voltage Vi from commercial ac power source 12 (will be made as [Vin] to the alternating voltage that dimmer 14 provides from commercial AC power 12) is provided, this AC power Vi imports rectification circuit 18 via supply line 44 through line filter 22.Import the alternating voltage Vi of rectification circuit 18, by this rectification circuit 18 carry out full-wave rectification, level and smooth after, supply to the reduction voltage circuit 20 of the primary side that is installed in rectification circuit 18 as the direct voltage Vdc of pulsating current.And, receive the reduction voltage circuit 20 of the direct voltage Vdc of the pulsating current supply to reduction voltage circuit 20, the steady state point light current that is depressured to predetermined voltage (for example, from several V to tens V) is supplied to lamp 16, lamp 16 is lighted.
In power circuit 10 of the present invention, the protection against noise through the coil 50 in the dimmer 14 of commercial ac power source 12, phase control mode, line filter 22 forms series LC R alternating current circuit (with reference to Fig. 2) with capacitor 40 and stabilisation resistance 42.When bidirectional triode thyristor 46 was connected, for bidirectional triode thyristor 46, the lamp point light current that lamp 16 is lighted was overlapping with the electric current that flows through this series LC R alternating current circuit.
In the electric current that flows to this series LC R alternating current circuit,, flow through " oscillating current " that the current value of this circuit vibrates significantly during extremely short also sometimes because above-mentioned " transient ".Can use inductance L [H], the protection against noise of coil 50 to judge with the capacitance C [F] of capacitor 40 and the resistance value R [Ω] of stabilisation resistance 42 whether this " oscillating current " takes place.
That is, satisfy R in above-mentioned physical quantity
2During>=4 * L/C, judge that this series LC R alternating current circuit is that " non-vibration property " is (wherein, at R
2Be called " critical " state during=4 * L/C.)。And, " oscillating current " in this case, not only do not take place, and the peak value of inrush current reduces also self.
For example, be made as 100 μ H, protection against noise when being made as 0.1 μ F with the capacitance C of capacitor 40 in the inductance L with coil 50, the value of 4 * L/C becomes 4,000.4,000 square root is 63.2, so at this moment, if the resistance value R of stabilisation resistance 42 >=64 [Ω], then series LC R alternating current circuit is " a non-vibration property ".
Otherwise the resistance value R of stabilisation resistance 42 (certainly, also comprises the situation (R=0) that does not have stabilisation resistance) under the situation below 63 [Ω], and series LC R alternating current circuit is " vibratility ".
Under the situation that appropriate stabilisation resistance 42 is not set (with reference to Fig. 6); Flow to the electric current of series LC R alternating current circuit; The danger of " oscillating current " that generation " transient " brings is arranged, when the electric current that flows to this series LC R alternating current circuit vibrates significantly (, when " oscillating current " takes place); Shown in Fig. 6 (c); Sometimes the timing that descends sharp at the current value I in that flows to dimmer 14, bidirectional triode thyristor 46 can't keep on-state and become shutoff (malfunction), till the ensuing half period not to power circuit 10 supply powers (promptly so-called " no waveform ")." no waveform " so for example takes place with 1 minute 1 time degree aperiodically; But owing to taking place to be somebody's turn to do in the half period of " no waveform "; The average current value of supplying with to lamp 16 descend significantly (almost vanishing); Thereby the illumination of the light that radiates from lamp 16 also reduces widely, and this illumination reduces as the undesirable flicker of the such single-shot property of flash of light and perceived by the people.In addition, the amplitude of " oscillating current " is big more, and the frequency that bidirectional triode thyristor 46 carries out malfunction is high more, and the frequency of " no waveform " is also high more, and " flicker " also increases thereupon.
In addition, the vibration frequency f of " transient " oscillating current of causing
bCan be with 1/ (2 π * (L * C)
1/2) expression, so under the situation of above-mentioned numerical example,
In addition, the amplitude of oscillating current slowly decay along with effluxion.
Under the situation of the stabilisation resistance 42 that appropriate resistance value R is arranged; As shown in Figure 3, " oscillating current " do not take place, and the current value I in that after bidirectional triode thyristor 46 becomes connection, and then flows to dimmer 14 can sharply not descend; But it is stable; " no waveform " do not take place, and (in Fig. 3 (e), the current value I i that flows to lamp 16 has become zero in the timing early than the shutoff of bidirectional triode thyristor 46 so do not have the problem of " flicker of single-shot property " of above-mentioned that kind; This is because for the electric current to lamp 16; If come the direct voltage Vdc comparison reduction voltage circuit 20 predefined minimum voltage actions of self-rectifying circuit 18 little, then the action of reduction voltage circuit 20 stops, no longer to lamp 16 supplying electric currents.Fig. 6 (e) too).In addition, become the also step-down of peak value self of inrush current of the timing of connection at bidirectional triode thyristor 46, so the noise terminal voltage that reaches supply line 44 is step-down also.
In addition; The power loss that causes about stabilisation resistance 42; Under the situation of the power circuit 10 that is used to make the lamp about 5W for example to light; Input current is roughly below 0.1 [A], and resistance value R is that the power loss in the stabilisation resistance 42 of 63 [Ω] is below the 0.63W, can not become the rank of loss energy-saving effect.
But, for the upper limit of the resistance value R of stabilisation resistance 42, compare with the power of supplying with to lamp 16 from power circuit 10, need be restricted to: the consumed power in the stabilisation resistance 42 can too not become greatly, the degree of not losing energy-saving effect.
If the power of supplying with to lamp 16 from power circuit 10 with apparent power Pa performance is (though also can show with effective power; But complicate owing to introducing power factor as parameter; So use apparent power Pa); The consumed power Pb of stabilisation resistance 42 (resistance value R) as Iin, can be expressed from the next input current generally.
As the rank of not damaging energy-saving effect; For example; If attempt considering that be that 10VA, alternating voltage Vin are the so typical example of 100V from power circuit 10 to the apparent power of the power of lamp 16 supplies; Then thinking that the consumed power Pb in the stabilisation resistance 42 is being (to be that Pb＜Pa/2), the upper limit of R is provided by following formula under the appropriate situation from power circuit 10 below 1/2 to the apparent power Pa of the power that lamp 16 is supplied with.
R＜(Vin
2/(2Pa))＝(100
2/(2×10))＝500[Ω]
The inductor L of the coil 50 in the filter circuit 48 of dimmer 14 is generally 100 μ H; So be made as 500 Ω when following at resistance value R with stabilisation resistance 42; In order to form the current waveform of " non-vibration property ", protection against noise is preferably more than the 0.0016 μ F with the capacitance C of capacitor 40.
R
2≥4×L/C←→C≥4×L/R
2
C≥4×100×10
-6/500
2
C≥0.0016×10
-6[F]
With capacitor 40, can use film capacitor (ceramic capacitor of perhaps such low capacity) as protection against noise.With the resistance value R of decision stabilisation resistance 42 in the above-mentioned following scope that is limited to the upper limit, thereby make protection against noise become appropriate capacitance C with capacitor 40.
From power circuit 10 under the big situation of the apparent power Pa of the power that lamp 16 is supplied with, the consumed power in stabilisation resistance 42 exceedingly becomes greatly, and the consumed power in the stabilisation resistance 42 is diminished with respect to the ratio of this apparent power Pa.For example, if be under the situation of 100VA at the apparent power Pa of the power of supplying with to lamp 16 from power circuit 10, be made as with the consumed power in the stabilisation resistance 42 be suppressed to apparent power Pa 1/5 (=20W) about, then have
R＜Vin
2/5×Pa＝20[Ω]。
Because the inductance of the coil 50 in the filter circuit 48 of dimmer 14 is generally 100 μ H; So when the resistance value R with stabilisation resistance 42 is made as 20 Ω; In order to form the current waveform of " non-vibration property ", need protection against noise be set at (C >=1 μ F) more than the 1 μ F with the capacitance C of capacitor 40.The capacitance C of this degree that protection against noise is required with capacitor 40 fully has substantial value, for example, can use film capacitor as protection against noise with capacitor 40.
Claims (1)
1. power circuit; To carrying out the rectification step-down from commercial AC power via the alternating voltage of the dimmer of phase control mode input and supplying power to lamp; This dimmer filter circuit of having bidirectional triode thyristor and possessing coil that is connected in series with said bidirectional triode thyristor and the capacitor that is connected with said coils from parallel connection of coils wherein
Said power circuit is characterised in that to possess:
Power supply circuits, have to said alternating voltage carry out rectification and form pulsating current direct voltage Vdc rectification circuit and to carry out the reduction voltage circuit of the on-off mode of step-down from the said direct voltage of said rectification circuit; And
Be arranged on the line filter of the primary side of said power supply circuits,
Said line filter has:
Between a pair of supply line with said power supply circuits and the electrical connection of said commercial ac power source, use capacitor with the protection against noise that said power supply circuits are in parallel installed with, and
In the primary side of said protection against noise with capacitor, the stabilisation resistance of at least one side of said a pair of supply line, installing,
If the capacitance that the inductance of the said coil in the said filter circuit of said dimmer is the said protection against noise in L, the said line filter uses capacitor is during as C, the resistance value R of said stabilisation resistance satisfies following formula,
R
2≥4×L/C，
Wherein, the unit of L is that the unit of H, C is F, and the unit of R is Ω.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110045829XA CN102651927A (en) | 2011-02-25 | 2011-02-25 | Power supply circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110045829XA CN102651927A (en) | 2011-02-25 | 2011-02-25 | Power supply circuit |
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|---|---|
| CN102651927A true CN102651927A (en) | 2012-08-29 |
Family
ID=46693798
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|---|---|---|---|
| CN201110045829XA Pending CN102651927A (en) | 2011-02-25 | 2011-02-25 | Power supply circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105846661A (en) * | 2015-02-02 | 2016-08-10 | 意法半导体(图尔)公司 | Inrush current limiting circuit |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1421986A (en) * | 2001-11-29 | 2003-06-04 | 三垦电气株式会社 | Switch type power source |
| JP2004296205A (en) * | 2003-03-26 | 2004-10-21 | Matsushita Electric Works Ltd | Led dimming and lighting device and illuminating equipment |
| US20100164406A1 (en) * | 2008-07-25 | 2010-07-01 | Kost Michael A | Switching power converter control with triac-based leading edge dimmer compatibility |
| CN101790269A (en) * | 2010-03-10 | 2010-07-28 | 李福南 | LED power supply with no-load and light-load protection output and capable of receiving phase-cut dimming stably |
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| CN1421986A (en) * | 2001-11-29 | 2003-06-04 | 三垦电气株式会社 | Switch type power source |
| JP2004296205A (en) * | 2003-03-26 | 2004-10-21 | Matsushita Electric Works Ltd | Led dimming and lighting device and illuminating equipment |
| US20100164406A1 (en) * | 2008-07-25 | 2010-07-01 | Kost Michael A | Switching power converter control with triac-based leading edge dimmer compatibility |
| CN101790269A (en) * | 2010-03-10 | 2010-07-28 | 李福南 | LED power supply with no-load and light-load protection output and capable of receiving phase-cut dimming stably |
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| CN105846661A (en) * | 2015-02-02 | 2016-08-10 | 意法半导体(图尔)公司 | Inrush current limiting circuit |
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Application publication date: 20120829 |