WO2018172980A1 - Circuit électronique pour piloter une chaîne de diodes électroluminescentes - Google Patents

Circuit électronique pour piloter une chaîne de diodes électroluminescentes Download PDF

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Publication number
WO2018172980A1
WO2018172980A1 PCT/IB2018/051963 IB2018051963W WO2018172980A1 WO 2018172980 A1 WO2018172980 A1 WO 2018172980A1 IB 2018051963 W IB2018051963 W IB 2018051963W WO 2018172980 A1 WO2018172980 A1 WO 2018172980A1
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WO
WIPO (PCT)
Prior art keywords
voltage
string
terminal
emitting diodes
light
Prior art date
Application number
PCT/IB2018/051963
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English (en)
Inventor
Sandro Toffoletto
Original Assignee
Cynergi S.R.L.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Cynergi S.R.L. filed Critical Cynergi S.R.L.
Priority to LTEPPCT/IB2018/051963T priority Critical patent/LT3603344T/lt
Priority to EP18717700.1A priority patent/EP3603344B1/fr
Priority to MA48993A priority patent/MA48993B1/fr
Priority to BR112019019975A priority patent/BR112019019975A2/pt
Priority to ES18717700T priority patent/ES2928692T3/es
Publication of WO2018172980A1 publication Critical patent/WO2018172980A1/fr

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/40—Details of LED load circuits
    • H05B45/44—Details of LED load circuits with an active control inside an LED matrix
    • H05B45/48—Details of LED load circuits with an active control inside an LED matrix having LEDs organised in strings and incorporating parallel shunting devices
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/40—Details of LED load circuits
    • H05B45/44—Details of LED load circuits with an active control inside an LED matrix

Definitions

  • the present invention generally relates to the electronics field .
  • the present invention concerns a circuit for driving a string of light-emitting diodes.
  • LEDs light-emitting diodes
  • the lamp is implemented using a string of LEDs, that is a plurality of LEDs serially connected each other (optionally arranged in groups, each one composed of several LEDs), in such a way that the series provides the luminosity required by the application.
  • the distributed line voltage is an alternating type (typically at 50 Hz) and has high values (typically an effective value of 120 or 220-230 Volts), it is necessary to use appropriate devices to convert the alternating voltage into lower values such to enable the LED string to be driven correctly.
  • a first solution for driving the LED string is to use an AC-DC converter (for example of the SMPS - switch mode power supply type) which converts alternating voltage into direct voltage with lower values (for example, 60 Volts).
  • AC-DC converter for example of the SMPS - switch mode power supply type
  • the first solution is efficient from an energy standpoint, but requires the use of transformers and large inductors and capacitors, which thus occupy space and moreover reduce reliability.
  • a second solution (commonly referred to as AC "direct drive”) is to avoid the use of AC-DC converters, i.e. the LED string is driven directly using alternating voltage and the LEDs light up in sequence following the sinusoidal waveform of the alternating voltage, through the use of appropriate control circuits; for example, use can be made of the integrated circuits identified with the codes TPS92410, by Texas Instruments, NSI45020, by ON Semiconductor, IS31 LT3170, by ISSI and the Acrich family by Seoul Semiconductor.
  • the second solution (and in part also the first) poses the problem of flicker in the LED string , i.e. the luminous intensity of the LED string is not constant over time as part of the LEDs of the string pulses following the frequency of the half wave generated by the rectifier with a frequency that is typically double that of the alternating voltage of theelectric line: this could induce visual fatigue and loss of concentration for the people present in the environment illuminated by the LED string in the event of long stays, as in the case of work environments.
  • the known direct AC drive solutions are capable of only partly reducing flicker in the LED string and, furthermore, have other disadvantages, such as, for example, that of requiring the use of an external reference voltage (generated, for example, by a battery; see US 9232576), or using an alternating voltage with a frequency higher than that of the line voltage, or it can function only with low values of the alternating voltage supply (again see US 9232576).
  • the present invention relates to an electronic circuit for driving a string of light- emitting diodes as defined in the enclosed claim 1 and by its preferred embodiments described in the dependent claims 2 to 10.
  • alternating voltage supply i.e. it can operate with high (1 15-230 Volts and even up to 400 Volts), medium and low voltage values;
  • the luminous flux generated by the LED string is adjustable in intensity (dimming).
  • Figure 1 shows a block diagram of an electronic circuit for driving a string of light- emitting diodes according to a first embodiment of the invention
  • Figure 2 shows a block diagram of an electronic circuit for driving a string of light- emitting diodes according to a second embodiment of the invention
  • Figure 3 shows a block diagram of an electronic circuit for driving a string of light- emitting diodes according to a third embodiment of the invention
  • FIG. 4A-4C schematically show a possible trend of some signals of the electronic driving circuit of the first embodiment.
  • FIG. 1 shows an electronic circuit 1 for driving a string 5 of light-emitting diodes according to a first embodiment of the invention.
  • string of diodes means a series connection of two or more light- emitting diodes, hereinafter indicated as LEDs.
  • a LED string can be divided into a plurality of segments, each segment comprising the series connection of a plurality of LEDs.
  • two or more LEDs connected in series can be grouped in such a way as to form a group of LEDs and thus a LED string can be composed of two or more groups of LEDs. Furthermore one or more groups (or segments) of LEDs can be in turn composed of the parallel connection of two or more series of LEDs.
  • the electronic driving circuit 1 comprises:
  • the rectifier 3 comprises two input terminals adapted to receive a positive alternating voltage VAC+ and a negative alternating voltage VAC- and comprises an output terminal adapted to generate a rectified alternating voltage V RT F, as a function of the positive and negative alternating voltages V A c+ and V A cr-
  • the rectifier 3 is implemented with a full wave diode bridge, as shown in Figure 1 .
  • the current regulator 4 is electrically connected to the rectifier 3 and to the LED string 5.
  • the current regulator 4 comprises an input terminal Ito adapted to receive the rectified alternating voltage V RT F and comprises four input terminals It-i, lt 2 , lt 3 , lt 4 electrically connected to four respective different voltages of the LED string 5, as will be explained in greater detail below.
  • the current regulator 4 has the function of regulating the total value of the current l s t r flowing across the LED string 5, as will be explained in greater detail below.
  • the current regulator 4 is an integrated circuit by Altoran Chip & Systems (www.altoranCNS.com), identified with the code ACS1404.
  • the LED string 5 comprises a first terminal connected to the rectified alternating voltage V RT F and comprises a second terminal connected to the current regulator 4.
  • the LED string 5 comprises the series connection of four LEDs 5- 1 , 5-2, 5-3, 5-4, wherein:
  • anode a ⁇ of the first LED 5-1 (i.e. the first terminal of the LED string 5) is connected to the output terminal of the rectifier 3 and thus it is such to receive the rectified alternating voltage V RT F;
  • cathode of the first LED 5-1 is connected to anode a 2 of the second LED 5-2; cathode of the second LED 5-2 is connected to anode a3 of the third LED 5-3; cathode of the third LED 5-3 is connected to anode a 4 of the fourth LED 5-4.
  • the first input terminal Iti of the current regulator 4 is connected to the anode a 2 of the second LED 5-2
  • the second input terminal lt 2 of the current regulator 4 is connected to the anode a3 of the third LED 5-3
  • the third input terminal It3 of the current regulator 4 is connected to the anode a 4 of the fourth LED 5-4
  • the fourth input terminal lt 4 of the current regulator 4 i.e. the second terminal of the LED string 5-4.
  • each of the LEDs 5-1 , 5-2, 5-3, 5-4 can be a series connection of two or more LEDs, that is, each series connection is a segment of the LED string 5.
  • the component 5-1 represents a first group of LEDs connected in series (i.e. a first segment of the LED string 5)
  • the component 5-2 represents a second group of LEDs connected in series (i.e. a second segment of the LED string
  • the component 5-3 represents a third group of LED connected in series (i.e. a third segment of the LED string 5) and the component 5-4 represents a fourth group of LEDs connected in series (i.e. a fourth segment of the LED string 5).
  • the current regulator 4 is such to control:
  • the current l 4 enters the fourth input terminal lt 4 of the current regulator 4 and flows towards the ground reference voltage.
  • the electronic switch 6 comprises a first terminal Ite, a second terminal Ot 7 and a control terminal lt 7 for controlling the opening and closing of the electronic switch 6.
  • the electronic switch 6 is switchable between an open position and a closed position as a function of the value of a control signal V g on the control terminal lt 7 , wherein:
  • the electronic switch 6 in the open position the electronic switch 6 is equivalent to an open circuit between the first terminal lt 6 and the second terminal Ot 7 ;
  • the electronic switch 6 is substantially equivalent to a short circuit between the first terminal ⁇ i & and the second terminal Ot 7 .
  • the capacitor 7 is interposed between the first terminal of the LED string 5 and the electronic switch 6.
  • the capacitor 7 comprises a first terminal connected to the anode ai of the first LED 5-1 (and thus connected to the output of the rectifier 3) and thus it is such to have the value of the rectified alternating voltage V RT F-
  • the capacitor 7 further comprises a second terminal connected to the first terminal ⁇ of the electronic switch 6.
  • the capacitor 7 has the function of storing electric energy in each period of the rectified alternating voltage V RT F when the latter has an increasing trend (or is in any case greater than a threshold voltage V t h).
  • the capacitor 7 has the function of discharging the electric energy stored therein at least in part through the LED string 5, when the rectified alternating voltage V RT F has a decreasing trend and smaller than the threshold voltage V t h: this allows to reduce the flicker of the luminous intensity of the
  • the electronic switch 6 is implemented with a transistor 6-1 of the n-channel IGBT (insulated gate bipolar transistor) type, having a collector terminal C which coincides with the first terminal lt 6 , having an emitter terminal E which coincides with the second terminal Ot 7 and having a gate terminal G which coincides with the control terminal lt 7 ; therefore, in this case the collector terminal C of the IGBT transistor 6-1 is connected to the second terminal of the capacitor 7, the emitter terminal E is connected to the ground reference voltage and the gate terminal G is connected to the output of the bias stage 8.
  • IGBT insulated gate bipolar transistor
  • the electronic switch 6 (in particular, the IGBT transistor 6-1 ) has the function of switching the capacitor 7 during charging/discharging in an active manner, as will be explained in greater detail below.
  • the electronic switch 6 is implemented with a p-channel IGBT transistor 6-2, as shown in Figure 3.
  • components other than the IGBT transistor can be used, provided that they are capable of switching between the open and closed conditions with a frequency of around 100 Hz, i.e. a switching period comprised between 1 millisecond and 12 milliseconds.
  • the bias stage 8 is interposed between the LED string 5 and the electronic switch 6.
  • the bias stage 8 comprises an input terminal Its adapted to receive a voltage signal Vd3 selected from a voltage internal to the LED string 5 and comprises an output terminal connected to the control terminal lt 7 of the electronic switch 6.
  • the bias stage 8 has the function of generating an appropriate value of the control signal V g of the control terminal lt 7 so as to control the closing and opening of the electronic switch 6 at appropriate time instants in order to charge and discharge the capacitor 7 with the purpose of reducing the flicker of the luminous intensity of the
  • LED string 5 caused mainly by the third and fourth LEDs 5-3, 5-4.
  • choosing a voltage value Vd3 selected from a voltage internal to the LED string 5 allows to anticipate (with respect to the known solution) the instant wherein it is activated the discharging of the capacitor 7 through the LED string 5 and this allows a larger number of light-emitting diodes of the string 5 to be maintained in a conduction state, thus reducing flicker of the luminous intensity of the LED string 5.
  • the input terminal of the bias stage 8 is connected to the anode a 4 of the fourth LED 5-4 and thus the voltage signal Vd3 is the voltage of the anode a 4 of the fourth LED 5-4 (which is equal to the cathode voltage of the third LED 5-3).
  • the bias stage 8 is alternatively such to draw the voltage signal Vd3 from voltage values different than the voltage of the anode a 4 of the fourth LED 5-4, such as for example the voltage of the anode a 3 of the third LED 5-3, as shown in Figure 2 in the second embodiment.
  • the bias stage 8 is such to draw a voltage value V D 3 selected from a voltage internal to the LED string 5 so as to generate, as a function of the selected internal voltage value, a value of a control voltage signal V g that is less than the value of the rectified alternating voltage VRTF, provided that said selected voltage value V D 3 is such to generate the control voltage V g controlling the closing of the electronic switch 6 so as to allow a sufficient charging at the appropriate time of the capacitor 7, whose charge is subsequently used to power the LED string 5 when the value of the rectified alternating voltage VRTF is not sufficient to power all of the LEDs of the string 5: in this way the flicker of the luminous intensity generated by the LED string 5 is reduced.
  • the bias stage 8 is implemented with a voltage divider comprising a first resistor 8-1 and a second resistor 8-2 serially connected each other, wherein the first resistor 8-1 is connected between the voltage Vd3 selected from the LED string 5 and the control terminal lt 7 of the electronic switch 6 and wherein the second resistor 8-2 is connected between the control terminal lt 7 of the electronic switch 6 and the ground reference voltage.
  • the electronic switch 6 When the rectified alternating voltage VRTF has an increasing trend (or is in any case greater than the threshold voltage V t h), the electronic switch 6 is closed and the capacitor 7 is charged; when, by contrast, the rectified alternating voltage V RT F has a decreasing trend and is less than the threshold voltage V t h, the electronic switch 6 opens and the capacitor 7 is discharged.
  • the discharge phase of the capacitor 7 allows at least part of the energy stored therein to be discharged through the LED string 5 and this allows to compensate the reduction of the voltage at the ends of the LEDs string 5, thus considerably reducing (even to the extent of eliminating) the flicker of the luminous intensity of the LEDs string 5.
  • the time instant wherein the discharge phase of the capacitor 7 occurs will vary depending on which voltage signal V D 3 is selected from the LED string 5; therefore it is possible to anticipate or postpone the activation of the capacitor 7 discharge (and thus modify the entity of the reduction of the flicker of the luminous intensity of the LED string 5) by changing the selected voltage signal Vd3 and thus changing the value of the selected voltage.
  • the electronic driving circuit 1 further comprises a discharge circuit 9 connected to the capacitor 7 (for example, interposed between the first terminal of the capacitor 7 and the ground reference voltage) and having the function of further contributing to the discharging of the capacitor 7.
  • the discharge circuit 9 is implemented with a resistor 9-1 having a first terminal connected to the first terminal of the capacitor 7 (and thus connected to the output of the rectifier 3) and having a second terminal connected to the ground reference voltage.
  • Figure 4A shows the trend in the rectified alternating voltage V RT F, the control voltage V g of the gate terminal of the IGBT transistor 6.1 and the selected voltage v d3 ;
  • Figure 4B shows the trend of the voltage drop ⁇ /C at the ends of the capacitor 7 and the voltage V c of the collector terminal of the IGBT transistor 6.1 ;
  • Figure 4C shows the trend of the current ⁇ - ⁇ flowing through the first LED 5-1 , the current flowing through the second LED 5-2, the current I3 flowing through the third LED 5-3 and the current l 4 flowing through the fourth LED 5-4.
  • the value of the gate voltage V G of the IGBT transistor 6-1 has a first value such to maintain the IGBT transistor 6-1 open: during this first phase the capacitor 7 is discharged at least in part through the LED string 5 and thus the voltage drop ⁇ /C at the ends of the capacitor 7 has a decreasing trend;
  • the value of the gate voltage V G of the IGBT transistor 6-1 has a second value such to maintain the IGBT transistor 6-1 closed: during this second phase the capacitor 7 is charged and thus the voltage drop AVC at the ends of the capacitor 7 has first an increasing trend and then a decreasing trend;
  • the value of the current l 3 flowing through the third LED 5-3 is equal to the maximum value l 3 , ma x most of the time and thus the luminous intensity of the third LED 5-3 is substantially constant;
  • the value of the current l 4 flowing through the fourth LED 5-4 is equal to the maximum value l 4 , max most of the time and thus the luminous intensity of the fourth LED 5-4 is substantially constant; the total current l s tr flowing through the LED string 5 has values that are always uniform and thus the luminous intensity of the LED string 5 is substantially constant, since any small fluctuations that might be present are compensated by the intrinsic hysteresis of the LEDs,thus the flicker of the luminous intensity of the LED string 5 is substantially null.
  • the electronic driving circuit 1 or 100 can be implemented with an integrated circuit.
  • the electronic driving circuit 1 or 100 can be realised on one or more printed circuit boards.
  • the electronic driving circuit 50 of Figure 2 differs from the electronic driving circuit 1 of Figure 1 in that the input of the bias stage 8 is the voltage signal V d 2 drawn from the anode a 3 of the third LED 5-3; therefore, the value of said voltage signal Vd2 controls the opening and the closing of the electronic switch 6 (in particular, it controls the cut-off and conduction state of the IGBT transistor 6-1 ).
  • the previous considerations related to the electronic driving circuit 1 may be similarly applied to the electronic driving circuit 50, therefore, the latter, too, is capable of considerably reducing (even to the extent of eliminating) flicker of the luminous intensity of the LED string 5.
  • FIG. 3 shows an electronic circuit 100 for driving a string
  • the electronic driving circuit 100 of Figure 3 differs from the electronic driving circuit 1 of Figure 1 in that:
  • an electronic switch 106 implemented with a transistor 6-2 of the p- channel IGBT type (instead of an n-channel IGBT transistor 6-1 ), wherein the IGBT transistor 6-2 has a collector terminal C connected to the rectified alternating voltage VRTF, an emitter terminal E connected to a first terminal of the capacitor 7 through a resistor 8-4 and a gate terminal G connected to the anode a 4 of the fourth LED 5-4 by means of the voltage divider 108;
  • the capacitor 7 is connected between the IGBT transistor 6-2 and the ground reference voltage (instead of between the IGBT transistor 6-1 and the rectified alternating voltage VRTF) ;
  • the bias stage 108 comprises an input terminal connected to the anode a 4 of the fourth LED 5-4, a first output terminal connected to the gate terminal G of the IGBT transistor 6-2 and a second output terminal connected to the emitter terminal E of the IGBT transistor 6-2;
  • resistor 8-4 having a first terminal connected to the electronic switch 1 06 (in particular, to the emitter terminal E of the IGBT transistor 6-2) and to the bias stage 1 08 and having a second terminal connected to the first terminal of the capacitor 7.
  • the bias stage 1 08 is implemented with a voltage divider comprising the resistors 8-1 , 8-2, 8-3, wherein:
  • the resistor 8-1 is connected between the anode a 4 of the fourth LED 5-4 and the control terminal of the electronic switch 1 06;
  • the resistor 8-2 is interposed between the resistor 8-1 and the ground reference voltage
  • the resistor 8-3 has a first terminal connected to the common terminal between the resistors 8-1 , 8-2 (and thus connected to the control terminal of the electronic switch 1 06) and a second terminal connected to the electronic switch 1 06 (in particular, to the emitter terminal E of the IGBT transistor 6-2) and the resistor 8-4.
  • the previous considerations related to the electronic driving circuit 1 may be similarly applied to the electronic driving circuit 1 00; therefore, the latter, too, is capable of considerably reducing (even to the extent of eliminating) flicker of the luminous intensity of the LED string 5.
  • the input terminal of the bias stage 108 can be connected to other voltage values selected from the LED string 5, such as, for example, the voltage of the anode a 3 of the third LED 5-3, similarly to what was illustrated previously in relation to the description of Figure 2.
  • the electronic driving circuit 1 further comprises a disconnecting stage having the function of disconnecting the LED string 5 from the alternating voltage supply V A c+ so as to interrupt parasitic currents which can activate the LEDs also with a null power signal.
  • the LED string 5 when the value of the alternating voltage supply VAC+ is less than a defined threshold value (for example equal to 1 0% of a reference voltage value VREF), the LED string 5 is disconnected from the rectified alternating voltage V_RTF; when the value of the alternating voltage supply V A c+ is instead greater than or equal to the defined threshold value, the LED string 5 is connected to the rectified voltage V_RTF.
  • a defined threshold value for example equal to 1 0% of a reference voltage value VREF
  • the disconnecting stage is implemented using a reference voltage V RE F generated by the current regulator 4 (for example, equal to 17 Volts), using the pulse-width modulator already used to regulate the luminous intensity of the LED string 5 and using a solid-state relay that interrupts the electrical connection between the rectified alternating voltage V_RTF and the LED string of 5.
  • V RE F generated by the current regulator 4 (for example, equal to 17 Volts)
  • the pulse-width modulator already used to regulate the luminous intensity of the LED string 5
  • a solid-state relay that interrupts the electrical connection between the rectified alternating voltage V_RTF and the LED string of 5.
  • the disconnecting stage comprises:
  • a pulse-width modulator (for example internal to the current regulator 4) configured to generate a square-wave periodic signal SPWM having a period width varying as a function of a configuration signal;
  • an input terminal adapted to receive a reference voltage VREF (for example, generated by the current regulator 4);
  • a comparator comprising a first input terminal adapted to receive a divided reference voltage (i.e. obtained by means of a voltage divider dividing the reference voltage VREF), a second input terminal adapted to receive the square-wave periodic signal SPWM and an output terminal adapted to generate a comparison signal having a high or low logical value, as a function of the comparison between the values of the divided reference voltage and the periodic square-wave signal SPWM;
  • a solid-state relay configured to connect or disconnect the LED string 5 to/from the rectified alternating voltage V_RTF, as a function of the value of the comparison signal.
  • the rectifier 3 is a full-wave diode bridge
  • the LED string 5 is composed of the series connection of four equal LEDs 5-1 , 5-2, 5-3, 5-4 having the same threshold voltage Vt (for example, equal to 3.5 Volts); - the electronic switch 6 is implemented with a transistor 6-1 of the n-channel IGBT type;
  • the current regulator 4 is the integrated circuit ACS1404 by Altoran Chip & Systems, comprising four input terminals It-i , It2, It3, lt 4 connected to the anode a ⁇ of the second LED 5-2, to the anode a3 of the third LED 5-3, to the anode a 4 of the fourth LED 5-4 and to the cathode c 4 of the fourth LED 5-4, respectively;
  • the bias stage 8 is implemented with a voltage divider composed of the resistors 8-1 , 8-2, wherein the voltage V g of the gate terminal G of the IGBT 6-1 is equal to the divided voltage of the terminal common between the resistors 8-1 and 8- 2;
  • a discharge circuit 9 is present and it is implemented with a resistor 9-1 .
  • the rectified alternating voltage V RT F has an increasing sinusoidal trend from the null value to the value of the threshold voltage V ⁇ : the IGBT transistor 6-1 is in the cut-off state, the capacitor 7 is discharged in part through the LED string 5 and in part through the resistor 9 and this allows to maintain the LEDs 5-1 , 5-2, 5-3, 5-4 in the conduction state.
  • the rectified alternating voltage V RT F continues to have an increasing sinusoidal trend and thus the operation is analogous to that at the instant t3, i.e. the IGBT transistor 6-1 conducts and the capacitor 7 is charged to the value of the rectified alternating voltage V RT F-
  • the rectified alternating voltage V RT F reaches a value equal to four times the threshold voltage Vt: the voltage of the gate terminal V g continues to have a high value (in the example considered, equal to 5 Volts) and thus the IGBT transistor 6-1 remains in the conduction state and the capacitor 7 continues to charge.
  • the rectified alternating voltage V RT F falls below the value 3 * Vt
  • the value of the voltage Vd3 of the cathode of the third LED 5-3 decreases and thus the voltage of the gate terminal V g has a transition from the high voltage value to the low voltage value: consequently, the IGBT transistor 6-1 enters the cut-off state and the capacitor 7 starts discharging in part through the resistor 9-1 and in part through the LED string 5, maintaining not only the first and second LEDs 5-1 , 5-2, but also the third and fourth LEDs 5-3, 5-4 in the conduction state.
  • the rectified alternating voltage VRTF continues to have a decreasing sinusoidal trend until reaching the null value: the capacitor 7 continues to discharge in part through the resistor 9-1 and in part through the LED string of 5, maintaining the first and second LEDs 5-1 , LED 5-2 and also the third and fourth LEDs 5-3, 5-4 in the conduction state.
  • the operation of the electronic driving circuit 1 is analogous to that previously described for the instants comprised between to and t3; therefore, the IGBT transistor 6-1 is in the cut-off state, the capacitor 7 is discharged in part through the LED string 5 and in part through the resistor 9 and this discharging maintains the third and fourth LEDs 5-3, 5-4, in addition to the first and second LEDs 5-1 , 5-2, in the conduction state.

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Abstract

L'invention concerne un circuit électronique (1) pour piloter une chaîne de diodes électroluminescentes (5). Le circuit comprend un régulateur de courant (4) comprenant une borne d'entrée configurée pour recevoir une tension alternative redressée (VRTF) et comprenant une pluralité de bornes d'entrée (It1, It2, It3, It4) connectées à des tensions respectives différentes sélectionnées parmi la chaîne de diodes électroluminescentes, le régulateur de courant étant configuré pour réguler la valeur du courant circulant à travers la chaîne de diodes électroluminescentes. Le circuit d'attaque électronique comprend en outre un commutateur électronique (6) configuré pour commuter entre une position fermée et une position ouverte, en fonction de la valeur d'un signal de commande (Vg). Le circuit d'attaque électronique comprend en outre un étage de polarisation (8) comprenant une borne d'entrée configurée pour recevoir une tension sélectionnée à partir d'une tension interne à la chaîne de diodes électroluminescentes et comprenant une borne de sortie configurée pour générer, en fonction de la tension sélectionnée, ledit signal de commande commandant le commutateur électronique. Le circuit d'attaque électronique comprend enfin un condensateur (7) intercalé entre le commutateur électronique et la chaîne de diodes électroluminescentes.
PCT/IB2018/051963 2017-03-24 2018-03-23 Circuit électronique pour piloter une chaîne de diodes électroluminescentes WO2018172980A1 (fr)

Priority Applications (5)

Application Number Priority Date Filing Date Title
LTEPPCT/IB2018/051963T LT3603344T (lt) 2017-03-24 2018-03-23 Elektroninė schema šviesos diodų eilutei valdyti
EP18717700.1A EP3603344B1 (fr) 2017-03-24 2018-03-23 Circuit électronique pour piloter une chaîne de diodes électroluminescentes
MA48993A MA48993B1 (fr) 2017-03-24 2018-03-23 Circuit électronique pour piloter une chaîne de diodes électroluminescentes
BR112019019975A BR112019019975A2 (pt) 2017-03-24 2018-03-23 circuito eletrônico para acionar uma série de díodos emissores de luz
ES18717700T ES2928692T3 (es) 2017-03-24 2018-03-23 Circuito electrónico para excitar una cadena de diodos emisores de luz

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT102017000032546A IT201700032546A1 (it) 2017-03-24 2017-03-24 Circuito elettronico per il pilotaggio di una stringa di diodi ad emissione di luce
IT102017000032546 2017-03-24

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WO2018172980A1 true WO2018172980A1 (fr) 2018-09-27

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PCT/IB2018/051963 WO2018172980A1 (fr) 2017-03-24 2018-03-23 Circuit électronique pour piloter une chaîne de diodes électroluminescentes

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EP (1) EP3603344B1 (fr)
BR (1) BR112019019975A2 (fr)
ES (1) ES2928692T3 (fr)
IT (1) IT201700032546A1 (fr)
LT (1) LT3603344T (fr)
MA (1) MA48993B1 (fr)
WO (1) WO2018172980A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT201900017960A1 (it) 2019-10-04 2021-04-04 Cynergi S R L Lampada LED per illuminazione con controllo radio
EP4072248A1 (fr) * 2021-04-08 2022-10-12 Tepcomp Oy Circuit de réduction de scintillement
WO2023050290A1 (fr) * 2021-09-30 2023-04-06 深圳市汇顶科技股份有限公司 Circuit de génération de signal d'impulsion d'onde sinusoïdale et appareil électronique associé

Citations (3)

* Cited by examiner, † Cited by third party
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ES2928692T3 (es) 2022-11-22
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MA48993A (fr) 2020-02-05
IT201700032546A1 (it) 2018-09-24
LT3603344T (lt) 2023-01-25
EP3603344A1 (fr) 2020-02-05

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