[go: up one dir, main page]

WO2011120855A1 - Appareil destiné à produire un signal d'attaque pour un dispositif à lampe, ainsi que procédé de production d'un signal d'attaque pour un dispositif à lampe - Google Patents

Appareil destiné à produire un signal d'attaque pour un dispositif à lampe, ainsi que procédé de production d'un signal d'attaque pour un dispositif à lampe Download PDF

Info

Publication number
WO2011120855A1
WO2011120855A1 PCT/EP2011/054446 EP2011054446W WO2011120855A1 WO 2011120855 A1 WO2011120855 A1 WO 2011120855A1 EP 2011054446 W EP2011054446 W EP 2011054446W WO 2011120855 A1 WO2011120855 A1 WO 2011120855A1
Authority
WO
WIPO (PCT)
Prior art keywords
pulse
pulse train
pulses
brightness
train
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/EP2011/054446
Other languages
English (en)
Inventor
Walter Englert
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
GLP German Light Products GmbH
Original Assignee
GLP German Light Products GmbH
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
Priority claimed from EP10159003A external-priority patent/EP2373125B1/fr
Priority claimed from US12/752,452 external-priority patent/US20110241560A1/en
Application filed by GLP German Light Products GmbH filed Critical GLP German Light Products GmbH
Priority to JP2012553356A priority Critical patent/JP2013519988A/ja
Priority to CN2011800180969A priority patent/CN102835188A/zh
Publication of WO2011120855A1 publication Critical patent/WO2011120855A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

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]
    • H05B45/10—Controlling the intensity of the light

Definitions

  • the present invention relates to the field of generating drive signals, especially for lamp devices, such as LED spots.
  • the adjustment of the brightness of an LED (light emitting diode) lightning device, such as an LED spot (for example, with a plurality of LEDs) is realized by a fast off and on switching of the LEDs.
  • the frequency of the on and off switching is above 100Hz, the human eye does not recognize the pulsing (the on and off switching) of the LEDs.
  • this on and off switching of the LEDs poses a problem.
  • the pulsing of the LEDs leads to interferences with shutter-times and refresh-rates of the HDTV cameras. This can be recognized by a pulsing of the light in the camera.
  • a modulation signal for the on/off switching of LEDs is typically based on pulse-width modulation (PWM).
  • PWM pulse-width modulation
  • the shutter time of a TV camera defines how long a shutter of the TV camera is opened to acquire one picture. If this mentioned shutter time is very short, then a very high PWM frequency is desired. It has been found that a PWM frequency of 600Hz is sufficient, but a PWM frequency of 1200Hz or 2400Hz offers a safety distance to obtain a picture without pulsing and jittering also in ambient lightning conditions.
  • a typical microcontroller with a typical instruction time of 100ns (which corresponds to a frequency of lOMz), this time is much too short to output impulses of this length. Furthermore, one microcontroller should be used to control a plurality of LEDs to save costs and effort. Therefore, a typical microcontroller cannot be used for providing a signal to drive an LED or a plurality of LEDs of an LED spot, which fulfils all the above- mentioned requirements for modern HDTV cameras. One possibility would be to use high- sophisticated digital signal processing processors, but which would result in a dramatically increase of costs and effort.
  • An object of the present invention is to provide a concept allowing to drive an LED or an LED spot for an HDTV camera with lower requirements to a drive signal generator for the LED or the LED spot than in the prior art.
  • a first drive signal for a first brightness for a lamp device differs from a second drive signal for a second brightness for the lamp device by a frequency or, in other words, by a number of pulses the drive signals contain in a certain amount of time. It has been found that by changing the frequency of the drive signals for a change in brightness, instead of keeping the frequency constant and changing the length of the pulses of the drive signals for changing the brightness, as this is done in PWM, the individual pulses of the drive signals can be made longer than in the conventional PWM. Therefore, a conventional microcontroller and especially a low-cost microcontroller can be used for generating a drive signal for a lamp device, such as an LED or an LED spot.
  • An advantage of the present invention is, therefore, that by changing the frequency to adjust the brightness of a light device, instead of changing the length of pulses and keeping the frequency constant, cheaper and easier devices for generating a drive signal for a lamp device or an LED or an LED spot can be used as this is known in the prior art.
  • Some embodiments of the present invention provide an apparatus for generating a drive signal for a lamp device.
  • the apparatus comprises a pulse generator for generating a first pulse train in response to a first brightness request for a first brightness and for generating a second pulse train in response to a second brightness request for a second brightness.
  • the first pulse train has a first frequency and the second pulse train has a second frequency, wherein the first frequency is different from the second frequency.
  • the second pulse train comprises two neighboring pulses of the first pulse train and a further pulse between the two neighboring pulses, the further pulse not being comprised in the first pulse train.
  • the pulse generator may be configured to generate the first and the second pulse trains such that a pulse length of the two neighboring pulses and of the further pulse is identical.
  • the pulse generator may be configured to change a brightness of the lamp device by adding or removing pulses of an equidistant length.
  • the frequency of the drive signal is constant and a change of brightness is attained by changing the on/off ratio of the pulses.
  • different drive signals for different degrees of brightness differ only by the on/off ratio of the pulses (and therefore by the length of the pulses) and not by the frequency of the drive signal itself.
  • the second brightness may be brighter than the first brightness, for example, if a pulse is a current pulse provided to the lamp device.
  • the apparatus may further comprise a brightness request generator, which is configured to provide at least a first and a second brightness request to an input terminal of the pulse generator.
  • the pulse generator may, for example, receive the first and the second brightness request at the input terminal and may output a drive signal with a corresponding pulse train, for example, depending on an internal lookup table.
  • FIG. 1 shows an apparatus according to an embodiment of the present invention coupled to a lamp device; shows two diagrams of pulse trains generated by a pulse generator of the apparatus shown in Fig. la; shows diagrams of the two pulse trains shown in Fig. lb and of corresponding PWM signals; shows a block diagram of an apparatus according to an embodiment of the present invention coupled to a lamp device; shows two diagrams of pulse trains generated by a pulse generator of the apparatus shown in Fig. 3 a; shows diagrams of the two pulse trains shown in Fig. 3b and of corresponding PWM signals;
  • Fig. 5 shows an apparatus according to an embodiment of the present invention coupled to a lamp device
  • Figs. 6a to 6d show diagrams of pulse trains generated by pulse generators of apparatuses according to embodiments of the present invention
  • Fig. 7 shows a flow diagram of a method according to an embodiment of the present invention.
  • a pulse length may in the following also be called as a pulse time or as a temporal extension of the pulse.
  • Fig. la shows a block diagram of an apparatus 100 according to an embodiment of the present invention coupled to a lamp device 110.
  • the apparatus 100 for generating a drive signal 120 for the lamp device 110 comprises a pulse generator 130.
  • the pulse generator 130 is configured to generate a first pulse train 140 (shown in Fig. lb) and to generate a second pulse train 160 (shown in Fig. lb).
  • the first pulse train 140 and the second pulse train 160 may be provided at an output terminal 180 of the apparatus 100 and may as a continuous stream create the drive signal 120 > wherein a drive signal 120 based on the first pulse train 140 would result in another brightness of the lamp device 110 than a drive signal 120 based on the second pulse train 160.
  • the pulse generator 130 is configured to generate the first pulse train 140 in response to a first brightness request for a first brightness and to generate the second pulse train 160 in response to a second brightness request for a second brightness.
  • the first pulse train 140 has a frequency f 140 , which is different to a frequency fi 60 of the second pulse train 160. Therefore, the first brightness may be different from the second brightness, for example, the first brightness may be higher than the second brightness.
  • Fig. lb shows a schematic diagram 150 of the first pulse train 140 and a schematic diagram 170 of the second pulse train 160
  • the first pulse train 140 comprises at least a first pulse 142a and a second pulse 142b.
  • the second pulse train 160 comprises the two neighboring pulses 142a, 142b of the first pulse train 140 and a further pulse 162a between the two neighboring pulses 142a and 142b.
  • the further pulse 162a is not comprised nor contained in the first pulse train 140. Because of the temporal arrangement of the further pulse 162a between the two neighboring pulses 142a, 142b a second time t 160 between two temporally-subsequent pulses of the second pulse train 160 is shorter than the first time t 140 (between the two neighboring pulses 142a, 142b) of the first pulse train 140.
  • a first time t 16 o between a rising edge of the first neighboring pulse 142a and a rising edge of the temporally- following further pulse 162a is shorter than the first time t 140 between the rising edge of the first neighboring pulse 142a and the rising edge of the second neighboring pulse 142b of the first pulse train 140. Therefore, a frequency f 1 0 of the second pulse train 160 is higher than a frequency f 140 of the first pulse train 140.
  • the further pulse 162a is temporally arranged between the two neighboring pulses 142a, 142b such that a time between the rising edge of the first neighboring pulse 142a and the rising edge of the further pulse 162a is the same, like a time between the rising edge of the further pulse 162a and a rising edge of the second neighboring pulse 142b.
  • the further pulse 162a could also be arranged in a temporally-arbitrary position between the two neighboring pulses 142a, 142b.
  • the frequency fi 60 of the second pulse train 160 is double the amount of the frequency f 14 o of the first pulse train 140.
  • a brightness of the lamp device 110 may be higher when the second pulse train 160 is provided as the drive signal 120 to the lamp device 110 than when the first pulse train 140 is provided as a drive signal 120 to the lamp device 110.
  • An amplitude I pu i se of the pulses of the first pulse train 140 and the second pulse train 160 may, for example, represent a current flowing through the lamp device 110.
  • the lamp device 110 is switched on more often at the same time (for example, the time t 140 ) than when the first pulse train 140 is applied as a drive signal 120.
  • the time unit in which the lamp device 110 is switched on and off is chosen such that the human eye is not able to see the on/off switching of the lamp device 110.
  • a pulse length t pu i se or of the two neighboring pulses 142a, 142b and the further pulse 162a may be identical.
  • the first time ti 40 and the second time t 16 o may be a multiple of the pulse length t pu i se .
  • a temporal extension of the first pulse train 140 and a temporal extension of the second pulse train 160 may be identical, as is shown in Fig. lb. In Fig. lb, the temporal extension of the first pulse train 140 is the first time t 140 and a temporal extension of the second pulse train 160 is twice the second time t 160 , wherein the second time ti 60 is half of the first time t 14 o.
  • the drive signal 120 may comprise a plurality of first pulse trains 140 or second pulse trains 160.
  • the drive signal 120 would, for example, be a continuous stream of pulse trains 140 and for the second brightness, the drive signal 120 would be a continuous stream of the pulse trains 160.1n a drive signal 120 based on the first pulse trains 140, a time between two rising edges of two temporally subsequent pulses would be the first time t 14 o.
  • a time between two rising edges of two temporally subsequent pulses would be the second time t 16 o-
  • a time between two rising edges of subsequent following pulses of a pulse train may vary within in the pulse train, therefore a time between two rising edges of pulses of the pulse train may be different for different subsequent following pulses of the pulse train.
  • the pulse generator 130 may be further configured to generate a plurality of pulse trains in response to a plurality of different brightness requests, such that a pulse train out of the plurality of pulse trains corresponds to a brightness request out of the plurality of brightness requests.
  • Different pulse trains may differ from each other by the number of pulses they comprise.
  • a temporal extension of the different pulse trains may be identical for all pulse trains.
  • the pulse train generator 130 may comprise a microcontroller, which is configured to provide the drive signal 120 or a plurality of drive signals 120 at an output terminal or at a plurality of output terminals.
  • An output terminal of the microcontroller may, for example, be an I/O pin of the microcontroller.
  • the I/O pin of the microcontroller may be coupled to the lamp device 110, by directly connecting the lamp device 110 to the I/O pin, or with a lamp device driver, which provides a drive current for the lamp device 110, between the I/O pin and the lamp device 110.
  • the lamp device 110 may comprise an LED or a plurality of LEDs or any other lightning devices.
  • a lamp device 110 comprising a plurality of lightning devices or LEDs may therefore comprise a plurality of input terminals for the plurality of drive signals 120, such that degrees of brightness of the different LEDs or lightning devices of the lamp device 110 can differ from each other.
  • the different LEDs or lightning devices of the lamp device 110 may comprise different colors, for example, an LED or a lightning device for red, an LED or a lightning device for green and an LED or a lightning device for blue.
  • the lamp device 110 may be an RGB lamp device.
  • Fig. 2 shows the schematic diagram 150 of the first pulse train 140 from Fig. 1 and a schematic diagram 210 of a corresponding PWM signal 220. Furthermore, Fig. 2 shows the schematic diagram 170 of the second pulse train 160 from Fig. lb and a schematic diagram 230 of a corresponding PWM signal 240.
  • the first PWM signal 220 corresponds to the first pulse train 140, because a sum of pulse durations of pulses of the first PWM signal 220 in a given time interval (for example, the time interval t 140 ) is equal to the sum of pulse durations of pulses of the first pulse train 140 in the given time interval.
  • the second PWM signal 240 corresponds to the second pulse train 160, because the sum of pulse durations of pulses of the second PWM signal 240 in the given time interval is equal to a sum of pulse durations of pulses of the second pulses train 160 in the given time interval.
  • a first number of charge carriers flowing into the lamp device 110 in the time interval t 1 0 is the same when the drive signal 120 is based on the first pulse train 240 or on the second PWM signal 220 and a second number of charge carriers flowing into the lamp device 110 is the same when the drive signal 120 is based on the second pulse train 160 or on the second PWM signal 240. Therefore, the first brightness corresponding to the first pulse train 140 also corresponds to the first PWM signal 220 and the second brightness corresponding to the second pulse train 160 also corresponds to the second PWM signal 240.
  • the first PWM signal 210 comprises four pulses 222a, 222b, 222c, 222d in the time interval t 140 between the two neighboring pulses 142a and 142b of the first pulse train 140.
  • a time interval tpwM between two rising edges of neighboring pulses of the second PWM signal 220 is a quarter of t 1 0 (tj 40 /4).
  • a frequency fpwM of the first PWM signal 220 is, therefore, four times higher than the frequency f 140 of the first pulse train 140.
  • a drawback of the conventional PWM is that the frequency for a conventional PWM drive signal stays constant for every brightness request.
  • a minimum pulse duration of a PWM signal has to be much shorter than in embodiments of the present invention, wherein drive signals 120 for different brightness requests differ by frequency.
  • a pulse length of the pulses 222a to 222d of the first PWM signal 220 is one-fourth of the pulse length t pu i S e of the pulses 142a, 142b of the first pulse train 140. Therefore, a pulse generator generating the second PWM signal 220 has to be at least four times faste than a pulse generator 130 for generating the first pulse train 140.
  • a low frequency of the first pulse train 140 compared to the second PWM signal 220 is not a problem, because TV cameras only react in a sensitive manner to low frequencies of the pulsing of the lamp device 110 with higher brightness (for example, half of the maximum brightness of the lamp device 110).
  • a brightness of the lamp device 110 is increased by raising the frequency of the drive signal 120, for example, a frequency of the drive signal 120 may be the highest when the TV camera is most sensitive to a pulsing of the lamp device 110.
  • the frequency of the drive signal 120 in a most sensitive region of a TV camera may be the same or even higher than a frequency of a corresponding PWM signal.
  • a brightness of the lamp device 110 is raised by raising the frequency of the drive signal 120. Therefore, the frequency f 160 of the second pulse train 160 is higher than the frequency f 14 o of the first pulse train 140 and, therefore, the frequency of the drive signal 120 is higher when the drive signal 120 is based on the second pulse train 160 than on the first pulse train 140.
  • the second PWM signal 240 which corresponds to the second pulse train 160, has the same frequency fpwM as the first PWM signal 220.
  • a drawback of these conventional PWM signals is that, therefore, pulse lengths of the pulses of the conventional PWM signal have to be kept much shorter than in embodiments of the present invention, wherein different degrees of brightness correspond to different frequencies of the drive signal 120.
  • hatched lines in the pulses mark the changes from the first pulse train 140 to the second pulse train 160 and from the first PWM signal 220 to the second PWM signal 240.
  • the further pulse 162a between the two neighboring pulses 142a, 142b in the second pulse train 160 more charge carriers flow into the lamp device 110 when the drive signal 120 is based on the second pulse train 160 than on the first pulse train 140.
  • the length of the pulses of the PWM signal would be extended to obtain more charge carriers flowing into the lamp device. This is shown in Fig.
  • a pulse length of the pulses 242a to 242d is half the pulse length t pu i se of the pulses 142a, 162a, 142b of the second pulse train 160.
  • the pulse length t pu i se of the pulses of the second pulse train 160 is identical with the pulse length t pulse of the pulses of the first pulse train 140.
  • a pulse generator for the second PWM signal 240 for example, a microcontroller would still have to be at least double as fast as the pulse generator 130 for generating the second pulse train 160.
  • a further pulse may be added between the two neighboring pulses 142a, 142b, wherein with each increase of brightness of the lamp device 110, the frequency of the drive signal 120 would be increased, too. Therefore, a drive signal 120 generated by the pulse generator 130 may have the same or even a higher frequency than a corresponding PWM signal for the same brightness of the lamp device 110.
  • the pulse generator 130 may be configured such that a frequency of the drive signal 120 is the highest, when a sensitivity of a TV camera used in conjunction with a lamp device 110 is the highest in regards of a pulsing of the lamp device 110.
  • the pulse generator 130 may be a conventional microcontroller with a comparatively low instruction cycle time compared to a pulse generator needed for generating a drive signal based on a conventional PWM signal and fulfilling the requirements of a TV camera used in conjunction with the lamp device 110.
  • the pulse generator 130 for generating the first pulse train 140 and the second pulse train 160 may be four times slower than a pulse generator for generating the first PWM signal 220 and the second PWM signal 240.
  • the pulse generator 130 may be significantly cheaper and/or may be used to control a plurality of lamp devices 110 compared to the conventional pulse generator for generating the first PWM signal 220 and the second PWM signal 240.
  • Fig. 3 a shows a schematic block diagram of an apparatus 300 for generating a drive signal 320 for a lamp device 110.
  • the apparatus 300 comprises a pulse generator 330 for generating a first pulse train 340 in response to a first brightness request for a first brightness and for generating a second pulse train 360 in response to a second brightness request for a second brightness.
  • the first pulse train 340 (shown in Fig. 3b) has at least three individual pulses.
  • the second pulse train 360 (shown in Fig. 3b) has at least three individual pulses, wherein less than all of the said at least three individual pulses have the same length. At least one of the at least three individual pulses of the second pulse train 360 has a different length compared to the corresponding individual pulse in the first pulse train 340.
  • the pulse generator may, for example, be a microcontroller (for example, directly connected or with a lamp driver in-between) coupled to the lamp device 110.
  • the drive signal 320 may be based on a continuous stream of first pulse trains 340 or on a continuous stream of second pulse trains 360, dependent on a brightness request.
  • a drive signal 320, which is based on the first pulse train 340 may lead to a different brightness of the lamp device 110 than a drive signal 320 based on the second pulse train 360.
  • a brightness of the lamp device 110 may be higher or larger when a drive signal 320 based on the second pulse train 360 is applied to the lamp device 110 than when a drive signal 320 based on the first pulse train 340 is applied to the lamp device 110.
  • Fig. 3b shows a schematic diagram 350 of the first pulse train 340 and a schematic diagram 370 of the second pulse train 360.
  • the first pulse train 340 comprises a first pulse 342a, a second pulse 342b and a third pulse 342c.
  • a temporal extension t 3 4 2a of the first pulse train 342a is twice the temporal extension t pu i se of the pulse 342b and the pulse 342c.
  • the three individual pulses 342a, 342b, 342c are individual, because the first pulse train 340 not comprises any pulses between two neighboring pulses of the three individual pulses 342a, 342b, 342c.
  • an amplitude of the three individual pulses 342, 342b, 342c is a current flowing into the lamp device 110 between the three individual pulses 342a, 342b, 342c, i.e. between a falling edge of one of the three individual pulses 342a, 342b, 342c and a rising edge of a temporally-following pulse of the three individual pulses 342a, 342b, 342c, no current flows into the lamp device 110.
  • the second pulse train 360 comprises three individual pulses 342a, 342b, 362c (from the first pulse train 340).
  • a temporal extension t 36 2 C or a pulse length of the third pulse 362c of the three individual pulses 342a, 342b, 362a of the second pulse train 360 differs from the pulse length t pu ise of its corresponding pulse 342c of the first pulse train 340.
  • the pulse length of the other two individual pulses 342a, 342b of the second pulse train 360 is identical to the pulse length of the corresponding individual pulses in the first pulse train 340.
  • the pulse length t 3 6 2c of the third pulse 362c of the second pulse train 360 is one pulse length interval t pu i se longer than the pulse length tpuise of the third pulse 342c of the first pulse train 340.
  • the time t pu ise may be the smallest possible pulse length, wherein pulse lengths of all pulses of pulse trains generated by the pulse generator 330 may be at least the smallest pulse length t pu i se or a multiple of the smallest pulse length tpuise-
  • the pulse length of a pulse of a pulse train may differ to a pulse length of another pulse of the same pulse train at maximum by the smallest pulse length tpuise.
  • the time between two rising edges of pulses of a pulse train may be a multiple of the smallest pulse length t pu i se .
  • an increase in the brightness of the lamp device 110 can be obtained with a pulse generator 330 by extending a pulse length of a pulse of a pulse train generated by the pulse generator 330.
  • a frequency of different pulse trains corresponding to different degrees of brightness of the lamp device 110 may be the same for all pulse trains.
  • Fig. 4 shows the schematic diagram 350 of the first pulse train 340 from Fig. 3b and a schematic diagram 410 of a corresponding first PWM signal 420. Furthermore, Fig. 4b shows the schematic diagram 370 of the second pulse train 160 from Fig. 3b and a schematic diagram 430 of a corresponding second PWM signal 440.
  • the first PWM signal 420 corresponds to the first pulse train 340, because a sum of the length of all pulses of the first pulse train 340 is the same as the sum of the length of all pulses of the first PWM signal 420.
  • a drive signal 120 based on the first pulse train 340 would generate the same brightness at the lamp device 110 as a drive signal based on the first PWM signal 420.
  • the first PWM signal 420 comprises three identical individual pulses 422a, 422b, 422c.
  • a length or temporal extension of each pulse is t4 22 , which is a third of the pulse length t pu i se (t pu i S e 3).
  • a time tp m between two following pulses of the first PWM signal 420 is the same, as the time t 3 4 0 between two following pulses of the first pulse train 340. Therefore, the first PWM signal 420 differs from the first pulse train 340 in the fact that all pulses 422a, 422b, 422c of the first PWM signal 420 have the same length.
  • the second PWM signal 440 corresponds to the second pulse train 360, because a brightness of the lamp device 110 generated by a drive signal 320 based on the second pulse train 360 is the same as the brightness generated by a drive signal based on the second PWM signal 440.
  • the second pulse train 360 differs from the first pulse train 340 by the pulse 362c, which length differs from its corresponding pulse 342c in the first pulse train 340.
  • the pulse 362c is compared to the pulse 342c extended by one pulse length t pu i S e.
  • the second PWM signal 440 differs from the first PWM signal 420 in the fact that all pulses 442a, 442b, 442c are longer than their corresponding pulses 422a, 422b, 422c of the first PWM signal 420.
  • An advantage of the pulse generator 330 for generating the first pulse train 340 and the second pulse train 360 compared to a conventional pulse generator for generating the first PWM signal 420 and the second PWM signal 440 is, that for a change of brightness, only a length of one pulse of a pulse train has to be changed by a certain time interval (for example, by the pulse length t pu ] Se ) instead of changing the time of all pulses of the pulse train by a much smaller pulse length (t pu i se /3).
  • a pulse generator 330 according to an embodiment of the present invention may, therefore, comprise a conventional microcontroller with a significantly lower instruction cycle time than a pulse generator for generating the conventional PWM signal. This leads to a significant cost reduction of the apparatus 300 compared to conventional apparatuses driving a lamp device with a conventional PWM signal.
  • the amplitude of the pulses of the pulse trains 140, 160 generated by the pulse generator 130 according to Fig. la are identical for the two pulse trains 140, 160
  • the amplitude of the pulses of the first pulse train 140 may be different from the amplitude of the pulses of the second pulse train 160. Therefore, the second pulse train 160 may differ from the first pulse train 140 generated by the first pulse generator 130 not only by the frequency of the pulse trains, but also by an amplitude of the pulses of the pulse trains.
  • the amplitude of the pulses of the first pulse train 140 may be lower than the amplitude of the pulses of the second pulse train 160.
  • this may also apply to the first pulse train 340 and the second pulse train 360 generated by the pulse generator 330 according to Fig. 3a.
  • the first pulse train 340 generated by the pulse generator 330 may, therefore, differ from the second pulse train 360 generated by the pulse generator 330 not only by a length of pulses of the pulse trains, but also by an amplitude of the pulses of the pulse trains.
  • an amplitude of the pulses of the first pulse train 340 generated by the pulse generator 330 may be lower than an amplitude of the pulses of the second pulse train 360 generated by the pulse generator 330.
  • Fig. 5 shows an apparatus 500 according to an embodiment of the present invention coupled to a lamp device 110.
  • the apparatus 500 may be the apparatus 100 according to Fig.
  • a brightness request generator 530 configured to provide at least the first brightness request and the second brightness request to an input terminal of a pulse generator 530 of the apparatus 500.
  • the pulse generator 530 may, for example, be the pulse generator 130 or the pulse generator 330.
  • the brightness request generator 590 may, for example, comprise a microcontroller or a control unit.
  • Fig. 6a shows schematic diagrams of pulse trains, for example, generated by the pulse generator 130 according to Fig. 1 as drive signals 120 for a lamp device 110.
  • Fig. 6a shows different pulse trains for different degrees of brightness of the lamp device 110 (plus one diagram with the value 0 for an off-state of the lamp device 110).
  • the value on the left side of the schematic diagrams designates the brightness which the corresponding pulse train generates at the lamp device 110, wherein a higher number corresponds to a higher brightness of the lamp device 110, and the value 16 corresponds to a maximum brightness of the lamp device 110.
  • the frequency factor on the right side of the schematic diagrams designates the frequency of the corresponding pulse train, wherein a higher number designates a higher frequency of the pulse train.
  • a pulse train shown in the second schematic diagram with a value 1 may, for example, be the first pulse train 140 and a pulse train shown in the second schematic diagram with a value 2 may, for example, be the second pulse train 160.
  • the different pulse trains only differ from each other by the number of pulses they contain, wherein for each increase in brightness, one pulse is added, which is marked with hatched lines. Therefore, with every brightness increase, a frequency of the pulse train and of the drive signal 120 is increased until a maximum frequency is achieved.
  • a maximum frequency is achieved at half of the brightness of the lamp device 110 (in the schematic diagram with the value 8), which is the brightness where TV cameras are most sensitive to the pulsing of the lamp device 110.
  • a pulse length of the pulses of the pulse trains is the same for every pulse.
  • An amplitude of the pulses in the schematic diagrams corresponds to a current, which flows through the lamp device 110 or an LED 110.
  • a frequency factor for example, by a factor of 2...256.
  • a frequency is reduced by the factor 8 which means a PWM signal corresponding to the first pulse train 140 would have 8 pulses in the one period shown in Fig. 6a, wherein a pulse length of the pulses would be one-eighth of t pu i se .
  • a frequency factor of 16 is a good compromise.
  • the concept shown is based on the fact that not one pulse with a variable length is used, like in the conventional PWM concept, but pulses are added based on the brightness.
  • a maximum frequency is not limited. The frequency is always dependent from the brightness, vice-versa, the brightness is always dependent on the frequency of a pulse train or the drive signal 120. A maximum frequency is achieved at half the brightness of the lamp device 110.
  • a frequency of the drive signal 120 may, at the half of the maximum brightness of the lamp device 110, be the same as the frequency of a corresponding conventional PWM signal.
  • Fig. 6b shows the schematic diagrams of Fig.
  • an amplitude of the pulses of the first pulse train may be one-sixteenth of the amplitude of the pulses of the 16 th pulse train (value 16).
  • This concept has the advantage that very small degrees of brightness can be adjusted soft and stepless (or at least nearly stepless or continuous).
  • drive signals based on the pulse trains with low frequencies have the lowest amplitudes and, therefore, very low degrees of brightness. This is advantageous, because as mentioned before, a camera like an HDTV camera shows a pulsing if a frequency of a drive signal of a lamp device is too low, only with higher degrees of brightness.
  • An amplitude of the pulses may be adjusted by a digital to analog converter of the pulse generator 130, wherein the pulse generator 130 may, for example, be a conventional microcontroller.
  • Fig. 6c shows schematic diagrams of drive signals with different pulse trains for different degrees of brightness for a lamp device 110.
  • the pulse trains shown in Fig. 6c differ from the pulse train shown in Fig. 6a in the fact that a maximum frequency of the pulse trains is limited (in the concrete embodiment shown in Fig. 6c to a frequency factor of 4) and when a maximum frequency of the pulse trains is reached, no further individual pulses are added, but a length of the pulses of the pulse trains is changed to further increase the brightness of the lamp device 110.
  • the first four pulse trains (value 1 to value 4) differ by the number of pulses they contain. Beginning from the fifth pulse train, the pulse trains differ by the length of the pulses they contain. A length of the pulses is not extended continually. This means that the pulses are always extended by a pulse length tpuise of the pulse of the first pulse train with a value 1.
  • the first pulse train with the value 1 may, for example, be the first pulse train 140 according to Fig. lb.
  • the second pulse train with the value 2 may, for example, be the second pulse train 160 according to Fig. lb.
  • the fourth pulse train (value 4) may, for example, be the first pulse train 340 according to Fig. 3b.
  • the fifth pulse train (value 5) may, for example, be the second pulse train 360 according to Fig. 3 b.
  • Fig. 6c reduces the frequency of the drive signal by a factor 2...256 compared to conventional PWM signals. For simplicity reasons, in Fig. 6c, a reduction of the frequency factor 4 is shown. As mentioned before, it has been shown that a frequency factor of 16 is a good compromise. The concept is based on this, that not one pulse with a variable length (PWM) is used, but instead several pulses are added, based on a required brightness. These pulses are added based on a binary method. As soon as, for example, sixteen pulses for a factor of 16 or four pulses for a factor of 4 are contained in a pulse train, for a further increase of the brightness, the length of the pulses are increased based on the same binary method.
  • PWM variable length
  • the frequency is raised, for example, until sixteen pulses or, in the concrete embodiment shown in Fig. 2c, four pulses for a period are provided. After this (beginning with the fifth pulse train with a value of 5), for a further brightness increase, the frequency is, furthermore, not raised. Instead, the pulse lengths from pulse-to-pulse are extended (which means the pulse lengths of the pulses contained in the pulse trains are extended). The pulse lengths of the pulses may not be continuously extended, but in steps of the length (t pu ise) of the first pulse of the first pulse train.
  • a first pulse of the first pulse train has a pulse length of 1ms
  • the first pulse is extended to 2ms (its pulse length is increased to 2ms).
  • the first pulse is extended to 3ms and ongoing, until the drive signal is a continuous high signal (value 16 in Fig. 6c).
  • Fig. 6d shows a schematic diagram from Fig.
  • a conventional PWM signal has a constant frequency, wherein a pulse-pause ratio is changed (for example, continuously changed). Furthermore, an amplitude of the pulses of the PWM signal is constant.
  • a length of the pulses in a base period of the drive signal may be different at arbitrary places within the base period. Additionally, an amplitude of the pulses may be varied.
  • Fig. 7 shows a flow diagram of a method 700 for generating a drive signal for a lamp device.
  • the method 700 comprises a step 710 of generating a first pulse train in response to a first brightness request for a first brightness.
  • the first pulse train has a first frequency.
  • the method 700 comprises a step 720 of generating a second pulse train in response to a second brightness request for a second brightness.
  • the second pulse train has a second frequency, wherein the first frequency of the first pulse train is different from the second frequency of the second pulse train.
  • the second pulse train further comprises two neighboring pulses of the first pulse train and comprises a further pulse between the two neighboring pulses.
  • the further pulse of the second pulse train is not comprised in the first pulse train.
  • the method 700 may comprise a step of receiving a first brightness request before the step 710 of generating the first pulse train.
  • the method 700 may comprise a step of receiving the second brightness request before the step 720 of generating the second pulse train.
  • the method 800 comprises a step 810 of generating a first pulse train in response to a first brightness request for a first brightness.
  • the first pulse train comprises at least three individual pulses.
  • the method 800 comprises a step 820 of generating a second pulse train for a second brightness.
  • the second pulse train comprises at least the three individual pulses of the first pulse train. Less than all of the at least three individual pulses of the second pulse train have the same length as in the first pulse train and at least one of the at least three individual pulses of the second pulse train has a different length compared to its corresponding individual pulse in the first pulse train.
  • the method 800 may comprise a step of receiving the first brightness request before the step 810 of generating the first pulse train. Furthermore, the method 800 may comprise a step of receiving the second brightness request before the step 820 of generating the second pulse train.
  • the methods 700 and 800 may be supplemented by any features or functions of the apparatus as described before.
  • embodiments of the invention can be implemented in hardware or in software.
  • the implementation can be performed using a digital storage medium, for example a floppy disk, a DVD, a Blue-Ray, a CD, a ROM, a PROM, an EPROM, an EEPROM or a FLASH memory, having electronically readable control signals stored thereon, which cooperate (or are capable of cooperating) with a programmable computer system such that the respective method is performed. Therefore, the digital storage medium may be computer readable.
  • Some embodiments according to the invention comprise a data carrier having electronically readable control signals, which are capable of cooperating with a programmable computer system, such that one of the methods described herein is performed.
  • embodiments of the present invention can be implemented as a computer program product with a program code, the program code being operative for performing one of the methods when the computer program product runs on a computer.
  • the program code may for example be stored on a machine readable carrier.
  • inventions comprise the computer program for performing one of the methods described herein, stored on a machine readable carrier.
  • an embodiment of the inventive method is, therefore, a computer program having a program code for performing one of the methods described herein, when the computer program runs on a computer.
  • a further embodiment of the inventive methods is, therefore, a data carrier (or a digital storage medium, or a computer-readable medium) comprising, recorded thereon, the computer program for performing one of the methods described herein.
  • a further embodiment of the inventive method is, therefore, a data stream or a sequence of signals representing the computer program for performing one of the methods described herein.
  • the data stream or the sequence of signals may for example be configured to be transferred via a data communication connection, for example via the Internet.
  • a further embodiment comprises a processing means, for example a computer, or a programmable logic device, configured to or adapted to perform one of the methods described herein.
  • a processing means for example a computer, or a programmable logic device, configured to or adapted to perform one of the methods described herein.
  • a further embodiment comprises a computer having installed thereon the computer program for performing one of the methods described herein.
  • a programmable logic device for example a field programmable gate array
  • a field programmable gate array may cooperate with a microprocessor in order to perform one of the methods -described herein.
  • the methods are preferably performed by any hardware apparatus.

Landscapes

  • Circuit Arrangement For Electric Light Sources In General (AREA)

Abstract

L'invention concerne un appareil (100) destiné à produire un signal d'attaque (120) pour un dispositif à lampe (110), comprenant un générateur d'impulsions (130) destiné à produire un premier train d'impulsions (140) en réponse à une première demande de luminosité fixant une première luminosité et à produire un second train d'impulsions (160) en réponse à une seconde demande de luminosité fixant une seconde luminosité. Le premier train d'impulsions (140) a une première fréquence et le second train d'impulsions (160) a une seconde fréquence, différente de la première. Le second train d'impulsions (160) comprend deux impulsions adjacentes (142a, 142b) du premier train d'impulsions (140) et comprend une autre impulsion (162a) entre les deux impulsions adjacentes (142a, 142b), l'autre impulsion (162a) n'étant pas comprise dans le premier train d'impulsions (140).
PCT/EP2011/054446 2010-04-01 2011-03-23 Appareil destiné à produire un signal d'attaque pour un dispositif à lampe, ainsi que procédé de production d'un signal d'attaque pour un dispositif à lampe Ceased WO2011120855A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2012553356A JP2013519988A (ja) 2010-04-01 2011-03-23 照明装置の駆動信号を生成する装置及び方法
CN2011800180969A CN102835188A (zh) 2010-04-01 2011-03-23 用于产生灯装置的驱动信号的设备和用于产生灯装置的驱动信号的方法

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
EP10159003.2 2010-04-01
EP10159003A EP2373125B1 (fr) 2010-04-01 2010-04-01 Appareil pour générer un signal de commande pour un dispositif de lampe et procédé de génération d'un signal de commande pour un dispositif de lampe
US12/752,452 2010-04-01
US12/752,452 US20110241560A1 (en) 2010-04-01 2010-04-01 Apparatus for generating a drive signal for a lamp device and method for generating a drive signal for a lamp device

Publications (1)

Publication Number Publication Date
WO2011120855A1 true WO2011120855A1 (fr) 2011-10-06

Family

ID=43827042

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2011/054446 Ceased WO2011120855A1 (fr) 2010-04-01 2011-03-23 Appareil destiné à produire un signal d'attaque pour un dispositif à lampe, ainsi que procédé de production d'un signal d'attaque pour un dispositif à lampe

Country Status (3)

Country Link
JP (1) JP2013519988A (fr)
CN (1) CN102835188A (fr)
WO (1) WO2011120855A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102012113024A1 (de) * 2012-12-21 2014-06-26 Hamilton Bonaduz Ag Optische Messvorrichtung
US9832829B2 (en) 2013-11-01 2017-11-28 Ohira Tech Ltd. LED driver circuit

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105593788B (zh) * 2013-07-22 2019-04-16 福西尔集团公司 用于在装置上显示面部表情和活动指示的表示的方法和系统

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050122065A1 (en) * 2003-12-05 2005-06-09 Dialight Corporation Dynamic color mixing LED device
WO2006107199A2 (fr) * 2005-04-08 2006-10-12 Wart Hog Ii Holding B.V. Procedes et appareils d'exploitation de groupes de del a haute puissance
US20070103086A1 (en) * 2005-11-10 2007-05-10 Neudorf Jason Christopher J Modulation method and apparatus for dimming and/or colour mixing utilizing leds
US20070257869A1 (en) * 2006-05-05 2007-11-08 Industrial Technology Research Institute Backlight device and method for controlling light source brightness thereof
US7598683B1 (en) * 2007-07-31 2009-10-06 Lsi Industries, Inc. Control of light intensity using pulses of a fixed duration and frequency

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU1047599A (en) * 1997-11-12 1999-05-31 Scintillate Limited Improvements relating to jewellery illumination
JP2005181421A (ja) * 2003-12-16 2005-07-07 Seiko Epson Corp 光源装置およびこの光源装置を備えたプロジェクタ。
JP4924916B2 (ja) * 2006-02-15 2012-04-25 株式会社デンソー 発光ダイオード駆動装置
JP4811126B2 (ja) * 2006-05-24 2011-11-09 パナソニック電工株式会社 照明システム
JP5054465B2 (ja) * 2007-08-27 2012-10-24 パナソニック株式会社 照明器具
US8339068B2 (en) * 2008-12-12 2012-12-25 Microchip Technology Incorporated LED brightness control by variable frequency modulation

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050122065A1 (en) * 2003-12-05 2005-06-09 Dialight Corporation Dynamic color mixing LED device
WO2006107199A2 (fr) * 2005-04-08 2006-10-12 Wart Hog Ii Holding B.V. Procedes et appareils d'exploitation de groupes de del a haute puissance
US20070103086A1 (en) * 2005-11-10 2007-05-10 Neudorf Jason Christopher J Modulation method and apparatus for dimming and/or colour mixing utilizing leds
US20070257869A1 (en) * 2006-05-05 2007-11-08 Industrial Technology Research Institute Backlight device and method for controlling light source brightness thereof
US7598683B1 (en) * 2007-07-31 2009-10-06 Lsi Industries, Inc. Control of light intensity using pulses of a fixed duration and frequency

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102012113024A1 (de) * 2012-12-21 2014-06-26 Hamilton Bonaduz Ag Optische Messvorrichtung
US9588039B2 (en) 2012-12-21 2017-03-07 Hamilton Bonaduz Ag Optical measuring device
US9832829B2 (en) 2013-11-01 2017-11-28 Ohira Tech Ltd. LED driver circuit

Also Published As

Publication number Publication date
JP2013519988A (ja) 2013-05-30
CN102835188A (zh) 2012-12-19

Similar Documents

Publication Publication Date Title
US9743499B2 (en) Dimming circuit for LED
US20090174338A1 (en) Led drive circuit
US20080048582A1 (en) Pwm method and apparatus, and light source driven thereby
CN106105392B (zh) 用于控制用于负载的电流供给的脉冲宽度调制的电路和方法
US20170006679A1 (en) Signal generating method and circuit for controlling dimming of led
RU2016100188A (ru) Способ и устройство управления задней подсветкой
CA2583357A1 (fr) Dispositif et procede de commande pour utilisation avec des sources de lumiere commandees numeriquement
US20110204802A1 (en) Led assembly driving circuit
US8643292B2 (en) Digital dimming device and digital dimming method
US8841861B2 (en) Dimming device
US8928245B2 (en) Driving circuit and its method of light emitting diode
CN108886852A (zh) 模块化照明应用
WO2016142154A1 (fr) Circuit d'attaque de del
US20110241560A1 (en) Apparatus for generating a drive signal for a lamp device and method for generating a drive signal for a lamp device
WO2011120855A1 (fr) Appareil destiné à produire un signal d'attaque pour un dispositif à lampe, ainsi que procédé de production d'un signal d'attaque pour un dispositif à lampe
US20160232832A1 (en) Display device and method for driving backlight thereof
US9743475B1 (en) Operation method for LED dimming device
US10045411B2 (en) Dual mode light emitting diode (LED) driver
EP2373125B1 (fr) Appareil pour générer un signal de commande pour un dispositif de lampe et procédé de génération d'un signal de commande pour un dispositif de lampe
US11388347B2 (en) LED driver and method of operating a camera
CN113496672A (zh) 电流驱动装置
CN102903339B (zh) 显示装置背光源的控制方法及控制装置
US10492250B2 (en) Lighting system, and related lighting module
CA2862615A1 (fr) Procede et appareil de commande d'un stroboscope a diode electroluminescente
US20180158399A1 (en) Display device, driving method thereof, and non-transitory computer readable recording medium

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: 201180018096.9

Country of ref document: CN

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 11709729

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 2012553356

Country of ref document: JP

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 11709729

Country of ref document: EP

Kind code of ref document: A1