• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    It is proposed an operating circuit for the operation of an LED track, comprising: - a switching regulator circuit for generating a current for the LED track and having at least one switch (S1) and serving as an energy storage coil (L1), and - a control circuit ( SR) for controlling the switch (S1) with a control signal (ST) in which a high-frequency pulse signal is superimposed by a comparatively low-frequency pulse signal (STLF), wherein the high-frequency pulse signal and the low-frequency pulse signal (STLF) are synchronized.
    公开号:AT15919U1
    申请号:TGM9023/2014U
    申请日:2014-04-03
    公开日:2018-09-15
    发明作者:Keller Ueli；Pereira Eduardo
    申请人:Tridonic Gmbh & Co Kg；
    IPC主号:
    专利说明:

    description
    LED CONTROL WITH OVERLAY HIGH-FREQUENCY AND LOW-FREQUENCY IMPULSES The present invention relates to a method and a circuit for operating lamps, in particular light-emitting diodes (LEDs) by means of, for example, switching regulators for providing an operating current for the LEDs.
    It is generally known to use switching regulators, in particular step-down converters for driving LEDs.
    A control unit controls a clocked semiconductor power switch, by means of which a coil is magnetized in its switched-on state. The energy built up in the coil is discharged via the LED path when the switch is switched off.
    There is thus a zigzag current flow through the LED path around a constant average, with a rising edge in the switched-on state and a falling edge of the light-emitting diode current when the switch is switched off. The temporal mean value of the LED current is set by a control unit by corresponding high-frequency clocking of the circuit breaker.
    Meanwhile, it is known that for dimming the LED path, the control unit of the high-frequency clocking of the switch can overlay a low-frequency pulse width modulation, also called PWM modulation. With this PWM modulation, the pulse duty factor or the pulse duty factor of a rectangular pulse is modulated at a constant frequency. In other words, if the pulse period is fixed, the control unit changes either the pulse duration or the pause duration after a pulse.
    Fig. 1 shows an example of the course of a PWM signal LFPWM that the high-frequency clocking of the switch is superimposed according to the prior art. In PWM modulation, the pulse period T LF remains constant, the frequency of the PWM signal being 500 Hz, for example. The pulse duration Ton LF or the pause duration Toff LF can then be changed to achieve the desired dimming level. The switching regulator for controlling the LED path is supplied in a known manner from a bus voltage Vbus shown in FIG. 1, which has a ripple or ripple of, for example, 100 Hz around an average value VO.
    With a positive edge of the PWM signal LF PWM, the switch of the switching regulator is closed, which leads to a linear increase in the LED current ILED. When a maximum value Imax is reached, the switch is opened. The LED current decreases linearly again until a lower threshold Imin is reached. The subsequent closing of the switch leads to the aforementioned zigzag current profile of the LED current around the value lamp during the pulse duration of the PWM signal LF PWM.
    After the control unit has received a dimming command, it calculates the corresponding pulse duration Ton LF , which is required for the desired dimming level. As soon as the previously calculated pulse duration Ton LF has expired, the switch is opened for the remaining pause duration Toff LF . To achieve an average LED current IO, the pulse duration Ton LF is calculated depending on the following formula:
    IO = lamp * Ton LF * (Ton LF + Toff LF ) However, it has been recognized that this type of switch control can be disadvantageous. The slope or the slope of the LED current is namely dependent on the ripple of the bus voltage Vbus and, for example, on the LED voltage, which in turn depends on the temperature. For a specific dimming command, the number of high-frequency pulses is therefore during / 15
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    Pulse duration tone LF variable.
    Furthermore, it was recognized that for a fixed duty cycle of the PWM signal LFPWM, the LED current can be in different phases when the pulse duration tone LF expires. At this time, for example, the LED current can have the maximum value Imax or the minimum value Imin. Alternatively, the LED current can be in the middle of an increase or decrease phase after the pulse duration Ton LF . This is due to the fact that the slope of the LED current does not always remain the same.
    This can e.g. with low dimming values lead to undesirable flicker phenomena.
    The present invention is based on the object of proposing an improved circuit for operating LEDs.
    [0013] This object is achieved by the features of the independent claims. Advantageous developments of the invention are the subject of the dependent claims.
    [0014] According to one aspect of the invention, an operating circuit for operating an LED section is proposed, comprising:
    - A switching regulator circuit for generating a current for the LED path and having at least one switch and a coil serving as energy storage, and [0016] - A control circuit for controlling the switch with a control signal, in which a high-frequency pulse signal is compared for this purpose, low-frequency pulse signal is superimposed, the high-frequency pulse signal and the low-frequency pulse signal being synchronized.
    A synchronization of the high-frequency clocking of the switch and the low-frequency modulation of this high-frequency clocking is proposed. The low-frequency modulation is thus carried out depending on the high-frequency clocking of the switch.
    According to a further aspect of the invention, a method for operating an LED section by means of a switching regulator circuit is proposed, comprising at least one switch and a coil serving as an energy store. The method has the step of controlling the switch with a control signal, in which a high-frequency pulse signal is superimposed on a low-frequency pulse signal, the high-frequency pulse signal and the low-frequency pulse signal being synchronized.
    According to a further aspect of the invention, an integrated circuit is proposed, preferably in the form of a microcontroller, an application-specific integrated circuit (ASIC) or a digital signal processor, for carrying out the method.
    A synchronization of the high-frequency clocking of the switch and the low-frequency modulation of this high-frequency clocking is proposed. The low-frequency modulation is thus carried out depending on the high-frequency clocking of the switch.
    The falling edges of the low-frequency pulse signal can be synchronized with the high-frequency pulse signal.
    The duration of each pulse of the low-frequency pulse signal can be chosen such that the high-frequency pulse signal has only complete pulses during this period.
    In other words, a falling edge of a low-frequency pulse should preferably not interrupt a high-frequency pulse. According to this example, a falling edge of a low-frequency pulse may only be generated at a time when the high-frequency pulse signal has no pulse.
    The overlay consists in particular in that e.g. to dim the LEDs
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    Control unit of the high-frequency clocking of the switch superimposed a low-frequency modulation.
    During each pulse of the low-frequency pulse signal, the high-frequency pulse signal can have the same number of complete pulses.
    The control unit can then generate a falling edge of the low-frequency pulse when it is detected that the current for the LED path is decreasing.
    The control unit can then generate a falling edge of the low-frequency pulse when it is detected that the current for the LED path has reached a minimum value.
    The number of high-frequency pulses during a low-frequency pulse can be independent of a degree of dimming for the LED path.
    With a constant degree of dimming for the LED path, the pulse duty factor of the low-frequency pulse signal can remain constant.
    For dimming the LED path, the pause time between two pulses of the low-frequency pulse signal can be adjustable.
    The pause duration can depend on the pulse duration and on a desired degree of dimming, preferably according to the following formula:
    tOFF / LF1 = tON / LF1 / dim + tON / LF1.
    The number of high-frequency pulses can be dependent on a degree of dimming for the LED path during a low-frequency pulse.
    With a varying degree of dimming for the LED path, the pulse duty factor of the low-frequency pulse signal can remain constant.
    For dimming the LED path, the number of high-frequency pulses can be adjustable during a low-frequency pulse.
    To synchronize the high-frequency pulse signal and the low-frequency pulse signal, the duration of a high-frequency pulse signal can be determined, e.g. by direct measurement of the high-frequency pulse signal or by direct or indirect measurement of the current for the LED section or by estimation based on the current value of the input voltage.
    [0037] The frequency of the low-frequency pulse signal can be variable.
    The control circuit can generate the high frequency pulse signal such that when the current for the LED path reaches a maximum value, the high frequency pulse signal has a negative edge to open the switch, and when the current for the LED path reaches a minimum value, the high frequency Pulse signal has a positive edge to close the switch.
    When the switch is switched on, energy can be built up in the coil, which discharges via the LED path when the switch is switched off.
    [0040] According to a further aspect of the invention, an operating circuit, preferably according to one of the above aspects, is proposed for operating an LED line, comprising:
    - A switching regulator circuit for generating a current for the LED path and having at least one switch and a coil serving as an energy store, and [0042] - A control circuit for controlling the switch with a control signal in which a high-frequency pulse signal is compared for this purpose, low-frequency pulse signal is superimposed, the duty cycle of the low-frequency pulse signal being reduced for dimming or dimming the LED path in a higher dimming range, and for dimming
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    Patent office or dimming down the LED path in a lower dimming range, the pause duration of the low-frequency pulse signal is increased.
    According to a further aspect of the invention, a method is proposed, preferably according to one of the above aspects, for operating an LED section by means of a switching regulator circuit having at least one switch and a coil serving as an energy store, having the control of the switch with a control signal, in which a high-frequency pulse signal is superimposed with a low-frequency pulse signal, the duty cycle of the low-frequency pulse signal (ST L f) being reduced for dimming or dimming the LED path in a higher dimming range, and for dimming or dimming the LED In a lower dimming range, the pause duration (TOFF) of the low-frequency pulse signal (ST LF ) is increased.
    According to a further aspect of the invention, an integrated circuit, preferably in the form of a microcontroller, an application-specific integrated circuit (ASIC) or a digital signal processor, is proposed for carrying out the method. [0046] The higher dimming range and the lower dimming range can adjoin.
    In the higher dimming range, the period of a low-frequency pulse preferably remains constant and only the pulse duration is reduced.
    In the lower dimming range, the pulse duration of the low-frequency pulse signal preferably remains constant and only the pause duration is increased.
    The pulse duration that is reached at the lower limit of the higher dimming range can be kept constant throughout the lower dimming range.
    The period of the low-frequency pulse, which is reached at the upper limit of the lower dimming range, can be kept constant throughout the higher dimming range.
    The control circuit can generate the high-frequency pulse signal such that when the current for the LED path reaches a maximum value, the high-frequency pulse signal has a negative edge to open the switch, and when the current for the LED path reaches a minimum value, the high-frequency Pulse signal has a positive edge to close the switch.
    When the switch is switched on, energy can be built up in the coil, which discharges via the LED path when the switch is switched off.
    Further aspects, features and properties of the present invention are explained in more detail from the following description of exemplary embodiments and with reference to the figures of the accompanying drawings.
    Fig. 2 [0056] Fig. 3 [0057] Fig. 4 [0058] Fig. 5 [0059] Fig. 6 [0060] Fig. 7 shows waveforms as they occur in an operating circuit the state of the art, shows an operational formwork for light emitting diodes according to an embodiment of the present invention, shows a modification of the operational formwork of FIG. 2, shows waveforms as they occur in an operational circuit according to a first embodiment, shows waveforms as they occur in an operating circuit according to a second embodiment, shows the profile of the LED current, the pulse duration and the frequency of the low-frequency pulse signal according to a third embodiment, and shows the profile of the LED current at different dimming values according to the third embodiment.
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    Patent Office [0061] FIG. 2 schematically shows a circuit for operating light-emitting diodes (LEDs) or for operating an LED section.
    In the example shown, the LED section comprises two LEDs connected in series. However, the operating circuit can adapt to the type and number of light-emitting diodes (LEDs) that are also connected in series. The operating circuit can be used for only one LED. Alternatively, the LEDs can also be connected in parallel or according to a serial and parallel arrangement. The LEDs can be OLEDs. Furthermore, it can be, for example, monochromatic LEDs, dye-converted white LEDs and / or RGB LED modules.
    The operating circuit can be referred to as a switching regulator in which the power supply to the LED path is ensured by means of at least one periodically operating electronic switch and at least one energy store.
    An input voltage or bus voltage Vin is fed to the operating circuit, and this input voltage Vin can be a rectified AC voltage or DC voltage. This rectified AC voltage or DC voltage can be a preferably approximately constant voltage having a ripple or ripple. The input voltage Vin can also be a constant DC voltage in the form of e.g. a battery voltage.
    2 is designed as a buck converter or step-down converter. The input voltage Vin is applied to a series circuit of a semiconductor power switch S1, such as a MOSFET, and a free-wheeling diode D1. A measuring resistor Rs for determining the current through the switch S1 is preferably also provided in series with the switch S1 and the free-wheeling diode D1. A series circuit consisting of a coil L1 and the LED path is arranged parallel to the free-wheeling diode D1. A capacitor C1 can be connected in parallel to the LED path.
    When switch S1 is on, a current flows through the LED path and coil L1. During this switch-on phase, the current through coil L1 increases. During a subsequent free-running phase i.e. When switch S1 is switched off, the energy stored in coil L1 is discharged in the form of a current through the LED path.
    A control circuit SR is provided, which specifies the timing of the switch S1 in the form of a signal according to the invention as the manipulated variable for regulating the LED power or the LED current. The control circuit SR can be designed as a control and / or regulating circuit.
    By means of the measuring resistor RS, the control circuit SR detects the current through the switch S1. This detection takes place when switch S1 is switched on. The control circuit SR can detect the potential on the lower-potential side of the LED path via a voltage divider R1, R2. Another voltage divider R3, R4 enables the input voltage Vin to be detected.
    Fig. 3 shows a modification of the circuit of Fig. 2 in that the arrangement of the coil L1, the freewheeling diode D1 and the orientation of the LED path is modified. 3 is designed as a boost converter or step-up converter.
    The present invention can also be used in a configuration of the operating circuit as a buck-boost converter, also known as a flyback converter or inverter.
    Fig. 4 shows the course of the input voltage Vin, the LED current ILED ie the current through the LED path, the low-frequency control signal ST LF and the control signal ST for driving the switch S1 according to a first embodiment aspect of the invention. If a capacitor C1 is arranged parallel to the LED path, the LED current is preferably the current through the parallel connection of capacitor C1 and the LED path.
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    Patent Office The low-frequency control signal ST LF has a first pulse period with a pulse duration tON / LF1 and a pause duration or switch-off duration tOFF / LFI. The next pulse period also has a pulse duration tON / LF2, followed by a pause. In contrast to the prior art, the duration of the pulse period is no longer constant in this exemplary embodiment.
    During a pulse period of the low-frequency control signal ST LF , the switch S1 is switched on and off alternately. When switch S1 is switched on for the first time during the pulse duration tON / LF1, the LED current ILED increases linearly from zero. As soon as the LED current reaches a maximum value Imax, switch S1 is switched off again. This is followed by the zigzag current flow of the current through the LED path, in which the switch is switched on and off alternately when a minimum value Imin or a maximum value Imax is reached.
    4 shows how the LED current initially rises from zero during a low-frequency pulse period, reaches the minimum value Imin at time t1A, and continues to rise up to the maximum value Imax. At time t1A + t1B, when the LED current e.g. for the third time to the minimum value Imin, the low-frequency pulse is ended. The time duration t1 A + t1 B corresponds to the pulse duration tON / LF1.
    The LED current then drops further during a time period t1C back to the zero value. Only after a further period of time t1 D does the LED current rise again. The time period t1C + t1 D corresponds to the switch-off time period tOFF / LF1 of the low-frequency pulse signal.
    The high-frequency pulse sequence of the control signal ST shown serves to regulate the LED current around the mean value lamp = (lmax + Imin) / 2. This high-frequency pulse signal is now modulated with the low-frequency pulse signal ST LF , so that dimming of the LED path is also possible.
    The low-frequency pulse signal ST LF is synchronized with the high-frequency pulse signal. The flicker phenomena mentioned at the outset can thus be counteracted.
    It is particularly advantageous if no high-frequency pulses are interrupted by the low-frequency pulse signal ST LF . This is indicated in FIG. 4 by the specification np = 3: during the first pulse period tON / LF1 + tOFF / LF1, the control unit SR outputs three complete low-frequency pulses for actuating the switch.
    The low-frequency pulse preferably stops when the LED current is in the falling phase between the maximum value Imax and the minimum value Imin.
    However, the flicker phenomena can occur in particular if the low-frequency pulse signal causes the switch to open in the rise phase of the LED current.
    The measuring resistor RS can be used to compare the LED current with the maximum value Imax during the switch-on period of the switch S1.
    The reaching of the minimum value Imin and the maximum value Imax can be determined directly or indirectly in a known manner. For example, the LED current can be measured directly and compared with the values Imin and Imax. For this, e.g. a measuring resistor (not shown) can be provided in series with the LED section or, if appropriate, in series with the parallel connection of capacitor C1 and LED section. Alternatively, the coil L1 can also be coupled to a secondary winding (not shown), so that the minimum or maximum value Imin, Imax is determined via the measured voltage of the secondary winding. The achievement of these values Imin, Imax can also be recognized by comparing the voltage on the LED path or the input voltage Vin with corresponding reference values.
    The duration of a low frequency pulse can either be calculated or measured 6/15
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    Patent Office sen. To achieve a predetermined number np of high-frequency pulses within a low-frequency pulse, e.g. the LED current can be measured in a known manner. As soon as the measured LED current reaches the minimum value np times in the descending phase, there is a negative edge of the low-frequency pulse signal. Alternatively, the time period tON / LF1 can be determined on the basis of the measured input voltage Vin: starting from the input voltage Vin, the slope of the LED current can be concluded and thus the time period tON / LF1.
    Alternatively, the negative edge of the low-frequency pulse can also be generated if it is determined by calculation or measurement that the LED current within the low-frequency pulse has reached the maximum value Imax np times.
    This embodiment preferably results in an LED operation in which the same number of complete high-frequency pulses is given within each low-frequency pulse. 4 there are exactly np = 3 high-frequency pulses within the first and the second low-frequency pulse.
    Preferably, the duty cycle of the low-frequency pulse signal ST LF remains constant. The pause duration tOFF / LF1 therefore depends on the pulse duration tON / LF1 and on a desired dimming level dim:
    tOFF / LF1 = tON / LF1 / dim + tON / LF1.
    According to this exemplary embodiment, the length np of the pulse packets is recorded even at different dimming levels. The duration of the low-frequency pulse packets is preferably a complete multiple of the duration of the high-frequency pulses. The duration of the high-frequency pulses, however, changes synchronously with the fluctuation in the bus voltage.
    For dimming, the length of the low-frequency pulses is now recorded to the integer multiple of the high-frequency pulses, so that the dimming level is changed by extending the switch-off period tOFF / LF1 of the low-frequency pulses and thus by reducing the low-frequency frequency. The limit of frequency reduction is the flicker frequency visible to the eyes. If, for example, the basic frequency for the low-frequency pulses is 500 Hz to 1000 Hz, this frequency can only be reduced to a range of, for example, 100 Hz to 200 Hz.
    In general, the following applies: the low-frequency pulses preferably have a frequency which is at least 10 times the frequency of the low-frequency pulses. For example. the low-frequency (PWM) pulses have a frequency of 100 Hz to 500 Hz. For example. the high-frequency pulses have a frequency of more than 5 kHz, preferably more than 10 kHz.
    5 shows the profile of the LED current according to a second exemplary embodiment according to the invention.
    The time period tONI ', tONI of a low frequency pulse, i.e. the number of high-frequency pulses within this low-frequency pulse can also be changed to dim the LED path.
    5 shows a special embodiment in which the time period tONT is selected for a desired dimming level of 1% such that three high-frequency pulses (dim = 3) are emitted by the control unit SR to the switch S1 within a low-frequency pulse become.
    To increase the dimming level, the number of high-frequency pulses within a low-frequency pulse is increased in this exemplary embodiment. In Fig. 5, six high-frequency pulses (dim = 6) are now delivered within a pulse packet, e.g. set a dimming level of 2%. The duration of the low-frequency pulses increases accordingly from tONT to tON1.
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    Patent Office The pause duration or switch-off duration tOFF1 ', tOFF1 of the low-frequency pulses again results from the following formulas:
    tOFFT = tONT / dim + tONT tOFF2 '= tON2' / dim + tON2 'where dim represents the desired degree of dimming.
    Even when the degree of dimming varies, the pulse duty factor of the low-frequency pulse signal (ST LF ) preferably remains constant.
    This aspect means that the duration of the high-frequency pulses can be changed for dimming, but this is only an incremental part (and not continuous), the increment length being a complete duration of a high-frequency pulse.
    Since the duration of the high-frequency pulse changes continuously together with the fluctuation of the input voltage Vin, information regarding the current high-frequency pulse length must be supplied to the low-frequency modulation unit in this case.
    [0099] Alternatively, the current duration of the high-frequency pulses can also be determined or estimated indirectly, for example by detecting the current value of the input voltage Vin.
    It can thus be avoided that the low-frequency pulses cut off the high-frequency pulses with a relatively low and thus visible frequency at different points, which would lead to a visible flickering.
    According to a third embodiment of the invention is dimmed differently in the upper dimming levels and in the lower dimming levels. At higher dimming levels, the LED section is dimmed by reducing the low-frequency duty cycle. At lower dimming levels, however, the frequency of the low-frequency pulse signal is reduced.
    Fig. 6 shows an exemplary course of the LED current, the pulse duration and the frequency of the low-frequency pulse signal according to this third embodiment.
    Fig. 7 shows the course of the LED current at different dimming values according to the third embodiment.
    In a higher dimming range from 100% to the dimming value D, the pulse duty factor of the low-frequency pulse signal is reduced. The period of a low-frequency pulse is preferably kept constant and its pulse duration is reduced.
    Preferably, the reduction of this pulse duration can be carried out in such a way that, according to the above exemplary embodiments, the control signal for the switch S1 has only complete high-frequency pulses during the period of a low-frequency pulse.
    The reduction in the duty cycle is also illustrated in FIG. 7. To e.g. dimming down from 25% to 3%, the duty cycle is reduced accordingly from 25% to 3%.
    In contrast, at lower dimming levels, e.g. below D%, the frequency of the low-frequency pulse signal is reduced. When the minimum value D is reached, the frequency is then reduced.
    This is also shown in Fig. 6, where below the dimming level D, the pulse duration TON remains constant at the value TONmin and the frequency fLF of the low-frequency pulse signal is reduced. Such as. 7, the pulse duration TON is not reduced further when the minimum pulse duration TONmin is reached. Starting from the dimming value D = 3%, the switch-off time of the low-frequency is reached in order to achieve a lower dimming value
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    Pulse signal increased, this increase being characterized in FIG. 7 by the value TOFFextra.
    There is preferably no mixed operation, but either only real PWM dimming - i.e. only a reduction in the duty cycle of the low-frequency pulse signal or pure dimming by changing the frequency of the low-frequency pulses with a predetermined minimum switch-on time TONmin.
    This procedure is caused by the fact that a reduction in the pulse duty factor of the low-frequency pulse signal is only possible for technical reasons up to a lower threshold value. From this threshold value D - and up to less than 1% or to far below 1% - an alternative dimming operation by changing the frequency should be proposed.
    In contrast, in the prior art, amplitude dimming is carried out at low dimming values, i.e. the LED current no longer runs zigzag between the values Imax and Imin but between lower limit values Imax 'and Imin'. However, such amplitude dimming can lead to an undesirable shift in the color location.
    Dimming in the lower dimming range by changing the frequency of the low-frequency pulses is advantageous in that a shift in the color locus is prevented.
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    权利要求:
    Claims (15)
    [1]
    Expectations
    1. Operating circuit for the operation of an LED line, comprising:
    - A switching regulator circuit for generating a current for the LED path and having at least one switch (S1) and a coil (L1) serving as an energy store, and
    - A control circuit (SR) for controlling the switch (S1) with a control signal (ST), in which a high-frequency pulse signal is superimposed with a low-frequency pulse signal (ST LF ), the high-frequency pulse signal and the low-frequency pulse signal (ST LF ) are synchronized.
    [2]
    2. Operating circuit according to claim 1, wherein the falling edges of the low-frequency pulse signal (ST LF ) are synchronized with the high-frequency pulse signal.
    [3]
    3. Operating circuit according to one of the preceding claims, wherein the period (tON / LF1, tON / LF2) of each pulse of the low-frequency pulse signal (ST LF ) is selected such that during this period (tON / LF1, tON / LF2) the high-frequency pulse signal shows only complete impulses.
    [4]
    4. Operating circuit according to claim 3, wherein during each pulse of the low-frequency pulse signal (ST LF ), the high-frequency pulse signal has the same number (np) of complete pulses.
    [5]
    5. Operating circuit according to one of the preceding claims, wherein the control unit (SR) generates a falling edge of the low-frequency pulse when it is detected that the current for the LED path decreases.
    [6]
    6. Operating circuit according to one of the preceding claims, wherein the control unit (SR) generates a falling edge of the low-frequency pulse when it is detected that the current for the LED path reaches a minimum value (Imin).
    [7]
    7. Operating circuit according to one of claims 3 to 6, wherein the number (np) of high-frequency pulses during a low-frequency pulse is independent of a degree of dimming for the LED path.
    [8]
    8. Operating circuit according to one of the preceding claims, wherein the duty cycle of the low-frequency pulse signal (ST LF ) remains constant with a constant degree of dimming for the LED path.
    [9]
    9. Operating circuit according to one of the preceding claims, the pause duration (tOFF / LF1) between two pulses of the low-frequency pulse signal (ST LF ) being adjustable for dimming the LED path.
    [10]
    10. Operating circuit claim 9, wherein the pause duration (tOFF / LF1) depends on the pulse duration (tON / LF1) and on a desired degree of dimming (dim), preferably according to the following formula: tOFF / LF1 = tON / LF1 / dim + tON / LF1.
    5 sheets of drawings
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    [11]
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    [12]
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    Fig.4
    [13]
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    Fig. 5
    [14]
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    I | _ED
    [15]
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    同族专利:
    公开号 | 公开日
    DE102013205859A1|2014-10-09|
    DE102013205859B4|2021-12-09|
    WO2014161934A1|2014-10-09|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    WO2001058218A1|2000-02-03|2001-08-09|Koninklijke Philips Electronics N.V.|Supply assembly for a led lighting module|
    US20030085749A1|2000-02-03|2003-05-08|Koninklijke Philips Electronics N.V.|Supply assembly for a led lighting module|
    US20070210725A1|2006-03-13|2007-09-13|Linear Technology Corporation|LED dimming control technique for increasing the maximum PWM dimming ratio and avoiding LED flicker|
    US20100277088A1|2009-04-30|2010-11-04|Infineon Technologies Austria Ag|System for supplying current to a load|
    WO2012025345A1|2010-08-26|2012-03-01|Osram Ag|Method for operating at least one light-emitting diode and lighting device for carrying out the method|
    US20120217889A1|2011-02-24|2012-08-30|Osram Sylvania Inc.|Adaptive frequency control to change a light output level|
    US8487546B2|2008-08-29|2013-07-16|Cirrus Logic, Inc.|LED lighting system with accurate current control|
    GB2476605B|2008-10-22|2014-02-05|Tridonic Gmbh & Co Kg|Circuit for the operation of at least one LED|
    EP2341760A1|2009-12-23|2011-07-06|Tridonic AG|Circuit for operating light emitting diodes |
    CN102014548B|2010-09-07|2011-12-14|凹凸电子（武汉）有限公司|Controller and method for adjusting brightness of light source as well as lighting system|
    US8638045B2|2011-02-07|2014-01-28|Cypress Semiconductor Corporation|Mutli-string LED current control system and method|
    JP5576818B2|2011-03-22|2014-08-20|パナソニック株式会社|Lighting device and lighting fixture using the same|DE102019210965A1|2019-07-24|2021-01-28|Ford Global Technologies, Llc|Method for dimming a light source|
    法律状态:
    2020-12-15| MM01| Lapse because of not paying annual fees|Effective date: 20200430 |
    优先权:
    申请号 | 申请日 | 专利标题
    DE102013205859.4A|DE102013205859B4|2013-04-03|2013-04-03|Method and operating circuit for operating light sources, in particular light-emitting diodes |
    PCT/EP2014/056687|WO2014161934A1|2013-04-03|2014-04-03|Led control system with superimposed high-frequency and low-frequency pulses|
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