• 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:
    In one aspect, an operating device for lighting means, in particular at least one LED, is provided comprising an active power factor correction circuit supplied from a mains voltage with a clocked switch controlled by a control unit, wherein the operating device has a control unit which is set up to clock the switch in temporal regions around the vertex of the mains voltage, for example in temporal regions in which the amplitude of the mains voltage is above a predetermined threshold value, the amplitude of the measuring signal is changed in such a way that during the temporal regions results in a reduced power consumption of the power factor correction circuit due to the resulting clocking of the switch.
    公开号:AT16263U1
    申请号:TGM26/2015U
    申请日:2015-02-02
    公开日:2019-05-15
    发明作者:Nesensohn Christian；Züger Dominik
    申请人:Tridonic Gmbh & Co Kg；
    IPC主号:
    专利说明:

    description
    PFC CIRCUIT WITH VOLTAGE-DEPENDENT SIGNAL FEEDING The invention relates to an operating device for operating lamps, in particular LEDs. The operating device has a PFC circuit, that is to say a power factor correction circuit. A clocked switch of the PFC circuit is controlled by a control unit and is operated, in particular, clocked. In this case, the control unit is supplied with at least one signal, on which the control unit controls the switch. In particular, the PFC circuit has a measuring winding on a choke, from which a current signal is supplied to the control unit. The control unit can use the current signal supplied in this way to detect, for example, a zero crossing of an electrical supply that supplies the operating device, in particular a rectified mains voltage, or can detect it by monitoring the current through the measuring winding. Usually, the control unit will control the switch so that the switch is always turned on when the current through the measuring winding has dropped to zero. The invention thus also relates to a circuit for power factor correction and a method for controlling such a circuit.
    A power factor correction (PFC) is used to eliminate or at least reduce harmonic currents in an input current. Harmonic currents can occur in particular in the case of non-linear consumers, such as, for example, rectifiers with subsequent smoothing in power supply units, since the phase of the input current is shifted and non-sinusoidally distorted in spite of the sinusoidal input voltage in such consumers. The higher-frequency harmonics that occur can be counteracted by an active or clocked power factor correction circuit connected upstream of the respective device.
    Power factor correction circuits are also used in operating devices for lamps, for example in electronic ballasts or LED converters. The use of such circuits in devices for operating lamps is desirable or necessary because standards restrict the permissible return of harmonics into the supply network.
    A circuit topology based on the topology of a step-up converter is often used for power factor correction circuits. In this case, an inductor or coil supplied with a rectified AC voltage is charged or discharged with energy by switching a controllable switch on and off. The discharge current of the inductance flows via a diode to an output capacitance, so that a DC voltage that is higher than the input voltage can be tapped at the output. However, other types of converters in power factor correction circuits are also common, such as flyback converters or buck converters.
    [0005] Such a power factor correction circuit can be operated in various operating modes. In particular, an operation with a continuous current through the aforementioned inductance (so-called "Continuous Conduction Mode, CCM), an operation with a discontinuous inductance or coil current (" Discontinuous Conduction Mode, also DCM operating mode) or an operation in the border area between continuous and discontinuous current through the inductance known. The last-mentioned operating mode, which is just on the border between continuous and discontinuous operation, is also referred to as the so-called “critical conduction mode,” “boundary conduction mode” or “borderline conduction mode (BCM operating mode).
    In order to operate a power factor correction circuit in the BCM operating mode, a control unit can be used which receives an input signal at an input which depends on the current in the inductance. The input signal can, for example, be detected inductively with a detection winding or measuring winding and fed to the input. The / 15
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    The control unit can be designed in such a way that it detects zero crossings of the current through the inductor based on the input signal and, in response thereto, modulates a control signal in order to start a new charging process for the inductor. The control unit can compare the signal, which depends on the current through the inductance, with a threshold value in order to initiate a renewed switching of the switch into the on state depending on a result of the threshold value comparison. Correspondingly designed control units can be designed in the form of integrated semiconductor circuits (or as an integrated circuit IC, application-specific integrated circuit ASIC, as a microcontroller, ...).
    In order to be able to adapt the output power, the time period in which the switch is switched to the on state, that is to say conductive, and which is also referred to as “T on time”, can be adapted.
    Operating devices for lamps should be usable for larger power ranges. In conventional power factor correction circuits, in which the control unit switches the switch again when the current through the inductance passes zero, the provision of output powers which are small compared to the maximum output power can be difficult. For example, the T on time cannot be shortened arbitrarily. An undesired transition into a so-called “burst mode” can occur, in which the power factor correction circuit remains temporarily switched off in order to avoid impermissibly high output voltages. The resulting fluctuations in brightness in the light that is emitted by the illuminant are perceived as unpleasant. The fluctuations in brightness can thus be perceived by the human eye as flickering, for example. This runs counter to the goal of ensuring the most uniform possible light emission.
    From the prior art is e.g. It is known that if an operating device is to operate a low load, but at the same time there is a high mains voltage amplitude, the operating mode changes.
    For example, the control can be switched from continuous, non-intermittent operation (CCM) to discontinuous, intermittent operation (DCM). In particular, the clocked switch is switched off when a maximum bus voltage is reached and the switch is switched on again after it has dropped below a predefined hysteresis value, in particular into a low-frequency range of in particular less than 10 Hz.
    Thus, there is also a problem in that in a limit operation between the non-intermittent operation and the intermittent operation (BCM) a predetermined minimum switch- on time period (T on time) is set and then because an energy transfer through the PFC circuit does not continue can be reduced, there is an increase in the output voltage output by the PFC circuit. This results in the aforementioned change in the brightness emitted by the connected illuminants or a brightness fluctuation.
    Since these periodic changes are perceptible, it is an object of the invention to avoid this rise in the PFC output voltage and in particular to allow operation without periodic interference. The invention is therefore based on the object of providing a method and a circuit for power factor correction which reduces the risk of a transition to the “burst mode when delivering smaller powers.
    [0013] The invention therefore provides an operating device and a method according to the independent claims.
    [0014] Further developments of the invention are the subject of the dependent claims.
    [0015] In a first aspect, an operating device for light sources, in particular at least one LED, is provided, comprising an active power factor correction circuit supplied from a mains voltage with a clocked controlled by a control unit
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    Switch, wherein the operating device has a control unit that is set up to carry out the clocking of the switch depending on a supplied measurement signal, and a signal processing unit that is in time areas around the peak of the mains voltage, for example in time areas in which the amplitude the mains voltage is above a predetermined threshold value, the amplitude of the measurement signal changes in such a way that during the time ranges there is a reduced power consumption of the power factor correction circuit due to the resulting switching of the switch.
    [0016] The signal processing unit can selectively deactivate and / or activate the power factor correction circuit.
    [0017] The measurement signal can reproduce a profile of a mains voltage. In particular, the measurement signal can be a voltage signal. The measurement signal can be a signal derived from the mains voltage.
    The measurement signal can reproduce a current through a coil of the power factor correction circuit.
    The measuring signal can be supplied to the control unit by a voltage divider and / or a current measuring resistor.
    The signal processing unit can change the measurement signal, and in particular raise a level of a measurement signal, in particular until the line voltage falls below a second threshold value.
    The measurement signal can be a current feedback signal which is fed from a measurement winding to an inductance of the power factor correction circuit of the control unit.
    The mains voltage can be a rectified AC voltage.
    The threshold value can be equal to the second threshold value.
    When the threshold value is reached, the signal processing unit can connect an input of the control unit to a certain potential. The certain potential can be mass.
    [0025] The signal processing unit can have a further switch which switches on when the mains voltage reaches the threshold value and switches off when the second threshold value is reached.
    The signal processing unit can bridge a resistor of a voltage divider, in particular when a further switch is conducting.
    The signal processing unit can activate yet another switch that connects an input of the control unit with a defined voltage, in particular a control unit supply voltage.
    In a further aspect, a luminaire or lamp with an operating device is provided, as described above.
    [0029] In yet another aspect, a method for operating an operating device for light sources, in particular at least one LED, is provided, comprising an active power factor correction circuit supplied from a mains voltage with a clocked switch controlled by a control unit, the operating device having a control unit, which carries out the clocking of the switch depending on a supplied measurement signal, and a signal processing unit which, in time areas around the peak of the line voltage, for example in time areas in which the amplitude of the line voltage is above a predetermined threshold value, the amplitude of the measurement signal changes that during these time ranges there is a reduced power consumption of the power factor correction circuit due to the resulting switching of the switch.
    The invention will now be described with reference to the figures. It shows:
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    Patentamt [0031] FIG. 1 shows a block diagram of an operating device according to the invention;
    Figure 2 shows an exemplary circuit arrangement;
    [0033] FIG. 3 exemplary signal profiles;
    Figure 4 shows an exemplary circuit arrangement according to the invention;
    [0035] FIG. 5 further exemplary signal profiles;
    6 shows a further exemplary circuit arrangement according to the invention; and [0037] FIG. 7 still further exemplary signal profiles.
    1 shows a block diagram of a lighting system 1, which comprises an operating device 2 for a lamp or a lamp path 3. The illuminant 3 can have at least one LED, for example. The operating device 2 can be connected to a bus or a wireless communication system in order to receive dimming commands and / or to issue status messages.
    The operating device 2 can be configured, for example, as an electronic ballast (EVG) for gas discharge lamps, fluorescent lamps or other fluorescent lamps, or as an LED converter. The operating device 2 has a rectifier 10 for rectifying a supply voltage, in particular a mains voltage. The operating device 2 also has a power factor correction circuit 11 (PFC circuit) which provides an output voltage for downstream components of the operating device 2. This output voltage is also referred to as the output voltage V OU t of the PFC circuit. A further voltage conversion and / or function can be achieved via a DC-DC converter 12, which can be designed as an LLC resonance converter and / or an output driver 13. A control unit 14 can perform various control or regulating functions, for example for implementing dimming commands that are operated via the bus 4.
    The operation of the operating device with the PFC circuit 11 will now be further described with reference to the other figures.
    Fig. 2 now shows an exemplary example of a PFC circuit 11. An AC supply voltage, for example the mains voltage, is converted by the rectifier 10 into a rectified AC voltage, which as input voltage V, N between an input terminal of the PFC circuit 11 and Mass is present.
    The AC input voltage V, N is filtered by an input capacitor C1 and fed to an inductor L1a, which can be designed as a coil. The inductor L1a is connected in series with a diode D1 between the input connection and an output connection of the PFC circuit 11. An output DC voltage V 0U t is provided at the output connection coupled to an output capacitance or an output capacitor C2. The DC output voltage V OU t serves to supply a load which is supplied by the PFC circuit 11.
    The load can be, for example, a DC-DC converter (direct voltage / direct voltage converter) 12 with a lamp 3 connected to it or a further operating device for a lamp.
    At the connection between the inductor L1a and the diode D1, a controllable switch S1 is connected, which serves as a controllable switching means. The controllable switch S1 can be connected to ground via a shunt resistor R4. The switch S1 is a controllable, electronic switch, in particular a power switch (for example field effect transistor FET or MOSFET).
    The switch is switched on and off by a control unit SE of the PFC circuit 11, that is to say put in a conductive or non-conductive state. The control unit SE has a corresponding output 27 for driving or for outputting a control signal with which, for example, the gate voltage of the
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    Switch S1 can be controlled.
    When switch S1 is on, inductor L1a is connected to ground via switch S1, so that inductor L1a is charged and energy is stored in inductor L1a. If, however, the switch S1 is switched off, that is to say open or not conducting, the inductance L1a is discharged via the diode D1 into the output capacitor C2. The energy stored in the inductor L1a is therefore transferred to the output capacitor C2.
    The switch S1 is controlled by the control unit SE. The power factor correction is achieved by repeatedly switching the switch S1 on and off, the switching frequency for the switch S1 being in particular greater than the frequency of the rectified input alternating voltage V | N. The PFC circuit 11 can work as a bus converter. The mode of operation of the control device is described further below.
    The control unit SE also has an input 25. Depending on an input signal received at input 25, control unit SE can switch switch S1 into the conductive or non-conductive state. The input signal received at input 25 thus determines the switch-off time period (T OF F time), that is to say the time period during which switch S1 remains in the off state or in the non-conductive state after switching, before it switches back to the conductive state State is switched.
    The control unit SE can compare the input signal received at the input 25 with a threshold value. For this purpose, the control unit SE can comprise, for example, a corresponding comparator. Depending on a result of the threshold value comparison, the control unit SE can switch the switch S1 to an on state. For example, the control unit SE can switch the switch S1 back into the conductive state when the input signal received at the input 25 falls below a threshold value. The control unit SE can be configured in such a way that a zero crossing is carried out for the input signal received at the input 5. A detected zero crossing can trigger the switch S1 to be switched to the on state.
    [0050] The control unit SE can have further inputs. For example, a further input 21 having a first voltage divider with resistors R5, R6 may be coupled to the output voltage V O ut of the PFC circuit 11 to be detected. Another input 23 can be connected to a second voltage divider with resistors R1, R2 in order to detect the smoothed input voltage. The control unit SE can thus also determine or control the switch- on period (T on time) of the switch S1 depending on the input voltage and / or the output voltage. The switch-on period can be determined independently of the input signal that is received at input 25. The input signal, which is provided at input 25, can be used by control unit SE to determine the point in time at which switch S1 is switched back to the on state and thus determine the switch-off period (T of f time).
    Due to the input signal received at the input 25, or depending on it, the control unit SE can trigger a renewed switching of the switch S1 into an on-state on the basis of the threshold value comparison and also allow operation in intermittent operation (DCM).
    Furthermore, the circuit has a further measuring inductance L1b, in particular a measuring winding or measuring coil, which is connected to the input 25 of the control unit via a measuring resistor R3. The inductor L1b is provided to detect the end of a free-running phase of the coil current through the inductor L1a. The coil current detected at the measuring inductance L1b is fed to the input 25 of the control unit SE via the measuring resistor R3. If the current through the inductance L1a reaches the value zero, ie there is a zero crossing, the switch S1 is switched on, that is to say switched on, in order to store energy in the inductance L1a. The switch-on period of the switch S1 can, as stated, be determined by the output voltage V OU t via the capacitor C2, which is connected to the
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    Patent office first voltage divider consisting of the resistors R5, R6 is detected. This voltage value is fed to the control unit at input 21.
    Furthermore, the switch-on time of the switch S1 can vary from the current supply voltage V | N depend, which is formed on the second voltage divider consisting of the resistors R1 and R2.
    If the switch S1 is closed, the current I L1 rises linearly through the inductance L1a due to the inductance behavior. However, if the switch S1 is opened, that is to say not switched on, the current is driven by the inductance L1a via the diode D1 to the capacitance C2, which is thereby charged.
    During this time, the current through the inductance L1a drops linearly to zero, which can be recognized at the input 25 of the control unit SE. The switch S1 would therefore be activated accordingly by activation via the output 27 of the control unit SE and switched on again.
    Exemplary signal profiles are shown in FIG. 3 for switch-on and switch-off phases 36, 37 of switch S1. Here, in particular, the current profile l L i at the inductor L1a is shown as an example (center) and also the voltage U | induced in the measuring inductor L1b N. The input signal at the input 25 is therefore dependent on the coil current I L through the inductance L1a and allows the detection of zero crossings of the coil current. The control unit SE can output a control signal for controlling the switch S1 via the output 27, which is shown at 31. The detected signal is, for example, proportional to a time derivative of the coil current by the inductor L1a.
    When switch S1 is switched to the on state, coil current 33 increases. Correspondingly, the input signal 32 at the input 25 of the control unit SE has a first value. When the switch S1 is switched back to the off state after the switch-on period 36, energy is transferred from the inductance L1a into the output capacitor C2. The coil current 33 drops accordingly. The drop in the coil current 33 means that the input signal 32 at the input 25 of the control unit SE has a second value. A drop in the coil current to zero or another, smaller threshold value can be detected by comparing the input signal 32 with a threshold value 34. Reaching the threshold value 34 is recognized as time T zx for a zero crossing. In response to this, the control unit SE switches the switch S1 back to the on state. The switch-off time period 37, that is to say the time period in which the switch S1 is not turned on, is selected such that the inductance L1a operates at the boundary between continuous and discontinuous current flow (non-intermittent operation and intermittent operation).
    The control unit SE can now adapt the operation of the power factor correction circuit 11 to different loads and / or dimming levels, for example by adapting the switch-on period 36. In this case, the switch-on time 36 can be reduced to an allowable minimum value with decreasing loads and / or smaller dimming levels. When the minimum value is reached, a transition to the DCM operating mode (intermittent operation) can be initiated.
    Since the control unit SE is set up to work in the limit mode (BCM), the available power range is limited. The smaller the load connected to the PFC circuit 11, the shorter the switch-on time T ON of the switch S1. This continues until the minimum switch-on time for switch S1 is reached. However, even this minimum switch-on time is sufficiently long to charge the output capacitance C2 at the output of the PFC circuit 11 and thus to increase the voltage V O ut.
    If a certain voltage value is now reached, the control unit SE switches the switch S1 off until the output voltage V OU t falls below a predetermined threshold value. This takes place in the course of surge protection. This results in the so-called “burst mode,” in which the output capacitance C2 is charged up to the area of the overvoltage protection and charging of the output capacitance C2 is then prevented.
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    This results in a high-voltage ripple with a repetition rate of possibly a few seconds at the output of the PFC circuit 11.
    To avoid the “burst mode”, the energy transmitted by the PFC circuit 11 must be limited. In particular, the invention now allows the switch-on period of the switch S1 to be limited at a specific value of the input voltage V, N or the smoothed mains voltage V, N s so that less energy is transmitted. This allows a higher energy transfer during working hours and therefore longer switch-on times for switch S1.
    An embodiment of the invention is now shown in FIG. 4, which has a signal processing unit SVE according to the invention (components in the dashed area). Components already described with reference to FIG. 2 are designated accordingly. As can be seen in FIG. 4, a third voltage divider consisting of the resistors R7 and R8 is provided between the input capacitor C1 and the second voltage divider as part of the signal processing unit SVE.
    A zener diode Z1 is provided at a center point of the third voltage divider and is connected to its cathode at the center point. The anode of the zener diode is connected to the base of a transistor Q1. The collector of transistor Q1 is connected to the base of a second transistor Q2 via a connecting resistor R9, while the emitter of transistor Q1 is connected to a further potential, in particular ground. An offset resistor R O ff can be provided in the path between the emitter of transistor Q1 and ground, which is shown in dotted lines in FIG. 4. In this way, a potential can be defined, which is set when transistor Q1 is activated. The connection resistor R9 is connected to the base of the second transistor Q2, whose emitter is connected to a voltage source or a potential of a voltage source. This is in particular the control unit supply voltage VCC. The collector of the second transistor Q2, however, is connected via a second diode D2 in the forward direction to the input 25 of the control unit SE.
    Is now a defined voltage across the resistor R8 of the third voltage divider (these can be set by dimensioning the resistors R8, R9 of the third voltage divider) and this defined voltage exceeds the breakdown voltage of the zener diode and the base-emitter voltage of the first transistor Q1, the path between the collector and the emitter of the first transistor Q1 becomes conductive. If the first transistor Q1 is conducting, then the second transistor Q2 is also conducting and the zero crossing detection input 25 of the control unit SE is connected to the potential VCC. As a result, the control unit SE cannot determine a zero crossing of the current I L i through the inductor L1a or a free-running phase of the inductor L1a, and the control unit SE will not switch on the switch S1.
    [0065] As a result, since the PFC circuit 11 is switched off at a peak value of the voltage or at voltage values of the electrical supply voltage above a threshold value, the switch-on period of the switch S1 must be increased during the active phase of the PFC circuit 11 in order to ensure sufficient power transfer. However, this prevents the “burst mode of the PFC circuit 11. The transistors Q1, Q2 are thus voltage-controlled switches.
    FIG. 5 shows a corresponding exemplary representation of the voltage profile through the input capacitor C1 (top) and the current profile through the inductor L1a (bottom). The shutdown threshold THR of the PFC circuit 11 is also shown by a dashed line. This threshold value THR therefore corresponds to the voltage value at which the first transistor Q1 is turned on. Thus, in time ranges in which the amplitude of the mains voltage lies above the predetermined threshold value, the amplitude of the measurement signal which is fed to the control unit SE is changed such that there is a reduced power consumption of the power factor correction circuit during the time ranges. The voltage V C i is plotted on the input capacitor C1 as it is at the top
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    Patent office on the third voltage divider is detected. When the threshold value THR is exceeded, ie from the point in time at which the transistor Q1 switches, the PFC circuit is deactivated. A resulting course of the current I L i through the coil L1a is plotted below.
    In general, in the area of the peak values of the electrical supply voltage, in particular the rectified mains voltage, the current detection at the input signal of the control unit SE is selectively changed. In particular, in this area, that is, in the area above the threshold value or in the area of the peak of the supply voltage, the current detection signal fed to the input 25 of the control unit SE can be shifted upwards in such a way that in the lateral area the peak values of the rectified mains voltage , The control unit cannot detect a zero crossing of the coil current through the inductor L1a. In this way, a kind of intermittent operation (discontinuos conduction mode, DCM) is achieved by manipulating the signal supplied by the measuring inductor Lb1 in the region of the peaks of the mains voltage. The operation, which is at least similar to the intermittent operation, can have a 100 Hz rhythm.
    However, the selective deactivation of the PFC circuit 11 can lead to an increased 100 Hz ripple, which may be audible under certain circumstances. In a further embodiment, which is shown in FIG. 6, a current signal supplied to the control unit SE is no longer changed, but the signal representing the smoothed mains voltage V, N s , which is detected at the second voltage divider, is changed.
    As is known, the control unit SE detects the mains voltage in such a way that the energy consumption by the PFC circuit 11 can emulate the sine curve of the electrical supply voltage. The switch-on period of the switch S1 is in particular chosen to be longer, the higher the current amplitude of the mains voltage V | N or the electrical supply voltage.
    FIG. 6 now shows an embodiment of the invention which largely corresponds to the circuit from FIG. 4. The same circuit parts are correspondingly labeled the same. Essentially, only the signal processing unit SVE 'is designed differently.
    As can be seen from FIG. 6, a third voltage divider with resistors R7 ', R8' is again provided, which is provided between the input capacitor C1 and the second voltage divider made up of resistors R1, R2. At a center point of the third voltage divider, as in FIG. 4, a Zener diode ZT is provided, which is connected to the base of a transistor QT. The collector of the transistor QT is connected to a center point of the second voltage divider and thus to the input 23 of the control unit SE. The emitter of the transistor QT is connected to a defined potential, in particular to ground. However, it can be provided that a further offset resistor R OF f 'is arranged in the connecting branch between emitter and ground, which can be selected in order to set a corresponding potential. The optional offset resistor R OFF 'is shown in dotted lines in FIG. 6.
    Now increases the voltage defined at the center point of the third voltage divider (this can be adjusted by appropriately dimensioning the resistors R7 'and R8') and consequently the voltage across the resistor R8 'corresponds to the breakdown voltage of the Zener diode Z1 plus the base Emitter voltage of transistor Q1, or exceeds it, the path between the collector and the emitter of transistor Q1 becomes conductive. As a result, the input 23 of the control unit SE is connected to ground or the defined potential. In particular, the potential-lower resistor R2 of the second voltage divider is bridged. As a result, the voltage detected at the input 23 of the control unit SE drops to zero. The control unit SE can determine the signal received at the input to determine the switch-on time of the switch S1. The switch-on period of the switch S1 is therefore reduced to a minimum.
    The signal processing unit SVE 'now manipulates the detection of the electrical supply voltage in such a way that at high amplitudes the electrical supply 8/15
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    Patent office supply voltage a lower line voltage amplitude is detected at the control unit SE. This is done by selectively short-circuiting the second voltage divider and in particular the resistor R2 of the second voltage divider by short-circuiting the center point and thus the signal at the input 23 of the control unit SE via the transistor Q1. Since a relatively low amplitude is now recognized on the control unit SE instead of a high amplitude of the electrical supply voltage, the switch-on time (TonTime) is set to a minimum value.
    The advantage over the arrangement from FIG. 4 is that the switching of the PFC switch S1 is not completely deactivated in the region of the high voltage amplitudes. Rather, switching takes place with a minimal switch- on time (T on time).
    Since overall the energy transmission would be reduced by the actually too low energy transmission in the area of the high amplitudes, the control unit SE or a control algorithm, which is implemented in the control unit SE and to which the output voltage of the PFC circuit 11 is supplied, compensates, this lower energy transmission in that, in order to avoid a drop in the bus voltage, the switch-on time outside the high voltage amplitudes is increased.
    7 illustrates a corresponding signal curve. In the upper part, on the one hand, the voltage V C1 is plotted on the input capacitor C1, as is detected on the third voltage divider. V R2 represents the voltage across the resistor R2 of the second voltage divider. When the threshold THR is exceeded, ie from the point in time at which the transistor Q1 'switches, the voltage VR2 falls to zero. A corresponding course of the current I L1 through the coil L1a is plotted below.
    The idea according to this aspect of the invention is very general that in the area of the line voltage peaks, that is to say whenever the line voltage exceeds a predetermined threshold value THR, the feedback measurement signal for the line voltage is specifically reduced.
    In the illustrated embodiment, a zero crossing of the mains voltage is actually simulated by short-circuiting the resistor R2 of the resistor divider. Alternatively, the emitter cannot be brought to ground potential, but to ground via a further resistor R O ff, Hoff '. Thus, the control unit SE would not be shown a zero crossing at the input 23, but only a reduced mains voltage amplitude greater than zero. This means that the control unit SE will then not set the minimum tone time for the zero crossing, but rather a reduced, but not the minimum tone time, which leads to the jumps between the activation / deactivation of the PFC circuit turn out to be less drastic in terms of the tone time, which also has advantages with regard to the 100 Hz ripple and acoustic interference.
    The further resistor R O ff, Roff 'can also be connected to the collector of the switch Q1, Q1'. Overall, the parallel connection of the resistor R2 with the at least one additional parallel resistor R O ff, Roff 'in the branch of the transistor Q1, Q1' will change the resistor divider such that the signal at the input 23 of the control unit SE of the PFCs has a lower mains voltage than actually currently auditioning.
    Since this distorts the distortion of the control of the PFC in terms of optimal power factor, the activation of the above-mentioned function can be applied to small load ranges, i.e. in particular when dimming down the connected lamp path.
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    权利要求:
    Claims (15)
    [1]
    Expectations
    1. Operating device for lamps (3), in particular at least one LED, comprising:
    - An active power factor correction circuit (11) supplied from a mains voltage (V, N ) with a clocked switch (S1) controlled by a control unit (SE), wherein
    - The operating device (2) has the control unit (SE), which is set up to carry out the clocking of the switch (S1) depending on a supplied measurement signal, and a signal processing unit (SVE, SVE '), which are in time ranges around the apex of the Mains voltage (V ! N ) around, for example in time ranges in which the amplitude of the mains voltage (V, N ) is above a predetermined threshold value (THR), the amplitude of the measurement signal changes in such a way that during these time ranges a by Resulting clocking of the switch (S1) results in reduced power consumption of the power factor correction circuit (11).
    [2]
    2. Operating device according to claim 1, wherein the signal processing unit (SVE, SVE ') selectively deactivates and / or activates the power factor correction circuit (11).
    [3]
    3. Operating device according to claim 1 or 2, wherein the measurement signal represents a profile of a line voltage (V | N ) and / or is a signal derived from the line voltage (V, N ).
    [4]
    4. Operating device according to one of the preceding claims, wherein the measurement signal reflects a current through a coil (L1a) of the power factor correction circuit (11).
    [5]
    5. Operating device according to one of the preceding claims, wherein the measurement signal of the control unit (SE) from a voltage divider (R1, R2) and / or a current measuring resistor (R3) is supplied.
    [6]
    6. Operating device according to one of the preceding claims, wherein the signal processing unit (SVE, SVE ') changes the measurement signal, and in particular raises a level of a measurement signal, in particular until the mains voltage (V ! N ) falls below a second threshold value.
    [7]
    7. Operating device according to one of the preceding claims, wherein the measurement signal is a current feedback signal which is fed from a measurement winding to an inductance (L1b) of the power factor correction circuit (11) of the control unit (SE).
    [8]
    8. Operating device according to one of the preceding claims, wherein the mains voltage (V, N ) is a rectified AC voltage.
    [9]
    9. Operating device according to one of the preceding claims, wherein the threshold value (THR) is equal to the second threshold value.
    [10]
    10. Operating device according to one of the preceding claims, wherein the signal processing unit (SVE, SVE ') is set up to connect an input of the control unit (SE) with a certain potential when the threshold value (THR) is reached.
    [11]
    11. Operating device according to one of the preceding claims, wherein the signal processing unit (SVE, SVE ') has a further switch (Q1) which turns on when the mains voltage (V ! N ) reaches the threshold value (THR) and switches non-conductive when the second threshold is reached.
    [12]
    12. Operating device according to claim 11, wherein the signal processing unit (SVE, SVE ') bridges a resistor of the voltage divider (R1, R2), in particular when the further switch (Q1) is conductive.
    [13]
    13. Operating device according to claim 11 or 12, wherein the signal processing unit (SVE, SVE ') activates yet another switch (Q1) which connects an input of the control unit (SE) with a defined voltage, in particular a control unit supply voltage (VCC).
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    [14]
    14. Luminaire or lamp with an operating device according to one of the preceding claims and with at least one lamp.
    [15]
    15. A method for operating an operating device for lighting means (3), in particular at least one LED, comprising an active power factor correction circuit (11) supplied from a mains voltage (V, N ) with a clocked switch (S1) controlled by a control unit (SE), The operating device (2) has the control unit (11), which carries out the clocking of the switch (S1) as a function of a supplied measurement signal, and a signal processing unit (SVE, SVE '), which in time ranges around the peak of the mains voltage (V | N ) around, for example in time ranges in which the amplitude of the mains voltage (V, N ) lies above a predetermined threshold value, the amplitude of the measurement signal changes in such a way that during these time ranges a resulting switching of the switch ( S1) results in reduced power consumption of the power factor correction circuit (11).
    4 sheets of drawings
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    Fig. 1
    Fig. 2
    V OUT
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    Fig. 4
    LV C1 THR / i!1 j i ii 1 AiJ 1 ä!!I uML Fig , 5
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    V OUT
    SVE '
    Fig. 6
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US20050219871A1|2004-03-30|2005-10-06|Hong-Chun Li|Piecewise on-time modulation apparatus and method for a power factor corrector|
    DE112010004983T5|2009-12-23|2013-01-24|Tridonic Ag|Circuit for the operation of light-emitting diodes |
    DE102012017397A1|2012-04-13|2013-10-17|Tridonic Gmbh & Co. Kg|A method of controlling a power factor correction circuit, power factor correction circuit, and lighting device driver|
    EP2713489A1|2012-09-27|2014-04-02|Siemens Aktiengesellschaft|Method for low power operation of an active PFC converters using window modulation with open-loop width control|DE102020209738A1|2019-08-19|2021-02-25|Dialog Semiconductor Inc.|SYSTEM AND PROCEDURE FOR IMPROVING THE POWER FACTOR AND THD OF A SWITCHING POWER CONVERTER|DE102009047984A1|2009-10-01|2011-04-07|Tridonic Gmbh & Co Kg|Method and circuit for power factor correction|
    US8853958B2|2011-11-22|2014-10-07|Cree, Inc.|Driving circuits for solid-state lighting apparatus with high voltage LED components and related methods|DE102016210517A1|2016-06-14|2017-12-14|Rudolf Polzer|Method for regulating an output power of an alternating electrical voltage|
    DE102016013733B4|2016-11-17|2019-01-31|Finepower Gmbh|Method for operating a power factor correction circuit|
    法律状态:
    2020-10-15| MM01| Lapse because of not paying annual fees|Effective date: 20200229 |
    优先权:
    申请号 | 申请日 | 专利标题
    DE102014221511.0A|DE102014221511A1|2014-10-23|2014-10-23|PFC circuit with voltage-dependent signal feed|
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