• 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:
    The invention provides a driver circuit for operating a lighting means, preferably at least one LED, comprising a floating, on the primary side clocked by a control unit by means of at least one controlled switch unit converter which feeds a rectifier, from which the light source can be supplied, wherein a detection circuit for indirect detection of the current on the secondary side of the converter has a transformer with at least one primary-side winding.
    公开号:AT15179U1
    申请号:TGM360/2014U
    申请日:2014-10-16
    公开日:2017-02-15
    发明作者:Phys Frank Lochmann Dipl；Ing Marte Patrick
    申请人:Tridonic Gmbh & Co Kg；
    IPC主号:
    专利说明:

    description
    ACTIVE CIRCUIT FOR DETECTING A LUMINAIRE CURRENT
    The invention relates to an active circuit, in particular a driver circuit, for detecting a current through a light path with at least one LED. In particular, the invention relates to an active circuit which is divided by a potential-separating and / or galvanically insulating barrier (for example a safety extra-low voltage barrier (SELV barrier)) into a primary side supplied by a supply voltage and a secondary side supplying the luminous flux path.
    It is known that in such circuits from the primary side of the circuit to the secondary side of the circuit, an energy transfer takes place.
    In particular, the transmission from the primary side to the secondary side of the circuit across the barrier occurs by means of a transducer, in particular a transformer which induces a voltage or a current on the secondary side by means of an electromagnetic coupling. Thus it is possible to supply the secondary side across the barrier.
    For determining the luminous flux through the lighting means, or the light-emitting means, which can be used to control the brightness of the illuminant, it is known to carry out a determination of the luminous flux on the secondary side. This is e.g. shown in WO 2014/060899. It is also known that, as shown by way of example also in FIG. 1, a control circuit SE drives a switch unit S with a clocked switch directly or indirectly, e.g. via a driver unit.
    The switch unit S may, for example, have a single clocked switch or a plurality of clocked switches. For example, the switch unit S may comprise an inverter with a high-side switch and a low-side switch.
    Starting from the switch unit S then a converter winding L2_1 (Induktivi ity, coil) is supplied. This converter winding L2_1 can be part of an LLC circuit and fed, for example, from a center of the inverter. In particular, therefore, a converter (eg resonant converter, LLC converter) is fed, starting from which the secondary side of the circuit by electromagnetic coupling of the primary-side converter winding L2_1 and the secondary-side converter winding L2_2, L2_3 (shown here as separate windings L2_2, L2_3) via a barrier B. is fed.
    About the diodes D1 and D2, which form a rectifier, the LED terminals LED + and LED- is fed via a smoothing capacitor C2 smoothed DC voltage for the operation of the light source.
    An auxiliary winding Lh is provided with a detection circuit E on the secondary side of the circuit, wherein the auxiliary winding Lh is electromagnetically coupled to the primary-side winding L2_1. The detection circuit E then detects, by means of the auxiliary winding Lh, a current induced on the secondary side of the circuit, or a parameter representing this. The corresponding parameter representing the current is determined by the detection circuit E and fed back to the control unit SE via the barrier B via a bridging element X, which may be, for example, an optocoupler or another transformer. The control unit SE can then evaluate the parameter as an actual value for the current through the lighting means, and use it to control the lighting means. In this case, the control unit SE can in particular compare the actual value for the current with a desired value and accordingly control the switch unit S.
    The circuit shown in Fig. 1, however, has the disadvantage that on the one hand the detection circuit E must be provided on the secondary side of the circuit, and further a bridging element X is required to bridge the barrier B, resulting in relatively high circuit costs and leads complicated circuitry.
    It is therefore an object of the invention to provide a circuit which enables primary-side detection of a parameter representing the current through the luminous means. In particular, it is the object of the invention to provide a possibility of detecting a parameter representing the current through the luminous means on the primary side of the circuit, thereby avoiding detection errors.
    A solution to this problem is described below and solved by the device according to claim 1 and the method according to claim 11.
    Further developments of the invention are the subject of the dependent claims.
    In a first aspect of the invention, a circuit, in particular a driver circuit for operating a light source, preferably at least one LED, provided comprising a potential-separated, clocked by a control unit by means of at least one controlled switch unit converter which feeds a rectifier of on the basis of the bulbs can be supplied. A detection circuit for indirectly detecting the current on the secondary side of the converter has a transformer with at least one primary-side winding.
    The detection circuit may comprise a detection rectifier, preferably an active detection rectifier, which may be formed as a polarity converter.
    To the control unit can be fed back from an output of the detection circuit, a current reproducing the current through the lamp parameters. In particular, the output can be connected directly or indirectly to a measuring input of the control unit.
    The switch unit may be a half-bridge or full-bridge inverter.
    The at least one primary-side winding may in particular be part of a resonant converter, an LLC circuit, a flyback converter, a push-pull flux converter, an up-converter or a buck converter.
    The control unit may control rectifier switches of the active rectifier of the detection circuit in response to the driving of the switch unit.
    The switch unit may comprise at least one switch, in particular a transistor, FET or MOSFET.
    The control unit may connect the secondary winding of the transformer by driving a first rectifier switch in synchronism with an inverter switch or by driving a second rectifier switch in synchronism with another inverter switch to ground.
    The parameter representing the current through the lighting means may be a voltage value output at an output of an integration circuit of the detection circuit.
    The first or the second rectifier switch can be controlled by the switch unit by a drive signal and the other rectifier switch can be controlled by an inverted drive signal from the switch unit.
    In a further aspect, the invention provides a method for detecting a parameter representing the current through a lighting means, preferably at least one LED, wherein a potential-separated clocked converter controlled on the primary side by a control unit by means of at least one switch unit feeds a rectifier, from which the light source is supplied. A detection circuit may detect a current indirectly on the secondary side of the converter on a transformer having at least one primary-side winding on the secondary side of the converter.
    The invention will also be described with reference to the figures. 1 shows schematically a known embodiment according to the prior art.
    Fig. 2 shows schematically a first embodiment storm according to the invention.
    Fig. 3 exemplifies a more detailed circuit arrangement according to the first Ausfüh tion of the invention.
    Fig. 4 shows exemplary curves of detected parameters.
    Fig. 5 shows schematically a second embodiment according to the invention.
    Fig. 6 exemplifies a more detailed circuit arrangement according to the second imple mentation form of the invention.
    Fig. 7 states of circuit parts with certain control.
    Fig. 2 now shows a first embodiment of the inventive circuit, wherein the same reference numerals denote substantially the same circuit parts as in Fig. 1. As shown in Fig. 2, in series with at least one secondary-side converter winding L2_2, L2_3 (es can also, as shown, two converter windings are provided) connected to a diode in turn connected to a primary winding L3_1 of a transformer in series. The primary winding L3_1 of the transformer and is arranged in the supply path of the lighting terminal LED +.
    The primary winding L3_1 of the transformer is electromagnetically coupled to a secondary winding L3_3 of the transformer.
    In Fig. 2 is shown in a dashed frame by way of example, connected with a diode D2 in series, primary-side further primary winding L3_2 of the transformer, which may be optionally provided.
    The secondary winding L3_3 of the transformer is connected to a detection circuit E ', which has a passive detection rectifier PG. This rectifies the, in particular alternately transmitted by the primary windings L3_1, L3_2 of the transformer voltage to a DC voltage.
    At an output of the passive detection rectifier PG, a detection of the parameter representing the current through the luminous means, e.g. via a current measuring resistor. The parameter is in turn fed back to a control unit SE ', which preferably evaluates it as an actual value for the current through the lighting means (not shown) and carries out a corresponding regulation. For connection of the luminous means, which preferably has at least one LED, as in Fig. 1, the terminals (terminals) LED and LED + are provided.
    An exemplary embodiment of the embodiment of Fig. 2 is shown in Fig. 3. Again, like reference numerals designate like circuit parts as shown in Figs. 1 and 2.
    In particular, a control unit SE 'is provided in Fig. 3, which drives an inverter with a first inverter switch Q1 and a second inverter switch Q2. The first inverter switch Q1 is here a "high-side switch", ie the switch "over" the load or the higher-potential switch, and is controlled by a driver T, while the second inverter switch Q2 a "low-side switch" (Switch "under" the load or potential-lower switch) represents.
    Starting from a midpoint between the first and second inverter switches Q1, Q2 of the illustrated inverter half bridge, a resonant converter (here LLC converter) is fed with a capacitance C1, an inductance L1 and a primary converter winding L2_1.
    The secondary side of the circuit is substantially identical to that of Fig. 2. Again, one of the primary windings L3_1, L3_2 of the transformer may optionally be provided.
    Furthermore, the passive detection rectifier PG 'as part of the detection circuit E' is formed on the primary side of the circuit as a diode full bridge and the control unit SE 'detects at its output a parameter representing the current through the light source via a measuring resistor R.
    With the arrangements of FIGS. 2 and 3, the parameter representing the current through the luminous means can now be detected on the primary side of the circuit. Since, in particular, both half-waves supplied to the lighting means are transmitted in a transforming manner, corresponding current values for both half-waves can also be detected.
    The problem here is, however, that the typically used on the secondary side of the circuit as a rectifier diodes D1, D2 at high temperatures have a "Rever-se-stream", ie that is not directly switched off by the diodes D1, D2, but a current through the diodes D1, D2 of the rectifier in the reverse direction of the diodes D1, D2 flows.
    Due to the transformer output and the rectification by the passive detection rectifier PG 'results in a potential error that bothers the signal detected by the control unit SE' strong signal, especially at high temperatures.
    This is shown by way of example in FIGS. 4a and 4b clearly illustrated, wherein Fig. 4a illustrates a curve at high temperatures. In the illustration, the black, initially from left to right curve, a current waveform through the diode D1, while the gray, falling from left to right curve, the signal detected at the measuring resistor R represents.
    However, the passive detection rectifier PG 'is unable to correctly output the negative "reverse current" of the diode, resulting in a shift of the measured signal detected to the measuring resistor R.
    In Fig. 4b corresponding curves for lower temperatures are shown. It can be seen from Fig. 4b that the smaller the temperature, the lower the influence of reverse-biased "reverse current" on the diode D1, thus reducing the detection error at low temperatures, the detected and erroneously positively measured " Reverse current "is much lower at low temperatures. The corresponding area is marked in FIG. 4b.
    It is to be understood that a corresponding signal curve can also result for the diode D2, so that a corresponding error addition results for each half-wave induced by the at least one primary transformer winding L3_1, L3_2 in the secondary transformer winding L3_3.
    It is further understood that in addition to a LLC converter, as shown in Figs. 1 and 2, other converters such as flyback converters, buck or boost converters and in particular other topologies of other clocked, potential-separated converter can be used. Overall, the invention thus relates to the detection of the LED current, wherein this current is determined based on an AC voltage which is rectified by means of the diodes D1, D2. A detection of the LED current thus takes place indirectly via the transformer, which has two primary windings L3_1 and L3_2, which are each connected in series with one of the diodes D1, D2.
    The circuit shown in Fig. 5 now allows detection of an LED current on the primary side of the circuit while avoiding the detection error caused by the "reverse current." Also in Fig. 5, like reference numerals denote substantially the same elements in the preceding Figs.
    Compared to Fig. 2 or 3, the passive detection rectifier PG, PG 'is replaced by an active detection rectifier AG in a detection circuit E "which may be a polarity converter In particular, the secondary winding L3_3 of the transformer is connected to the active rectifier AG, which is preferably connected directly to the switch unit S (eg synchronously) from the control unit SE "is controlled.
    In Fig. 6, a more detailed embodiment of the inventive circuit is now shown by way of example. The secondary winding L3_3 of the transformer is here connected to two rectifier switches Q11, Q12, which are preferably driven alternately directly to the inverter switches Q1, Q2 (e.g., synchronously) of the inverter half-bridge (using, for example, an LLC topology).
    By means of the transistors Q11, Q12 alternately one of the two terminals of the secondary winding L3_3 of the measuring transformer is grounded. Thus, the voltage at the secondary winding L3_3 is tapped in constantly inverting manner via the voltage divider R1 / R3 or R2 / R3. The resistors R1, R2 are preferably selected to be identical.
    During the dead time, i. During the period in which neither the transistor Q11 nor the transistor Q12 is turned on, although no signal can be tapped from the secondary winding L3_3. However, with proper operation of the converter (e.g., LLC or flyback converter), it is not intended that current flow to the secondary side of the converter during this period of time.
    The switching of the rectifier switch Q11, Q12 thus takes place, in particular, synchronously with at least one switch of the switch unit S. When using a fly-back converter, this is a driver signal for driving the second transistor, for example Q12, if necessary to be generated by inverting.
    The output signal of the RC circuit is fed back to the control unit SE "in which a control algorithm is implemented .This feedback signal is evaluated as a value representative of the LED current and as an actual value compared to a desired value Clocking the switch of the LLC or flyback converter (or other primary side clocked potential separate converter).
    FIGS. FIGS. 7a and 7b show circuit configurations at certain switching states of the transistors Q11, Q12. In Fig. 7a, a voltage divider with resistors R1, R2 (alternatively with mutual activation of transistors Q11, Q12 with resistors R1, R3) feeds a capacitor C3 of the RC circuit I. The signal actually returned to the control circuit is thus the voltage on the storage capacitor C3. The secondary winding L3_3 of the transformer is connected to ground when the transistor Q11 (alternatively, the transistor Q12) is turned on. The current detected by the control unit SE "is thus positive. The parasitic reverse current can be measured by the RC circuit I by averaging by means of the capacitor C3, the resistor R3 and the resistor R1 or R2.
    In the dead time, the capacitor C3 discharges, as shown in Fig. 7b, not via a parallel connection of the resistors R1, R2 but only through the resistor R3. In the dead time, the voltage at the capacitor C3 can be used as a measuring signal, but there is no food (charge) of the capacitor C3, starting from the secondary winding L3_3 of the measuring transformer during the dead time.
    Thus, in the embodiment of Figs. 5 and 6 thus detects an alternating current at the secondary winding L3_3. If a current flows through the diode D1, then there is a positive current, a current flows through the diode D2, then there is a negative current. The switching of the transistors Q11 and Q12 then becomes like the one polarity change on the secondary winding L3_3. The integration circuit I (RC circuit then supplies a voltage value which correlates with the current through the lighting means.
    It should be understood that the described switches may be implemented as transistors (e.g., FET, MOS-FET, ...). The control unit SE ', SE "can be designed, for example, as a microcontroller, IC or ASIC.
    权利要求:
    Claims (11)
    [1]
    claims
    1. Driver circuit for operating a light source, preferably at least one LED, comprising a potential-separated, primary side of a control unit (SE1, SE ") by means of at least one controlled switch unit (S) clocked converter which feeds a rectifier (D1, D2), of which starting from the light source can be supplied, characterized in that a detection circuit (E ', E ") for indirect detection of the current on the secondary side of the converter has a transformer (L3_1, L3_3) with at least one primary-side winding (L3_1).
    [2]
    2. Driver circuit according to claim 1, wherein the detection circuit (E ', E ") comprises a detection rectifier (PG, PG', AG, AG '), preferably an active detection rectifier (AG, AG').
    [3]
    3. Driver circuit according to claim 1 or 2, wherein to the control unit (SE ', SE ") from an output of the detection circuit (E', E") is fed back a current through the illuminant reproducing parameters, and in particular the output directly or indirectly is connected to a measuring input of the control unit (SE ', SE ").
    [4]
    4. Driver circuit according to one of the preceding claims, wherein the switch unit (S) is a half-bridge or full-bridge inverter.
    [5]
    A driver circuit according to any one of the preceding claims, wherein the at least one primary side winding (L3_1) is part of a resonant converter, an LLC circuit, a flyback converter, a push-pull flux converter, an up converter or a down converter.
    [6]
    6. Driver circuit according to one of the preceding claims, wherein the control unit (SE ', SE ") rectifier switch (Q11, Q12) of the active rectifier (AG, AG') of the detection circuit (E ', E") in response to the control of the switch unit (S) controls.
    [7]
    7. Driver circuit according to one of the preceding claims, wherein the switch unit (S) comprises at least one switch, in particular a transistor, FET or MOSFET.
    [8]
    8. Driver circuit according to one of the preceding claims, wherein the control unit (SE ', SE ") the secondary winding (L3_3) of the transformer by driving a first rectifier switch (Q11) in synchronism with an inverter switch (Q2) or by driving a second rectifier switch (Q12) synchronously with another inverter switch (Q1) connects to ground.
    [9]
    The driver circuit according to claim 8, wherein the parameter which reflects the current through the lighting means is a voltage value output at an output of an integration circuit (I) of the detection circuit (E ', E ").
    [10]
    10. Driver circuit according to one of the preceding claims, wherein the first or the second rectifier switch (Q11 / Q12) by the switch unit (S) is driven by a drive signal and the other rectifier switch (Q12 / Q11) by an inverted drive signal from the switch unit (S ) is driven.
    [11]
    11. A method for detecting a current through a light source, preferably at least one LED, reproducing parameter, wherein a potential-separated, on the primary side of a control unit (SE ', SE ") by means of at least one switch unit (S) controlled clocked converter a rectifier (D1, D2), from which the light source is supplied, characterized in that a detection circuit (E ', E ") indirectly on the secondary side of the transformer to a transformer (L3_1, L3_3) with at least one primary-side winding (L3_1) on the secondary side of the converter detects a current.
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    法律状态:
    2020-08-15| MM01| Lapse because of not paying annual fees|Effective date: 20191031 |
    优先权:
    申请号 | 申请日 | 专利标题
    DE102014214746.8A|DE102014214746A1|2014-07-28|2014-07-28|Active circuit for detecting a luminous flux|
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