• 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:AT15177U1
    申请号:TGM363/2014U
    申请日:2014-10-16
    公开日:2017-02-15
    发明作者:Bachmann Johannes；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, a converter winding L2_1 (inductance, coil) is then supplied. This converter winding L2_1 can be part of an LLC circuit and fed, for example, from a center point of the inverter. In particular, therefore, a converter (eg, resonant converter, LLC converter) is supplied, 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) across a barrier B away is fed.
    About the diodes D1 and D2, which form a rectifier, LED terminals LED + and LED- is fed via a smoothing capacitor C2 smoothed DC voltage for operation of the lamp.
    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 to detect on the primary side of the circuit a parameter representing the current through the luminous means, 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 13.
    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.
    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 flow converter, an up-converter or a buck converter.
    The control unit may control rectifier switches of the active detection rectifier of the detection circuit in response to the driving of the at least one switch.
    The switch unit may comprise at least one transistor, in particular a FET or MOSFET. The other switches of the circuit can also be designed as transistors (FET, MOSFET,...).
    The control unit may activate / deactivate a first diagonal of the active detection rectifier in synchronism with the first inverter switch. The control unit may activate / deactivate a second diagonal of the active detection rectifier in synchronism with the second inverter switch. Only the first or the second diagonal can be active.
    The secondary winding of the transformer may be part of each of the diagonals of the active detection rectifier.
    The first and second diagonals may each have at least one, preferably two rectifier switches. Preferably, one rectifier switch can each be connected to one terminal of the secondary-side winding of the transformer.
    The one diagonal may each have a rectifier switch and a diode.
    The control unit may activate a diagonal of the active detection rectifier only after a certain time, i. after a dead time after deactivation of the other diagonals of the active detection rectifier.
    In another aspect, the invention provides a method for detecting a current through a light source, preferably at least one LED, reproducing parameter, a potential-separated, driven on the primary side by a control unit by means of at least one switch unit clocked converter 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 according to the invention.
    3 shows by way of example a more detailed circuit arrangement according to the first
    Embodiment 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
    Embodiment 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 a, 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 "above" the load or the higher-potential switch, and is controlled by a driver T, while the second inverter switch Q2 is a "low-side switch" (Switch "under" the load or potential-lower switch) represents.
    Starting from a mid-point between the first and second inverter switches Q1, Q2 of the inverter half-bridge shown, a resonant converter (here LLC converter) with a capacitance C1, an inductance L1 and a primary converter winding L2_1 is fed.
    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.
    Further, the passive detection rectifier PG 'is formed as part of the detection circuit E' on the primary side of the circuit as a diode full bridge and the control unit SE 'detects at its output a current through the illuminant reproducing parameters 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 no immediate shutdown occurs through the diodes D1, D2, but a current through the diodes D1, D2 of the rectifier in Sperrrichtunq 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 greatly disturbs the signal detected by the control unit SE', 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 caused by the "reverse current" detection error.
    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 ", in which the secondary winding of the transformer L3_3 is connected to at least two rectifier switches, but in particular four rectifier switches.
    In this case, the rectifier switches are controlled such that in each case one diagonal of the rectifier active, that is turned on, so that ultimately a tap of the secondary winding takes place alternately. Preferably, the control unit SE "controls the rectifier switch, which also controls the switch unit S.
    Also in Fig. 5, like reference numerals denote substantially the same elements as in the previous Figs.
    In Fig. 6 an exemplary embodiment of the embodiment of Fig. 5 is shown. This is apparent from the exemplary circuit shown in Fig. 3 according to the first embodiment. Substantially already shown in Fig. 3 circuit components are correspondingly denoted analogously.
    In particular, the active detection rectifier AG 'is shown in Fig. 6, wherein the secondary winding L3_3 of the transformer with a first rectifier switch Q3 and a second rectifier switch Q6 is connected and forms a first diagonal, while the secondary winding L3_3 of the transformer with a third Rectifier switch Q4 and a fourth rectifier switch Q5 is connected and thus forms a second diagonal.
    More specifically, as shown in Fig. 6, the first rectifier switch Q3 and the second rectifier switch Q6 of the first diagonal are switched in synchronism with the low-side inverter switch Q2, while the third rectifier switch Q4 and the fourth rectifier switch Q5 synchronously with the high-side inverter switch Q1 can be controlled. In this case, other controls of the rectifier switch are possible. It is important, however, that the control unit SE "knows the polarity currently present on the secondary side of the circuit and correspondingly controls the rectifier switches Q3, Q4, Q5, Q6 of the two diagonals.
    In comparison to the passive rectifiers PG, PG 'of Figs. 2 and 3, therefore, by switching the tap of the secondary winding L3_3, the fault-inducing "reverse current" is measured as a negative current, so that the luminous flux can be effected by the control unit SE "by a corresponding drive control of the switch unit S on the primary side of the circuit. The "reverse current" can then be compensated by such a corresponding control.
    The detection of the current through the illuminant reproducing parameter can then be done by means of an integration circuit I, in particular an RC integration circuit. For example, at a voltage divider, which is formed from the resistors R1, R2, at the midpoint of which a feedback signal can be detected by the control unit SE ", the voltage divider R1, R2 is connected in parallel with a capacitor C3. The parallel connection becomes at the higher potential terminal of the capacitor C3, the rectified output signal from the active detection rectifier AG 'supplied.
    It is to be understood that both in the first and in the second diagonal each have a rectifier switch can be replaced by a diode.
    FIGS. 7a and 7b now show measuring diagrams for different states of the active rectifier: If the active detection rectifier AG, AG 'is operated by the control circuit SE "in such a way that exclusively one diagonal is active in each case, positive and negative Currents are supplied directly to the RC integration circuit I consisting of the capacitor C3 and the voltage divider connected in parallel with the resistors R1 and R2, distinguishing the polarity of the secondary winding L3_3 which is synchronous with the driving of the inverter switches Q1 and Q2.
    When the detection rectifier AG, AG 'is operated near the resonant frequency of the converter (here LLC), a current also flows in the dead time of the inverter, that is, at the time when none of the inverter switches Q1 and Q2 are active. The current then flows through the body diodes of the rectifier switches Q3-Q6 and thus also into the RC integration circuit I. However, this only occurs at very high loads and the error caused thereby is marginal in comparison to the error of using a passive one Rectifier PG, PG 'occurs.
    The invention thus relates generally to the detection of a measurement signal to primary windings L3_1, L3_2 a transformer, which are connected in series with diodes D1, D2, wherein the secondary winding L3_3 of the transformer as the diagonal of an active bridge circuit (in particular full bridge circuit) connected is. The control of the rectifier switches Q3-Q6 preferably takes place by direct use of the control signals of the at least one clocked switch S of the converter supplying the secondary side. Thus, no further detection input to the control unit SE ', SE "is required, and the rectifier switches Q3-Q6 can be activated without a separate driver circuit, ie the primary windings L3_1, L3_2 are switched directly in the power supply paths of the light path.
    Between the active switching of the two diagonals, a dead time is provided in which neither of the two diagonals is active, that is to say switched on. As shown in FIG. 7b, in this intermediate period, the so-called body diodes of the rectifier switches assume the rectifier functions, so that there is no active but passive detection rectifier in the circuit in this period.
    It should be understood that the described switches may be implemented as transistors (e.g., FET, MOS-FET, ...). The control unit SE, SE "may, for example, be designed as a microcontroller, IC or ASIC.
    权利要求:
    Claims (13)
    [1]
    claims
    1. Driver circuit for operating a light source, preferably at least one LED, comprising a floating, primary side of a control unit (SE ', SE ") by means of at least one controlled switch unit (S) clocked converter which feeds a rectifier (D1, D2) of starting from which 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 (Q3-Q6) of the active rectifier (AG) of the detection circuit (E', E") in response to the control of the at least one switch unit ( S) controls.
    [7]
    7. Driver circuit according to one of the preceding claims, wherein the switch unit (S) has at least one switch, in particular one a transistor, FET or MOSFET.
    [8]
    Driver circuit according to one of the preceding claims, wherein the control unit (SE ', SE ") activates / deactivates a first diagonal of the active rectifier (AG, AG') in synchronism with the first inverter switch (Q1), and wherein the control unit (SE '; , SE ") activates / deactivates a second diagonal of the active rectifier (AG ', AG") in synchronism with the second inverter switch (Q2), and only one of the first and second diagonals is active.
    [9]
    9. Driver circuit according to claim 8, wherein the secondary winding (L3_3) of the transformer (L3_1, L3_3) is part of each of the diagonals of the active detection rectifier (AG, AG ').
    [10]
    10. Driver circuit according to one of the preceding claims, wherein the first and the second diagonal each have at least one, preferably two rectifier switch (Q3, Q4, Q5, Q6), wherein preferably each a rectifier switch (Q3, Q4, Q5, Q6) with a Connection of the secondary winding (L3_3) of the transformer is connected.
    [11]
    11. Driver circuit according to one of the preceding claims, wherein a diagonal each having a rectifier switch (Q3, Q4, Q5, Q6) and a diode.
    [12]
    12. Driver circuit according to one of the preceding claims, wherein the control unit (SE ', SE ") activates a diagonal of the active rectifier after a certain time, ie after a dead time after deactivation of the other diagonal of the active detection rectifier (AG, AG') ,
    [13]
    13. 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:
    2021-06-15| MM01| Lapse because of not paying annual fees|Effective date: 20201031 |
    优先权:
    申请号 | 申请日 | 专利标题
    DE102014214744.1A|DE102014214744A1|2014-07-28|2014-07-28|Active circuit for detecting a luminous flux|
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