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AssigneeTridonic GmbH & Co KG
InventorsAndre Mitterbacher, Ueli Keller, Eduardo Pereira
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The invention relates to a method for activating at least one LED, which is supplied with a direct current voltage or a rectified alternating current voltage and which by means of a coil (L1) and a first switch (S1) clocked by a control/regulating unit (SR) provides a supply voltage for at least one LED, wherein when the first switch (S1) is switched on the coil (L1) temporarily stores energy that discharges via a diode (D1) and at least one LED when the first switch (S1) is switched off and wherein the control unit (SR) activates the first switch (S1) by means of a dimming signal. Said method is characterized in that the dimming signal is generated by externally combining a low-frequency signal and a high-frequency signal, wherein the pulse width (TON*LF) of the low-frequency signal is selected as an integral multiple of the cycle duration of the high-frequency signal.
An operating circuit for at least one LED, to which a DC voltage or rectified AC voltage is supplied, and which provides a supply voltage for at least one LED by means of a coil (L1) and a first switch (S1) clocked by a control unit (SR), wherein when the first switch (S1) is switched on, energy is buffer-stored in the coil (L1), which is discharged via a diode (D1) and via at least one LED when the first switch (S1) is switched off, the control unit (SR) actuates the first switch (S1) with a dimming signal, wherein the dimming signal is generated by linking of a low-frequency signal and a high-frequency signal, and wherein the operating circuit is arranged such that a pulse width (TON*LF) of the low-frequency signal, which is defined as a width of a pulse packet of the high-frequency, is selected as an integral multiple of the period (T_HF) of the high-frequency signal and wherein the operating circuit is arranged in order to generate the high-frequency signal dependent on a control loop, at least the first switch (S1) is clocked depending on at least one predefined reference value for a current and/or voltage within the operating circuit and a comparison with an actual value, the control unit (SR) is arranged to turn on the first switch when a zero crossing of the current through the coil (L1) occurs.
A method for actuating at least one LED, to which a DC voltage or rectified AC voltage is supplied, and which provides a supply voltage for at least one LED by means of a coil (L1) and a first switch (S1) clocked by a control unit (SR), wherein, when the first switch (S1) is switched on, energy is buffer-stored in the coil (L1), which is discharged via a diode (D1) and via at least one LED when the first switch (S1) is switched off, wherein the control unit (SR) actuates the first switch (S1) with a dimming signal, the dimming signal is generated by external linking of a low-frequency signal and a high-frequency signal, wherein the operating circuit is arranged such that a pulse width (TON*LF) of the low-frequency signal, which is defined as a width of a pulse packet of the high frequency, is selected as an integral multiple of the period (T_HF) of the high-frequency signal and wherein the operating circuit is arranged in order to generate the high-frequency signal dependent on a control loop, at least the first switch (S1) is clocked depending on at least one predefined reference value for a current and/or voltage within the operating circuit and a comparison with an actual value, the control unit (SR) is arranged to turn on the first switch when a zero crossing of the current through the coil (L1) occurs.
Dependencies are inferred from the claim text.