×

Operating circuit for LEDs, having dimming signal comprising high-frequency modulated pulse packet signal with harmonized frequencies

  • US 9,433,041 B2
  • Filed: 03/21/2013
  • Issued: 08/30/2016
  • Est. Priority Date: 03/21/2012
  • Status: Active Grant
First Claim
Patent Images

1. 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.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×