Patent ID: 8525442
Filing Date: 2013-09-03
Classification: H05B

Abstract:
1. An operating circuit for at least one LED, which is supplied with direct current voltage or rectified alternating current voltage, and which provides a supply voltage for the at least one LED by a coil (L 1 ) and a first switch (S 1 ) that is clocked by a control/regulation unit (SR), where during the activated state of the first switch (S 1 ), energy is temporarily stored in the coil (L 1 ), which is discharged when the first switch (S 1 ) is turned off through a free wheeling diode (D 1 ) and through at least one LED, wherein a capacitor (C 1 ) is provided, which is arranged in parallel to at least one LED, and which maintains the current through the LED during a demagnetization phase of the coil (L 1 ), a first sensor unit (SE 1 ) is provided, which generates a sensor signal (SES 1 ) which is dependent on the current flowing through the first switch (S 1 ), and with a second sensor unit (S 2 ), which detects that the demagnetization of the coil (L 1 ) has been reached and generates a sensor signal (SES 2 ), the sensor signals (SES 1 , SES 2 ) are supplied to and processed by a control/regulation unit (SR) at a point in time when the first switch (S 1 ) is turned on again, when the coil (L 1 ) is demagnetized and thereby the free wheeling diode (D 1 ) is blocking.