Operating circuit for an LED circuit with at least one LED, - wherein the operating circuit may be supplied by a supply voltage (V bus) via at least one input-side connection, and wherein the operating circuit comprises a coil (L Buck) and a first switch, which is high-frequency clocked by a control unit of the operating circuit, a first shunt resistor (R VbusShunt), a second shunt resistor (R Shunt), and a third shunt resistor (Rv l e dSh unt), - wherein the control unit is arranged to detect a switch current (I LS) through the first switch when the first switch is switched to the second shunt resistor (R Shunt), - wherein the operating circuit is so configured such that, when the first switch is switched in a conductive manner, energy is temporarily stored in the coil (L Burk), while the LED circuit discharges via a diode of the operating circuit when the first switch is switched in a non-conductive manner, characterized in that - the operating circuit further comprises a low-pass filter, wherein the low-pass filter is adapted to time-average the switch current (I LS) detected at the second shunt resistor (R Shunt), - wherein the control unit is configured to calculate - the time-averaged switch current (I LS) through the first switch to the second shunt resistor (R Shunt) and the low-pass filter, - the supply voltage (V bus) at the first shunt resistor (R VbusShunt), and - to determine a measured voltage (V led) at the LED circuit at the third shunt resistor (R VledShunt), and to calculate the LED current (I LED) through the LED circuit therefrom, - wherein the control unit is configured to combine the high-frequency clocking of the switch current (I LS) with a PWM signal, which is low-frequency compared to the former, - wherein a second switch is provided in the operating circuit, which is configured to open a current path between the second shunt resistor (R Shunt) and the low-pass filter only during a switched-on period of the PWM signal, and to interrupt the current path during a switched-off period of the PWM signal. - wherein the operating circuit may be supplied by a supply voltage (V bus) via at least one input-side connection, and wherein the operating circuit comprises a coil (L Buck) and a first switch, which is high-frequency clocked by a control unit of the operating circuit, a first shunt resistor (R VbusShunt), a second shunt resistor (R Shunt), and a third shunt resistor (Rv l e dSh unt), - wherein the control unit is arranged to detect a switch current (I LS) through the first switch when the first switch is switched to the second shunt resistor (R Shunt), - wherein the operating circuit is so configured such that, when the first switch is switched in a conductive manner, energy is temporarily stored in the coil (L Burk), while the LED circuit discharges via a diode of the operating circuit when the first switch is switched in a non-conductive manner, - the operating circuit further comprises a low-pass filter, wherein the low-pass filter is adapted to time-average the switch current (I LS) detected at the second shunt resistor (R Shunt), - wherein the control unit is configured to calculate - the time-averaged switch current (I LS) through the first switch to the second shunt resistor (R Shunt) and the low-pass filter, - the supply voltage (V bus) at the first shunt resistor (R VbusShunt), and - to determine a measured voltage (V led) at the LED circuit at the third shunt resistor (R VledShunt), and to calculate the LED current (I LED) through the LED circuit therefrom, - wherein the control unit is configured to combine the high-frequency clocking of the switch current (I LS) with a PWM signal, which is low-frequency compared to the former, - wherein a second switch is provided in the operating circuit, which is configured to open a current path between the second shunt resistor (R Shunt) and the low-pass filter only during a switched-on period of the PWM signal, and to interrupt the current path during a switched-off period of the PWM signal. - the time-averaged switch current (I LS) through the first switch to the second shunt resistor (R Shunt) and the low-pass filter, - the supply voltage (V bus) at the first shunt resistor (R VbusShunt), and - to determine a measured voltage (V led) at the LED circuit at the third shunt resistor (R VledShunt), and to calculate the LED current (I LED) through the LED circuit therefrom, - wherein the control unit is configured to combine the high-frequency clocking of the switch current (I LS) with a PWM signal, which is low-frequency compared to the former, - wherein a second switch is provided in the operating circuit, which is configured to open a current path between the second shunt resistor (R Shunt) and the low-pass filter only during a switched-on period of the PWM signal, and to interrupt the current path during a switched-off period of the PWM signal.