Patent ID: 8115418

Claim:
A method for driving series-connected light-emitting diodes of an illumination device, in particular an illumination device for film, video and photographic recordings with a pulse-width-modulation of the light-emitting diode current, wherein the pulse-width-modulated light-emitting diode current is detected by a current sensor, wherein the detected current measurement value is amplified and a current-proportional current sensor signal is formed from the amplified current measurement value, wherein said current sensor signal is digitized and output as a digitized value of the current sensor signal to a microprocessor, wherein the microprocessor calculates the pulse-width-modulated light-emitting diode current flowing through the light-emitting diodes at a switch-on instant from the relationship I PWM =ADval*GN* 100%/PWM where ADval is the digitized value of the current sensor signal, GN is the gain of the current measurement value and PWM is a modulation of the pulse-width-modulation from 0% to 100%, wherein said microprocessor outputs a drive signal for the pulse-width-modulation and for the setting of the light-emitting diode voltage applied to the light-emitting diodes, depending on the detected current sensor signal, and wherein a controllable voltage source for setting the light-emitting diode voltage is driven in such a way that a predetermined pulse-width-modulated light-emitting diode current flows through the light-emitting diodes.