A variable frequency modulation, VFM, pulse generator for controlling brightness of a light emitting diode, comprising: a one-shot pulse generating circuit having a trigger input and a pulse output, wherein the pulse generating circuit is configured to receive a plurality of trigger signals at the trigger input and to generate a plurality of pulses at the pulse output, wherein each of the plurality of pulses has a constant width and amplitude and wherein the pulse output is configured to be coupled with said LED; a light intensity detector adapted to generate a voltage proportional to the LED light brightness; an operational amplifier for controlling a brightness of said LED and having negative and positive inputs and an output, the negative input is coupled to the light intensity detector for receiving the voltage proportional to the LED light brightness and the positive input of the operational amplifier receives a voltage signal representing a desired light brightness from the LED; a pseudo random offset generator configured to introduce random voltage perturbations at the voltage input of a voltage controlled frequency generator, the voltage controlled frequency generator having a frequency control input and a frequency output, and a zero-crossing detector coupled between the trigger input of the one-shot pulse generating circuit and the frequency output of the voltage controlled frequency generator, wherein the plurality of trigger signals are generated from the zero-crossing detector, wherein the frequency control input is coupled to the output of the operational amplifier, whereby the voltage controlled frequency source causes the pulse generating circuit to produce the plurality of pulses necessary for producing the desired light brightness from the LED. a one-shot pulse generating circuit having a trigger input and a pulse output, wherein the pulse generating circuit is configured to receive a plurality of trigger signals at the trigger input and to generate a plurality of pulses at the pulse output, wherein each of the plurality of pulses has a constant width and amplitude and wherein the pulse output is configured to be coupled with said LED; a light intensity detector adapted to generate a voltage proportional to the LED light brightness; an operational amplifier for controlling a brightness of said LED and having negative and positive inputs and an output, the negative input is coupled to the light intensity detector for receiving the voltage proportional to the LED light brightness and the positive input of the operational amplifier receives a voltage signal representing a desired light brightness from the LED; a pseudo random offset generator configured to introduce random voltage perturbations at the voltage input of a voltage controlled frequency generator, the voltage controlled frequency generator having a frequency control input and a frequency output, and a zero-crossing detector coupled between the trigger input of the one-shot pulse generating circuit and the frequency output of the voltage controlled frequency generator, wherein the plurality of trigger signals are generated from the zero-crossing detector, wherein the frequency control input is coupled to the output of the operational amplifier, whereby the voltage controlled frequency source causes the pulse generating circuit to produce the plurality of pulses necessary for producing the desired light brightness from the LED.