Synchronous buck converter for supplying a led load

A synchronous buck converter for supplying a LED load comprising:

• a high side switch and a low side switch connected in series,
• an inductor connected to the midpoint of these switches, and
• a control circuitry controlling the alternate switching operation of the two switches,
• wherein the switches are controlled such that there are time periods in which a negative current is flowing through said low side switch,
• wherein the control circuitry is supplied with a feedback signal indicating the level of the negative current and is arranged to issue a switching-off command to the low side switch as soon as the feedback signal reaches or crosses a threshold value,
• wherein a least one feedback from the LED load is fed back to the control circuitry,
• wherein the at least one feedback signal comprises at least one of LED voltage and LED current,
• wherein the control circuitry is arranged to adapt its threshold value depending on the at least one feedback signal.