Method for dynamic reduction of LED current in LED driver, and associated drivers, driver circuits and lighting circuits

摘要

There is disclosed a driver for driving a series arrangement being a variable number of strings of LEDs wherein each string has a capacitance connected in parallel with the respective string; the driver comprising: a controllable current source adapted to be connected in series between the series arrangement and a rectified AC supply to and source a controllable current (Istr) through the series arrangement; and a current source controller adapted to control the controllable current source; wherein the current source controller is operable to source a relatively lower current (I_LED′) when a difference (Vstr3A) between the voltage across the series arrangement and the voltage of the rectified AC supply is relatively higher and a relatively higher current (I_LED) when the difference is relatively lower. Associated driver circuits and lighting circuits, and methods are also disclosed.