A driving circuit for powering a plurality of light-emitting diode (LED) light sources includes a power converter and a plurality of current balance controllers. The power converter receives an input voltage and provides a regulated voltage to the LED light sources. The current balance controllers coupled to the power converter control a plurality of currents through the LED light sources respectively. The current balance controllers receive a first reference signal indicative of a target average level and a second reference signal indicative of a maximum transient level, and regulate an average current of each of the currents to the target average level and a transient level of each of the currents within the maximum transient level.