A driving circuit for regulating current in a light source using a tracking component. The tracking component detects the voltage difference between an input node in the input stage and an output node in the output stage. The input stage is connected to a current source and includes an input transistor. The output stage is connected to the light source and includes an output transistor. The tracking component generates an output that controls the input and output transistors based on the voltage difference between the input node and the output node so that the voltage at the input node tracks the voltage at the output node. By using the tracking component, the LED driver can achieve accurate current control through one output transistor instead of cascaded transistors, resulting in lower output operating voltage and reduced power dissipation of the LED driver. Further, the tracking component is intermittently operated or shared across different channels to reduce energy consumption of the LED driver.