Current adjusting system and method for light emitting diode lighting system

The invention discloses a current adjusting system and method for a light emitting diode lighting system. The system and the method are used for adjusting current. An exemplary system controller comprises a first controller terminal, a second controller terminal, a fourth controller terminal and an error amplifier, wherein the first controller terminal is configured to receive input voltage, and the first controller terminal is also configured to, in response to turn-on of one or more switches, allow first current to flow into the system controller at least partially based on the input voltage; the second controller terminal is configured to, in response to turn-on of the one or more switches, allow the first current to flow out of the system controller via a second controller terminal; the fourth controller terminal is coupled to a third controller terminal via a first capacitor, and the first capacitor is not any part in the system controller; and the error amplifier is configured to generate compensation signals at least partially based on current sensing signals, and the error amplifier comprises a second capacitor.