Led driver, and method and device for controlling fixed value of led driver

Provided in an embodiment of the present invention are an LED driver, and method and device for controlling the fixed value of the LED driver, the method comprising: detecting whether an existing terminal of an LED driver inputs a control signal; when the control signal is detected, determining the fixed value of the LED driver according to the control signal; when the LED driver is an LED driver having no dimming function, the fixed value is the rated current of the LED driver; when the LED driver is an LED driver having a dimming function, the fixed value includes the upper limit or lower limit of the output current value of the LED driver. The method, device and the LED driver provided in the embodiment of the present invention can save LED driver costs.