Abstract: A control device includes a rectification circuit, a filter circuit, a detection circuit, a voltage regulator circuit, a constant current circuit and at least one light emitting diode (LED). The rectification circuit is provided for receiving an input voltage of 5 to 24V, and the detection circuit is provided for detecting a quantity of LEDs and an actual required voltage to produce an actual required voltage value, such that the voltage regulator circuit and the constant current circuit can adjust an output current and an output voltage for the LED according to a detection result.