Illumination device with adjustable luminance and luminance adjustment method thereof

An illumination device, comprising:

• a light source module;
• a power supply module;
• a driving module, coupled to the light source module and the power supply module, wherein the driving module receives a direct current voltage and converts the direct current voltage into a driving voltage and outputs a driving current to the light source module;
• a control module, coupled to the driving module, the control module controlling a magnitude of the driving current outputted by the driving module based on a first voltage signal outputted by the power source module;
• and
• a start module, coupled to the power supply module, wherein the start module selectively enters into a conduction state to allow the power supply module to provide a power to the driving module and output the first voltage signal to the control module, the start module selectively enters into an open circuit state to cut off the power received by the driving module from the power supply module;
• wherein after the control module receives the first voltage signal, the control module will control the driving module to perform a first stage output to steadily increase an amplitude of the driving current, and after the start module selectively enters into the open circuit state, the start module will selectively enters into the conduction state again, the control module will receive the first voltage signal again and control the driving module to perform a second stage output to output a constant driving current equal to the driving current at the end of the first stage output.