Light-emitting device and light generating method

The invention provides a light-emitting device which comprises a power conversion circuit, a light source module, a driving circuit and a control circuit. The power conversion circuit is used for providing power voltage. The light source module is coupled to the power conversion circuit to receive the power voltage. The driving circuit is coupled to the light source module, and is used for driving a plurality of light emitting units in the light source module, and detecting a current value flowing through each light emitting unit to generate a current signal. The control circuit is coupled to the power conversion circuit, the light source module and the driving circuit and is used for detecting the cross voltage of the at least one light-emitting unit. The control circuit calculates a voltage deviation value according to a difference value between the cross voltage and the power supply voltage, and generates a control signal according to the voltage deviation value and the current signal, thereby controlling