Light source driving circuit and projection device using the same

A projection device comprising:

• a plurality of optical source modules;
• and
• a plurality of optical source driving circuits, respectively coupled to and driving the plurality of optical source modules,
• wherein each of the optical source driving circuits includes:
• an optical source driving unit, coupled to and driving the optical source module, the optical source driving unit receiving an input voltage, the optical source driving unit receiving and controlled by an enable signal, the enable signal determining whether the optical source driving unit is activated, the optical source driving unit further receiving and controlled by a selection signal, the selection signal determining a timing at which the optical source driving unit outputs a drive current to the optical source module, the optical source driving unit receiving and controlled by a pulse width modulation signal, the pulse width modulation signal controlling a current amplitude of the drive current from the optical source driving unit to the optical source module;
• a voltage conversion circuit, coupled to the optical source driving unit and the optical source module, the voltage conversion circuit converting the input voltage and outputting to the optical source module, the voltage conversion circuit providing feedback of a drive voltage of the optical source module to the optical source driving unit, and the optical source driving unit performing constant current control on the drive current output of the optical source module;
• a hysteresis comparator circuit, coupled to the optical source driving unit, the hysteresis comparator circuit controlling the enable signal based on an adjusted threshold voltage to determine whether to release the enable signal;
• and
• a delay circuit, coupled to the optical source driving unit, the delay circuit controlling the selection signal based on the adjusted threshold voltage to determine when to release the selection signal,
• the plurality of delay circuits in the plurality of optical source driving circuits release the selection signals synchronously, enabling the plurality of optical source driving circuits to synchronously output the plurality of drive currents to the plurality of optical source modules.