Visible laser digital control modulation driver

A photodiode is often included in the laser tube drive circuit, which can generate a current proportional to the laser beam intensity (optical power), but the response of this type of phototube is relatively slow, and it is generally unable to track the peak optical power of the modulated laser tube. Therefore, this drive circuit controls the laser generator by monitoring the average optical power. The visible laser digital control modulation driver circuit is shown in the figure, which includes a 10-bit digital-to-analog converter (DAC) with a 3-wire serial interface, which is used to control a visible light laser tube to output a constant average optical power; a separate digital input line (MOD) feeds pulses to the laser diode VD1 through a comparator (IC4) with an open-drain output and VTl to achieve digital communication.