Why laser diode needs to be driven by a constant current laser driver?
A. The laser diode itself is a very vulnerable device, so when it is working, a larger current will cause the laser diode to burn out, and a lower current will not make the laser diode work properly. With a constant current source, the current can be just right and the laser diode can work normally without damage.
B. Laser diodes are extremely temperature-sensitive in the operation. The forward voltage of the laser diode decreases as the temperature increases, and the reverse current increases as the temperature increases. The temperature varies with the driving current. If the laser diode is driven by a constant voltage driver, the current change causes the temperature to change. The light intensity is related to the current and has nothing to do with the voltage.
C. Mode hop noise. If a constant voltage laser driver is used, the current jump causes a power jump, then increasing mode hop noise. If a constant current laser driver is used, no matter how the mode hop noise jumps, the current is constant and the output power remains constant.
Because of the importance of a constant current laser driver for laser diodes, how to choose a diode laser driver that just meets your needs?
Diode laser drivers can be categorized by different ways:
A. By input voltage type. There are 2 types of diode laser drivers: AC input and DC input. The former accepts AC power source, and the voltage can be 110V in some countries, 220V or 240V in some other countries. Such as AAS12A12V2, AAS40A4V2, AAS45A4V2, etc. http://www.analogtechnologies.com/High_Efficiency_AC_Input_Laser_Drivers.html
The latter accepts different ranges by the DC voltage ranges, such as 3.2V to 5.5V, 4.7V to 16V, 4.7V to 28V, etc. Below are some typical laser drivers with different voltage ranges:
Ultra Low Noise Diode Laser Drivers/Controllers ATLS100MA103:
http://www.analogtechnologies.com/ATLS_XXX_103.html
High Voltage Constant Current Laser Driver ATLSxA216D:
http://www.analogtechnologies.com/high_voltage_constant_current_laser_driver_ATLSxA216.html
High voltage 15A Laser Driver ATLS15A218D:
http://www.analogtechnologies.com/high_voltage_15a218_laser_driver.html,
B. By output stage type. There are 2 types: PWM based or linear driver type. The former uses a high efficiency PWM (Pulse Width Modulation) output stage as the power output driver, which features high efficiency but high ripple noise and low speed. The latter uses a linear output stage as the power output driver, which features low noise and high speed but low efficiency. When the current is less than 1A, we can choose the laser driver both linear mode and switch mode. When the current is more than 1A, it’s recommended to choose a switch mode laser driver.
C. By the packaging. There are 3 types of packaging: PCB mount, chassis mount, and bench top.
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