15
Power Supply
To obtain a good pulsing performance with the driver, it requires an appropriate power supply unit (PSU). The
PSU has to supply not only the power that is delivered to the laser diode but also the power to compensate
for the losses in the driver itself.
As the valid supply voltage ranges from 24V to 48V, it depends on the configured voltage of the capacitor
bank. The internal DC-DC converter needed at least 5 Volts above the desired capacitor bank voltage (VCap).
Cooling
The maximum thermal dissipation of the LDP-QCW depends on the configured pulse length,
repetition rate and capacitor bank voltage.
Test Load
A common method to test the driver is to connect a regular silicon rectifier diode to the driver
output. Here has to be paid attention to the junction capacitance of the diode. Only fast recovery
diodes (or similar) have a low parasitic capacitance as laser diodes. To achieve reasonable test results,
the parasitic elements of the test diode and the connection must be very similar to a laser diode
approach. Regular silicon rectifier diodes have a junction capacitance of several microfarads and are
not a suitable test load! The use of these diodes will yield in incorrect current measurement at the
pulse edges!
It is also possible to test the driver using a shortcut. This will not damage it, but result in an incorrect
measurement for the rise and fall time of the current pulse.
