www.teamWavelength.com
© 2010
QCL500, QCL1000, QCL1500 Low Noise Quantum Cascade Laser Drivers
PAGE 12
QCL1500-00400-D
8. Enable Output Current & Set Current Setpoint
Flip the ENABLE switch to ON. The ENABLE LED lights. If the LED does not power on, review
REMOTE vs. LOCAL switch settings (Step 4) and the state of the REMOTE ENABLE signal (Pin
6 referenced to Pin 5). Rotate the SET trimpot clockwise to increase the current setpoint. Current
monitor should now show voltage equivalent to output current.
EXAMPLES:
QCL500 - Want 400 mA Output Current, equivalent voltage is (0.400 A / 0.2 A / V) or 2 V.
QCL1000 - Want 950 mA Output Current, equivalent voltage is (0.950 A / 0.4 A / V) or 2.375 V.
QCL1500 - Want 1.25 A Output Current, equivalent voltage is (1.25 A / 0.6 A / V) or 2.08 V.
Note, wait at least one second between turning POWER ON and enabling current. Allow one hour for
best performance.
9. Disable Output Current and Power Down the unit
Flip the ENABLE switch to the OFF position (or send a LO voltage to REMOTE ENABLE). The
ENABLE LED goes out. After a 9.5 msec delay, the current turn off ramp is 5.5
sec.
Flip the POWER switch to the OFF position. The POWER LED goes out. Turn off the power to the
dual DC power supplies.
10. Remove test load and wire in a Quantum Cascade Laser
Wire the QCL for proper current direction. Note that pin 19 (QCL +) is also internally attached to
ground.
11. Recovery from a Protection Circuit trip or FAULT error
If the voltage from the dual power supplies to the QCL driver is over or under voltage limits, the
protection circuits will trip and latch off. Output Current is disabled. To restart after correcting the
cause of the error, disable the current (using switch or remote ENABLE signal) then toggle the Power
OFF then ON (signal or switch). Wait 1 second to re-enable current.
If voltage to the QCL driver is reversed, protection diodes go into conduction. The rail is held one
diode drop from ground. This condition will continue until power from the power supply is removed
or the fuse for that rail blows. To restart after correcting the cause of the error, disable the current
(using switch or remote ENABLE signal) then toggle the Power OFF then ON (signal or switch). Wait 1
second to re-enable current.
OPERATING PROCEDURES, continued
QC
Laser
-V
QCL +
QCL -
QCLxxx
Current Sink
Figure 11
QCL wiring polarity and grounding