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12
QCL OEM SERIES LOW-NOISE DRIVER
CONNECT THE QUANTUM CASCADE LASER
Once you are comfortable with operating the QCL driver,
disable the output, switch off all power to the driver,
disconnect the test load, and connect the laser. Refer to
Figure 6
for proper wiring polarity.
Note that the Positive Terminal of the QC Laser is connected
to ground, and the Negative Terminal is connected to the
Driver. The QCL driver acts as a
current sink
.
-V
Pin J5-4
QCL +
Pin J5-3
QCL -
QCL Driver
Current Sink
QCL
Figure 6. QCL Wiring and Polarity
ENABLE THE QCL DRIVER OUTPUT
Enable the output current by setting the ENABLE switch to
ON (right). The blue ENABLE LED on the front panel will
illuminate. The output is disabled by setting the switch to
the OFF position (left).
RECOVER FROM A POWER SUPPLY
PROTECTION CIRCUIT FAULT
If the voltage from the dual power supplies is over or under
voltage limits, the protection circuit will disable the output
and latch the driver in a FAULT state. If a fault is indicated,
switch off the QCL driver and power supplies.
After correcting the cause of the power supply error, the
driver must be reset. Toggle the Power OFF then ON using
either the remote signal or front panel switch. After switching
on the power, wait one second to re-enable current.
If supply voltage to the QCL driver is reversed, protection
circuits activate and the current from the power supplies
is shunted through a protection diode. The internal fuses
may blow, and the QCL driver will not operate under
this condition. Switch off all power, correct the error, and
re-enable the driver.
RECOVER FROM AN INTERNAL
OVER-TEMPERATURE FAULT
The QCL driver is equipped with a protection circuit to switch
off the output if the internal temperature exceeds a safe
operating value. If an over-temperature fault is detected the
FAULT LED will illuminate red, and the signal on J1 :7 will
go HI. Switch off the output using the onboard switch or
the remote output enable signal. The QCL will not allow the
output to be enabled until the internal temperature is within
the safe operating range.
