© 2020
7
PLDXK-CH SERIES LASER DIODE DRIVER
SAFETY INFORMATION
SAFE OPERATING AREA — DO NOT EXCEED
INTERNAL POWER DISSIPATION LIMITS
Before attempting to operate the PLDxK-CH driver, it is
imperative that you first determine that the unit will operate
within the
Safe Operating Area
(SOA). Operating outside
of the SOA may damage the laser and the PLDxK-CH.
Operating outside of the SOA will void the warranty.
To determine if the PLDxK-CH driver is suitable for your
application and if it will be operating in the safe range,
consult the instructions for calculating the Safe Operating
Area online:
www.teamwavelength.com/support/design-tools/soa-ld-calculator
SOA charts are included in this datasheet for quick reference
(
), but we recommend you use the online tools
instead.
!
To ensure safe operation of the PLDxK-CH
driver, it is imperative that you determine if
the unit is going to be operating within the
internal heat dissipation Safe Operating
Area (SOA).
If you have any questions about the Safe Operating Area
calculator, call the factory for free and prompt technical
assistance.
THEORY OF OPERATION
The PLDxK-CH Series drivers are controlled current
sources: they deliver the current commanded by the
setpoint. The current source continually monitors the actual
output current, compares it to the setpoint, and adjusts the
current if there is a difference between the two signals.
It may be useful to remember that you do not directly set
the drive current setpoint; instead, you adjust a voltage
signal that represents the output current. The voltage and
output current are related by a transfer function that varies
by driver model number.
The setpoint voltage is adjusted with the onboard trimpot or
by an external input that sums with the onboard setpoint.
The adjustable current limit is set using an onboard trimpot.
As current is driven through the load, there is a voltage drop
across the load because of the impedance. As the current
increases, the voltage drop may increase to the point that it
reaches the Compliance Voltage limit of the current source.
Once that occurs, the current source is no longer able to
increase the current driven to the load even if you increase
the setpoint.
The PLDxK-CH driver includes features that help protect
your laser and make the driver more versatile in a wide
array of applications:
• The user-adjustable latching current limit protects the
laser from over-current situations by switching off the
output when a limit condition is detected. Toggling the
Enable resets the current limit circuit.
•
Output current switches on after approximately 1.5
seconds from the time the Enable signal is applied.
•
Output slow-start ramps the current to setpoint over
250 msec.