© 2020
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PLDXK-CH SERIES LASER DIODE DRIVER
CABLE LENGTHS AND HIGH CURRENT
The length and gauge of cable from the power supply or
to the laser diode can impact performance. The resistance
and inductance of the wire can reduce bandwidth or cause
the voltage to the PLDxK-CH to droop.
If the output current starts to oscillate as setpoint voltage
approaches the limit setting, then the power supply cables
may be too long. If you cannot shorten the cables, place a
470 µF capacitor across pins H1:1 and H1:2 to minimize
droop. Always twist the wire pairs to eliminate reactance.
ADD LASER DIODE PROTECTION FOR LONG
CABLES
With a cable longer than two feet, add a Schottky diode
.
Laser
Diode
Schottky
Diode
(1N5818)
Cable > 2 feet
H1:3
H1:4
LD Anode
LD Cathode
Figure 18. Long Cable Laser Protection
ADDITIONAL NOISE FILTERING
The PLDxK-CH drivers provide low-noise current to the
laser diode, but in some cases additional filtering may be
needed. Refer to
for a simple and effective filter.
LD Anode
LD Cathode
Schottky
Diode
(1N5818)
0.1 µF
10 µF
H1:3
H1:4
Figure 19. PLDxK-CH Output Filter
MONITOR CALIBRATION CIRCUIT
A small offset may be present when measuring the PMON,
IMON or LMON voltage with respect to the actual output.
Use the circuit shown in
Common
Pin J2:1
+
10 kΩ
10 kΩ
10 kΩ
20 kΩ
-
Monitors
Pin J2:2, 3, 4
Calibrated
Current
Setpoint
Figure 20. Monitor Calibration Circuit
REVISION B TIMING CHARACTERISTICS
describes the timing and bandwidth characteristics
of the PLDxK-CH Series Revision B units.
Table 4. Output Timing, Revision B
MODEL
TURN-ON
TIME
TURN-OFF
TIME
SLOWSTART
DELAY
PLD5K-CH
6.8 µsec
6.8 µsec
≥1.5 sec
PLD10K-CH
10 µsec
12 µsec
≥1.5 sec
PRODUCT VARIATIONS
We design and manufacture our products in-house, and
that gives us the unique ability to modify our drivers and
controllers to suit your application. Our Product Variation
service allows us to quickly and cost-effectively address
your design requests, from prototype quantities to long-term
high-volume manufacturing.
Examples of past Product Variations include:
•
Increasing the compliance voltage limit
•
Replacing current limit trimpots with fixed-value
resistors to maximize long-term stability in an OEM
laser controller system
• Changing the controller input voltage
