PICOLAS LDP-CWL 06-20 User manual

User Manual
LDP-CWL 06-20
LDP-CWL 12-20
- Preliminary Manual -
PicoLAS GmbH
Burgstr. 2
52146 Würselen
Germany
Phone: [phone]
Fax: [phone]
E-mail: [email protected]
Web:
www.picolas.de
Rev.2102

2
Table of Contents
Product overview...................................................................................................................... 3
How to use this manual........................................................................................................ 3
Dos and don’ts..........................................................................................................................4
Required laser diode pin out..............................................................................................8
Laser driver block diagram ..................................................................................................9
Description of the connectors of the LDP-CWL 06-20 / LDP-CWL 12-20.... 9
Modes and power dissipation..........................................................................................13
Frequency response..............................................................................................................17
Trigger delay............................................................................................................................18
Test load ....................................................................................................................................19
Power supply............................................................................................................................19
Crowbar......................................................................................................................................19
Current limiter .........................................................................................................................19
Mechanical dimensions .......................................................................................................20
Absolute maximum ratings (limits that can destroy the unit) ...........................20

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4
How to use this Manual
Remark: The LDP-CWL 06-20 and LDP-CWL 12-20 described in this manual
are base plate cooled laser diode drivers. Improper cooling may cause an
internal overtemperature shutdown (max. 80 °C).
Base plate cooling: Depending on the final application and operation mode, this
unit may stay non-cooled or must be assembled onto a heat sink. Please refer to
section “Working Areas and Power Dissipation” for more details about the thermal
power losses during operation.
Before powering on your unit, read this manual thoroughly and make sure you
understood everything!
Please pay attention to all safety warnings.
If you have any doubt or suggestion, please do not hesitate to contact us!
Dos and Don’ts
Keep the cable connection between power supply and laser diode driver
and the connection between driver and laser diode as short as possible to
minimize the stray inductance.
Please set the laser diode driver only in the scheduled working area and only while
the power supply is turned off. Therefore please have a look at the section
“Description of the Connectors of the LDP-CWL 06-20 / LDP-CWL 12-20”.
Never disconnect or connect the load while the driver is operational, as it destroys
the driver and/or the connected load. Make sure that the control ground is
connected to the supply ground. Any unexpected current flow through the control
board may damage the driver.
Mount the driver on an appropriate heat sink.
Please be aware that there might be hot surfaces, be careful not to touch
them!

5
How to get started
Picture 1: LDP-CWL driver with connectors, jumper and measurement points
The basic settings such as output current limit setting for the crowbar
can be adjusted by the Potentiometer 1. The actual adjusted maximum
output current limit can be measured at MP1 (measurement point 1).
An additional waveform generator might be needed which has to be
connected to the input terminal. There is no AWG (arbitrary waveform
generator) included within the driver!
GND and LD- are internally directly connected!

6
Step What to do Check
1 Connect a dummy diode between
LD+ and LD-. Alternatively make a
short circuit there.
Refer to section “Test Load”.
Range of compliance voltage
0 V .. 20 V.
2 Set the working point of the LDP-
CWL to modulation mode (Mod.).*
There are three different working
points: CW mode, modulation
mode and manual mode.*
Refer to the section “Description
of the Connectors of the LDP-
CWL 06-20 / LDP-CWL 12-20”
3 Connect GND, Vcc on power
connector (power source yet
disabled).
Range of Vcc 15 V .. 48 V.
Minimum 10 V above compliance
voltage. Required max. current is
about 7 A - 13 A.
4 Connect waveform generator on
input terminal (no pulse before
power supply enabled, 0 V at current
set pin (10. pin of the pin header).
Refer to all sections referencing
input (connector #2).
5 Enable the power source. Crowbar LED is on (red)
6 Adjust max. current scaling of the
crow-bar.
Use the Set_Imax potentiometer 1
(refer to the picture 1 above) for
scaling of the crowbar. Scale:
3 A/V (example: 4 V at MP1 would
limit the output current to 12 A).
7 Disable (reset) the crowbar by
toggling the 7. pin of the pin header
(set low and then high 7. pin;
“Disable / reset crowbar”).
Crowbar LED is off (no light)
8 Feed a signal on the input terminal
(current set pin (10. pin). For
example 1 kHz sine wave with 1 V
amplitude and 0.5 V DC offset while
Make sure not to overload the
laser diode or the driver.
Range of input signal 0 V .. 4.8 V.
(0.4 V/A)

7
the LDP-CWL is in the “modulation
mode”.
9 Monitoring of the output current. On current monitor you can
measure a signal comparable
with the input signal. Use an
oscilloscope with a 1 MEG ohm
termination. Scale 3 A/V. (example:
4 V at current monitor read means 12 A
at the output)
10 Disable the input signal and turn off
the power source. Remove the test
diode or bypass and assemble the
final laser diode.
11 Turn the power supply for the Vcc
back on.
Range of Vcc 15 V .. 48 V.
Minimum
10 V above compliance voltage.
12 Feed a signal to the input terminal. Make sure not to overload the
laser diode!
*Important: Please refer to the position of the jumper as in the Picture 4, the
printing on the board may be different. However, it does not have any impact
on the functionality of the driver itself.
.
Required Laser Diode Pin Out
The LDP-CWL 06-20 / LDP-CWL 12-20 is designed for the direct connection of
almost any kind of laser diode with a maximum compliance voltage of 20 V.
The pitch of the LD- and LD+ connectors is 15.5 mm.

8
Laser Driver Block Diagram
Picture 2: Block diagram of the laser driver
Description of the Connectors of the LDP-CWL 06-20 /
LDP-CWL 12-20
Picture 3: Connectors of the laser driver

9
#1 and #2. Power Supply absolute maximum Ratings
Pin Allowed range Best
performance
Destroying limit
1 Vcc
(laser supply)
15 V .. 48 V 10 V above
compliance
49 V
2 (GND) GND GND
Connector Function Description
1 Power connector: Vcc Screw terminal M3
2 Power connector: GND for Vcc and
input signal
Screw terminal M3
3 Pin header See section “Connection
Pin header”
4 Jumper J1 Set the working area. See
section “Modes and
Power Dissipation”
5 Laser diode connector (anode) LD+
6 Laser diode connector (cathode) LD-

10
#3. Connection Pin header (for LDP-CWL 12-20)
Pin
number
Function
1 N.C.
2 +5 V
3 GND
4 V compliance
(output voltage)
5 GND
6 N.C.
7 Disable /
reset crowbar
(connect to GND to
disable/reset)
8 N.C.
9 Current monitor
output
(3 A/V, ± 5%))
(example: 4 V at current
monitor output
corresponds to 12 A at
the output)
10 Set output current
(0.4 V/A)
(example: 4.8 V
reference voltage
corresponds to 12 A at
the output)