PICOLAS LDP-QCW 300-12 User manual

User
UserUser
User Manual
Manual Manual
Manual Rev.
Rev. Rev.
Rev. 1
11
12
22
2.0
.0.0
.06
66
6
LDP
LDPLDP
LDP-
--
-Q
QQ
QC
CC
CW
WW
W 300
300 300
300-
--
-1
11
12
22
2
Your distributor:

2
Table of Contents
LDP-QCW 300-12....................................................................................................................... 1
Table of Contents ....................................................................................................................... 2
How to use the Manual .............................................................................................................. 3
How to get started refer to drawings on next 2 pages) .............................................................. 4
Description of available Connectors ............................................................................................ 5
Interface Specifications ............................................................................................................... 6
Dos and Don’ts........................................................................................................................... 8
Functional Description ................................................................................................................ 9
Trigger modes........................................................................................................................... 10
Regulator.................................................................................................................................. 13
LED codes ................................................................................................................................. 14
Power Supply............................................................................................................................ 15
Cooling..................................................................................................................................... 15
Test Load .................................................................................................................................. 15
Over Temperature Shutdown.................................................................................................... 16
Absolute Maximum Ratings ...................................................................................................... 16
Mechanical Dimensions ............................................................................................................ 17
Controlling the LDP-QCW using a PLB-21 ................................................................................. 18
Controlling the LDP-QCW via USB ............................................................................................ 22
The PicoLAS Protocol ................................................................................................................ 29

3
How to use the Manual
Remark
RemarkRemark
Remark: The LDP
: The LDP: The LDP
: The LDP-
--
-QCW described in this manual is a base
QCW described in this manual is a baseQCW described in this manual is a base
QCW described in this manual is a base-
--
-plate cooled laser diode
plate cooled laser diode plate cooled laser diode
plate cooled laser diode
driver. Improper cooling may cause an internal over temperature shu
driver. Improper cooling may cause an internal over temperature shudriver. Improper cooling may cause an internal over temperature shu
driver. Improper cooling may cause an internal over temperature shutdown. The two
tdown. The two tdown. The two
tdown. The two
fans in one side of the unit have to prevent local thermal hot spots inside the unit. They
fans in one side of the unit have to prevent local thermal hot spots inside the unit. They fans in one side of the unit have to prevent local thermal hot spots inside the unit. They
fans in one side of the unit have to prevent local thermal hot spots inside the unit. They
can not compensate improper base plate cooling. The air inside an enclosure within an
can not compensate improper base plate cooling. The air inside an enclosure within an can not compensate improper base plate cooling. The air inside an enclosure within an
can not compensate improper base plate cooling. The air inside an enclosure within an
OEM application is usually enough to yield enough air flow. Plea
OEM application is usually enough to yield enough air flow. PleaOEM application is usually enough to yield enough air flow. Plea
OEM application is usually enough to yield enough air flow. Please
se se
se do not cover any
do not cover any do not cover any
do not cover any
ventilation slots.
ventilation slots.ventilation slots.
ventilation slots.
Base plate cooling
Base plate coolingBase plate cooling
Base plate cooling: Depending on the final application and operation regime, this unit
: Depending on the final application and operation regime, this unit : Depending on the final application and operation regime, this unit
: Depending on the final application and operation regime, this unit
may stay none
may stay nonemay stay none
may stay none-
--
-cooled or must be assembled onto a heat sink.
cooled or must be assembled onto a heat sink. cooled or must be assembled onto a heat sink.
cooled or must be assembled onto a heat sink.
Please refer to chapter Power dissipation for more details about the
Please refer to chapter Power dissipation for more details about the Please refer to chapter Power dissipation for more details about the
Please refer to chapter Power dissipation for more details about the thermal power
thermal power thermal power
thermal power
losses during operation.
losses during operation.losses during operation.
losses during operation.
You me use a passively or an actively air/water cooled device.
You me use a passively or an actively air/water cooled device. You me use a passively or an actively air/water cooled device.
You me use a passively or an actively air/water cooled device.
Housing: All units are delivered with housing. Changes are possible; the units can be
Housing: All units are delivered with housing. Changes are possible; the units can be Housing: All units are delivered with housing. Changes are possible; the units can be
Housing: All units are delivered with housing. Changes are possible; the units can be
delivered without housing upon request.
delivered without housing upon request. delivered without housing upon request.
delivered without housing upon request.
Before powering on your u
Before powering on your uBefore powering on your u
Before powering on your unit, read this manual thoroughly and make sure your
nit, read this manual thoroughly and make sure your nit, read this manual thoroughly and make sure your
nit, read this manual thoroughly and make sure your
understood it fully.
understood it fully. understood it fully.
understood it fully.
Please pay attention to all safety warnings.
Please pay attention to all safety warnings.Please pay attention to all safety warnings.
Please pay attention to all safety warnings.
If you have any doubt or suggestion, please do not hesitate to contact us!
If you have any doubt or suggestion, please do not hesitate to contact us!If you have any doubt or suggestion, please do not hesitate to contact us!
If you have any doubt or suggestion, please do not hesitate to contact us!

4
How to get started refer to drawings on next 2 pages)
refer to drawings on next 2 pages) refer to drawings on next 2 pages)
refer to drawings on next 2 pages)
Step # What to do Check
1 Unpack your device and place it in front of you
as shown on the next page.
2 Connect a load for example your laser diode)
to the output. Make sure to use both anode
and cathode connectors in
parallel.
3 Connect the PLB-21 or the USB cable A driver is required in order to use the
LDP-QCW with a PC. See chapter
“Controlling the LDP-QCW via USB”
for more information
4 Connect the input power supply; make sure
that polarity is correct. The supply voltage must
be at least 24 V and about 5 V above the
desired capacitor bank voltage.
Make sure that your power
supply does not have any
voltage overshoots when
switching on or off. Do not exceed the
maximum operating voltage of 48 V
5 Switch the power supply on
6 If a PLB-21 is used, its display may show a
message about downloading a new driver.
Confirm this with YES.
See chapter “Controlling the LDP-QCW
using a PLB-21” for more information
7 Set all required parameters using the PLB-21 or
USB interface See chapter “Controlling the LDP-QCW
using a PLB-21” for more information
8 Apply +5V to the MasterEnable pin of the BOB
connector See chapter “Interface specifications”
for more information
9 Apply +5V to the Enable pin of the BOB
connector. This will enable the output See chapter “Interface specifications”
for more information
10 Monitor the current pulses using an
oscilloscope connected to the current monitor
output
See chapter “Interface specifications”
for more information
11 Verify that the PULSER_OK signal is +5V See chapter “Interface specifications”
for more information

5
Description of available Connectors
The following drawing shows all connections which are available to the user.
PLB
Mini USB type B
GND
V
in
LD+
LD-
LD+
LD-
BOB
connector (edgewise)
LDP- BOB
onnector
See section interface specifications for detailed information. Break-out-board
connector.)
PLB Connector for PLB-21 protected against polarity reversal)
V
in
Supply voltage
GND Supply ground
LD+ Positive laser diode output anode). Use both connectors parallel for high
currents.
LD- Negative laser diode output cathode). Do not connect to ground! Use both
connectors parallel for high currents.
Mini USB Mini USB connector for connecting the driver with a computer.
For a more convenient use of the driver e.g. in laboratory use) we recommend the optional available
product accessory LDP-C-BOB. Please see LDP-C-BOB manual for further details.

6
Interface Specifications
The following figure shows the input and output signals of the external analogue BOB connector.
The BOB Break-out Board) is recommended for easy testing of the driver. It will be replaced in the
application by your machine interface.
Functional Description of BOB-Connector Interface

7
Pin Description numerical assorted)
Pin1: Pulser OK
Pin1: Pulser OKPin1: Pulser OK
Pin1: Pulser OK
The state of this Signal indicates weather the driver is ready 5V) or it has an error pending 0V).
Pin 2: 5V
Pin 2: 5VPin 2: 5V
Pin 2: 5V
This pin provides 5 Volts for external usage. Please note that the load should not exceed 10mA, otherwise
the voltage will drop.
Pin 3: GND
Pin 3: GNDPin 3: GND
Pin 3: GND
This pin is connected to ground.
Pin 4: U
Pin 4: UPin 4: U
Pin 4: U
diode
diodediode
diode
This signal provides near real-time measurement of the laser diodes compliance voltage. The scaling is 10
volts per volt measured into 1MOhm.
Pin 5: GND
Pin 5: GNDPin 5: GND
Pin 5: GND
This pin is connected to ground.
Pin 6: Pulse
Pin 6: PulsePin 6: Pulse
Pin 6: Pulse
This signal is used in the external end external controlled trigger mode. Connect your external trigger
source to this pin. The signal amplitude should be within 3 to 6Volts.
Pin 7: Enable
Pin 7: EnablePin 7: Enable
Pin 7: Enable
This signal is used to enable / disable the current output of the driver during operation.
It must be pulled low to reset an error condition or to re-enable the driver after Master Enable was pulled
low.
Pin 8: Master Enable
Pin 8: Master EnablePin 8: Master Enable
Pin 8: Master Enable
This signal is used as an interlock safety feature that disables the complete driver if set to 0V during
operation. In order to re-enable the driver after this emergency shutdown the enable signal must first set
to 0V.
If this feature is not required this pin can be connected to Pin 2 5V).
Pin 9: I
Pin 9: IPin 9: I
Pin 9: I
diode
diodediode
diode
This signal provides near real-time measurement of the laser diodes current flow. The scaling is 200
amperes per volt measured into 1MOhm.
Pin 10: I
Pin 10: IPin 10: I
Pin 10: I
setpoint
setpointsetpoint
setpoint
This signal is used to provide an external current set point. The voltage at this pin is periodically sampled
by the driver if it is configured to use the external set point current

8
Dos and Don’ts
Never
NeverNever
Never ground any output connector.
Never
NeverNever
Never use any grounded probes at the output.
Do not
Do notDo not
Do not connect your oscilloscope to the output!
This will immediately destroy the driver and the probe!
For measuring current and voltage you connect the scope to Pin 9 or Pin 4 of the BOB connector
respectively.
Keep connecting cables between power supply and driver as well as the connection between driver
and laser diode as short as possible.
Mount the driver on an appropriate heat sink!
Mount the driver on an appropriate heat sink!Mount the driver on an appropriate heat sink!
Mount the driver on an appropriate heat sink!
Please
Please Please
Please be aware that there might be hot surfaces, be careful not to touch them!
be aware that there might be hot surfaces, be careful not to touch them!be aware that there might be hot surfaces, be careful not to touch them!
be aware that there might be hot surfaces, be careful not to touch them!
Do never connect the oscilloscope to the output connectors!!!!
Please Note: above picture shows another but similar PicoLAS driver)

9
Functional Description
The driver uses a DC-DC converter to load a capacitor bank to a defined voltage. A PI regulator uses
T
1
and a shunt to control the current flow through the laser diode.
Laser diode current and compliance voltage are pre-processed and fed to the external BOB-connector.
Several security features protect the laser diode and driver from damage. D
1
protects the laser diode
from reverse currents. The switch S
1
is automatically opened when an over current as well as an
internal failure such as over temperature, etc.) is detected.
Operation Principle of LDP-QCW driver
Element Function
1 Input Buffer Capacitor
b Capacitor bank
S1 Security Switch
D1 Laser diode protection diode
T1 Current regulation MosFET
Shunt LD-current monitor

10
Trigger modes
The LDP-QCW supports tree different trigger modes as explained below
Internal
InternalInternal
Internal
The pulse generation is performed by an internal pulse generator. The pulse width and repetition
rate is user configurable via the PLB-21 or the serial interface.
In addition, the number of pulses to be generated can be configured. To use this feature the
wie soll das gehen?
user has to set the TRG_COUNT bit in the LSTAT register to “1”. The current output is automatically
disabled after an internal counter reaches the configured value. The counter is reset by setting the
L_ON bit of the LSTAT register to “0” or by setting the ENABLE pin to 0V.
Please note that the maximum pulse width depends on the current repetition rate as well as the
maximum repetition rate on the current pulse width.
The following diagram shows an example of generated pulses. The lower graph shows the internal
pulse generator, the upper two graphs the trigger pulses generated out of it.
meaning
T
1
enabling of the output
T
1
-T
2
The delay between output enable and the first generated pulse depends on the
configured repetition rate. It nearly equals the pulse pause time.
T
2
-T
3
Pulse rise time. It depends on the load inductance.
T
4
-T
5
Pulse fall time. It depends on the load inductance.
T
6
disabling of the output
T
7
re-enabling of the output

11
External
ExternalExternal
External
The pulse generation is performed by an external pulse generator connected to the pulse input on
the BOB connector. The pulses can be inverted by setting the TRG_EDGE bit in the LSTAT register to
“0”.
The following diagram shows an example of generated pulses. The lower graph shows the external
pulse input, the upper two graphs the trigger pulses generated out of it.
meaning
T
1
enabling of the output
T
2
-T
3
Pulse rise time. It depends on the load inductance.
T
4
-T
5
Pulse fall time. It depends on the load inductance.
T
6
disabling of the output
T
7
re-enabling of the output

12
External
ExternalExternal
External controlled (ext. ctrl.)
controlled (ext. ctrl.) controlled (ext. ctrl.)
controlled (ext. ctrl.)
This trigger mode uses the external trigger input to control the internal pulse generator. It is used to
generate a number of pulses per rising of falling edge of the external trigger input. Setting the
TRG_EDGE bit in the LSTAT register to “1” uses the rising edge, setting it to “0” uses the falling
edge.
The following diagram shows an example of generated pulses. The lower graph shows the external
pulse input, the upper two graphs the trigger pulses generated out of it.
meaning
T
1
enabling of the output
T
2
-T
3
Pulse rise time. It depends on the load inductance.
T
4
-T
5
Pulse fall time. It depends on the load inductance.
T
6
disabling of the output
T
7
re-enabling of the output

13
Regulator
The LDP-QCW implements a proportional – integral PI) regulator to control the current flow through
the connected load. The following diagram shows a simplified layout:
Depending of the chosen operating mode the user has the possibility to modify all relevant
parameters to a specific need. This is done through the digital interface PLB-21 or USB).
The “P” value defines the strength of the proportional part of the current regulator. This values
ranges from 0 to 4095. During normal operation this part is not used and can be set to zero. If this
value is too high it may lead to a current overshoot.
The “I” value defines the strength of the integral part of the current regulator. This value ranges from
0 to 4095. A recommended value for normal operation is 30 … 60. If this value is too high it may lead
to a current overshoot.
PicoLAS implemented an active nonlinearity compensation of the output stage. This speeds up the
device, prevents excessive current overshoots and yields a better accuracy with high impedance loads.
The influence of this part of the regulator can be user defined and is called FFwd.
However, the interconnection between the voltage and the current flow on the output is calibrated
during fabrication. This is used in operating mode 1. So it is not necessary to change this value at all. If
needed, it can be adjusted between the values 0 to 7.5 by the customer.
Be careful if changes are performed with the FFwd-value. The effect is high and may cause
damage if not adjusted properly. Wrong settings are not covered by warranty.
Mode 0: manual
Mode 0: manualMode 0: manual
Mode 0: manual
In this operation mode all parameters can be modified.
This mode is recommended only for experienced users as any wrong setting may lead to a
current overshoot at the output.
Mode 1: semi
Mode 1: semiMode 1: semi
Mode 1: semi-
--
-auto
autoauto
auto
In this operation mode the feed forward value is automatically chosen in dependence of the current
setpoint. This is recommended for normal operation as it guarantees no current overshoot at the
output.
The P and I values can be freely chosen, but the default values are sufficient for most applications.

14
V ap
V apV ap
V ap
The VCap value defines the voltage of the capacitor bank see chapter functional description). This
value is a bit tricky to determine as it depends on the chosen pulse width, repetition rate and
compliance voltage.
If his value is too low the current will drop during the pulse or not even reach the set point, if it is too
high the output stage will heat up fast and lead to an over temperature shutdown.
The following equation can be used to calculate the capacitor voltage in dependence of the output
current, compliance voltage and pulse width:
))
112
.
0
011.0((5
pulse
LDLDcap
T
IUV +++=
where
LD U = compliance voltage
LD
I
= current setpoint
pulse T = pulse width
This equation does not use the repetition rate. Hence this value must be increased if a current drop is
measured during operation.
For first tests or low pulse width and repetition rate it can safely be set to maximum, but the higher
this value the greater the power losses are in the output stage.
ED codes
The LDP-QCW is equipped with a red and a green status LED.
The red LED is connected to the Pulser_ok pin of the BOB connector and will lit if the signal goes low.
The green LED the following codes:
Permanent on: The LDP-QCW operates normally and the current output is enabled
Blink 1x: Master Enable is given, but Enable not
Blink 2x: Master Enable is not given

15
Power Supply
To obtain a good pulsing performance with the driver, it requires an appropriate power supply unit PSU). The
PSU has to supply not only the power that is delivered to the laser diode but also the power to compensate
for the losses in the driver itself.
As the valid supply voltage ranges from 24V to 48V, it depends on the configured voltage of the capacitor
bank. The internal DC-DC converter needed at least 5 Volts above the desired capacitor bank voltage VCap).
Cooling
The maximum thermal dissipation of the LDP-QCW depends on the configured pulse length,
repetition rate and capacitor bank voltage.
Test oad
A common method to test the driver is to connect a regular silicon rectifier diode to the driver
output. Here has to be paid attention to the junction capacitance of the diode. Only fast recovery
diodes or similar) have a low parasitic capacitance as laser diodes. To achieve reasonable test results,
the parasitic elements of the test diode and the connection must be very similar to a laser diode
approach. Regular silicon rectifier diodes have a junction capacitance of several microfarads and are
not a suitable test load! The use of these diodes will yield in incorrect current measurement at the
pulse edges!
It is also possible to test the driver using a shortcut. This will not damage it, but result in an incorrect
measurement for the rise and fall time of the current pulse.

16
Over Temperature Shutdown
To protect the Laser Diode and the driver itself, the LDP-QCW automatically disables itself if its
temperature rises above the maximum allowed operating temperature. This condition is latched and
the LDP-QCW will not start working until temperature drops five degrees and the ENABLE-pin is
toggled. During the over temperature shutdown, the Pulser_ok output Pin 1 of the BOB-Connector) is
pulled low.
Absolute Maximum Ratings
Output current 50 … 300A
Max. compliance voltage 12V short-circuit proof)
Min. pulse duration < 100us
Max. pulse duration 5 ms
Max. repetition rate > 1 KHz
Max. duty cycle 10%
Max. rise time < 10us
Current overshoot < 5% depending on regulator settings)
Pulse trigger input 5V TTL
external current setting input 200 A/V
Current monitor 200 A/V
Connectivity LDP-C BOB
PLB-21
USB 2.0
Supply voltage 24 … 48V min. 5V above VCap)
Max. power dissipation TBD
Dimensions in mm 100 x 180 x 100
Weight 1.2 Kg
Operating temperature 0 to +55°C

17
Mechanical Dimensions
The following dimensions are in millimetres mm).
A 100
B 94
C 85,71
D 65,39
E 62,82
F 55,26
G 45,7
H 32,37
I 26
J 17
K 6
L 6
M 6
N 4,5
O 13,5
P 15,8
Q 19
R 27
S 169
T 174
U 180
V 31,73
W 43,8
X 55,86
Y 67,93

18
Controlling the DP-QCW using a P B-21
To control the LDP-QCW with a PLB-21 it must be connected via the enclosed cable.
The PLB
The PLBThe PLB
The PLB-
--
-21 will not work if
21 will not work if21 will not work if
21 will not work if USB and
USB and USB and
USB and PLB
PLBPLB
PLB-
--
-21
2121
21 are connected
are connected are connected
are connected at
at at
at the s
the sthe s
the same time.
ame time. ame time.
ame time.
When the PLB-21 is connected the first time to a LDP-QCW you are asked to download a new driver.
This must be confirmed with “yes” for working the PLB-21 properly.
Menu Structure
Menu StructureMenu Structure
Menu Structure
The following diagram shows the structure of the PLB-21 menu which affects the LDP-QCW. All
entries are described in detail. All other menu entries are described in the PLB-21 manual. For detailed
instructions see the PLB-21 manual.
Menu root
-Pulseparameter
oWidth
oReprate
oCur int/ext)
-Config
oMode
oCur. stp.
oOverCur
-Trigger
oInput
oEdge
oCount
-Defaults
oAutoload
oSave
oLoad
-Temperature
oOff
oTemp1
oTemp2
oTemp3
oTemp4
-Regler
oI-Delay
oI
oFFwd
oVoltage
-Regler2
oP

19
Pulseparameter
Width
WidthWidth
Width
This value defines the pulse width of the internal trigger generator. When the value reads external the
internal generator is not used.
Reprate
ReprateReprate
Reprate
This value defines the repetition rate of the internal trigger generator. When the value reads external
the internal generator is not used.
Cur int/ext)
Cur int/ext)Cur int/ext)
Cur int/ext)
This value defines the setpoint current.
When using the internal setpoint, the value can be modified by the user.
When using the external setpoint, the value shown is measured value supplied at Pin 10 of the BOB
connector. The display is updated every few seconds, so it is not accurate when using analogue
modulation.
onfig
Mode
ModeMode
Mode
In this menu point the operation mode of the LDP-QCW can be selected. See chapter “current
regulator” for more information.
Cur. stp.
Cur. stp.Cur. stp.
Cur. stp.
The LDP-QCW can be configured to use the internal or external setpoint current. If switched to
external, an appropriate voltage must be applied to the BOB connector.
OverCur
OverCurOverCur
OverCur
If enabled, the LDP-QCW disables automatically if the current flow reaches the given value.
Temperature
The LDP-QCW is equipped with several temperature sensors. In this submenu, the actual and
shutdown temperatures can be read and modified. All values are in °C.
Dev. Off
Dev. OffDev. Off
Dev. Off
This shows the shutdown temperature. If the LDP-QCW reaches this temperature during operation,
the output will be disabled and an error message is displayed.
Te
TeTe
Temp 1
mp 1mp 1
mp 1…
……
…4
44
4
This shows the actual temperatures measured by the sensors of the LDP-QCW.
Trigger
Input
InputInput
Input
This setting defines which trigger input / mode is used. Please see chapter trigger for more
information.
Edge
EdgeEdge
Edge
This setting defines which edge / polarity is used for the trigger. It is not available in every trigger
mode. Please see chapter trigger for more information.
Count
CountCount
Count
This setting defines the number of pulses generated per trigger event. It is not available in every
trigger mode. Please see chapter trigger for more information.

20
Defaults
def. pwron
def. pwrondef. pwron
def. pwron
If enabled the LDP-QCW loads default values every time it is powered on. These values are CRC
checked at power-up. If this check fails the values are not loaded and an error message is displayed.
Save defaul
Save defaulSave defaul
Save defaults
tsts
ts
When the Jogdail is turned or the ENTER key is pressed all current values are saved.
Load defaults
Load defaultsLoad defaults
Load defaults
When the Jogdail is turned or the ENTER key is pressed all current values are overwritten by the saved
ones. If the output was enabled at this time it becomes disabled.
Regler
I
II
I-
--
-Delay
DelayDelay
Delay
This value represents the switching-point of the integral part of the current regulator. It is defined in
percent of the setpoint current. See chapter current regulator for more information.
I
II
I
This value defines the strength of the integral part of the current regulator. The value ranges from 0
to 4095.
FFwd
FFwdFFwd
FFwd
This value represents the feed forward voltage of the current regulator. See chapter current regulator
for more information.
Voltage
VoltageVoltage
Voltage
This value represents the precharge voltage of the current regulator. See chapter current regulator for
more information.
Regler2
P
PP
P
This value defines the strength of the proportional part of the current regulator. The value ranges
from 0 to 4095.