PICOLAS LDP-QCW 150 User Manual Download

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How to use the Manual

Remark:

The LDP-QCW 150 described in this manual is a primarily baseplate cooled

laser diode driver. Improper cooling may cause an internal overtemperature shutdown.

Heat sink cooling with fans:

Depending on the final application and operation regime a

sufficient airflow created by the fans through the heat sink must be possible.

Please refer to section “Cooling” for more details about the thermal power losses during
operation.

You may use a passive or an active air/water cooler.

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!

Summary of Contents for LDP-QCW 150

Page 1: ...594 60 Fax 49 0 2405 64594 61 E Mail info picolas de Web www picolas de 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 ...

Page 2: ...le of Contents Please pay attention to all safety warnings Pulse current Please pay attention to all safety warnings Valuable information remark Do not Please pay special attention Risk of electrical hazard ...

Page 3: ...eration regime a sufficient airflow created by the fans through the heat sink must be possible Please refer to section Cooling for more details about the thermal power losses during operation You may use a passive or an active air water cooler 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...

Page 4: ...y Technical Specifications 1 The compliance voltage strongly correlates to the pulse current and pulse duration Output current 1 150 A Compliance voltage 0 30 V 1 Min pulse duration 10 µs Max pulse duration 1 ms Max repetition rate 1 kHz Max duty cycle 10 Max rise time TBD Current overshoot 5 depending on regulator settings Pulse trigger input Analog Interface TTL Connectivity Analog interface RS ...

Page 5: ...r that is triggered by either an external trigger signal or via software through the RS 232 interface Several security features protect the laser diode and the driver from damage D1 protects the laser diode from reverse currents The switch S1 is automatically opened when an internal failure or an interlock condition is detected Operation Principle of LDP QCW Driver Element Function C1 Input buffer...

Page 6: ...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 if only these operat...

Page 7: ...7 Description of available Connectors ...

Page 8: ...8 Mechanical Dimension ...

Page 9: ...ows the input and output signals of the external analogue BOB connector The LDP C BOB Breakout 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 ...

Page 10: ...t your external trigger source to this pin The signal amplitude should be within 3 to 6 Volts 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 This signal is used as an interlock safety feature that disables the comp...

Page 11: ...11 The interface is a standard RS 232 interface connection It can be used to connect the PC to the driver ...

Page 12: ...the maximum operating voltage of 52 V 5 Switch the power supply on 6 Set all required parameters using the RS 232 interface Make sure that the capacitor voltage is set to a safe value See section Controlling the LDP QCW via RS 232 for more information 7 Apply 5 V to the interlock pin of the BOB connector This will enable internal power conditioner See section Interface Specifications for more info...

Page 13: ...at sink for new operational conditions Test Load A common method to test the driver is to connect a regular silicon rectifier diode to the driver output Please pay attention to the junction capacitance of the diode Only fast recovery diodes or similar have a low parasitic capacitance comparable to laser diodes To achieve reasonable test results the parasitic elements of the test diode and the conn...

Page 14: ...discharged The enable signal must be disabled before the interlock can be re enabled The storage discharge slowly Be careful when powering off the driver as they may still hold a high voltage Touching them might result to an electrical shock The enable input controls the current regulator and the internal trigger generator When it is enabled the driver will generate output pulses according to the ...

Page 15: ...otocol the PING command is used To initialise the text protocol use the init command The acknowledgement of this command indicates a successful communication PLB 21 To use the PLB 21 to control the driver simply connect it using the cable supplied with the PLB 21 No further actions are required as the driver supplies all required signals communication and power to the PLB 21 The menu structure is ...

Page 16: ... the driver s current regulator offers two different operation modes which applies to both pulse shape modes 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 significant current overshoot at the output Mode 1 semi auto In this operation mode the feed forward FFwd value is automatically chosen ...

Page 17: ...utput stage will heat up fast and lead to an overtemperature shutdown The following equation can be used to calculate the capacitor voltage Vcap in dependence of the output current compliance voltage and pulse width 046 0 011 0 5 pulse LD LD cap T I U V where LD U Compliance voltage in V LD I Current setpoint in A pulse T Pulse width in s This equation does not use the repetition rate Hence this v...

Page 18: ...e generated when the driver is enabled can be set from a single pulse to a continuous pulse generation while the driver is enabled 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 Symbol Meaning T1 Enabling of the output T1 T2 Delay between output enable and the first generated ...

Page 19: ...by setting the TRG_EDGE bit in the LSTAT register to 0 or 1 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 Symbol Meaning T1 Enabling of the output T2 T3 Pulse rise time It depends on the load inductance T4 T5 Pulse fall time It depends on the load inductance T6 Disabling of the o...

Page 20: ... the rising edge setting it to 0 uses the falling edge The number of pulses and the repetition rate can be set via software 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 Symbol Meaning T1 Enabling of the output T2 T3 Pulse rise time It depends on the load inductance T4 T5 Pulse f...

Page 21: ...ock signal to 0 while the enable signal is given will disable the output stage discharge the capacitor bank and put the driver into an error condition This is reset by setting the enable signal to 0 Alternatively the enable signal can be controlled via software Set the ENABLE_EXT bit in the LSTAT register to 0 to switch to software control If the text protocol is used the commands are enable_int e...

Page 22: ...hat there is no residual voltage Timing Diagram The following diagram shows the effect of the MEN Master Enable ENABLE and trigger input signals to the external current flow Symbol Meaning Min Max Avg Description t1 MEN given t0 t2 Power on self test 2 5 s 14 s 4 s t3 ENABLE given t4 t5 t8 t9 t12 t13 Rise time 1 µs Depends on the inductance of the connected load t6 t7 t10 t11 t14 t15 Fall time Dep...

Page 23: ...onnector respectively Never create a short over the capacitor clamps while the capacitors contain energy 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 Please be aware that there might be hot surfaces be careful not to touch them Do never connect the oscilloscope to th...

Page 24: ...um allowed operating temperature This condition is latched and the LDP QCW will not start working until temperature drops five degrees and the ENABLE signal is toggled If an Error Occurs If an error occurs during operation the pulse output is switched off All error conditions are latched and cleared by disabling the driver either using the switch or the software control ...

Page 25: ...Rev 01 2020 25 Mechanical Dimensions The following dimensions are in millimetres mm Please note that the picture is horizontally compressed ...

Page 26: ...ned for communication with a terminal program the PicoLAS protocol is designed as a system interact protocol The switching between the two protocols occurs automatically as soon as the LDP QCW receives a certain sequence The corresponding commands are PING for the PicoLAS protocol init followed by Enter for the text interface The connection settings are Baud rate 115200 Data bits 8 Stop bits 1 Par...

Page 27: ... a 01 If there is an error pending the response will be 10 otherwise 11 If the command requires an answer parameter this parameter is sent before the confirmation is given Example The user would like to read out the actual setpoint current User input gcur Enter Output of the LDP CW 150 0 CR LF 00 CR LF Example 2 The user would like to set a new setpoint current User input scur 100 5 Enter Output o...

Page 28: ...ic loading of default settings on power on gerrtxt returns the error register in text form gerr returns the error register as a 32 bit number clrerr clears the error register glstat returns the laser status register slstat 32 bit number sets the laser status register to the given value gtrgedge returns 0 for negative edge or 1 for positive edge strgedge 0 or 1 sets the trigger edge for external tr...

Page 29: ...possible repetition rate in Hz grepratemax returns the maximal possible repetition rate in Hz sreprate reprate in Hz sets the pulse repetition rate to the given value The return value is the new repetition rate gvcap returns the actual pre charge voltage of the internal capacitor bank in V gvcapmin returns the minimum pre charge voltage of the internal capacitor bank in V gvcapmax returns the maxi...

Page 30: ...to the given value 0 positive 1 negative Please note that it is used only in trigger modes 1 and 2 See section Trigger Modes for more information gtrgedge Returns the actual configured polarity gtemp returns the value of temp sensor in C gtemphys returns the temperature at which the device switches back on after an overtemperature shutdown in C gtempwarn returns the temperature at which the TEMP_W...

Page 31: ...wed by a 32 bit data word and an 8 bit checksum Each of the words are little endian encoded This leads to the following structure Protocol frame Byte 0 1 2 3 4 5 6 Meaning Command Command Data Data Data Data CRC Bits 0 7 8 15 0 7 8 15 16 23 24 31 0 7 The CRC byte is calculated by an XOR of the six other bytes of the frame Any frame received with an invalid checksum is discarded without further not...

Page 32: ...rame Answer frame Command Data Command Data PING 0xFE01 0 0xFF01 0 IDENT 0xFE02 0 0xFF02 Device ID GETHARDVER 0xFE06 0 0xFF06 Hardware version GETSOFTVERST 0xFE07 0 0xFF07 Software version control board GETSERIAL 0xFE09 0 0xFF09 Device serial number GETIDSTRING 0xFE08 0 0xFF08 Device description string Command Name Command frame Answer frame Command Data Command Data GETTEMP 0x0101 0 0x8100 Int32 ...

Page 33: ...mand 0xFF14 UNAVL Command Name Command frame Answer frame Command Data Command Data GETERROR_1 0x0300 0 0x8300 Uint32 register CLEARERROR 0x0301 0 0x8300 0 Command Name Command frame Answer frame Command Data Command Data GETWIDTH 0x0400 0 0x8400 Uint32 in us GETWIDTHMIN 0x0401 0 0x8400 Uint32 in us GETWIDTHMAX 0x0402 0 0x8400 Uint32 in us SETWIDTH 0x0403 Uint32 in us 0x8400 Uint32 in us GETREPRAT...

Page 34: ... V GETVCAPMIN 0x0501 0 0x8500 Uint32 in 0 1 V GETVCAPMAX 0x0502 0 0x8500 Uint32 in 0 1 V SETVCAP 0x0503 Uint32 in 0 1 V 0x8500 Uint32 in 0 1 V Command Name Command frame Answer frame Command Data Command Data GETCUR 0x0600 0 0x8600 Uint32 in A GETCURMIN 0x0601 0 0x8600 Uint32 in A GETCURMAX 0x0602 0 0x8600 Uint32 in A SETCUR 0x0603 Uint32 in A 0x8600 Uint32 in A Command Name Command frame Answer f...

Page 35: ...hould be used with caution If the regulator is in any other mode the answer frame will contain the command 0xFF14 indicating that the command is unavailable Command Name Command frame Answer frame Command Data Command Data LOADDEFAULTS 0x0800 0 0x0800 0 SAVEDEFAULTS 0x0801 0 0x0800 0 Command Name Command frame Answer frame Command Data Command Data GETFFWD 0x1000 0 0x9000 Uint32 in 0 01 V SETFFWD ...

Page 36: ... edge is used 4 reserved ro 5 ENABLE_LOCK ro Indicates that the Enable pin must be set to 0 in order to continue normal operation 6 7 TRG_MODE r w Trigger mode 0 internal 1 external 2 external controlled 3 software controlled 8 MASTER_ENABLE ro Indicates the state of the interlock pin 9 ENABLED ro Indicates weather the driver s output is enabled of not 10 ENABLE_EXT r w When 1 the external enable ...

Page 37: ...ger mode 3 15 EXECUTING_PULSES ro Indicates that the driver is currently executing a software trigger 16 ABORT_EXEC_PULSES r w When 1 the driver will abort the current software trigger 17 DIS_INTEGRAL ro Controls the integral part of the current regulator 0 Enabled default 1 Disabled 18 31 reserved ro reserved ...

Page 38: ...d forward calibration of channel 1 is faulty 5 CRC_ISOLLCAL_FAIL ro Indicates that the current setpoint calibration of channel 0 is faulty 6 TEMP_OVERSTEPPED ro The internal temperature was beyond safe operating limits 7 TEMP_WARNING ro The internal temperature is 5 C before shutdown 8 TEMP_HYSTERESE ro Device is cooling down Temperature needs to drop below maximum 10 C 9 VCC_FAIL ro Internal supp...

Page 39: ... Fax 49 0 2405 64594 61 E Mail info picolas de Web www picolas de CEO Dr Ing Markus Bartram Registration Court Amtsgericht Aachen Registration Number HRB 13040 Tax ID Ust IdNr DE 243221335 WEEE Reg Nr DE 28806084 No liability will be accepted for errors and omissions Technical modifications reserved ...

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