PICOLAS LDP-QCW 150 User Manual

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Before powering on your unit, read this manual thoroughly and make sure

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Please pay attention to all safety warnings.

If you have any doubt or suggestion, please do not hesitate to contact us!

PicoLAS GmbH

Burgstrasse 2

52146 Würselen

Phone:

+49 (0) 2405-64594-60

Fax:

+49 (0) 2405-64594-61

E-Mail:

info@picolas.de

Web:

www.picolas.de

User Manual

LDP-QCW 150

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Summary of Contents for PICOLAS LDP-QCW 150

Page 1 User Manual LDP-QCW 150 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 Table of Contents Please pay attention to all safety warnings! Pulse current Please pay attention to all safety warnings! Risk of electrical hazard Please pay special attention Do not Valuable information, remark...
Page 3 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.
Page 4 Overview The LDP-QCW 150 (LDP-QCW for short) is a high power linear regulated laser diode driver. It supports the following features: o Supports up to 30 V compliance voltage o Linear output driver for rectangular current pulses with ripple < 1 %...
Page 5 Functional Description The driver uses a DC-DC converter to load a capacitor bank to a defined voltage. It can provide a maximum voltage of 34 V to load the storage capacitor bank Cb. A P-I regulator using T and T are controlling the current flow through the laser diode.
Page 6 This is done through the digital interface (RS-232). See below for more information. 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.
Page 7 Description of available Connectors...
Page 8 Mechanical Dimension...
Page 9 Analogue Interface Specifications The following figure shows 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 Pin Description (numerical assorted) Pin 1: Pulser OK The state of this signal indicates weather the driver is ready (5 V) or it has an error pending (0 V). Pin 2: 5 V This pin provides 5 Volts for external usage. Please note that the load should not exceed 10 mA, otherwise the voltage will drop.
Page 11 The interface is a standard RS-232 interface connection. It can be used to connect the PC to the driver.
Page 12 How to get started Step What to do Check Unpack your device and place it in front of you as shown on the next page. Connect a load (for example your laser diode) to the output. Connect the RS-232 cable / PLB-21 See section “Controlling the LDP- QCW via RS-232”...
Page 13 Cooling The maximum thermal dissipation of the LDP-QCW depends on the configured pulse length, repetition rate and capacitor bank voltage. The driver is cooled by a heat sink and two fans for continuous high-power operation. The maximal thermal dissipation can be estimated by: ...
Page 14 Digital Interface Specifications The interface provides the following connections: o RS-232 interface o Interlock input o Enable input o Trigger input The RS-232 interface gives access to all internal settings and registers. It uses a communication speed of 115200 baud with 8 data bits, 1 stop bit and even parity. In order to test the interface connection, the PING or init command may be used, depending on which protocol should be used.
Page 15 115200 baud, 8 data bits, 1 stop bit and even parity. In order to initialise the PicoLAS protocol, the PING command is used. To initialise the text protocol, use the init command. The acknowledgement of this command indicates a successful communication.
Page 16 Pulse current The LDP-QCW is capable of generating a single rectangular shaped current pulse. The pulse current, pulse width and repetition rate can be configured via RS-232 / PLB-21 or via the BOB interface connector. In the current hardware revision, the pulse current can only be set via digital interface. Regulator Operation Modes T the driver’s current regulator offers two different operation modes, which applies to both pulse shape modes.
Page 17 Capacitor Voltage The capacitor bank is charged by an internal DC-DC converter. It transforms the supply voltage into a configurable capacitor voltage. The power conversion is controlled by the interlock input. Setting the interlock to “1” while the enable signal is “0” will start the capacitor loading procedure. If the enable signal is given before the interlock, the driver will enter an error condition and no power is transferred into the capacitors.
Page 18 Trigger Modes The LDP-QCW supports four different trigger modes as explained below. In order to change the trigger mode, the driver must be disabled (enable = 0) and the TRG_MODE and TRG_EDGE bits in the LSTAT register must be set accordingly. Internal (trgmode = 0) The pulse generation is performed by an internal pulse generator.
Page 19 External (trgmode = 1) The pulse generation is performed by an external pulse generator connected to the pulse input on the BOB connector. The pulse width and repetition rate is defined by the trigger signal. The pulses can be inverted by setting the TRG_EDGE bit in the LSTAT register to “0”...
Page 20 External controlled (trg mode = 2) 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 or falling edge of the external trigger input. The pulse width and repetition rate are defined by the internal pulse generator and can be set using the serial interface.
Page 21 Output Enable The output stage of the driver is controlled by the interlock and the enable signal. Setting the enable to “1” while the interlock is given, the driver will start to produce output current pulses according to the selected trigger mode. The driver will produce output current as long as the trigger condition is matched and the enable and interlock signals are given.
Page 22 Exchange Dummy Load for Laser Diode Before removing the dummy load, it is recommended to set the interlock signal to “0” as well. This will discharge the capacitor bank and put the driver into a safe condition. After setting interlock to “0”, the capacitors require a certain amount of time to discharge.
Page 23 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 the output connectors!!!! (Please note: above picture shows another but similar PicoLAS driver)
Page 24 Overtemperature 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 signal is toggled.
Page 25 Mechanical Dimensions The following dimensions are in millimetres (mm). Please note that the picture is horizontally compressed. Rev. 01/2020...
Page 26 Introduction The RS-232 interface allows communications over a serial text interface as well as using the PicoLAS protocol. While the text interface is designed for communication with a terminal program, the PicoLAS protocol is designed as a system interact protocol.
Page 27 The Serial Text Interface The following section describes the structure and commands of the text interface. Structure Every command that is sent to the LDP-QCW must be completed with a CR (Enter). It consists of a command word followed by one ore more parameters. If the command was successfully executed a “00”...
Page 28 Commands for the serial text interface The following table contains a command reference for the LDP-QCW. Command Parameter Description ghwver returns the hardware version number gswver returns the software version number gserial returns the serial number gname returns the device name prints out all settings loaddef load default values...
Page 29 Command Parameter Description gcur returns the actual setpoint current in [A]. gcurmin returns the minimum setpoint current. gcurmax returns the maximum setpoint current. scur <current> sets the internal setpoint current to the given value. This value must be within the minimum/maximum borders (see above).
Page 30 Command Parameter Description gcount returns the actual configured number of pulses to be generated gcountmin returns the minimum possible number of pulses to be generated gcountmax returns the maximum possible number of pulses to be generated scount number sets the number of pulses to be generated execpuls generates a software trigger strgmode...
Page 31 The PicoLAS protocol The following section describes the structure and commands of the PicoLAS protocol. PicoLAS Protocol Structure The protocol uses a frame-based structure. Each frame consists of 7 bytes which must be sent consecutively. Otherwise, the protocol will time out and the transmission must start again. For each valid frame received, an answer is sent to the host after it has processed the command.
Page 32 General These commands have various general functions. Command Name Command frame Answer frame Command Data Command Data PING 0xFE01 0xFF01 IDENT 0xFE02 0xFF02 Device ID GETHARDVER 0xFE06 0xFF06 Hardware version GETSOFTVERST 0xFE07 0xFF07 Software version control board GETSERIAL 0xFE09 0xFF09 Device serial number GETIDSTRING 0xFE08...
Page 33 ERROR Register These commands give access to the driver’s error registers. These are read only and will be cleared if the error condition is removed and the enable signal is toggled or the CLEARERROR command is received. Please refer to the ERROR register description later in this document for more information.
Page 34 Capacitor Voltage These commands give access to the capacitor bank pre charger. Command Name Command frame Answer frame Command Data Command Data GETVCAP 0x0500 0x8500 Uint32 in 0.1 V GETVCAPMIN 0x0501 0x8500 Uint32 in 0.1 V GETVCAPMAX 0x0502 0x8500 Uint32 in 0.1 V SETVCAP 0x0503 Uint32 in 0.1 V...
Page 35 Default values These commands give access to the driver’s default value set. Each operating parameter can be saved to this default set and recalled later. Command Name Command frame Answer frame Command Data Command Data LOADDEFAULTS 0x0800 0x0800 SAVEDEFAULTS 0x0801 0x0800 Feed Forward (FFwd) These commands give access to the current regulators feed forward part.
Page 36 Description of the LSTAT Register The following list contains a description of the individual LSTAT bits. These can be read with the GETLSTAT and written with SETLSTAT command. Name Read/Write Meaning ENABLE_OK ro / r/w Indicates the state of the ENABLE signal.
Page 37 Name Read/Write Meaning EXEC_SW_PULSE When “1”, the driver will execute a pulse (in trigger mode 3). EXECUTING_PULSES Indicates that the driver is currently executing a software trigger. ABORT_EXEC_PULSES r/w When “1”, the driver will abort the current software trigger. DIS_INTEGRAL Controls the integral part of the current regulator: 0: Enabled (default)
Page 38 Description of the ERROR Registers The device has two 32-bit wide error registers. The following lists contain a description of the individual bits of each register. Unless otherwise noted, a “1” indicates an error or warning condition. Name Read/ Meaning Write CRC_DEVDRV_FAIL A CRC error was detected in the internal...
Page 39 Impressum PicoLAS GmbH Burgstrasse 2 52146 Würselen Germany Phone: +49 (0) 2405-64594-60 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.