LDRVMINI is a current drive and temperature control module for Butterfly-Shaped Semiconductor lasers. Its main functions include: controlling the internal temperature of the laser, generating a constant current signal to drive the laser, and converting the external input voltage signal into current drive. The module has two maximum current driving ranges, which are suitable for lasers with different power levels (selected by circuit board jumpers).
Laser Drive Current
Laser Driving Voltage
Temperature Control Range
TEC Output Current
TEC Output Voltage
Please make sure that the laser is compatible with the current linear order by referring to the laser manual, the linear order of the corresponding connector and the wiring on the circuit board. Power supply under incorrect linear order may cause laser damage!
The negative power input of the module, the bottom plate and the negative NTC are grounded. And the positive pole and the negative pole of the driving output are not grounded. Attention is required when the laser to be installed has any functional pin grounded (connected to its housing).
When there is a laser function of the pin grounding (such as laser positive electrode grounding), it is necessary to pad a piece of viscous conductive silica gel between the laser and the bottom shell, and do not use metal screws to fix the laser, in order to make the laser shell and the bottom shell insulation. If not sure, please consult the seller's engineer! Improper grounding will lead to abnormal function of the module and even burn the laser.
Main Device Indicators
Hardware Parameter Configuration
Before power-on, the module needs to adjust the circuit parameters to adapt to the installed laser. Parameters are controlled by jumpers and dip switch on the circuit board. Be sure to operate in case of power failure!
Set the maximum driving current of LDRVMINI to be equal to or slightly larger than the maximum allowable current of laser. If the driving current is set too high, the risk of laser burning will increase. Setting consists of P2 jumper and dip switch on the circuit board:
From left to right:
Power Interface: 3.81mm connector, 5V3A
Communication Interface: serial communication, baud rate 115200bps, 8 data bits, 1 stop bit, no check bit; TTL level of 3.3v. Jumpers can be used to go short the GND and RX pins, so that the system can start driving the laser according to the set internal current,Please use this function after all parameters are completely set.
COM Light: communication indicator light, which shows red light when GND and RX are shorted
SYS Light: system status light. When the laser is not installed or the temperature of the laser is not stable to the set value, a yellow light is displayed. Green light is displayed when the laser temperature has stabilized. When the internal driving current is turned on, a red light is displayed.
INPUT: SMB connector, input voltage 0~2.5V, input frequency 0~10MHz
External Signal Input
The instrument rear panel signal INPUT terminal is used to receive external input.When the internal bias signal is not turned on, the equivalent circuit is shown in the following figure:
The driving current of the laser is:
ILaser = (V1/1.25V) x Imax
Imax=149mA or 378mA
When the internal signal is turned on, the equivalent circuit is as follows:
If only internal signals are used, all connections on the INPUT interface should be disconnected. If you want to use internal and external signals at the same time, please calculate the final effect by yourself according to the above equivalent circuit.
PC Control Interface
Replace the instrument cover, connect the controller to the power supply, and connect the computer with USB cable. Press power button ① to turn on the instrument. WIN7 and above system will prompt to install USB driver automatically. Please download the corresponding driver in http://www.ftdichip.com/Drivers/VCP.htm when using other systems or being unable to connect to the Internet. After the driver is installed, the virtual serial device will appear in the Device Manager.
Open the special software on the computer, as shown in the figure below:
Find the corresponding virtual serial port in Communication Port, if not, click Refresh button. Click the Connect button, the console will light up after normal handshake, and read the current set value of the controller. Enter the required working temperature at LD Temp Setpoint, and click Set Temperature setting. Start slider bar sets the constant working current value, and Limit slider bar sets the maximum limiting current. Click Set Parameters below to send the parameters to the instrument. Click Save All Settings to save all parameters in the instrument.
Click Run:DC to start the laser with the set current value. The Limit slider is used to protect the laser, and can also limit the current under external input,Please set it to the maximum working current in the laser parameter table.
Before starting the laser , please carefully check whether the parameters are within the allowable working range of the laser!
A dedicated conversion cable connects the circuit board to the USB or serial port of the computer. The USB converter uses FT232R chip to simulate serial port, and the system above WIN7 will automatically install the driver on the network. Please download the corresponding driver in http://www.ftdichip.com/Drivers/VCP.htm when other systems are not connected to the Internet. After the driver is installed, a new serial device will appear in the "Device Manager", and the default communication rate is 115200bps. Parameters are changed by receiving serial commands in ASCII format, and the commands end with Backspace.
The following describes the communication method with PuTTY as an example. After opening PuTTY, select Serial for connection, enter the same port number as in Device Manager, enter 115200 in Speed, click Open to open the black interactive port, and enter relevant instructions through the keyboard (the Backspace key is invalid). After entering the command correctly, the system will prompt to set the result, and the error will return the error message.
The computer is the main control terminal (upper computer) and sends string commands. Start a line of commands with ":" as the starter, and end a line with Enter (\r\n),The lower computer returns information after executing it. All the following functions can be accessed through supporting software,it is suggested that after setting up with supporting LDPD software and obtaining the correct waveform, click save to save the parameters to the lower computer, and then transfer them to other clients for control.
Operation mode is as follows:
>> > > > > send auto on to start and return to (1)Auto run started.[[OK]]\r\n
>> > > > > laser loads the set current
>> > > > > send auto off to stop and return to (0)Auto run stopped.[[OK]]\r\n
Function and return value
Return the current parameters of the lower computer:
> > the first line (%f) TEC.\r\n
> > (floating point number, consistent with the issued parameters)
> > second line (%d,%d,%d) PGA,freq,amp.\r\n
> > (for LDRV module, the above parameters are meaningless)
> > the third line (%d,%d,%d) bias.\r\n
> > (the value is consistent with the issued commands bias a,b,c b and c)
> > the fourth line (%d,%d) dm,phase.\r\n
> > (meaningless parameters on LDRV)
RYMLASER < local model > < version number >
Return to the current ambient temperature value, laser temperature
X is the celsius temperature, and the target temperature of the laser is set, which can be a decimal.
tecp kP kI kD
Set the PID parameters of the temperature control system to ensure the stability of the temperature control system, and users can adjust the parameters to achieve fast or slow response
Only for professional users! Poor PID parameters will lead to temperature oscillation and even damage the laser
Ex-factory value of system: kP =1500; kI=4000; kD=10
TEC normal mode, using stored PID parameters
TEC slow mode, making kP2, kI8 reduce the time constant of temperature system
Bias a b c
A: current setting (0~65535)
B: current limit setting (0~65535)
C: meaningless parameter, set to a value above 1
The values of a and b are calculated by the following formula
a = (IsetImax)*65536
Iset is the current to be set, Imax is the maximum current of the instrument (according to the model of this machine, check it in Instrument.ini)
Save all current parameters, and call them automatically at the next startup.