LPLDD-5A-24V-PID-H Laser Diode Driver

About the LPLDD-5A-24V-PID-H Laser Diode Driver

The new version (fourth) of the LPLDD-5A-24V-PID-H medium-power laser diode driver has been released.

Main features of the LPLDD-5A-24V-PID-H Laser Diode Driver:

• Screw connectors - all in the same size, easier to connect wires
• Test jumper - the possibility of switching on the driver without external analog signal
• Current monitor output - the convenient place to measure the current flowing through the diode
• Signal diodes: diode enable, TEC, warning
• Labels on the board - more intuitive and easier to set
• High TEC current - up to 15 A
• Included heat sink

The logic part of the laser controller is powered from TEC line, it allows to use 3.3 V PSU to power the infrared diodes without a big amount of dissipated heat. TEC part should be connected even if not used to the voltage in 7.5 V - 24 V range.

This is the professional driver for laser diodes with a built-in digital temperature controller using the PID algorithm. Its size allows for mounting it in small devices such as compact laser projectors. Thanks to an included heat sink you do not need to worry about heat dissipation, drilling holes, and isolation of power transistors from the heat sink. It is a fully functioning component ready to be mounted in laser devices.

Despite its small size, the driver is able to work with thermocouples (Peltier modules) such as 12706, 12708, 07113, and many others that draw up to 15 A of current. Despite the high current, thanks to using PWM the controller does not heat up. Used PID algorithm learns the behavior of the system, hence quicker reacts to changes in temperature and provides higher accuracy of stabilization. The driver easily handles all laser diodes of up to 5 W, and at the customer's request, it is possible to customize the driver up to 10 A version. Separate laser diode supply voltage input and TEC input enable the selection of any components the driver can work with. Analog input allows for the modulation of the current flowing through the diode up to 100 kHz. Two potentiometers are used to set the values of maximum diode current and bias current. The third potentiometer is responsible for setting the setpoint temperature, measured by the thermistor, at which the Peltier’s module is triggered. The setpoint temperature can be set in the range 0 – 40 degrees Celsius. Note: Peltier's module can operate only in cooling mode. The possibility to power laser diodes of any wavelength and control the Peltier modules with a rated voltage from 7.5 to 24 V and current up to 15 A make this driver truly unique and extremely versatile. Diode line can be powered with voltages from 3 V up to 24 V so it makes it fully functional for any kind of laser diode.

You can find the same driver but without a heat sink. This reduces the shipping and production costs but requires the ensuring of adequate cooling for the driver.

Recommendations:

The minimum diode input voltage should be higher or equal to 7 V, in other situations, it is given by the formula:

• Vin = 0.4* I + Vd + 0.6 V
• Vin - input voltage
• Vd - diode working voltage
• I - desired maximum current

Modulation input can be used as TTL input with its logic levels of 0 V and 5 V or as an analog input. Analog modulation means that by using 2.5 V on ANG input you get 50% output power, analogically by using 4 V you get 80% output power, etc. This input can also be used as PWM input the only requirement is that the base frequency of the PWM signal is in range of 5-20 kHz,

You should be very careful not to cause a short circuit between the + (VCC) of the power supply and - (GND) of the analog input, as a thin GND analog path can be irreparably damaged.

We recommend the use of power cables with the cross-section of at least 0.5 mm2.

Protection:

The circuit responsible for powering a laser diode is protected against reversed polarity. The high current Schottky diode of an extremely low forward voltage secures the laser diode against connecting reversed voltage with the aim of protecting frequently the most expensive part of the entire device - a laser diode. In turn, the low forward voltage does not cause excessive heat loss during normal operation.

The analog input is protected by a 5V1 Zener diode on occasion there appears the voltage higher than 5V. Despite everything, this input should not be used with higher voltages.

A microcontroller ensures the proper operation of the entire system.

At the start, the microcontroller is checking the connection with a thermistor. If there is no thermistor used the WARNING LED is blinking but the driver is still working. If the connection with the thermistor is lost during normal work, the microcontroller turns off the laser diode supply circuit and does not allow for its further load, it also switches off the DIODE LED and switch on WARNING LED. The TEC line is also switched off. The same situation happens when the thermistor reaches a temperature above 50 degrees Celsius

The laser diode controller is fitted with a two-second soft-start designed to protect the laser diode against switch-on effects.