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Intensify Nx50 setup guide

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Intensify Nx50 PCB from top side

This is the intallation & user guide for the Intensify Nx50 laser diode driver. Read it through before operating the device.

In case of any questions, please don't hesitate to contact us.

Physical installation and cooling[edit | edit source]

Nx50 should be mounted inside an enclosure by using spacer feet attached to the four corner holes.

Nx50 (single board) efficiency vs load current at various laser diode forward voltages

Nx50 has low power losses due to highly efficient multiphase switching converter technology. Power loss can be calculated by using the offered efficiency data as setpont.

In most cases Nx50 is sufficiently cooled with natural convection. This is best achieved by mounting boards vertically and leaving at least 25 mm free air space around both sides.

However, if natural convection does not offer sufficient cooling (i.e. if peak surface temperature is near or exceeds 100°C), then forced convection is necessary. This can be achieved by placing a fan or blower on the side of PCB so that air flow passes along board surface.

Wiring[edit | edit source]

Before wiring, review Nx50 electrical specifications.

J1 connector[edit | edit source]

J1 connector is the user side I/O of the driver. This connector contains the control and feedback signals. All signal lines of the port are ESD protected by dedicated suppressors.

Mating connector type is a 10 pin flat ribbon cable connector with 0.1"/2.54 mm pin pitch and a polarity key. See spec sheet of compatible connector here.

J1 pin out[edit | edit source]

10 Pin IDC connector pinout. Pin order is relative to the connector's polarity key.
Pin # Signal name Direction Signal description Impedance vs GND
1 PULSE In Pulse control:
  • When LOW or open, output current is 100% of ISET
  • When HIGH, output current is 3.5% of ISET
10 kOhm
2 GND I/O and power ground I/O and Analog ground 0 Ohm
3 IMON Out Current monitor 0-10 V analog output 1 kOhm
4 GND I/O and power ground I/O and Analog ground 0 Ohm
5 VMON Out Voltage monitor 1:1 analog output 1 kOhm
6 GND I/O and power ground 0 Ohm
7 ISET+ In Current setpoint 0-10 V positive input (differential) 51 kOhm
8 ISET- In Current setpoint 0-10 V negateive input (differential) 51 kOhm
9 ENABLE In LDD enable:
  • When HIGH, LDD output enabled
  • When LOW or open circuit, LDD output disabled
6.6 kOhm
10 GND I/O and power ground I/O and Analog ground 0 Ohm

Impedances[edit | edit source]

When driving an J1 input pin, the source impedance of controller should be significantly lower than input impedance of the corresponding pin. I.e. if input impedance is 51 kOhm, then recommended source impedance is less than 5 kOhm max, preferrably 0.5 kOhm. Lower source impedance yields lower voltage drop error.

Also when an output of J1 is connected to the input of controller, the controller input impedance should be significantly higher than J1 pin impedance. I.e. when connecting VMON (1 kOhm) to analog input or ADC, the controller input impedance should be at least 10 kOhm. However all outputs are short circuit proof and input impedance recommendation affects only monitor accuracy.

See impedance column of pin out table

Digital signals[edit | edit source]

All digital signals (PULSE & ENABLE) are referenced to GND and applicable voltage levels are:

State Voltage range
Logic LOW -0.3 .. 0.6V
Logic HIGH 4.5 - 26 V

Analog signals[edit | edit source]

Analog input signal support differential signaling to cancel noise and ground loop induced error. These are designed to be compatible with another differential source as well as single ended systems. The differential signals allow up to +/- 1.5V difference on ground reference potentials between Nx50 and controller without losing accuracy.

Connection to differential 0-10V analog I/O:

Controller J1 signal
Analog in 1 + IMON
Analog in 1 - GND
Analog in 2 + VMON
Analog in 2 - GND
Analog out 1 + ISET+
Analog out 1 - ISET-
Ground GND

Connecting to single ended 0-10V analog I/O. Assuming that I/O is referenced to Ground.

Controller J1 signal
Analog in 1 IMON
Analog in 2 VMON
Analog out 1 ISET+
Ground ISET-
Ground GND

Power[edit | edit source]

A regulated 12VDC power supply should be connected to hole terminals labeled GND and +12V. Required power is nearly directly proportional to output power plus losses.

For example outputting 40A to 2.0V diode equals output power of 80W. With losses the needed power is about 85-90W which equals 7.0-7.5A @ 12V.

Laser diode[edit | edit source]

Laser diode is connected to hole terminals labeled O+ and O-. O+ goes to LD anode and O- to cathode.

Connecting parallel[edit | edit source]

Three Nx50 drives connected parallel by stacking with hex standoffs and ribbon cable with three IDC connectors

Nx50 boards may be connected parallel to increase output current range simply by connecting all power and I/O lines parallel pin-by-pin basis.

This can be achieved by stacking them by using metallic standoffs to form conductive path between O+, O-, GND, and +12V terminals. Use M4, M5, 10-24, 8-36, or #8 threaded standoffs with minimum height of 16 mm / 0.63".

J1 connector may be paralleled by inserting multiple 10 pin IDC connectors to the single ribbon cable. By this method all J1 pins are properly connected parallel pin-to-pin basis.

CMD connector output signals in parallel mode[edit | edit source]

When mutliple boards are wired parallel, the output of current and voltage monitor pins will be the average of individual driver board values.

I.e. if we have three Nx50 in parallel with the setpoint set of 10V (which normally outputs 150A current), then current monitor output would also give 10V. If one of boards is in fault state (overtemperature etc), then output current would be only 100A (two boards driving, one inactive). In such condition the current monitor output would be 6.67V (the average of 10V, 10V and 0V).

Usage[edit | edit source]

The device starts operating instantly after powered and and proper signals fed to J1 pins. No other initialization is needed. Sequence order of signals and power are not critical - device will not get harmed or produce erratic output regardless of start-up order.

CW usage[edit | edit source]

Mandatory connections
  • LD connected between O+/O-
  • 12VDC supply connecter between +12V/GND
  • J1 connector pins:
    • GND connected to controller's ground reference:
    • 0-10V current setpoint signal fed to ISET+/ISET-
    • ENABLE set to HIGH or tied to GND
Optional J1 connections
  • IMON wired to analog input
  • VMON wired to analog input
  • PULSE set to HIGH or left open

Pulsed usage[edit | edit source]

LD current rise from 2.5A to 50A when PULSE set to LOW
LD current fall from 50A to 2.5A when PULSE set to HIGH. Current typically dips to 0A temporarily.

For pulsed usage it is recommended to use PULSE input or modulate the ISET analog voltage. It is not recommended to set current to 0 during off-periods for to achieve faster pulse rise times and zero overshoot. Recommended bias current during off-periods is 2-10% of current setpoint.

Mandatory connections
  • LD connected between O+/O-
  • 12VDC supply connecter between +12V/GND
  • J1 connector pins:
    • GND connected to controller's ground reference:
    • 0-10V current setpoint signal fed to ISET+/ISET-
    • ENABLE set to HIGH or tied to GNDA
    • PULSE set pulse source. Logic LOW means 100% of set current and HIGH reduces output current to 3.5% (bias current to allow faster rise time)
Optional J1 connections
  • IMON wired to analog input
  • VMON wired to analog input

Safety[edit | edit source]

Nx50 enable or setpoint inputs should not be used as means of safety shutdown alone. If device is malfunctioning, any signal sent to CMD connector may be ineffective.

In the worst case, Nx50 hardware failure may cause the device to drive any current or voltage to the output pads (i.e. internal short circuit from power supply pads to output pads). Because of that, the recommended shut-down method is to cut the 12V supply voltage to the device. User of Nx50 should have method of detecting over current or unexpected laser radiation condition and perform the safety shut-down by powering off the Nx50.


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