Difference between revisions of "Intensify Nx50 setup guide"

Revision as of 20:01, 20 February 2013

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

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 reference.

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

CMD connector

CMD 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.

CMD pin out

10 Pin IDC connector pinout

Impedances

When driving an CMD input pin, the source impedance of controller should be significantly lower than input impedance of the corresponding pin. I.e. if input impedance is 50 kOhm, then recommended source impedance is 500 Ohm max. Lower source impedance yields lower voltage drop error.

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

See impedance column of pin out table

Digital signals

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

Analog signals

Analog input & output signals 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:

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

Power

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

Laser diode is connected to hole terminals labeled O+ and O-. O+ goes to LD anode and 0- to cathode.

Connecting parallel

To be written

Usage

The device starts operating instantly after powered and and proper signals fed to CMD pins. No other initialization needed, however following start up & shut down sequences are recommended to prevent current overshoot:

Note: items with "or" means that either of these should be fulfilled or both of them. However fulfilling both does not cause further improvement.

Power-on

1. ENABLE=HIGH
2. PULSE=HIGH or ISET=0V (start condition)
3. Power on 12V
4. Set ENABLE to LOW
5. set PULSE=LOW or set ISET to desired voltage.

Power-off

1. Set PULSE=HIGH or ISET=0V (this step optional)
2. Set ENABLE=HIGH
3. Power off 12V

CW usage

Mandatory connections

• LD connected between O+/O-
• 12VDC supply connecter between +12V/GND
• CMD connector pins:
  • GNDA connected to controller's ground reference:
  • 0-10V current setpoint signal fed to ISET+/ISET-
  • ENABLE set to LOW or tied to GNDA

Optional CMD connections

• IMON+/IMON- wired to analog input
• VMON+/VMON- wired to analog input
• PULSE set to HIGH or left open

Pulsed usage

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
• CMD connector pins:
  • GNDA connected to controller's ground reference:
  • 0-10V current setpoint signal fed to ISET+/ISET-
  • ENABLE set to LOW or tied to GNDA
  • PULSE set pulse source. Logic LOW means 100% of set current and HIGH reduces output current to 5% (bias current to allow faster rise time)

Optional CMD connections

• IMON+/IMON- wired to analog input
• VMON+/VMON- wired to analog input