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Assemblies: Laser Power Supply

 

Laser Power Supply

Description

Drives 2 laser diodes in constant-current mode while controlling their temperatures through Peltier coolers. It assumes lasers require less than 500 mA current each and the coolers less than 1 ampere each. Temperature is monitored with a thermistor in the laser.  The supply uses 2 Thorlabs Diode Drivers and 2 Thorlabs Temperature Control Modules.  It has a dual digital voltmeters to indicate laser current, temperature, power, setpoints, limits, etc. and a single custom-made circuit board to connect with front-panel components.  To build device, first drill holes in the Bud utility enclosure (see drawings).  Small holes are designed to mate with the 4 corners of a circuit board. Big holes (1/2") are usually ventilation holes and are placed for maximum  convection of hot air out of the box.  Note that the box has an overlapping welded seam on one of its edges.  This edge should be oriented on the TOP of the box because drilling ventilation holes through the welded seam would be difficult. Note the thick rubber feet are essential because otherwise the ventilation holes in the bottom of the box would be blocked.  The second step is to solder all components in the custom PC board. Many of these components must mate with holes in the front panel.  Therefore it is good to first mount the 4-40 spacers on that panel and then place the board and panel together with the (loose) components sticking through the panel holes. Then solder the components so they have the correct tilt where they go through the panel.  Note the plastic LED Spacers help keep all the LEDs at the correct height.  

Setup: Adjust the tempurature control module by turning the "I-gain" counter-clockwise to minimize the difference between setpoint and measured temperature. On the diode drive board, turn the "I-lim" trim pot adjustment counter-clockwise until the current limit reading (on panel meter) equals the Laser Operating Current specifiied by Lumics at the Maximum Operating Power according the spec sheet. Also, adjust the "P-lim" trim pot with a voltmeter hooked to the p-lim test point and ground on the diode driver board until the voltage corresponds to the Monitor Current at Maximum Operating Power according to the Lumics spec sheet (i.e. 1 V = 1 uA of monitor photodiode current). Note: red limit LED comes on when you try to exceed the maximum current; however, when you try to exceed the maximum power without exceeding the current, the power will be limited but the red LED will not illuminate.


Type Instrument
Drawing
Pictures
Picture
Laser Power Supply Board
side that faces away from front panel

Laser Power Supply Board
Picture
panel plus board

panel plus board
Picture
Diode Driver Board Modified
Thorlabs IP 500 diode driver modified by soldering in wire harness. Remove trim pot "P/I ADJ" and solder 3 wires into holes. Requires careful work with a "solder sucker". The board is connected to a socket 16 through 12" ribbon cable.

Diode Driver Board Modified
Picture
a) Laser power supply

a) Laser power supply
Picture
Back view

Back view
Picture
Front panel

Front panel
Picture
Front view of power supply wiring

Front view of power supply wiring
Picture
Over the front

Over the front
Picture
panel back side

panel back side
Picture
wires to laser

wires to laser
Picture
Wiring harness inside power supply
Red = +5 V, Black = ground, Yellow = -5 V

Wiring harness inside power supply
Picture
Jumpers
Jumper (J5) from panel board to panel meter

Jumpers
Parents
Children laser power supply circuit board
Parts
NameManufacturerVendorRequiredStockCost
Box, utilityBud CU-879Mouser Electronics1$56.40
Cable, coaxialRG179U-1 ftPasternack2$20.80
Connector housing 2 pos. vert friction-lockMolex 22-01-3027Allied Electronics2$0.12
Connector housing 3 pos vert friction-lockMolex 22-01-3037Newark4$0.12
Connector, BNCAmphenol 31-10-RFXAllied Electronics2$3.20
Connector, DB-9 FemaleAmphenol L77-DE09S Allied Electronics2$5.27
Dial, 15 turns, countingBourns H-22-6ADigiKey2$8.54
Diode, signal 1N4148DigiKey2$0.14
extender nut setAMP 5205817-8Newark2$0.76
Ferrite beadFair Rite 2631540202Newark2$0.79
FuseBussman AGC-3ANewark1$1.38
Fuse holderLittelFuse H342004Newark1$2.28
Laser diode driver500 mAThorlabs2$360.00
Laser power supply front panelcustom shopFront Panel Express, LLC1$100.00
Meter, digital panelJewell BL-330302-01UAllied Electronics2$91.07
Nut, SShex 4-40McMaster Carr4$0.03
potentiometerBournsMouser Electronics2$13.38
Power cord71535K51McMaster Carr1$5.04
Power supply 5VSL-Power HB5-3-OV-A+GAllied Electronics2$67.53
Receptacle, ACVolex 17252ANewark1$1.29
Ribbon cable 16 Condalpha 3580/16Allied Electronics2$1.11
Ribbon cable 26 cond3M 3302/26Mouser Electronics1$2.74
Ribbon Socket, 16AMP-Tyco 1658622-3Mouser Electronics2$1.48
Ribbon Socket, 26AMP-Tyco 1658622-6DigiKey4$1.46
Rubber foot3M Corp. SJ-5514DigiKey4$0.46
Screw, SS Pan-Head6-32x1/2McMaster Carr4$0.06
Screw, SS Pan-Head4-40x1McMaster Carr4$0.05
Spacer, AluminumThreaded 4-40, 5/8", hexMcMaster Carr4$0.38
Status Wires AssemblyThorlabsThorlabs2$16.00
Switch, power103-0013-EVXMouser Electronics1$4.76
Temp controllerTCM1000TThorlabs2$336.60
Estimated cost: $2037.73
 

List all the parts for "Laser Power Supply"

last changed 2010/10/26 16:34

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