Hi everybody,
quite some time ago I asked for high side laser diode driver designs and after some help from Steve built a first prototype of my driver (see http://www.photonlexicon.com/forums/...9912#post99912). In the meantime I started to construct a nice red laser for my new projector. In this process I significantly improved the old circuit and added some more features. I also designed a TEC driver. To make mounting easy I designed both new drivers to be the same size and have mounting holes.
Now I have finished this project and thought I add the gained knowledge to the already huge amount of interesting projects on PL. I hope that it is useful to you as well.
I provide everything needed to build these drivers on your own, including schematics, layout, partlists and even digikey order numbers . You are free to built the driver for yourself but not to sell it. If you want to use it commercially just drop me a PM, and we will find an agreement as well! If there is sufficient interest I could also try to find a manufacturer to produce the drivers and organize a groupbuy.
So here is picture of the laser I used the drivers for:
Attachment 15661
Specs: 300mW 642nm mirror combined Opnext HL6385 diodes
Specs of the Diode driver:
High side, that means you don't have to isolate diodes which have the cathode at the case.
Rise/Fall times: 1us 100mA->500mA
Reference voltage to make bias current independent from supply voltage
Input modulation voltage limiting to protect the diode
Current limiting to prevent current peaks trough the diode
Up to 1W can be continously burned by the power mosfet. Depending on the input voltage that means up to ca. 1A current.
Schematic and image of LD Driver:
Attachment 15665Attachment 15663
The layout in the attached file is a bit different from the image. This is because after I measured the current design, I decided to increase the copper area of the mosfet for improved heat dissipation. I also added many thermal vias to efficently thransfer heat to the backside of the driver. I have not built the current layout but there should be no problems just better cooling for the mosfet.
Schematic of the TEC driver (inspired by http://pagesperso-orange.fr/redlum.x...lePWM-TEC.html ):
Attachment 15664
Specs:
10k NTC for temperature sensing
up to 2.5A current
up to 4.5V at 5V input
ca. 0.1°C temperature stability
At the end the file with the layouts:
EagleLayouts..zip
Have a lot of fun with the circuits!
Andreas
Edit: I don't know whats wrong but in the first time the images did not work and now there are strange not working links in the text.