Search found 87 matches

by Viking
Fri Jan 02, 2009 4:16 am
Forum: General Discussion
Topic: MOSFET heat
Replies: 18
Views: 3054

Yes, probably 40 degrees is a bit in the low side. Would probably be closer to 60 degrees. So if limiting temp rise to 80C, then for a 20C rise, single device would need a 1C/W heatsink and two devices a 2C/W heatsink. With a die-cast box and the heatsink bolted to the side, with two devices bolted ...
by Viking
Thu Jan 01, 2009 7:04 am
Forum: General Discussion
Topic: MOSFET heat
Replies: 18
Views: 3054

Hello Nepo, Forgot to give an answer to parallel devices. With two device, dissipation is halved, so at 16A, the dissipation is around 10W, so a 3C/W heatsink would be needed to give the 70 degree C limit. MOSFETS are easy to drive in parallel, but watch out that you don't increase dissipation by re...
by Viking
Thu Jan 01, 2009 6:45 am
Forum: General Discussion
Topic: MOSFET heat
Replies: 18
Views: 3054

Hello Nepo, Assuming that you are driving your IRL540 fully into conduction and assuming that it is conducting for 100% of the time, then the proximate dissipation would be as follows:- 4.5A 1.56W 9A 6.25W 16A 19.7W Assuming a 40 degree C maximum ambient temperature and limiting the maximum temperat...
by Viking
Mon Sep 22, 2008 8:43 am
Forum: General Discussion
Topic: Problems with 74HC165 of ST
Replies: 2
Views: 1051

Hello Carlos Can you post a schematic, this is otherwise going to be almost impossible to diagnose. To add attachments (if you haven’t already done so), set your Board Style to FI Subsilver Shadow in your profile. This will bring up an 'Add image to post' option just below the message dialog box R...
by Viking
Sun Sep 21, 2008 12:35 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 41476

Hello Dyarker Thanks for the test program, this will save me a lot of time as I won’t need to construct a waveform simulator. I would have needed something to generate a test signal so I could de-bug the hardware/PIC code for the receiver. So this is a great news. I will just have to construct a s...
by Viking
Sat Sep 20, 2008 8:03 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 41476

Hello Dale,

The clock is 4MHz and the basic time interval is 1us. So the timing can be adjusted in 1us intervals, e.g. 25us..26us..etc.

Regards
Rob
by Viking
Mon Sep 15, 2008 3:58 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 41476

Hello Federico, I’m back now in the UK. I have received the CD from you, thank you. News from brother, he has written an initial version of the PIC code for testing, So I need to make up some hardware to test it in. And also need to make the data stream simulator to test this, so I’ve got plenty...
by Viking
Tue Sep 09, 2008 3:38 pm
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 41476

Hello Federico,
I had forgotten about the 'PCB Pool' approach. Just note that we may have to make changes round the PIC area, but fine for a first prototype.

Gradually going nuts here, everything is happening so frustratingly slowly, only a few more days to go.

Rob
by Viking
Fri Sep 05, 2008 4:38 pm
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 41476

Hello Federico, Good morning from Clark, Philippines (ex Clark Airforce base) If you are intending to use a PCB manufacturer, then they will be able to do double sided boards. All the designs I have sent you have assumed it would be single sided, so there are wire links on the component side. Obviou...
by Viking
Tue Sep 02, 2008 12:26 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 41476

Hello Federico, Just checked in to my hotel in Singapore. If I send you the gerber files for the extender board (the one without the PIC), this will be the final design (hopefully) for that board, so you can build and test one. And you will be able to experiment with the CNC machine at the same time...
by Viking
Mon Sep 01, 2008 4:19 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 41476

Hello Federico, I'm just off now on my trip, waiting for the taxi to turn up. I've produced the code for the EPROM that will run the signal simulator. I have a design for the simulator, which I will build on my return. Brother is looking at the coding for the PIC. I've almost completed the PCB layou...
by Viking
Thu Aug 28, 2008 12:39 pm
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 41476

Hello Federico, It can be interesting. Some of the wafer fab plants are massive, production halls so large you need binoculars to see someone on the other side of the room. I will concentrate on getting the PIC working and building the tester and other support circuitry needed to the PIC. This will ...
by Viking
Wed Aug 27, 2008 9:52 pm
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 41476

Hello Federico, No I'm afraid it is business. So I will be wandering around a TI wafer fab facility in a bunny suit for the next week, not much of a holiday I'm afraid. I could use your CNC PCB making facility for the one-off test unit. I will see if it is quicker to hand build it or to spend the ex...
by Viking
Wed Aug 27, 2008 11:32 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 41476

Hello Federico, Yes, you are probably right that the camera is the best option. It gives you the opportunity of having a ‘Blue Flower’ webcam sight. And it allows you to check it for maintenance. If you can control it remotely, you can log in, run a test pattern and observe the results live. If ...
by Viking
Wed Aug 27, 2008 4:27 am
Forum: General Discussion
Topic: help on DC-AC inverter for Public art Project. Thks
Replies: 168
Views: 41476

Hello Federico, Just a thought about Goal 2 – shadow tracking. If each panel had a handful of photo sensors fitted evenly across its surface, so that the display as a whole would have about 100 sensors evenly distributed. The display would thus become a simple compound eye. The control PC could sc...