tag:blogger.com,1999:blog-824114889882641219.post1099653947056596581..comments2024-03-13T22:23:03.736-07:00Comments on effluvia of a scattered mind: TLC5940, TLC5941 and ArduinoAndrew Stonehttp://www.blogger.com/profile/04769383353032832222noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-824114889882641219.post-87972759189000314192018-07-04T06:21:15.394-07:002018-07-04T06:21:15.394-07:00This is a smart blog. I mean it. You have so much ...This is a smart blog. I mean it. You have so much knowledge about this issue, and so much passion. You also know how to make people rally behind it, obviously from the responses.<br /><a href="https://www.ukled.co.uk/led-drivers.html" rel="nofollow">Meanwell LED Power Supply</a><br />atif xhaikhhttps://www.blogger.com/profile/02930570824595079707noreply@blogger.comtag:blogger.com,1999:blog-824114889882641219.post-41934839183215105522016-09-01T01:14:49.015-07:002016-09-01T01:14:49.015-07:00Woo scary info. Thanks a lot for sharing. I am pla...Woo scary info. Thanks a lot for sharing. I am planning to upgrade software based pwm via shift registers to this chip , as heard a lot about it. Inoacehttp://www.inoace.comnoreply@blogger.comtag:blogger.com,1999:blog-824114889882641219.post-6905112278422305282015-06-05T07:34:05.482-07:002015-06-05T07:34:05.482-07:00Can you please suggest a "high-side driver ch...Can you please suggest a "high-side driver chip" and how it would be used to prevent the LED vs Chip Power issue? It's not something I'm familiar with but I do intend to use this chip to control the brightness of a 12V LED tape strip so it's a real concern.RossWhttps://www.blogger.com/profile/09113618715111512576noreply@blogger.comtag:blogger.com,1999:blog-824114889882641219.post-90318599085074207142014-06-21T13:08:48.774-07:002014-06-21T13:08:48.774-07:00To solve problem #0 would it not be a good idea to...To solve problem #0 would it not be a good idea to power the TLC5940 from the same supply as the LEDs - with a suitable voltage reduction when the LED supply is greater than 5v - and also to have the 5v go back to an input pin on the Arduino so that you don't send any signals back to the TLC5940 until you know there is power.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-824114889882641219.post-83761995479900601562014-06-19T08:41:05.614-07:002014-06-19T08:41:05.614-07:00I'm assuming you mean when you are sampling th...I'm assuming you mean when you are sampling the circuit with your scope, not just turning on your scope. If the latter, that implies your scope is putting some very bad waveforms onto your household power. But anyway both seem very unlikely unless your scope is somehow very broken. It would have to be introducing a > 3.3v transient into the circuit. Look at my edit (gotcha #0) -- that is much more likely to be your problem.Andrew Stonehttps://www.blogger.com/profile/04769383353032832222noreply@blogger.comtag:blogger.com,1999:blog-824114889882641219.post-42584568603843771082014-06-19T08:19:40.911-07:002014-06-19T08:19:40.911-07:00It is hard to know the exact problem and I think i...It is hard to know the exact problem and I think it depends on your physical topology. In my case, 4 chips were put on a daughter card and then 8 daughter cards were plugged into a simple "backplane". If you imagine the 3D shape of a single "clock" copper wire running through this, you can see how it forms a nice antenna, and travels through quite a few physical connectors. And the wire shares this space with significant current being PWMed through the LEDs (these wires become RF transmitters). While today's chips "sip" so little current that fanout is not a problem, Tom's suggestion to buffer the clock is a good one because it would break the antenna and regenerate the degraded signal into a clean digital waveform. At the same time, processors are so cheap -- if you have to add any chip it opens the question of adding a uP and just generating the signal rather than a buffer and regenerating it.Andrew Stonehttps://www.blogger.com/profile/04769383353032832222noreply@blogger.comtag:blogger.com,1999:blog-824114889882641219.post-11614339525400267232014-06-10T15:17:48.911-07:002014-06-10T15:17:48.911-07:00The issue is not fanout, as such. Fanout refers to...The issue is not fanout, as such. Fanout refers to the total ability of the output gate to drive current into the others. The issue with driving a long chain of TLCs from a single chip is that of degradation of the clock signal as it travels a longer distance, and the timing skew created by passing the serial data through a larger number of chips.LeoNerdhttps://www.blogger.com/profile/06161372680495361467noreply@blogger.comtag:blogger.com,1999:blog-824114889882641219.post-90571292443672542302014-05-20T01:31:34.610-07:002014-05-20T01:31:34.610-07:00hello,
i tried adding 1000 mifrofarads capacitor...hello, <br /><br />i tried adding 1000 mifrofarads capacitor to protect the ic when i turn on my scope (an old crt) but i still fry my 5940<br /><br />can you help me about this ?<br /><br />how do i know the right value to put in the circuit ? how do i calculate that ?<br /><br />thxAnonymoushttps://www.blogger.com/profile/07769168747678222203noreply@blogger.comtag:blogger.com,1999:blog-824114889882641219.post-1785562411698773062014-05-14T03:22:09.832-07:002014-05-14T03:22:09.832-07:00biggest crap IC ever...if you can find an on-the-g...biggest crap IC ever...if you can find an on-the-go appliance, prefer it to this unstable overheating shit Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-824114889882641219.post-44029026244865670362012-08-22T12:34:52.890-07:002012-08-22T12:34:52.890-07:00Issue number 6 is not a show stopper. Every digit...Issue number 6 is not a show stopper. Every digital output pin can only drive a certain number of digital input pins, called the "maximum fanout"--typically around 10 or 20. If you want to drive more than 10 inputs from one output, you have to add non-inverting buffers like the 74HC244. Then the Arduino can drive 10 buffers, and each buffer can drive 10 TLCs, and you can drive 100 chips at once.Tomhttps://www.blogger.com/profile/06026946142377348342noreply@blogger.com