Hello I am Vijay.
I have received an assignment in my college. The assignment description is as follows:
Product Design Electronics(ULN Driver)
Objective:
Design a complete electronic circuit that utilizes an ATmega328P micro controller to
control and power a 12V LED strip using a ULN2003 Darling-ton transistor array
driver IC, with the primary input power sourced from a 48V battery.
Expected Deliverables:
Circuit Diagram:
■ Complete schematic presented in A4 sheet format.
■ The circuit should clearly demonstrate all connections between
components, including power supply regulation, micro controller I/O,
driver IC inputs/outputs, and LED load interface.
Power Management:
■ Proper voltage step-down mechanism from 48V to 12V (for the LED
strip).
■ Additional regulation to provide 5V supply to the ATmega328P and
other logic-level components.
Component Labeling and Notation:
■ Use standard electronics naming conventions (e.g., U1, R1, C1, D1).
■ Label all connections (e.g., VCC, GND, INx, OUTx, COM).
■ Indicate signal direction where applicable.
Design Considerations:
■ Ensure all power grounds are properly referenced (common ground).
■ Include protection elements where necessary (e.g., fuses, bypass
capacitors, fly-back protection).
■ Clearly show the interfacing between ATmega328P, ULN2003, and the
LED strip.
Expected Output
● Schematics.
I have few doubts reagarding the assignment.
How to convert 48V DC to 12V DC? Do I need to use a readymade buck converter like the LM5118 or LM2596HVS or do I need to redraw a new circuit for the buck converter?
Will it be correct to connect the 12V output of buck converter to ULN2003 driver and to 12V LED strip. Won't there be any voltage drop for the 12V LED strip?
I couldn't get the footprint for 12V led strip. Can I connect 8 LEDs (Each 1.5V) in an array and represent it as 12V LED strip?
I don't need any kind of 3D PCB design for it. My only aim is to show proper 2D Schematic connection. It should also work if implemented using hardware components.
I do not think the forum can answer that question for you. Certainly you could do either of those things but whether you would get fewer marks or penalties for using a ready made module over a bare chip, only the college will know.
You would not connect the 12V power to the ULN, only to the LED strip. The ground wire from the 12V power must be connected to the ground of all the other components. There is no need to connect the COM pin of the ULN to anything in this project.
12V LED strips usually contain groups of 3 or maybe 4 LEDs in series, each group having a current limiting resistor. If your strip contains 30 LEDs, there will probably be 10 groups, each group having 3 LEDs and a resistor.
Is this another AI generated project? If so this is the second we have had, and be aware that AI is not all it is cracked up to be.
While each driver in a ULN2003 is capable of driving a 500mA load thermal considerations restrain how much power can be driven at any one time from the chip.
In fact the sum of current that can be passed through this chip at any one time is only about 650mA. So I would have a word with whoever set the assignment and inform him / her about this. Other wise you are being set up to fail.
Hi
There is no marks or grades for this assignment. We can choose any approach for the 48V to 12V conversion. The only purpose is to show how do we represent this in the Schematic diagram.
Ok, then it would be simpler to use a buck converter module. You would simply represent this on the schematic as a box, labelled to indicate it's purpose, and showing and labelling the terminals it has.
By the same principal, it would be easier to use a module containing an atmega328, such as an Arduino Nano. Such a module would contain it's own voltage regulator and could be powered by 12V, removing the need for a separate 12V to 5V converter circuit.
Sorry I had a tutorial on this but my internet service provider pulled the plug on the free web space they offered and took my whole site off line and didn't even offer a web redirection service. Tech support says every time they suggest this the CEO of the company says it will cost hundreds of thousand pounds to implement.
This file
See post #10 for the working file.
When un-compressed you can double click the .HTML file and it should load just that page into your default browser. Let me know if you have any problems with this. Of course none of the links off this page will work.
Thanks, I had heard of this but never used it before. You can navigate the web site just as before which is good.
Being an archived site some of the personal information is out of date. Since my stroke I no-longer am able to give talks or undertake any commissions.
I just had a quick look and most of it is there. There are two short comings I spotted.
It seems that often links to accompanied software files are missing. So if you want a specific software bundle for a project you will have to ask me on the forum to supply it to you.
The links to my videos on Vimeo do not work because the access to Vimeo has changes since the page was archived, so you can't just click on a video to see it. Fortunately the videos are still on Vimeo and can be accessed from outside the archive.
To access the site from the start then use this link:- Welcome
Thanks again for telling me about this.
Further exploration shows the site is not all there and some sections do not exist and in others the formatting is wrong.
This "any Electrical Vehicle" company is going to have some difficulty choosing between all the interview candidates who provide excellent but identical answers to the "ULN2003" puzzle.
