Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
With the LM393, the problem is that when I put a 4,7k resistor between the output and the 24V the circuit goes to 24% efficiency, but without it gets 67%. Should I get the pull up from the 48V or from the 24V that is feeding the comparator? I used other resistor values but no success
Some news, I am still searching for the higher inductance inductor, so I am trying to work on BradtheRad's design, I soldered it on a board, but something strange is happening. As you can see on the circuit, there is a resistor on the output of the comparator but the circuit works, with 67%...
Sorry my bad, I got 11V on the output, probably because of the zener diodes (I ran out of 12V because I damaged the other in a test, so I bought 13V, now the regulation is 11V), and the local stores have no more of them. I ordered more on the internet, just waiting now. And I think my multimeter...
I am using a choke for 2.2A, more than enough I guess, but I am using two 220uH 2.2A chokes in series to get 440uH, that should be why I am getting a bit less efficiency. I tried to increase inductance to make it work with the 50mA load but no success so far.
I replaced the UA741 with a LM393, I still need to put the series diodes?
- - - Updated - - -
Working Like a charm E-Design! At 0,5A 0,13A input 0,5A output, best efficiency until now. Do you think is there any way to make it work with low loads like 50mA? A high gain transistor maybe...
The efficiency is bad because the circuit is no identical, I will get the components for identical circuit now, My only problem will be to find a 470uH inductor, but I have 2 220uH I will put in series
Got it to work! Now I got the circuit to work, with low efficiency but working, 0,5A I get some bad eff. but I think it's only tweaking the values. One interesting thing I noticed, is with a 50mA load I got the circuit to not oscillate, do you think there is a way of making it better at small...
From the beginning I never stopped considering the fact that I could be making some mistakes. If it works for it must work for me, I will buy brand new components and try again! Thank you very much E-Design for the effort you put in helping me, as soon as I can I will put results
Yes I can, but I don't think you will find what you are searching for. I downloaded TINA-TI and some simulations worked, this especific one I don't think so, maybe the waveforms are fine but not the frequency, I will send the pictures so you can understand what I am talkling about. The...
Helo Akanimo, the ambient temperature can be measured using a specific circuit that changes it's characteristics with the temperature, but I don't think you will need to worry about that, take the temperature of the place you will put your circuit, leave any component that can get hot away and...
I couldn't edit my last post, I don't know why, but I made some changes and got new good efficiency, 48V and 0,15A on the input and 11,8V 0,5A on output, 82% efficiency approx.. Can be better I guess, changing for a comparator and using a better transistor as pull-down (I only have one 2N2222...
So, I switched the PNP transistor for an P Channel MOSFET, now I can hear the switching noise but it is a very high-pitched sound, however with a 0,6A load I got 0,6A on the input, so my efficiency is something around 25%. This is the actual circuit I am using. I will try now to change some...
I mistakenly said about changing the NPN transistor, I meant changing the PNP transistor for a P Channel MOSFET to make the switching better, I would work right? And the reason I used a voltage divisor was beacuse the 48V would be too much for the OpAmp so I divided the output voltage just in...
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
