Silent Jack Posted July 21, 2010 Author Report Share Posted July 21, 2010 I appreciate you reformatting the image to a more suitable file format so that it will be of more help to others reading our ongoing discussion. How would you modify the circuit to use that portion of the LM393 as you propose? I was unaware this was possible. Also, since the bank is now a fraction of the size it was originally designed at, I was considering adding a second identical bank and charging it alongside the other so as to reduce service downtime. What is the simplest way to accomplish this? Quote Link to comment Share on other sites More sharing options...
Hero999 Posted July 21, 2010 Report Share Posted July 21, 2010 The LM393 can be configured as an oscillator so a 555 is not needed, here's an example.Two capacitor banks can easilly be connected in parallel. Quote Link to comment Share on other sites More sharing options...
Silent Jack Posted July 25, 2010 Author Report Share Posted July 25, 2010 Perhaps you could explain a little of how this works? Also, what do all those open ends connect to in your diagram? Quote Link to comment Share on other sites More sharing options...
Hero999 Posted July 25, 2010 Report Share Posted July 25, 2010 What open ends? There's only one which is the output and that's because I forgot to label it.U1 is an oscillator and performs exactly the same function as the 555 in your circuit, look up Schmitt trigger comparator oscillator on Google for more information.U2 is a comparator which shuts off M1 when the output voltage is high enough, similar to the comparator in your circuit which stops the 555 oscillating.V2 represents a voltage reference which can be an LM78L05, TL431 or just a potential divider from the 12V power supply. Quote Link to comment Share on other sites More sharing options...
Silent Jack Posted July 25, 2010 Author Report Share Posted July 25, 2010 Thank you for the additional explaination, it is helping. The part I asked about being "open" are the highlighted areas of this image. I don't recognize this notation or symbol. I've made certain to keep it in the more legible PNG format that you recommended. Overall, I am endevouring to improve my overall understanding of symbols, circuit diagrams, and the flow and function of the circuit and components. I appreciate your continued efforts in aiding my ellucidation. Quote Link to comment Share on other sites More sharing options...
Hero999 Posted July 25, 2010 Report Share Posted July 25, 2010 I tell you what: guess?Even if you don't understand the symbol, it shouldn't be hard to figure it out by looking at similar schematics. Quote Link to comment Share on other sites More sharing options...
Silent Jack Posted July 25, 2010 Author Report Share Posted July 25, 2010 Common ground, seems a sensible solution. Quote Link to comment Share on other sites More sharing options...
Silent Jack Posted July 29, 2010 Author Report Share Posted July 29, 2010 Been reading through data sheets and IC layouts/circuit diagrams. Would pins 1-4 be one half and pins 5-8 be the available portion that you mentioned substituting for the 555?Went back and added the diagram I was referencing. Thought it might help. Quote Link to comment Share on other sites More sharing options...
Hero999 Posted July 29, 2010 Report Share Posted July 29, 2010 Please think more before asking questions. Quote Link to comment Share on other sites More sharing options...
Silent Jack Posted July 29, 2010 Author Report Share Posted July 29, 2010 Well, the diagram you posted has two LM393's much like the one I am working from. Mine labels the pins used on each and uses differing symbols, suggesting different purpose. U1, in my diagram has pins 8 & 4 connected; these are designated as Vcc & gnd respectively. While U1.1 specifies that pins 1, 2 & 3 are connected; designated Output1, IN1(-) & IN1(+). I note, based on the diagram that pins 1, 2 & 3 seem to correspond to pins 7, 6 & 5. If these two pin sets are capable of the same things, and if as it appears there is no overlap in pin usuage, why are two used? Would it not be possible to use a single chip to perform the needed functions? Also, which portion of the IC supplants the use of the 555 you mentioned? Quote Link to comment Share on other sites More sharing options...
Hero999 Posted July 29, 2010 Report Share Posted July 29, 2010 Of course a single chip can be used, there are only two on my diagram because LTSpice uses separate symbols with their own power supply pins. Quote Link to comment Share on other sites More sharing options...
Silent Jack Posted August 1, 2010 Author Report Share Posted August 1, 2010 Unless it were a topology issue. I'll work on redrafting it and see how it works out. Quote Link to comment Share on other sites More sharing options...
Silent Jack Posted August 2, 2010 Author Report Share Posted August 2, 2010 Another thought. How much affect will the inductor have on nearby ICs and semiconductors? Should I do anything to isolate or shield it? And if the affects are significant enough on certain components, what is the most effective way to rearrange them? Quote Link to comment Share on other sites More sharing options...
Hero999 Posted August 2, 2010 Report Share Posted August 2, 2010 Please provide more information. Quote Link to comment Share on other sites More sharing options...
Silent Jack Posted September 13, 2010 Author Report Share Posted September 13, 2010 Basically I was looking to avoid arcing or magnetic inductance negatively affecting other nearby components or traces. Is there a standard recommended separation tolerance for given components? Quote Link to comment Share on other sites More sharing options...
Hero999 Posted September 13, 2010 Report Share Posted September 13, 2010 There are no hard and fast rules for EMC.Use a proper shielded inductor designed for use in SMPSes and keep the traces on the feedback section as short as possible and away from the inductor and MOSFET traces.There shouldn't be any arcing because the voltage is too low. Quote Link to comment Share on other sites More sharing options...
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