Is that a 35V capacitor on the input? And the input can be as high as 35v?
Is that a 35V capacitor on the input? And the input can be as high as 35v?These converters are just over a buck each delivered. I don't imagine safety margins were at the top of their design priority list.
BTW, these modules can easily be used unchanged to generate a negative voltage. Just swap output and ground. And pay attention not to exceed the maximum 40 V, which in this configuration includes the output. E.g. the more negative the output the less the maximum input voltage can be.
The input and output grounds are common so they really aren't very useful for generating a negative voltage. The only way they'd work for that is if the system under power ground is isolated from the input power.
BTW, these modules can easily be used unchanged to generate a negative voltage. Just swap output and ground. And pay attention not to exceed the maximum 40 V, which in this configuration includes the output. E.g. the more negative the output the less the maximum input voltage can be.
The input and output grounds are common so they really aren't very useful for generating a negative voltage. The only way they'd work for that is if the system under power ground is isolated from the input power.
QuoteThe input and output grounds are common so they really aren't very useful for generating a negative voltage. The only way they'd work for that is if the system under power ground is isolated from the input power.
Is there a way to get + and - 15 v for op amps using 2 of these and one 19v source? If not how about using 2 input sources (laptop power supply)
http://www.ti.com/general/docs/lit/getliterature.tsp?baseLiteratureNumber=slua288&fileType=pdf
This shows you how to get a dual output out of a boost converter. I haven't had much success with this method, but I haven't put more than a couple of hours into it. I was also trying to power opamps with +/- 15V rails. If you get this working well, please share.
http://www.ti.com/general/docs/lit/getliterature.tsp?baseLiteratureNumber=slua288&fileType=pdf
This shows you how to get a dual output out of a boost converter. I haven't had much success with this method, but I haven't put more than a couple of hours into it. I was also trying to power opamps with +/- 15V rails. If you get this working well, please share.
And there's http://bitsavers.trailing-edge.com/pdf/national/_appNotes/AN-1081.pdf for the LM2596 That method works for most buck converters.
The question is, how much current do you need? The LM2596 is a 3A buck converter and the inverting circuit can deliver up to 0.7A. If you just need a few mA, there are better solutions.
Strange AN why does C1 have to be 63VDC while it only buffers 3.3VDC?
It's probably to make sure the esr is low enough. A 270uF 6.3v or 10v rated Nichion PL (which is already discontinued and replaced with Nichicon PM, so think how old this series is) would have current ripple too low or too high esr.
The application note is from 1999, in 2015 you could switch to a polymer capacitor, just make sure its technical specs match the values you calculate with the formulas in the application note.
QuoteThe question is, how much current do you need? The LM2596 is a 3A buck converter and the inverting circuit can deliver up to 0.7A. If you just need a few mA, there are better solutions.
A few mA as in experimenting (and learning) with op amps. The above circuits look complicated. I have not researched this out but I will look for a better solution. I wanted to use two laptop 19v power supplies and two bucks and reverse the leads - sounds like not. tks
A few mA as in experimenting (and learning) with op amps. The above circuits look complicated. I have not researched this out but I will look for a better solution. I wanted to use two laptop 19v power supplies and two bucks and reverse the leads - sounds like not. tks