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How would you power 4x separate isolated RS485 transceivers?
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jneudorf:
I am considering using 4x Recom RFMM-0505S DC-DC modules ($1.31 each at Mouser) for power, and Analog's ADUM1201ARZ-RL7 ($0.65 at LCSC) to get the signal across.
I'd rather just make some isolated converter like in http://www.ti.com/lit/ug/tidu590/tidu590.pdf but the Wurth 760390014 only has a single output and costs $1.25 on its own.
Should I consider using Coiltronics Versa-Pac or Coil-Craft Hex-Path HPH1 series, or are there other options that might work? I can't find Asian sources that seem similar to these.
The context is bi-directional DMX/RDM at 250kbps.
David Hess:
I would use a pair of trifillar wound transformers in an inverter circuit. This only requires one simple driver.
T3sl4co1l:
Hex-Path is a good option, mind the isolation is only a hundred volts or whatever -- fine for signal purposes, but beware of ESD damaging it. (You could bridge grounds with a little MOV or TVS to control this.)
If I needed more, or lower cost, I might consider planar transformers -- do it all in the PCB itself. This is a more advanced option though, as you're doing the transformer design yourself, and you don't have many protos to iterate on.
--- Quote from: David Hess on December 19, 2019, 01:10:56 am ---I would use a pair of trifillar wound transformers in an inverter circuit. This only requires one simple driver.
--- End quote ---
An interesting option would be to abuse some CMCs (data or data/power type), driven with a few logic gates or a gate driver, to make a simple chopper; FWB the secondaries and there you go. Put a bunch of primaries in parallel -- one for each channel -- not really a need for multifilar, the dual-line kind (which are usually bifilar) should be good enough. Downside is the lack of current limiting, which may have workarounds (e.g., use a motor-driver H-bridge chip, and use its internal current limiting, or supply it with a current limiter), and of course the cross-regulation is limited by leakage inductance.
Tim
rvalente:
This topic is very similar to yours,
https://www.eevblog.com/forum/projects/isolated-5v-5-10ma-supply/msg2816550/#msg2816550
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