Author Topic: pulse transformer vs digital gate drive for H-bridge?  (Read 3014 times)

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Offline SuperJeepTopic starter

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pulse transformer vs digital gate drive for H-bridge?
« on: November 26, 2013, 04:01:14 pm »
Hi,

All the application notes I have read on this topic seem to suggest these digital gate drive solutions (ADUM3223 for example)
are an amazing substitute for a traditional pulse transformer-not to mention how much more simplified
the control logic is.

My question is: Does anyone have any reasons or thoughts as to why these should not be used as a replacement
to a pulse transformer driving Full H-bridge(regards to isolation/safety)? The type of inverter in the application im considering
is a bipolar square wave generator with <500V high side and approx 1.5A max output.

Thank you for any thoughts/opinions on the matter!
« Last Edit: November 26, 2013, 04:04:49 pm by SuperJeep »
 

Offline penfold

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Re: pulse transformer vs digital gate drive for H-bridge?
« Reply #1 on: November 26, 2013, 08:20:18 pm »
The only real point I can think of is part availability.  You can pretty much guarantee that 10 years down the line mankind will still have the capability to manufacture a pulse transformer, whether it be in house or externally as a custom part, but its often difficult to tell how long an IC will continue to be produced and how the prices will change in the long term.

Further to that, a pulse transformer is easy to manufacture with very high voltage withstand but is also quite predictable under faults.  If a crack forms in an IC coupler then there's potential for some unexpected breakdown in isolation, if by some bizarre coincidence all the insulation disappeared from the wire of a transformer then there is still a physical separation between the windings,
 

Offline SuperJeepTopic starter

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Re: pulse transformer vs digital gate drive for H-bridge?
« Reply #2 on: November 28, 2013, 04:06:52 pm »
Thank you for the feedback. I appreciate it. I have decided to move forward with this digital isolator because I have an isolated supply available for the output. Its functionality is somewhat like an integrated pulse transformer only the digital control only requires a single pwm input source (and a second one to complement it in a full bridge design). I just needed to scope out some opinions on the matter because it's always good to see things from a different perspective. Thanks again guys!
 


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