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<?xml-stylesheet type="text/xsl" href="https://devzone.nordicsemi.com/cfs-file/__key/system/syndication/rss.xsl" media="screen"?><rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:slash="http://purl.org/rss/1.0/modules/slash/" xmlns:wfw="http://wellformedweb.org/CommentAPI/" xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>intrinsic safety DCDC inductor</title><link>https://devzone.nordicsemi.com/f/nordic-q-a/20845/intrinsic-safety-dcdc-inductor</link><description>Hi, 
 Assume the internal FET(s) that bucks the voltage down for the DC/DC got stuck on. I would like to calculate the current through the DC/DC inductor when it reaches it&amp;#39;s DC state. To do this I need know the resistance characteristics of the current</description><dc:language>en-US</dc:language><generator>Telligent Community 13</generator><lastBuildDate>Mon, 27 Mar 2017 19:22:42 GMT</lastBuildDate><atom:link rel="self" type="application/rss+xml" href="https://devzone.nordicsemi.com/f/nordic-q-a/20845/intrinsic-safety-dcdc-inductor" /><item><title>RE: intrinsic safety DCDC inductor</title><link>https://devzone.nordicsemi.com/thread/81403?ContentTypeID=1</link><pubDate>Mon, 27 Mar 2017 19:22:42 GMT</pubDate><guid isPermaLink="false">137ad170-7792-4731-bb38-c0d22fbe4515:d287baf3-2ffe-4258-abaf-dfc56db4f7e9</guid><dc:creator>AmbystomaLabs</dc:creator><description>&lt;p&gt;A buck converter is a series configuration.  There is no quiescent current if the fet is stuck on.  If it were to stay on the 1.8V rail would rise to VDD through a time constant determined by the 1.8V load activity, to a minor extent the FET Rds since it is so small and the size of the buck inductor.  After this the 1.8V rail would forever be at VDD.
This would likely destroy the components sitting on the 1.8V rail, but that is really a different problem.
For reference, below is the wiki drawing of a classic buck converter:&lt;/p&gt;
&lt;p&gt;&lt;img src="https://devzone.nordicsemi.com/cfs-file/__key/communityserver-discussions-components-files/4/300px_2D00_Buck_5F00_circuit_5F00_diagram.png" alt="image description" /&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item></channel></rss>