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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>Main power and battery power selection circuit</title><link>https://devzone.nordicsemi.com/f/nordic-q-a/85473/main-power-and-battery-power-selection-circuit</link><description>Hi, 
 I&amp;#39;m using nRF52805. 
 The main power is 3.3V LDO output. 
 When main power is out, the battery(3V, Coin battery) should be a power source of nRF52805. 
 But, when battery power is used, nRF52805 will enter into sleep mode while RTC is active. 
</description><dc:language>en-US</dc:language><generator>Telligent Community 13</generator><lastBuildDate>Tue, 08 Mar 2022 14:35:51 GMT</lastBuildDate><atom:link rel="self" type="application/rss+xml" href="https://devzone.nordicsemi.com/f/nordic-q-a/85473/main-power-and-battery-power-selection-circuit" /><item><title>RE: Main power and battery power selection circuit</title><link>https://devzone.nordicsemi.com/thread/356935?ContentTypeID=1</link><pubDate>Tue, 08 Mar 2022 14:35:51 GMT</pubDate><guid isPermaLink="false">137ad170-7792-4731-bb38-c0d22fbe4515:7c617903-fa1f-40f5-9652-080089d6346e</guid><dc:creator>Priyanka</dc:creator><description>&lt;p&gt;Hi,&lt;/p&gt;
&lt;p&gt;In order to switch the supply, you could use a relay circuit, but a hot swap should be properly tested as sometimes this can result in a brown-out reset (depending on your device).&lt;/p&gt;
&lt;p&gt;You can take a look at the &lt;a href="https://www.analog.com/en/analog-dialogue/articles/understanding-hot-swap.html"&gt;Hot Swap controllers&lt;/a&gt; too.&lt;/p&gt;
&lt;p&gt;As for sleep mode, if you want your system to go to sleep when mains are out, you could have a check at the GPIO pins. So if the main power is active, then the GPIO pins are high and system can come out form sleep mode and vice versa.&lt;/p&gt;
&lt;p&gt;But if you want to go to sleep whenever it is battery powered, then you should define some way for the system to understand this switch from mains to battery.&amp;nbsp;But for this, you might have to use an external circuit for this, maybe even a custom IC for this.&lt;/p&gt;
&lt;p&gt;Regards,&lt;/p&gt;
&lt;p&gt;Priyanka&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item></channel></rss>