Author Topic: How do I create a negative 3V3 power supply from a 1 cell lipo?  (Read 1015 times)

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Offline Commander CloudTopic starter

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How do I create a negative 3V3 power supply from a 1 cell lipo?
« on: October 25, 2019, 06:53:48 pm »
Hello all,

I am a newbie teen designing a PCB for a project with a display, and the display I am set on using needs a -3V3 power source. How can I best and most efficiently create this power rail from a 1 cell lipo? (It is already protected and regulated to 3V3, fyi). Thanks in advance,

CommanderCloud.
« Last Edit: October 25, 2019, 07:18:33 pm by Commander Cloud »
 

Offline madires

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Re: How do I create a negative 3V3 power supply from a 1 cell lipo?
« Reply #1 on: October 25, 2019, 07:36:07 pm »
By an inverting DC/DC converter.
 
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Offline artag

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Re: How do I create a negative 3V3 power supply from a 1 cell lipo?
« Reply #2 on: October 25, 2019, 09:03:17 pm »
For the simple case of inverting a power rail (and if the current demand is small), you might be able to use a 7660

http://www.ti.com/product/TL7660
 

Offline tooki

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Re: How do I create a negative 3V3 power supply from a 1 cell lipo?
« Reply #3 on: October 25, 2019, 09:05:56 pm »
If it's an LCD that just needs the negative supply for the contrast pin, then you should also be able to use a cheap ICL7660 chip. Easy to work with and inexpensive, but limited to very, very small amounts of current. (Many 3.3V 1602 LCDs, as well as some large or extended-temperature versions, even at 5V, use an ICL7660 precisely to create the LCD contrast voltage.)

Edit: heh, great minds think alike, artag!
 

Offline iMo

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