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I want to design a DC power supply for my Intel NUC small form factor PC using a battery.

The data-sheet for the PC:

https://www.intel.com/content/dam/support/us/en/documents/boardsandkits/D53427RKE_TechProdSpec05.pdf

There are internal power supply connectors and external DC jack. Both support only 19V. I have a LiFePO4 battery that can supply 12 volts (at 10A max continuous discharge)

The input required for the PC is 19V drawing upto 3.42A

I am thinking of connecting a DC-DC step-up module at the battery output and supply the output to PC. The characteristics of the step-up module from its data sheet:

Input voltage : DC 10 - 32 V 
Output Voltage : DC 12-35 V(Adjustable) 
Output Current : 6A(MAX)
Input current : 10A (MAX) (more than 10A please strengthen heatsink)  
Output Power : 100W (MAX)
Conversion efficiency : 94% (when Input 19V 2.5A Output 16V, Reference)
Output ripple : 2% (MAX)
Working Temperature : industrial (- 40 ° c to +85 °c) ( environmental temperature, more than 40 degrees, please reduce power to use, or - enhance cooling).
Full-Load temperature : 45 degrees
No-load current : 25mA typical
Voltage regulation :  ± 0.5%
Load regulation :   ± 0.5%
Dynamic response speed :  200us 5%

Will the step-up-module's output ripple affect the PC? How can I reduce the ripple if it is a problem?

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  • \$\begingroup\$ This question is off-topic because you are asking if an off-the-shelf part from what I would call a source of less-than perfect reputation AND originating from a manufacturer of unknown quality, can be trusted without knowledge of the part's design or even a decent data sheet. Note that this is a fairly standard reason to vote to close and is covered in a link you can open if you click on the "close" button. \$\endgroup\$
    – Andy aka
    Jan 23, 2019 at 12:14
  • \$\begingroup\$ @Andyaka Thanks for the heads-up!. Removed the link, I have added the data supplied by them. \$\endgroup\$ Jan 23, 2019 at 12:23
  • \$\begingroup\$ Why consumer electronics questions are (usually) off-topic \$\endgroup\$
    – Andy aka
    Jan 23, 2019 at 13:01
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    \$\begingroup\$ I'd check if the PSU in the NUC can be replaced, because it is likely that the only reason they use 19V on input is that 19V bricks are cheap, because they are a standard laptop charging voltage, and that is because this allows laptops to charge 4S configurations with a step-down converter. The 4S configuration in turn is common because it allows powering the 12V rail with a step-down until the battery is empty. So my suspicion is that the NUC does not really need 19V for anything, and you'd be losing a lot of power stepping the voltage up and back down again. \$\endgroup\$ Jan 23, 2019 at 14:05
  • \$\begingroup\$ The board is tiny, I am not sure if I can hack it to use a lower voltage, of course don't want to brick the NUC :) \$\endgroup\$ Jan 23, 2019 at 16:37

1 Answer 1

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Without knowing anything about the manufacturer, the DC/DC module looks good on paper. Conversion efficiency will be down around 80% or less in your application. At 80%, the input current from the battery estimates at 6.8 A. Note that converters like this one usually require external capacitors on the input and output to reduce conducted and radiated noise.

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  • \$\begingroup\$ Can you point to any circuits in which Capacitors are used for this purpose? \$\endgroup\$ Jan 24, 2019 at 3:07
  • \$\begingroup\$ I think the cap should be in parallel am I right? \$\endgroup\$ Jan 24, 2019 at 3:17
  • \$\begingroup\$ Almost every switching power supply ever has input and output filters. Google 'switching power supply schematic'. \$\endgroup\$
    – AnalogKid
    Jan 24, 2019 at 4:20

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