Constant voltage from battery

Discussion in 'General Electronics Chat' started by zoom, Aug 1, 2015.

  1. zoom

    Thread Starter New Member

    Jul 11, 2014
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    As far as I know neither li-po batteries nor AA size 1.5 volts batteries supply constant voltage (Even not sure if there is any battery type that supply constant voltage).

    So, I am working on a project which will be powered by one of those options, either one cell 3.7 volts Li-po battery or 3-4 AA size batteries connected in series.

    I need to power an AVR (atmega328p) and a bluetooth module, which require constant voltage.

    What is the best option to sustain the same amount of voltage for those ICs ?
     
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Low-Dropout linear regulator, especially if you are using the ADC.

    Boost switch-mode regulator?
     
  3. tcmtech

    Well-Known Member

    Nov 4, 2013
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    What are you powering that needs a highly stable voltage source?
     
  4. zoom

    Thread Starter New Member

    Jul 11, 2014
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    As I mentioned in the original post, an AVR and a bluetooth module
     
  5. tcmtech

    Well-Known Member

    Nov 4, 2013
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    Okay. Now I have to call BS on the constant voltage requirement being the specs sheets for the atmega32 series devices are all listed to have a 1.8 - 5.5 working voltage range making them universally compatible with most any common 2 - 3 cell battery systems or single lithium cell and similar with the bluetooth modules of generic searches that all appear to also be designed to work with a ~1.8 - 3.8 volt power making them compatible with most any common 2 cell battery setup or single cell lithium cell systems. :rolleyes:
     
    #12 likes this.
  6. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Unless, as I said earlier, the TS is using the ADC in the mode where the ADC Reference voltage is derived from Vdd.
     
  7. Brownout

    Well-Known Member

    Jan 10, 2012
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    In addition, some specs, such as max clock frequency, are VCC dependent.
     
  8. Bordodynov

    Active Member

    May 20, 2015
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    I use a good chip boost converter L6920D.
    0.6 TO 5.5V OPERATING INPUT VOLTAGE
    1V START UP INPUT VOLTAGE
    3.3V AND 5V FIXED OR ADJUSTABLE
    OUTPUT VOLTAGE (2V UP TO 5.2V)
    REVERSE BATTERY PROTECTION
     
  9. tcmtech

    Well-Known Member

    Nov 4, 2013
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    Possible but a precision voltage reference IC would be a far easier and more efficient method to get a stable voltage source point for such functions.

    Given the info supplied I am still not buying it for that reason.
     
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