Battery Saver Circuit

Discussion in 'General Electronics Chat' started by Sumner, Mar 10, 2005.

  1. Sumner

    Thread Starter New Member

    Mar 10, 2005
    2
    0
    I'm looking for a simple, very low power< 10uA, yet reliable circuit timer that will output a logic level after a period of about 10-20 minutes. I prefer not to use a 555 timer due to current restraints. Any ideas?
     
  2. pebe

    AAC Fanatic!

    Oct 11, 2004
    628
    3
    You could use a 4060. It is a CMOS 14stage binary counter with a built-in oscillator.
     
  3. mozikluv

    AAC Fanatic!

    Jan 22, 2004
    1,437
    1
    hi pebe,

    have not yet thoroughly studied the datasheet, if i were to use the 4060 as a timing device where would i put the timing components, is it between pin 10 & 11?

    thanx

    moz
     
  4. cyberhehe

    Well-Known Member

    Oct 6, 2004
    61
    0
    Use EPSON MCU with corresponding firmware. Can provide you and guarantee 5 years battery life using those 3V coin cell batteries. Halt current goes about 1uA. And even some of its family derivaties can provide you less than 1uA currents.

    But since its an MCU, it might be too complex for your ad hoc purpose.
     
  5. cyberhehe

    Well-Known Member

    Oct 6, 2004
    61
    0

    I have some configuration suggestion below for RC type oscillation.

    But if you are not so much concerned about currents, I would suggest to use a crystal oscillator or ceramic resonator for your purpose. It will provide you more accurate timing.
     
  6. Sumner

    Thread Starter New Member

    Mar 10, 2005
    2
    0


    Thanks for the suggestion.

    Since the application is going to be used around radio receivers I would prefer not to use anything with an oscillator thus preventing any low level signals in the radios. I was hoping for an RC design with a simple logic type device. I've seen one that uses a 4538B but I'm sure there's a better option out there. Any other suggestions?
     
  7. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    Sumner,

    Since you don't want to use an oscillator in your application, you must be planning on triggering this 10 to 20 minute time interval manually. For example you would trigger the start of a pulse with a momentary pushbutton and after the desired time period the pulse would return to its untriggered state.

    Does this correctly describe what you have in mind?

    If so, that sounds like a monostable multivibrator (one-shot) application to me. The 4538B is a cmos device that is capable of being configured to produce a single pulse of programmable duration when triggered and therefore you may have the solution you need.

    Good Luck.
     
  8. pebe

    AAC Fanatic!

    Oct 11, 2004
    628
    3
    The 4538 is a 'one-shot' where the delay is decided by the time constant of a singlw R and C. Hitherto, a TC of 1200 secs would have been unattainable but now that very large caps - of the order of Farads - are available, it would seem possible, though I have no experience in using them here.

    Alternatively the 4060 fed with an RC oscillator as cyberhehe has shown would also be OK. Note that the osc must run at about 14Hz to get 20 minutes after a count of 16384, so that rules out crystals or ceramic resonators. If you want the RC values worked out I will do so. It should not prove noisy at RF.
     
Loading...