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designing a battery operated device without a regulator

Started by John Smith January 14, 2004
What are some issues associated with using vs. not using a regulator
when designing a consumer electronic device that runs off 2x1.5v
alkalines?

Obviously cost is the issue here. Do most ultra-cheap electronic
devices intended to run off replaceable batteries have regulators?
What drives the decision?

Thanks.
"John Smith" <googlegroups.20.bennny@neverbox.com> schreef in bericht
news:ccd3f595.0401140819.48975061@posting.google.com...
> What are some issues associated with using vs. not using a regulator > when designing a consumer electronic device that runs off 2x1.5v > alkalines? > > Obviously cost is the issue here. Do most ultra-cheap electronic > devices intended to run off replaceable batteries have regulators? > What drives the decision?
The neccesity, I guess. If it isn't needed... A small PIC may run happily on 3.3V (fresh alkalines) down to 2V. But if the device is powered by a 9V (for some other circuitry) some form of regulation is needed. If the current is stable and predictable it may be a simple resistor! -- Thanks, Frank. (remove 'x' and 'invalid' when replying by email)
John Smith wrote:

> What are some issues associated with using vs. not using a regulator > when designing a consumer electronic device that runs off 2x1.5v > alkalines? > > Obviously cost is the issue here. Do most ultra-cheap electronic > devices intended to run off replaceable batteries have regulators? > What drives the decision? > > Thanks.
There are lot's of issues but they are very application dependent. The obvious ones are battery voltage versus time, battery volts versus current, peak to average current ratio and how all of these affect the electronic devices connected to the batteries. The last battery powered development I was involved in was a CO2 monitor which needed to meet both UL and BS specifications for five years when operated from a PP3. To meet these specs you have to sample at least once per minute and be able to operate an 80dB SPL sounder for 30 minutes at then end of five years. Perhaps the biggest issue is the inability/unwillingness of the battery manufacturers to commit to any battery performance over these timescales. Ian
"Frank Bemelman" <fbemelx@euronet.invalid.nl> wrote in
news:40056e69$0$35155$1b62eedf@news.euronet.nl: 

> run happily on 3.3V (fresh alkalines) down to 2V. But if the > device is powered by a 9V (for some other circuitry) some form > of regulation is needed. If the current is stable and predictable > it may be a simple resistor!
Or diode. -- - Mark -> --