Re: [PIC] High Power Consumption for a Battery operated application - Electronic Safe

On Wed, 8 Jan 2025 at 21:48, David C Brown <[email protected]> wrote:

> Perhaps reducing the supply voltage to 4.5v (3 Cells) would help.
> The PIC16F88 is specified down to 4.0 volts up to 20MHz
> And the LF version down to 2.0 volts up to 4MHz.
> I have powered F88s from a 3R12 battery (the "flat" torch battery) quite
> succesfully
>
>>
>> For reference.
Alkaline cells start at 1.65V (maybe a tad more).
This falls witty storage to under1.6V>
Below 1.55V a new battery is usually very old. (Years).

Cells  are almost fully exhausted at 1.0V (even 1.1V) but have some energy
left down to about 0.9V.

So say you use 1V as the lowest operating voltage per cell and 1.65 as the
max for safety that gives.
3 cells: 3V - 5V
4 cells: 4V - 6.5V

3 cells drops under 4V at 1.33V/cell (quite a lot of life) but happily
meets the 2V level very well.

Depending on what Vdd_max you can tolerate a low Iq LDO may be in order.
Buying from eg LCSC cost can be very low - usually far below US
supplier prices for the same parts - and they are close to as reputable as
more usually-favoured suppliers.

At the risk of abuse :-) :-(  - I am using Ardu inos with LGT8F328P
processors.
They operate at 1.8V and 20 MHZ (!!!).
They are low cost, come "ready made", an d they "just work".
With or without USB.
(Many come with 5V regulators and some with 3V3.
I'm running them direct from 1 x LiIon cell with an LDO to clip thge cell
Vmax to keep Vdd in spec not for the processor but for "3V" peripherals.
Not quite as efficient as a buck converter to get the battery energy when
mostly charged but "close enough".

[I dislike the Arduino environment and CPP generally BUT the available
libraries (especially LORA and NRF... make it a good compromise choice.




 Russell