AVR-Chat

erikc wrote:
> ----- Original Message -----
> From: "jay marante" <jaythesis@yahoo.com>
> To: <AVR-Chat@yahoogroups.com>
> Sent: Wednesday, April 07, 2004 04:29
> Subject: Re: [AVR-Chat] current in MCU and thte sleep mode
> at mega16 issue
>
>
>> any suggested DC-DC converter? i prefer from texas
> intruments or maxim. they're the only company i can ask for
> samples. it should be five volts output.
>>
>> thanks for the help.
>>
>> -jay


If you are using only an AVR with LCD and keyboard, I guess you don't need
to have exactly 5V for supply. The AVR stands lower voltages and also the
LCD.  Try to find out what is the minimum voltage you should supply for the
LCD to work properly. I guess anything above 4.2V will be ok.  Reducing VCC
will also reduce AVR current consumption, what extends battery life.

There is a little trick to use LCD and AVR to reduce current consumption.

It involves to supply the LCD with the minimum possible voltage, lets say
4.2V, then supply the AVR with the same 4.2V but with a series diode to its
vcc pin, capacitor to ground.  It reduces VCC to AVR to around 3.6V.
If the AVR stands that low voltage, it will run fine and the logic up level
of AVR, around 3.6V, will be considered "up" level by the LCD, so no
problem.

The main idea is that AVR reduces current consumption with low VCC, so,
inserting the diode in series, will also reduce its overall current
consumption.


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