Need a regulator or step-down circuit that steps a battery down from 7.2v to 4.7v

I want to step down a 7.2v lithium ion (Li-ion) camcorder battery to 4.7v to power my digital camera for long periods of time, can someone send me schematic via email or post one that fits my needs. Thank you for help with this. I forgot the email address: please send to snipped-for-privacy@juno.com of snipped-for-privacy@juno.com .

Reply to
IdeaMan
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power my digital camera for long periods of

Thank you for help with this. Simple and cheap; since you don't indicate a peak current requirement, you'll have to calculate a value for R.

Any 3 diodes capable of handling the max expected current will work; yes, the diode polarity is correct as drawn.

R ___

7.2v in-|___|-+-----o ~4.5v out | V D1 - | | V D2 - | | V D3 - | GND

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Reply to
Randy Day

power my digital camera for long periods of

Thank you for help with this. I forgot the

You come here to read the answer...

There are tons of switchers available from various manufacturers. texasinstruments, lineartech, ...

Rene

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Reply to
Rene Tschaggelar

The diode circuit as drawn will only have about 2.1 volts output.

Reply to
amdx

Why go to a shunt regulator? It wastes current in the diode string paralleling your load. A "series" diode regulator will only see the load current:

Gnd---+7.2v--->|--->|--->|--->|---+4.7---Gnd

This could be a mixture of standard silicon diodes and schottky diodes (with appropriate current and power ratings) to get the right voltage drop.

Reply to
Ken Moffett

DOH!!!

What was I thinking?

Reply to
Randy Day

I suggest you were probably thinking " why did I drink so much beer last night" or similar.

Reply to
Mjolinor

snipped-for-privacy@juno.com .

Reply to
Tam/WB2TT

Very true!

Reply to
Ken Moffett

"Roger Gt" wrote in message news:... : : "IdeaMan"

Reply to
Roger Gt

A SCHEMATIC WAS Send to the EBS group, IT didn't make it yet! "Roger Gt" wrote in message news:pNRkc.58817$ snipped-for-privacy@newssvr25.news.prodigy.com... : : "Roger Gt" wrote in message news:... : : : : "IdeaMan"

Reply to
Roger Gt

I agree. A switching regulator would be best in this case. A digital camera is a relatively large load for a battery, and you want to get all the efficiency you can. Diodes or linear regulators will waste alot of energy as heat.

BRW

power my digital camera for long periods of

Thank you for help with this. I forgot the

Reply to
Bennet Williams

use a standard Post 5 volt regulator with 1 silicon diode in series on the output, this will give you a drop enough to put the final output to aprox 4.6 volts. P.S. the anode side will be connected to the Post output and the cathode would be your final out.. you may want to place a bypass cap at the output on the Post reg and cathode side of the diode.

IdeaMan wrote:

power my digital camera for long periods of

Thank you for help with this. I forgot the

Reply to
Jamie

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