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SanGaL
Jul26-04, 11:02 PM
hi everyone :smile:

i am a 2nd year engineering student....i have a problem here... :confused: i was asked to build a 3V to 5V dc-dc boost converter but i have no idea how to build it... i have search all over the webs but the information they gave me ain't what i want.

i was asked to build a step up from 3V to 5V converter using only discreet components. I can't uses switches too... :frown: The current must be within 30mA.

I would appreciate it very much if anyone can help me... :wink:

Thankz :biggrin:
Heathcliff
Jul27-04, 01:54 AM
Take a 3V battery and connect a 2V battery in series.
SanGaL
Jul27-04, 02:01 AM
i can only use two 1.6V batteries in the circuit.
Heathcliff
Jul27-04, 02:10 AM
http://www.powerdesigners.com/InfoWeb/design_center/articles/DC-DC/converter.shtm . This help?
SanGaL
Jul27-04, 02:16 AM
hehe... i've tried building this circuit already but don't know why it can't work.
is it because of the values i use for the components?
i've used:
1)150uH inductor
2)BC817-25 transistor
3)0.47uF cap
4)BAS85 diode

can give suggestions on what components i can use?
Thanz =)
Heathcliff
Jul27-04, 02:43 AM
Got me there. My experience consists in building a capacitive discharge ignition system from a kit forty years ago that had a 12 to 400V dc-dc converter in it. Put out a hell of a spark--actually advanced the timing.
SanGaL
Jul27-04, 02:48 AM
Then how can i calculate the values of the components i need to boost the voltage from 3V to 5V??
Cliff_J
Jul27-04, 07:27 AM
Are you certain your timing circuit is sending pulses to the transistor that saturate it?

How much of a load are you placing across the outputs of the boost converter?

What does the behavior across the components look like on a scope?

Cliff
MAYJ
Jun10-07, 08:15 PM
I was searching for a single component to do this and ran across your request.
Try the attached circuit. It is an astable multivibrator tied to a voltage doubler.
It's very straight forward.
Mayj
ranger
Jun10-07, 08:20 PM
I was searching for a single component to do this and ran across your request.
Try the attached circuit. It is an astable multivibrator tied to a voltage doubler.
It's very straight forward.
Mayj
This thread is going to be 3 years old soon.

BTW, you forgot to attach the circuit for those who may interested in it.
hmms
Jan12-08, 04:53 AM
try this link
http://www.instructables.com/id/MintyBoost!---Small-battery-powered-USB-charger/