How to Build a 3V to 5V DC-DC Boost Converter with Discrete Components?

[SanGaL]

hi everyone

i am a 2nd year engineering student...i have a problem here... 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... The current must be within 30mA.

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

Thankz

 

[Heathcliff]

Take a 3V battery and connect a 2V battery in series.

 

[SanGaL]

i can only use two 1.6V batteries in the circuit.

 

[Heathcliff]

http://www.powerdesigners.com/InfoWeb/design_center/articles/DC-DC/converter.shtm . This help?

 

[SanGaL]

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]

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]

Then how can i calculate the values of the components i need to boost the voltage from 3V to 5V??

 

[Cliff_J]

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]

try this i requires no inductors

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]

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]

try this instructable

try this link
http://www.instructables.com/id/MintyBoost!---Small-battery-powered-USB-charger/