Boost converter circuit

Thread Starter

Miracletech

Joined Nov 15, 2019
52
I want to create a simple boost converter circuit to boost a 3.7v battery to 5v dc voltage with npn transistors.(for a project). Please does anyone have a schematic?

i have bc547 transistors, bc 337 transistors, in4007 diodes, 1000uf 10 v capacitors, 220 uh inductors and many others.

Thanks in advance!
 

jpanhalt

Joined Jan 18, 2008
8,116
And please jpanhalt what should i remove or add in your circuit sir?
????
1) Which circuit? I presented two to you.
2) Neither is my circuit; although, I had saved both in my files as "interesting." Black's is particularly simple.
3) If you just want to solder stuff together, there are easier ways toget what you want than discrete components. If you want to study and learn, then do some experimentation. The Roman Black link has a lot of information to get you started.
 

BobaMosfet

Joined Jul 1, 2009
839
I want to create a simple boost converter circuit to boost a 3.7v battery to 5v dc voltage with npn transistors.(for a project). Please does anyone have a schematic?

i have bc547 transistors, bc 337 transistors, in4007 diodes, 1000uf 10 v capacitors, 220 uh inductors and many others.

Thanks in advance!
Use a MC34063A as your booster. It is the most ubiquitous, most documented buck/boost converter IC on the market. Knowing the voltage isn't enough, you have to know how much current you need on the output side as well, or you can't do the necessary calculations. For sake of discussion, we'll assume you want 100mA out. Here is the circuit and the component values necessary:

1573998405644.png

R1: 3300 Ohms
cT in pF: 170
Rsc: 0.9479 Ohms
Lmin in uH: 35.8
cO in uF: 382.9
R2: 9900 Ohms
R: 180 Ohms

It will operate at about 1.28W, with a peak current draw of 348mA (converting to a higher voltage has to come from somewhere.) Vin tolerance is 10% around 3.7V. Output is 5V @ 100mA.
 

BobaMosfet

Joined Jul 1, 2009
839
Thanks for mc 34063, at least i can buy from local shop but cant i increase amperage?
Yes, you can set amperage to whatever you need within limits of what your input is compared to output. Amps have to come one way or another from the input power. Period. I simply chose 100mA because I had not yet seen you specify an output current leve you needed.

And in case you find it useful in your journey in electronics:

Title: Understanding Basic Electronics, 1st Ed.
Publisher: The American Radio Relay League
ISBN: 0-87259-398-3
 
Last edited:

SamR

Joined Mar 19, 2019
1,299
There are simple voltage multiplier circuits using diodes and capacitors. However Ohms law still applies, what you gain in Voltage you lose is Ampacity. You cant get out more than what you put into the circuit.
 

DickCappels

Joined Aug 21, 2008
5,950
You can get 5 volts ±something from the Roman Black #2 that you jpanhalt talked with boost converter by changing the Zener diode at the output to 5.1 volts. It is not going to give you a lot of current but it will give you whatever the Zener will permit.

The MC36043 regulators are versatile and siginficantly less complex than other regulators. I heartily endorse its use. What's more, what seem like good copies can be bought for as little as U.S. $0.05, cheaper than the outboard boost transistors I use.
 

Thread Starter

Miracletech

Joined Nov 15, 2019
52
Ok, but the thing here is that i want to economize space. Also, my plan was to use bjt as a switch for the boost converter. But anyway, transistors would be more smaller.

But anyway, im gonna try mc34063
 
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