# power supply voltage booster

#### hhsting

Joined Apr 25, 2024
154
I have 3VDC power supply. Is there anyway I can turn that 3vdc into 12vdc or 15vdc voltage? Any circuits you all might know that can do this using discreet transistors, inductors, resistors, capacitors efc etc but No ICs, no op amp?

#### Tonyr1084

Joined Sep 24, 2015
7,991
The fundamental law is that if you boost voltage you lose amperage. 6 volts at 1 amp can (in theory) be boosted to 12 volts 1/2 amp. I say "In theory" because you always lose something in the translation. Yes, you CAN boost 3V into 12 or 15V but you lose a lot of amperage. 3V into 15V is a five times boost in voltage. Assuming ZERO LOSS, the amperage will be 20% of whatever your 3V source is. It's impractical. With such heavy losses you're probably better off getting a 15 volt power supply rated at sufficient amperage to run whatever it is you are needing 15 volts for. You can always buck the voltage down, which offers the inverse of going up in voltage. Namely at 15 volts and 1 amp (in theory) bucked down to 12 volts you get 1 1/4 amps. Again assuming zero losses. Real world losses apply. You won't get the full 1.25A. It depends on how efficient your buck converter is.

#### LowQCab

Joined Nov 6, 2012
4,290
Is this Homework ???
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#### hhsting

Joined Apr 25, 2024
154
The fundamental law is that if you boost voltage you lose amperage. 6 volts at 1 amp can (in theory) be boosted to 12 volts 1/2 amp. I say "In theory" because you always lose something in the translation. Yes, you CAN boost 3V into 12 or 15V but you lose a lot of amperage. 3V into 15V is a five times boost in voltage. Assuming ZERO LOSS, the amperage will be 20% of whatever your 3V source is. It's impractical. With such heavy losses you're probably better off getting a 15 volt power supply rated at sufficient amperage to run whatever it is you are needing 15 volts for. You can always buck the voltage down, which offers the inverse of going up in voltage. Namely at 15 volts and 1 amp (in theory) bucked down to 12 volts you get 1 1/4 amps. Again assuming zero losses. Real world losses apply. You won't get the full 1.25A. It depends on how efficient your buck converter is.
Yes I am aware of this situation. Power is conserved. You cannot create power. P=I*V and so I would lose current by boosting voltage power equation is quite clear. However, my power stays constant.

yes I still like to know of such circuit still

#### hhsting

Joined Apr 25, 2024
154

#### Irving

Joined Jan 30, 2016
4,047
Why the restriction on no ICs or opamps? While technically possible, its a huge amount of work and components to do it properly... The basic circuit is shown below. The MOSFET is turned on for a short while, a few uS typically, charging up the magnetic field in the inductor. When the MOSFET turns off the back emf of the inductor is channeled through to the capacitor by the diode, charging the capacitor. Not shown here is the feedback loop that regulates the output voltage by varying the duty cycle (on-off ratio) of the pulse. That's the tricky bit to get right.

#### Michal Podmanický

Joined May 11, 2019
112
You have two choices:

A)Some of inductor/transformer single switch boost converter - suitable for medium wattage like 1W-100W.

B) Capacitor Charge pump - below 1W

Both can be done easily but hardest is feedback. You can avoid feedback by placing zener on output but energy that is not used will be waisted.

What power level are you focusing?
How precise the output voltage needs to be?
Is efficiency an issue?

#### dl324

Joined Mar 30, 2015
17,100
I have 3VDC power supply. Is there anyway I can turn that 3vdc into 12vdc or 15vdc voltage?
What current can the 3V source supply and what current do you need at the boosted voltage?
Any circuits you all might know that can do this using discreet transistors, inductors, resistors, capacitors efc etc but No ICs, no op amp?
Can you tell me where I can find for less or equal $1? #### Irving Joined Jan 30, 2016 4,047 #### Papabravo Joined Feb 24, 2006 21,302 Can you tell me where I can find for less or equal$1?
\$1 won't even pay for the shipping of a single part if you decide to design and build your own.

#### MisterBill2

Joined Jan 23, 2018
19,370
YES, you can build an oscillator inverter using germanium transistors and a transformer with both a power winding and a feedback winding. But you will need to wind your own transformer.