Increasing voltage using operational amplifier

In summary: This application note explains how to use operational amplifiers to create a switched-mode power supply.In summary, the circuit in this application note creates a switched-mode power supply that can output more than the supply voltage.
  • #1
zxcvb
10
1
I want to build own circuit usinghttps://ez.analog.com/external-link.jspa?url=http%3A%2F%2Fwww.kynix.com%2FProduct%2FCate%2F470.htmland resistors. I have 12V power source (car accumulator) and 6V input voltage (Vin). I want to get 12V Vout and 25W at the output. So that is about 2A current(25/12=2).

I heart that operational amplifiers (OA) work only in low currents. Therefore I am not sure that it is appropriate to use OA to implement my aim.

My aim is to get 12V voltage and 25W power at the ouput from input voltage Vin=6V and 12V power source(car accumulator) using following circuit.
e3759.png

So is this appropriate circuit? If, no can someone provide alternative curuits? Thanks!
 
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  • #2
zxcvb said:
I want to build own circuit usinghttps://ez.analog.com/external-link.jspa?url=http%3A%2F%2Fwww.kynix.com%2FProduct%2FCate%2F470.htmland resistors. I have 12V power source (car accumulator) and 6V input voltage (Vin). I want to get 12V Vout and 25W at the output. So that is about 2A current(25/12=2).

I heart that operational amplifiers (OA) work only in low currents. Therefore I am not sure that it is appropriate to use OA to implement my aim.

My aim is to get 12V voltage and 25W power at the ouput from input voltage Vin=6V and 12V power source(car accumulator) using following circuit.

zxcvb said:
I have 12V power source (car accumulator) and 6V input voltage (Vin)

ok so a 12V car battery

What is this 6V in you are talking about ? 6V into what ?

zxcvb said:
My aim is to get 12V voltage and 25W power

so why are you not just taking the 12V from the battery directly ?
what are you wanting to power ?

You cannot get more power out of something than what you put into it... in fact there will ALWAYS be less power out due to various losses
Reread the last sentence in the graphic you posted

you really need to read up on OP-Amps and how they work

here's a good starting video ...

https://www.eevblog.com/2014/04/06/eevblog-600-opamps-explained/cheers
Dave
 
Last edited:
  • #3
If you want to have an output greater than the supply voltage, you must use a specialized circuit. In short: You chop up the input voltage into a pulse train, use inductors or capacitors to increase the amplitude and rectify the result.

Start by reading this application note : http://cds.linear.com/docs/en/application-note/an19fc.pdf
 

Related to Increasing voltage using operational amplifier

1. How does an operational amplifier increase voltage?

An operational amplifier (op-amp) is a type of electronic device that is designed to amplify an input signal. It has a high gain, which means it can increase the voltage of the input signal by a large factor. This is achieved by using a feedback loop, where a portion of the output voltage is fed back to the input, resulting in an amplified output signal.

2. What is the maximum voltage that can be achieved using an operational amplifier?

The maximum output voltage of an operational amplifier is determined by its power supply voltage. If the op-amp is powered by a single supply, the maximum output voltage will be equal to the supply voltage. If it is powered by a dual supply, the maximum output voltage will be equal to the difference between the positive and negative supply voltages.

3. Can the voltage gain of an operational amplifier be adjusted?

Yes, the voltage gain of an operational amplifier can be adjusted by changing the values of the external feedback resistors in the circuit. By using different resistor values, the ratio of the output voltage to the input voltage can be changed, resulting in a different voltage gain.

4. Are there any limitations to increasing voltage using an operational amplifier?

Yes, there are limitations to increasing voltage using an operational amplifier. One limitation is the maximum output voltage, as mentioned earlier. Another limitation is the maximum output current, which is determined by the op-amp's internal circuitry. Additionally, the op-amp may have a limited bandwidth, which can affect the quality of the amplified signal.

5. What are some practical applications of increasing voltage using an operational amplifier?

An operational amplifier is commonly used in many electronic circuits, including audio amplifiers, power supplies, and sensor interfaces. It can be used to increase the voltage of a weak signal from a sensor, making it easier to process and analyze. It is also used in feedback control systems to amplify and control signals for various applications.

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