Is there such a boost converter?

[Leokras]

Hi!

Will really appreciate if you could help me with the following DC-DC boost converter:
I need that Vout=Vin+dV, i.e that Vout will follow Vin with a certain delta V.
Is there such thing?
If not, how can I make it?

Thanks!

 

[KrisBlueNZ]

Hi there and welcome to Electronics Point

I can see two ways to do what you want. The first is to use an "inverting" converter, which generates a fixed voltage of the opposite polarity to the input voltage, and take the output across the combination of the input and output voltages, effectively putting them in series. With the usual kind of inverting converter, which generates a negative voltage from a postive voltage, this would mean that the positive side of the output voltage would be common with the positive of the input voltage, but the negative side of the output wuold not be common with the negative side of the input.

The other way is to change the feedback circuit of a regulator so that its output follows its input voltage with a particular offset. This can be done using a bit of circuitry in the feedback loop.

To give you a full answer, we need a full description. Answer ALL of these questions THOROUGHLY.

• What is the overall purpose of this project?
• Where does the input supply come from?
• What will the output supply be used for?
• What is the input voltage range?
• How much voltage do you want to add to the input voltage?
• Do you need to be able to adjust the additional voltage? If so, over what range?
• How much output current is needed?
• Do you need the output to be fully isolated from the input? Or do they need to have the negative side in common? Or does it not matter how the voltages are related in terms of common terminals?