On a boost converter, what limits the top end output voltage. Like 10 volt input turn the pot to get 15 volt 20,volt 30 volt and so on .What limits how high it can go. Thanks

 

It depends entirely on the design of the particular boost converter you have.

 

It depends entirely on the design of the particular boost converter you have.

I know that the many different boost all have different top ends. Do you know what limits the top end. Why will the voltage increase and then stop, what stops it from increasing on any giving boost. Thanks

 

I know that the many different boost all have different top ends. Do you know what limits the top end. Why will the voltage increase and then stop, what stops it from increasing on any giving boost. Thanks

Well, can you share a schematic? What type of boost converter is this? Usually the chip makes sure the voltage doesn't get too high, but it sounds like you're asking what fundamentally limits it. I'll assume you're talking about a standard boost converter like this.

Well, not much. So to understand possible limits, you have to understand how a boost converter works. This video explains it really well. The supply first charges up the capacitor, through the inductor and diode. The inductor builds up a magnetic field. Then, it collapses. There is a very large negative voltage spike. This effectively places the inductor in series with the input voltage. Then this is connected to the load and capacitor. There is very little limiting the voltage. The only thing that does is the capacitor and the load. If there is no load, then it will reach extremely high voltages. But also, another factor is the duty cycle. If the inductor has more time to build up its field, it can supply more voltage to a given load. Now, even with no losses, it still must obey the rule power in = power out. So if the volts go up, the amps it can supply goes down.

Now why limit the output voltage? Well, aside from the fact that high voltage is dangerous, the capacitor may be destroyed if it cannot handle the voltage.

 

Thanks very much, made very good sense and I understand.

 

Thanks very much, made very good sense and I understand.

You're welcome.