Boost Converter Question

Thread Starter

ben sorenson

Joined Feb 28, 2022
106
If I had a Pulsed DC Source, (E.G a battery that as soon as it was turned on we're to pulse positive current seeking ground.)

Could a boost or buck boost type converter be created without the switch to ground that's in between the inductor and diode?
 

Papabravo

Joined Feb 24, 2006
19,579
If I had a Pulsed DC Source, (E.G a battery that as soon as it was turned on we're to pulse positive current seeking ground.)

Could a boost or buck boost type converter be created without the switch to ground that's in between the inductor and diode?
No. For a boost converter, the switch provides a conduction path from the output capacitor through the diode to the load. The path back to the DC source is through the inductor.

I'll have to get back to you on the buck-boost, but I think the answer is the same.
ETA: I was wrong on the buck-boost. If your source has a duty cycle control, then it should be possible to do that.
 
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Thread Starter

ben sorenson

Joined Feb 28, 2022
106
No. For a boost converter, the switch provides a conduction path from the output capacitor through the diode to the load. The path back to the DC source is through the inductor.

I'll have to get back to you on the buck-boost, but I think the answer is the same.
ETA: I was wrong on the buck-boost. If your source has a duty cycle control, then it should be possible to do that.
Thank you so much! It would need a duty control because if it was at 100 percent duty it would NOT be able to raise the voltage?
 

Papabravo

Joined Feb 24, 2006
19,579
Thank you so much! It would need a duty control because if it was at 100 percent duty it would NOT be able to raise the voltage?
So, what do you imagine is the difference between building an actual buck-boost converter and one with an on/off DC source? In my mind there is not a great deal of difference.
 

Thread Starter

ben sorenson

Joined Feb 28, 2022
106
So, what do you imagine is the difference between building an actual buck-boost converter and one with an on/off DC source? In my mind there is not a great deal of difference.
I needed only one direct path from positive to ground, without any of the positive signal reaching ground before the voltage was increased.
 

Papabravo

Joined Feb 24, 2006
19,579
I needed only one direct path from positive to ground, without any of the positive signal reaching ground before the voltage was increased.
I don't understand what you mean. The point where the diode and the inductor come together needs to float. It should NEVER be connected to ground. Your duty cycled supply need to do the same thing. It must provide a voltage for some period of time and then it must go "high-impedance" for the remainder of the switching period.
 

Danko

Joined Nov 22, 2017
1,492
I needed only one direct path from positive to ground, without any of the positive signal reaching ground before the voltage was increased.
Use piece of copper wire, which plated on one end by tallium-204 or strontium-90.
Then wire will charged positive, up to some kV (depends on wire holder isolation properties).
 
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