charge pump basics (very basics)

I have a question: I scanned a series of timeshots, and i will go through them, the way i like to think about capacitors (maybe that's where the problem begins)
1: If i connect a totally uncharged capacitor on one side to Vdd, then immediately the other side will show Vdd (for a fsec only). So there will be some current through the buffer (one end in Vdd and one in 0), and after sometime
2: the other side of the Capacitor will be in 0V. So i will have 0 current and Vdd stored on the capacitor
3: If i disconnect the capacitor from Vdd (i wrote high z) and i apply Vdd in the left end of the buffer, i get Vdd, and thx to the stored charge on the capacitor, the other end reaches 2Vdd.

Now my question is, how can i use this?? How can i store this 2Vdd somewhere?
I checked wikipedia, and the general idea is another capacitor, that will store this value, and i will use this new "extra" capacitor, while i will recharge the intermediate capacitor

BUT 4: If i connect a capacitor, which is uncharged, and it will show 2Vdd on both sides, then in node A (if we consider it a branch A, with a very small resistor across it) will show some current, and i will end up with 0V there.
5:If i have Vdd, and 0 as i show them, what has happened on node B? I guess it's been brought back to Vdd! How could i save the 2Vdd so it's useful??

PLEASE HELP i'm desperate! I see no problem to my train of thoughts and no solution on the other hand on how to use this 2Vdd that i created!

Thx beforehand

geozog86,

First, I know that English is not your first language, but you should still practice capitalizing the first letter at the beginning of a sentence, and ending it with a period. Also the pronoun 'I' is capitalized. No need to be sloppy.

You are correct in that you are not thinking about capacitors the correct way. Capacitors do not store charge. The amount of charge stored on one plate is match by a loss of charge on the opposite plate for a net change of zero. Since voltage is the energy density of the charge, you do not store voltage. Density is not stored, it is accumulated. Therefore, capacitor voltage is accumulated, not stored. Since a capacitor stores energy, you should say a capacitor is energized, not charged.

You seem to be describing a voltage doubler. There never can be a voltage greater across the capacitor than the source voltage. If you reverse the lead of the capacitor and put it in series with the source voltage, then the sum of the source and cap voltage can be twice the source voltage. That is different than saying the voltage across the cap is twice what the source voltage is. You refer to things like "Vdd, branch A, node A", but you don't provide a schematic to define them. No one can answer your questions or affirm your statements unless they know what you are talking about. Would you like to resubmit your inquiry and provide a schematic?

Ratch

Charge Pumps are used in numerous applications, one of the most common being a RS-232 Transceiver like the MAXIM MAX232 and other variants.

The following is a design guide/tutorial covering charge pumps:

Charge Pump Circuits: An Overview on Design Strategies and Topologies



**broken link removed**

BigDog

The charge-pump finds uses in a variety of voltage multipliers.

The principle of operation covers two parts of an AC cycle:
(1) charge a capacitor with current going in one direction, then
(2) add its charge to current flowing in the other direction.

I have a Youtube video showing a simple charge-pump voltage doubler, as an animated simulation. It portrays capacitors charging and discharging, as well as current bundles flowing through wires.

Here is the link:

www.youtube.com/watch?v=3czj7J_FE_k

Unbelievable that I have to make such comments in a scientific blog, but @Ratch, I hope you're not a professor, cause your students must be suffering from your way of thinking and expressing "your truth" (possibly scientifically correct) over the "common language" used everywhere: I will not defend my style of writing or my way of expressing myself, and more importantly, since I've never been corrected by my professors for the phrase "capacitors are charged", I just consider your comments pointless and unnecessarily "patronizing".

To the point now for all of you: I did create and scan a document, which appears (VERY SMALL, i'm sorry, was not my intention) in the end of my post. If you click on it, you will see it pop up bigger. Thx for all the advice and the links, I will go through all of them, and they may contain the answer to my problem. Thank you all very much.

geozog86,

Unbelievable that I have to make such comments in a scientific blog, but @Ratch, I hope you're not a professor, cause your students must be suffering from your way of thinking and expressing "your truth" (possibly scientifically correct) over the "common language" used everywhere:

Click to expand...

Have no fear, I am not a professor.

I will not defend my style of writing or my way of expressing myself,

Click to expand...

Style and expression are not the problem. Punctuation is.

since I've never been corrected by my professors for the phrase "capacitors are charged"

Click to expand...

Do your professors even realize what they are saying or accepting?

Ratch