I am trying to understand a charge pump circuit here but one part has me scratching my head and this sort of scenario happens a lot with me in electronics. It’s a question of what happened first??
If you look at the image below:
I understand the left image where the capacitor is basically in parallel with Vs and GND so this configuration is charging it up to VS .
In the next drawing, If I understand correctly, the Capacitor is connected in series with VS thus giving you 2VS. Then, because VS goes through the mosfets Drain -> Source thus connecting VS to what was previously the GND node of the capacitor
How did the mosfet turn on to let that through?
It seems like to get 2VS the mosfet has to have BEEN on, So basically a catch22 , which happened first? I don’t understand.
I think an answer might be if you switch S1 to off position first, that way the gate is not grounded and the source is still at ground and then the cap begins to charge the gate and once the mosfet is on then you flip S2 off and it works as described to give you 2VS ???
Any insight would be much appreciated. Thanks.