Hi all, Lets say I intend to design a simple circuit that shoud connect a (large) capacitor with a pulsed voltage-source, if and only if the voltage of the pulsed source is at a higher level than the voltage of the capacitor (the cap is charged). To do this I want to use a (certain) MOS-Fet Transistor.
Now I've got the problem, that there is no signal where the potential is allways at the highest level in the circuit. E.g. If the pulsed source is charging the capacitor with a large current, there will be quite a bit of voltage-drop across the MOS-Fet, and while the source is at level 0 the transistor will be turned off an there will be a voltage drop the other way.
So how schould I connect the bulk of the mosfet in a way that the source-to-bulk-diode never becomes foreward biased (to high)?
I thought maybe a kind of "bulk-switch-circuit" could help? Maybe also just a simple diode (with a foreward voltage lower than that of the transistors-diodes)?
Any ideas, experience?
So far, Thanks for reading, Regards,