Why Bootstrap switch removes Vgs non linearity

[yefj]

Hello,in the theory they say that by connecting the voltage source inthat manner the non linear dipendancy on Vin is removed. Buy we are not connecting gate and source with this voltage we are connecting gate and drain. Why its removing Vgs Vin dependancy?the connection should be the opposite. Thanks.

 

[yefj]

i usendstand that its a PMOS
Then why on the hold stage we put it to GND,GND wil not CLOSE PMOSit will open it.

 

[sutapanaki]

What is PMOS and what is drain o source?

 

[yefj]

Hello Sutapanaki, i have sighned the PMOS its source and drain.
In the lecture they say that on Track we connect VDD to it and on Hold stage we connect GND to it.
But connecting VDD will close the PMOS in the track phase, and connecting GND will OPEN the PMOS, itwill not HOLD the value.
Where am i worng?

 

[FvM]

Obviously, it's a NMOSFET rather than PMOS.

 

[yefj]

then if its a NMOS the we are not connecting Vgs with this capacitor but we are connecting Vds

 

[sutapanaki]

The way the circuit is drawn, it is a NMOS transistor. It is also a switch, so it doesn't really matter what you call source and what drain. In the hold phase transistor is really off. In the track phase it has VGS=VDD

 

[FvM]

How dou you know what drain and source is? The voltage across the transistor channel can have both polarities (rising or falling Vin), drain and source role change respectively.