"Flash Memory"? How Does It Work In Chips?

Discussion in 'General Electronics Chat' started by ajm113, Apr 7, 2011.

  1. ajm113

    Thread Starter Member

    Feb 19, 2011
    How does "flash memory" work? I know memory on a hard drive is pretty much self explanatory even when you look at the box, but when it comes to ICs, how does it store memory/data even when the circuit has no power?

    And also has anyone ever created a circuit to interact with a floppy disk or a hard drive? I kinda want to look into schematics to get the knowledge of how memory is kept on them and see if I can do something like this myself for experience.

    Of course I tried Google, but I couldn't get a more detail or schematic popping result that explained every inch about it.

    Thank you, Andrew.
  2. debjit625

    Well-Known Member

    Apr 17, 2010
  3. Papabravo


    Feb 24, 2006
    The simple answer is that charge is stored on a floating gate. MOSFETS have three terminals a SOURCE, a DRAIN, and a GATE. During programming charge is injected into a floating gate. There is no place for the charge to go so it stays there and keeps the MOSFET on. If no charge is injected onto the floating gate then the MOSFET off.

    I've designed many floppy disc and hard drive circuits over the years. There is only one tricky part and that is the data separator that recovers data and clock from the FM or MFM data stream. Writing is nearly trivial and seeking uses a standard stepper or servo motor interface. Not much to learn after that.