Bit Switch Drive for a Four-Transistor Sense Amplifier
Original Publication Date: 1985-Jul-01
Included in the Prior Art Database: 2005-Feb-18
This circuit generates RESTORE, SELECT, and DESELECT pulses at the bit switch gates and eliminates the separate set of transistors usually employed for bit line restore and bit line decoding. This can be accomplished most easily if a high level supply is available, such as VH. Tieing the drain of transistor T7 to this supply will restore node N3 to the proper level to restore the bit lines. This supply should be VL+VT+OVERDRIVE. In the event supply VH is not available, N3 must be capacitively coupled to the required restore level. This means adding a bootstrap capacitor to N3. At the beginning of a cycle, the node N3 voltage level must be lowered to approximately VL for the selected sense amplifier and to ground for the deselected sense amplifier.