Localized direct sense architecture

#1. Field of the Invention

#The present invention relates generally to a localized direct sense architecture, and more particularly pertains to a localized direct sense architecture which includes a large number (e.g. 8) of microcells, each having a primary sense amp PSA, coupled to one global data line which is coupled to one secondary sense amp SSA. Each PSA includes its own bias current device, which supplies bias current to sense devices in the PSA and is also used for precharge, such that the bias current does not flow along the highly capacitive global data line. With this technical approach, the size of each bias current supply device can be substantially reduced, and the number of PSAs on one global data line can be increased for greater layout density.

#2. Discussion of the Prior Art

#The foregoing objects and advantages of the present invention for a localized direct sense architecture may be more readily understood by one skilled in the art with reference being had to the following detailed description of several embodiments thereof, taken in conjunction with the accompanying drawings wherein like elements are designated by identical reference numerals throughout the several views, and in which:

#FIG. 1 illustrates a typical prior art direct sense circuit wherein 4 microcells, each having an associated primary sense amp PSA, are coupled to one global data line PDL which is coupled to one secondary sense amp SSA.

#FIG. 2 illustrates a localized direct sense architecture circuit pursuant to the present invention which includes 8 microcells, each having an associated PSA, coupled to one global data line PDL which is coupled to one secondary sense amp SSA.

#In the localized direct sense architecture and circuits of the present invention, the bias current device is included in each primary sense amp PSA, such that the bias current does not flow along a highly capacitive global data line. With this technical approach, the size of each bias current supply device can be reduced by a factor of 8, and the number of PSAs on one global data line can be doubled for increased layout density.

#FIG. 2 illustrates a localized direct sense architecture circuit pursuant to the present invention which includes 8 microcells, each having a primary sense amp PSA, coupled to one global data line PDL which is coupled to one secondary sense amp SSA. The SSA of FIG. 2 is much simpler and smaller than the SSA of FIG. 1, and includes a precharge device T4, an output device T3, and a much smaller inverting Minimum Latch, as the relatively large latch of FIG. 1 is no longer required, which results in a density advantage.

#FIG. 3 illustrates a first embodiment of a primary sense amp PSA for a localized direct sense architecture pursuant to the present invention which includes: