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Positive Level-Shifting Wordline Drivers for DRAMS

IP.com Disclosure Number: IPCOM000101213D
Original Publication Date: 1990-Jul-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 3 page(s) / 81K

Publishing Venue

IBM

Related People

Dhong, SH: AUTHOR [+2]

Abstract

Disclosed are new positive level-shifting wordline drivers for DRAMs. In the current and future DRAMs, the high level of the wordline is frequently higher than that of the wordline decoders and other peripheral circuits. A positive level-shifting wordline driver is needed to interface these different voltage levels between the wordlines and decoders. Without the level-shifting wordline driver, some devices in the word driver may not completely turn off for certain conditions, resulting in loss of boost-levels and/or unnecessary power drain.

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Positive Level-Shifting Wordline Drivers for DRAMS

       Disclosed are new positive level-shifting wordline
drivers for DRAMs.  In the current and future DRAMs, the high level
of the wordline is frequently higher than that of the wordline
decoders and other peripheral circuits.  A positive level-shifting
wordline driver is needed to interface these different voltage levels
between the wordlines and decoders. Without the level-shifting
wordline driver, some devices in the word driver may not completely
turn off for certain conditions, resulting in loss of boost-levels
and/or unnecessary power drain.

      Three different positive-level shifting drivers are shown in
Figs.  1 through 3.  In Fig. 1, VWLH is the wordline high level and
is assumed higher than the high level of RESET and WLDEC.  In
standby, RESET is high and WLDEC is low.  The node B is at GND
(ground) and QPR is on, clamping the wordline to VWLH.  QPL is off
and QNL is on, helping to clamp the node B to GND.  QNR is connected
to GPLS which can provide a small negative voltage.  In the active
mode, RESET falls to GND. For the unselected wordlines, WLDEC stays
low and the feedback provided by QNL keeps the node B low and the
wordline at VWLH.  For the selected wordline, WLDEC become high and
QNR turns on.  This pulls the wordline down, which turns QNL and QPL
on and off, respectively.  Consequently, the node B is pulled up to
VWLH and shuts QPR off completely.  Resetting is done by first
lowering WLDEC...