The assignee for this patent, patent number 8526226, is
Reporters obtained the following quote from the background information supplied by the inventors: "The present invention relates to a semiconductor integrated circuit, and more particularly, to a current control apparatus and a phase change memory having the same.
"Nonvolatile memory apparatuses maintain stored data even though power supply is cut off. Therefore, the nonvolatile memory apparatuses are widely adopted in computers, mobile telecommunication systems, memory cards, and so on.
"A representative example of the nonvolatile memory apparatus is flash memory. The flash memory adopts a memory cell structure such as a stacked gate structure. In such a flash memory, a film quality of a tunnel oxide layer should be improved, and a coupling ratio between cells should be increased, in order to enhance the reliability and program efficiency of flash memory cells.
"Currently, a phase change memory apparatus having a random access property of DRAM is being developed as a replacement for flash memory.
"In general, a phase change memory apparatus includes a plurality of word lines, a plurality of bit lines arranged in such a manner as to intersect the plurality of word lines, and a plurality of phase change memory cells in the respective intersection points between the word lines and the bit lines.
"Each of the phase change memory cells includes a switching element coupled to a word line and a variable resistor element coupled between the switching element and a bit line. The variable resistor element may be formed of a phase change material whose resistance value changes according to the amount of current provided.
"Referring to FIG. 1, the phase change material used as the variable resistor element of the phase change memory cell is characterized in that the resistance value changes with temperature. Therefore, the phase change material has a relatively low resistance value at high temperature and a relatively high resistance value at low temperature. Accordingly, while the property change of the phase change material used as the variable resistor material at high temperature is larger than at a nominal temperature, the property change at low temperature is smaller than at the nominal temperature. The nominal temperature may be, for example, 70.degree. F. Therefore, the resistance value of the phase change material may not be consistent for a predetermined program pulse because the degree of the property change differs depending on temperature. In this case, a data storage error may occur depending on the temperature at the time of storage."
In addition to obtaining background information on this patent, VerticalNews editors also obtained the inventors' summary information for this patent: "In one embodiment of the present invention, a current control apparatus of a phase change memory includes a temperature sensing block having an output node whose voltage level varies depending on temperature of an internal circuit and a write driver configured to control an amount of program current provided to a memory cell in response to the voltage level at the output node.
"The temperature sensing block may be configured to provide an output voltage level at the output node that is directly proportional to temperature.
"The write driver may be configured to output current that is inversely proportional to temperature.
"In another embodiment of the present invention, a current control apparatus of a phase change memory includes a temperature sensing block configured to provide a different level of output voltage depending on temperature ranges, a reset control unit coupled to the temperature sensing block and configured to be driven during a reset mode, a set control unit coupled to the temperature sensing block and configured to be driven during a set mode, and a write driver configured to provide current to a memory cell in response to the level of the output voltage of the temperature sensing block.
"In another embodiment of the present invention, a phase change memory includes a phase change memory cell including a variable resistor having a resistance value which varies depending on temperature and a current control apparatus configured to sense the temperature, and output current to the phase change memory cell that is inversely proportional to temperature."
For more information, see this patent: Lym,
Keywords for this news article include:
Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2013, NewsRx LLC
Most Popular Stories
- Hezbollah Chief's Assassination Claimed by Sunni Group
- Allstate Seeks to Invest in Minority Firms
- SpaceX's Satellite Launch Is 'Game-Changer'
- Latin Music Conference Turns 25
- U.S. Growth Stayed Steady During Shutdown, Fed Says
- Newtown Massacre Heard on 911 Recordings
- Climate Change Early Warning System Urged
- Guardian Pressured to Stop NSA Stories: Editor
- New Home Sales Shoot up 25 Percent in October
- Reid Confident Congress to Pass Immigration Bill