Electrically programmable resistance cross point memory sensing method
View Patent ↗A method of reading a selected resistive memory bit having its output connected to a bitline, which is connected to a plurality of unselected electrically parallel resistive memory bits, is provided. The method comprises selecting the resistive memory bit to be read by applying a read voltage to an input of the resistive memory bit, and unselecting the plurality of unselected resistive memory bits by applying a deselect voltage to all inputs of the unselected resistive memory bits. The current out of the bitline is then sensed by a current sensor. A memory device is also provided comprising a plurality of resistive memory bits connected to a shared bitline, a means for selecting a single bit from the plurality of resistive memory bits, a means for deselecting the remaining, unselected bits from the plurality of resistive memory bits and a means for sensing the output current from the bitline.
1. A method of reading a selected resistive memory bit having its output connected to a bitline, which is connected to a plurality of unselected electrically parallel resistive memory bits, comprising;
a) selecting the resistive memory bit to be read by applying a read voltage to an input of the resistive memory bit;
b) unselecting the plurality of unselected resistive memory bits by applying a deselect voltage to all inputs of the unselected resistive memory bite;
c) sensing current out of the bitline to road the selected memory bit; and
wherein sensing current out of the bitline comprises sensing current through an input load of a current sensor with an input impedance of less than 10 ohms.
2. The method of claim 1 , wherein the deselect voltage is 0 volts.
3. The method of claim 1 , wherein the current sensor has an input impedance of less than 1 ohm.
4. The method of claim 1 , wherein the current sensor has an input impedance of less than 0.1 ohms.
5. The method of claim 1 , wherein the current sensor is an op amp, an odd stage cascade inverter, a differential amplifier or simple CMOS current sensor.
6. A resistive memory device comprising:
a) a resistive memory bit to be read connected to a word line and a shared bitline;
b) a plurality of resistive memory bits connected to a plurality of word lines and the shared bitline;
c) a current sensing device connected to the bitline; and
wherein the current sensing device has an input impedance of less than 10 ohms.
7. The resistive memory device of claim 6 , wherein the resistive memory bit is a colossal magnetoresistance (CMR) material.
8. The memory structure of claim 7 , wherein the colossal magnetoresistance (CMR) material is Pr 0.7 Ca 0.3 MnO 3 (PCMO).
9. The memory structure of claim 7 , wherein the colossal magnetoresistance (CMR) material is Gd 0.7 Ca 0.3 BaCo 2 O 5+5 .
10. The memory structure of claim 6 , wherein the current sensing device has an input impedance of less than 1 ohms.
11. The memory structure of claim 6 , wherein the current sensing device has an input impedance of less than 0.1 ohms.
12. The memory structure of claim 6 , wherein the current sensing device is an op amp, an odd stage cascade inverter, a differential amplifier or simple CMOS current sensor.
13. A resistive memory device comprising:
a plurality of resistive memory bits electrically connected to a bitline;
a means for selecting a single bit connected to the bitline;
a means for deselecting the plurality of resistive memory bits that have not been selected; and
a means for sensing an output current from the bitline, the sensing means having an input impedance of less than 10 ohms.