Thin film magnetic memory device having data read current tuning function
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorHideto Hidaka
Life of this patent
Estimating the term…
Abstract
A constant current supply circuit generates a constant current according to a control voltage. A data read current passing through a tunneling magneto-resistance element constituting a memory cell during data write is set according to the constant current. Constant current supply circuit includes a voltage adjustment circuit generating a reference voltage adjustable according to an external input, a current source generating the constant current according to the reference voltage, and a voltage switch circuit transmitting the reference voltage to the current source as a control voltage during a normal operation.
Claims19
A thin film magnetic memory device comprising:
- a plurality of memory cells each executing data storage;
- and
- a plurality of data lines arranged according to predetermined segments of said plurality of memory cells, respectively, wherein
- each of said plurality of memory cells includes:
- a magnetic storage portion magnetized in a direction according to a level of stored data, and having a different electric resistance according to a magnetization direction, and
- an access element electrically connected to said magnetic storage portion in series between corresponding one of said plurality of data lines and a first voltage, and turned on in at least one selected memory cell as a data read target memory cell,
- said thin film magnetic memory device further comprises:
- a select gate electrically connecting the data line corresponding to said selected memory cell among said plurality of data lines to an internal node;
- and
- a data read circuit for reading said stored data of said selected memory cell, and wherein
- said data read circuit includes
- a constant current circuit electrically connected between a second voltage and said internal node, and supplying a constant current according to a control voltage adjustable in a nonvolatile manner according to an external input, to said internal node, and
- a voltage amplification circuit generating read data according to a voltages of said internal node.
A thin film magnetic memory device comprising:
- a plurality of memory cells each executing data storage;
- and
- a plurality of data lines arranged according to predetermined segments of said plurality of memory cells, respectively, wherein
- each of said plurality of memory cells includes
- a magnetic storage portion having one of first and second electric resistances according to a level of stored data, and
- an access element electrically connected to said magnetic storage portion in series between corresponding one of said plurality of data lines and a first voltage, and selectively turned on,
- said thin film magnetic memory device further comprises:
- a current supply circuit supplying a current passing through said magnetic storage portion, said current supply circuit supplying a first constant current to at least one of said plurality of data lines in a normal operation mode, and supplying a second constant current higher than said first constant current, to at least one of said plurality of data lines in another operation mode.
Dependencies are inferred from the claim text.