| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a read-out circuit of an MRAM of a self-reference system in which area is small, power consumption is low, high speed read-out can be performed. <P>SOLUTION: In first read-out, a current inputted from a selecting cell 13 is converted into a pulse having a frequency being inversely proportional to its current value by a pre-amplifier 3 and a VCO 4, the number of pulses in a fixed time is counted by a counter 5, and stored in a read-out value register 6. Next either of two storage states of the selecting cell is written, and second read-out is performed. A storage state of the selecting cell is discriminated by comparing a count value of the counter in the second read-out, a count value at the time of the first read-out stored in the read-out value register, and a reference value stored in a reference value register 7. An integration capacitor of current and a reference pulse generating means being required conventionally are unnecesitated using VCO, area is small, power consumption is low, and high speed read-out can be performed. <P>COPYRIGHT: (C)2003,JPO |
