Write driver circuit in phase change memory device and method for applying write current
First Claim
1. A circuit for performing a write operation in a phase change memory device having a phase change memory cell, comprising:
- a programmable fuse unit for adjusting the magnitude of write current through the phase change memory cell.
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Abstract
A write driver circuit including a plurality of programmable fuses for a phase change memory device in which a write operation is correctly performed even in the case where a current output shift in a write current generation circuit; or in the case where a phase change memory cell having a phase change property shift due to an external factor or due a process change. The write driver circuit includes a write current control unit for outputting a first or second level of voltage selected, by selecting one of a first or second programmable current path, based on whether a first or second selection pulse signal is applied; and a current driving unit for generating a write current controlled by the output voltage of the write current control unit. Each of the first and second programmable current paths includes fuses that can be programmed to adjust their resistance to adjust the respective selected output voltage to compensate for the current output shift in the write current generation circuit or for the phase change memory cell having the phase change property shift.
174 Citations
33 Claims
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1. A circuit for performing a write operation in a phase change memory device having a phase change memory cell, comprising:
a programmable fuse unit for adjusting the magnitude of write current through the phase change memory cell. - View Dependent Claims (2, 3, 4)
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5. A write driver circuit for a phase change memory device having a plurality of phase change memory cells each having first and second resistance states, the circuit comprising:
a write current control unit for outputting a first level of voltage by establishing a first programmable current path while a first selection pulse signal is applied, and outputting a second level of voltage by establishing a second programmable current path while a second selection pulse signal is applied. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12)
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13. A write driver circuit for performing a write operation in a phase change memory device having a plurality of phase change memory cells having first and second resistance states, the circuit comprising:
a write current control unit for outputting a first level of voltage by establishing a first programmable current path if a first selection pulse signal is applied, and outputting a second level of voltage by establishing a second programmable current path if a second selection-pulse signal is applied. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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21. A write driver circuit for a phase change memory device having an array of phase change memory cells having first and second resistance states, the circuit comprising:
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a pulse selection unit for selecting one of first and second state pulses that are applied to change the resistance state of a phase change memory cell based upon the logic state of applied write data, and for outputting the selected pulse as a first or second selected pulse signal;
a write current control unit for outputting a first level of voltage by establishing a first current path having a first programmable resistance, and outputting a second level of voltage by establishing a second current path having a second programmable resistance if the second selection pulse signal is applied; and
a current driving unit for generating a write current in response to the output voltage of the write current control unit. - View Dependent Claims (22, 23, 24, 25, 26)
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27. A method for applying write currents to a phase change memory cell in a phase change memory device, the method comprising the step of:
adjusting the magnitude of a first write current determined by a first logic state of write data by programming a first fuse. - View Dependent Claims (28, 29, 30, 31, 32, 33)
Specification