One-time programming (OTP) magneto-resistive random access memory (MRAM) bit cells in a physically unclonable function (PUF) memory in breakdown to a memory state from a previous read operation to provide PUF operations

A memory access circuit for programming one or more physically unclonable function (PUF) magneto-resistive random access memory (MRAM) bit cells in an MRAM PUF array comprising at least one MRAM bit cell row circuit of PUF MRAM bit cells, the memory access circuit comprising:

• a data output circuit comprising:
• a means to receive a PUF data signal representing a resistance of at least one PUF MRAM bit cell in at least one MRAM bit cell column circuit for a selected MRAM bit cell row circuit for a PUF read operation;
• and
• a means to generate a PUF output indicating a memory state in the at least one PUF MRAM bit cell in the at least one MRAM bit cell column circuit for the selected MRAM bit cell row circuit, based on the PUF data signal;
• and
• a write driver circuit coupled to the PUF output, the write driver circuit comprising:
• a means to generate a first program write signal to program the at least one PUF MRAM bit cell in the at least one MRAM bit cell column circuit to a permanent memory state based on the memory state indicated by the PUF output.

A method of programming at least one physically unclonable function (PUF) magneto-resistive random access memory (MRAM) bit cell in an MRAM PUF array in an MRAM for performing a PUF operation, the MRAM PUF array comprising a plurality of MRAM bit cell row circuits each comprising a plurality of PUF MRAM bit cells, and a plurality of MRAM bit cell column circuits each comprising a PUF MRAM bit cell from an MRAM bit cell row circuit among the plurality of MRAM bit cell row circuits, the method comprising:

• receiving a PUF data signal representing a resistance of at least one PUF MRAM bit cell in at least one MRAM bit cell column circuit for a selected MRAM bit cell row circuit for a PUF read operation;
• generating a PUF output indicating a memory state in the at least one PUF MRAM bit cell in the at least one MRAM bit cell column circuit for the selected MRAM bit cell row circuit, based on the PUF data signal;
• and
• generating a first program write signal to program the at least one PUF MRAM bit cell in the at least one MRAM bit cell column circuit to a permanent memory state based on the memory state indicated by the PUF output.

A magneto-resistive random access memory (MRAM), comprising:

• an MRAM array, comprising:
• a plurality of MRAM bit cell row circuits each comprising a plurality of MRAM bit cells;
• and
• a plurality of MRAM bit cell column circuits each comprising an MRAM bit cell from an MRAM bit cell row circuit among the plurality of MRAM bit cell row circuits;
• an MRAM physically unclonable function (PUF) array comprising one or more MRAM bit cell row circuits among the plurality of MRAM bit cell row circuits in the MRAM array not included in an MRAM data array, wherein MRAM bit cells in the MRAM PUF array comprise a plurality of PUF MRAM bit cells;
• and
• a memory access circuit, comprising:
• a data output circuit configured to, in response to a PUF read operation selecting an MRAM bit cell row circuit of PUF MRAM bit cells to be read:
• receive a PUF data signal representing a resistance of at least one PUF MRAM bit cell in at least one MRAM bit cell column circuit for the selected MRAM bit cell row circuit for the PUF read operation;
• and
• generate a PUF output indicating a memory state in the at least one PUF MRAM bit cell in the at least one MRAM bit cell column circuit for the selected MRAM bit cell row circuit, based on the PUF data signal;
• and
• a write driver circuit coupled to the PUF output, the write driver circuit further configured to, in response to the PUF read operation selecting the MRAM bit cell row circuit of the PUF MRAM bit cells to be read:
• generate a first program write signal to program the at least one PUF MRAM bit cell in the at least one MRAM bit cell column circuit to a permanent memory state based on the memory state indicated by the PUF output.