Method and apparatus for storing data in an integrated circuit
AssigneeTexas Instruments Incorporated
InventorRobert L. Pitts
Life of this patent
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Abstract
A circuit (100) for protecting sensitive data stored in a storage area (108) includes a one time programmable device such as a fuse element (104) coupled to the input data path (102), and a one time programmable device such as fuse element (112) coupled to the output data path (118). Once sensitive data is loaded into the storage area (108), either one of, or both of the fuses (104, 112) can be activated (blown) in order to prevent access to the data stored in storage area (108). Optionally, a fuse element (130) can also be added to the internal circuit data line (120) that would prevent both internal and external access to the stored data.
Claims14
A circuit for protecting sensitive data, comprising:
- an input data path;
- a memory area for storing the sensitive data, the memory area coupled to the input data path;
- a first one-time programmable device coupled to the input data path which when placed in a first state, sensitive data applied to the input data path is allowed to be loaded into the memory area, and when it is placed in a second state, sensitive data applied to the input data path is not allowed to be loaded into the memory area;
- and
- wherein the one-time programmable device comprises a logic protection circuit comprising:
- a first logic gate having a first input port coupled to the input data path and an output port coupled to the memory area;
- a register having a protection bit stored therewith;
- a second logic gate having a first input port coupled to the output port of the first logic gate and a second input port coupled to the register, and an output port;
- said first logic gate having a second input port coupled to the output port of the second logic gate;
- and
- wherein when said protection bit stored within the register is presented to the second logic gate, the first logic gate prevents data located in the input data path from being sent to the memory area.
A circuit for protecting sensitive data, comprising:
- an output data path;
- a memory area for storing the sensitive data coupled to the output data path;
- and a one-time programmable device coupled to the output data path which when placed in a first state, data located in the memory area data path is allowed to be retrieved via the output data path, and when the one-time programmable device is placed in a second state, data stored in the memory area is not allowed to be retrieved via the output data path;
- and
- the one-time programmable device comprises a logic protection circuit comprising:
- a first logic gate having a first input port coupled to the output data path and an output port coupled to the memory area;
- a register having a protection bit stored therewith;
- a second logic gate having a first input port coupled to the output port of the first logic gate and a second input port coupled to the register, and an output port;
- said first logic gate having a second input port coupled to the output port of the second logic gate;
- and
- wherein when said protection bit stored within the register is presented to the second logic gate, the first logic gate prevents data stored in the memory area from being accessed via the output data path.
Dependencies are inferred from the claim text.