Method and apparatus for detecting an unused state in a semiconductor circuit
View Patent ↗An unused state detection circuit is disclosed that detects an unused state in a semiconductor circuit. A semiconductor circuit is “unused” when the unused state detection circuit has not been permanently cleared. When a semiconductor circuit is first powered up, the unused state detection circuit will detect that the semiconductor circuit has not previously been “used” and can automatically activate a boot up procedure or a testing procedure (or both). After the semiconductor circuit is used, the unused state detection circuit provides an indication that the semiconductor circuit is no longer unused. The unused state detection circuit uses the state of a dedicated non-volatile memory array or a dedicated region of the general non-volatile memory portion of the semiconductor circuit to detect whether the semiconductor circuit has been previously unused.
1. A semiconductor circuit comprising:
a processor for executing one or more instructions;
a memory device; and
a circuit for detecting whether said semiconductor circuit is unused;
wherein said circuit comprises a dedicated mini-array of non-volatile memory cells for use in unused detection,
wherein said dedicated mini-array of non-volatile memory cells includes at least two active bit lines corresponding to program and erase, and wherein said first bit line is only programmable and said second bit line is only erasable.
2. The semiconductor circuit of claim 1 , wherein said cells in said dedicated mini-array of non-volatile memory are initially in approximately a same state and wherein said unused state is detected by sensing said at least two active bit lines.
3. The semiconductor circuit of claim 1 , wherein an offset current is added to one of said at least two active bit lines to detect when said semiconductor circuit is first used.
4. A semiconductor circuit comprising:
a processor for executing one or more instructions;
a memory device; and
a circuit for detecting whether said semiconductor circuit is unused;
wherein said memory device is a non-volatile memory array and wherein said circuit comprises a dedicated region of said non-volatile memory array,
wherein one or more dedicated bytes in said dedicated region are compared to a reference current,
wherein said one or more dedicated bytes in said dedicated region are in a neutral state when said semiconductor circuit is unused and wherein a used state of said semiconductor circuit is detected by evaluating a current generated by said one or more dedicated bytes.
5. A semiconductor circuit comprising:
a processor for executing one or more instructions;
a memory device; and
a circuit for detecting whether said semiconductor circuit is unused;
wherein said memory device is a non-volatile memory array and wherein said circuit comprises a dedicated region of said non-volatile memory array
wherein one or more dedicated bytes in said dedicated region are compared to a predefined pattern,
wherein said one or more dedicated bytes in said dedicated region have a uniform pattern that does not match a predefined pattern until said semiconductor circuit has been used.