On-chip usable life depletion meter and associated method

An integrated circuit chip comprising:

• a substrate;
• a usable life depletion meter on said substrate,
• said usable life depletion meter comprising multiple first programmable bits,
• said first programmable bits representing units of usable life of said integrated circuit chip, each unit of usable life represented by each first programmable bit corresponding to a specific number of power-on hours at a nominal operating voltage and a nominal operating temperature,
• said first programmable bits being sequentially ordered from an initial programmable bit to a last programmable bit,
• said first programmable bit being automatically programmed, during operation of said integrated circuit chip, in order starting with said initial programmable bit as an expected usable life of said integrated circuit chip is depleted, and
• said first programmable bits being readable to determine a remaining usable life of said integrated circuit chip;
• a power-on hours monitor measuring actual power-on hours of said integrated circuit chip;
• a voltage monitor monitoring actual operating voltage of said integrated circuit chip;
• a temperature monitor monitoring actual operating temperature of said integrated circuit chip;
• a read/write circuit;
• and
• a read/write circuit controller in communication with said power-on hours monitor, said voltage monitor, said temperature monitor and said read/write circuit,
• said read/write circuit controller noting whenever, given any differences between said actual operating voltage and said nominal operating voltage and between said actual operating temperature and said nominal operating temperature, said actual power-on hours have increased by an amount equivalent to said specific number of power-on hours at said nominal operating voltage and said nominal operating temperature and, in response, automatically causing said read/write circuit to program a next programmable bit in said usable life depletion meter.

A method comprising:

• mounting an integrated circuit chip onto a printed circuit board, said integrated circuit chip comprising:
• a substrate and a usable life depletion meter on said substrate,
• said usable life depletion meter comprising multiple first programmable bits,
• said first programmable bits representing units of usable life of said integrated circuit chip and being sequentially ordered from an initial programmable bit to a last programmable bit;
• and,
• during operation of said integrated circuit chip, automatically programming said first programmable bits in order starting with said initial programmable bit as an expected usable life of said integrated circuit chip is depleted,
• said integrated circuit chip further comprising a second programmable bit and said method further comprising, after said mounting of said integrated circuit chip on said printed circuit board, performing the following:
• reading said second programmable bit to determine whether said integrated circuit chip was previously mounted on a different printed circuit board;
• when said integrated circuit chip was previously mounted on said different printed circuit board, determining whether re-use of said integrated circuit chip on said printed circuit board is allowable based on specifications for re-using integrated circuit chips;
• and,
• when said re-use of said integrated circuit chip is allowable, reading said first programmable bits to determine a remaining usable life of said integrated circuit chip and only allowing said re-use when said remaining usable life is sufficient based on said specifications.