University of Minnesota

Hyung-Il Kim

Keshab K Parhi

Muqing Liu

Chen Zhou

William Moy

Po-Wei Chiu

Hao Lo

Yingjie Lao

Ibrahim Ahmed

A coupled ring oscillator circuit includes a first ring oscillator, a second ring oscillator and a coupling circuit. The first ring oscillator includes a series of delay stages, each delay stage including an inverter gate. The second ring oscillator includes a series of delay stages, each delay stage including an inverter gate. The coupling circuit includes a coupling cell having a first modified tri-state inverter connected in parallel with one of the inverter gates of the first ring oscillator, and a second modified tri-state inverter connected in parallel with one of the inverter gates of the second ring oscillator.

Logic based ring oscillator coupling circuit

A fully connected ring oscillator circuit includes a plurality of first ring oscillator loops, a plurality of second ring oscillator loops, a plurality of ring oscillators and a plurality of coupled ring oscillators. Each first ring oscillator loop extends along a first axis. Each second ring oscillator loop extends along a second axis that is transverse to the first axis and intersects each of the first ring oscillator loops. Each ring oscillator includes one of the first ring oscillator loops connected to one of the second ring oscillator loops. Each coupled ring oscillator includes two of the ring oscillators that are connected to each other through a programmable weighted coupling block.

Circuitry having fully connected ring oscillators

Compute engine circuitry configured to represent a spin network mapping of a graph representing a combinatorial optimization problem includes a plurality of ring oscillator cells, each of which includes a ring oscillator having an oscillator output, at least one coupling block, and a read block. Each coupling block connects the ring oscillator of the cell to the ring oscillator of one of a plurality of neighboring cells to form a coupled ring oscillator. The read block generates a state output for each coupled ring oscillator that indicates whether the coupled ring oscillator is in one of a same-phase state, in which the connected ring oscillators oscillate in phase with each other, and an opposite-phase state, in which the connected ring oscillators oscillate in an opposite phase from each other. A controller is configured to output a total energy of the mapping based on the state outputs.

Probabilistic compute engine using coupled ring oscillators

A method includes setting an output of each memory cell in an array of memory cells to a same first value, decreasing power to the array of memory cells and then increasing power to the array of memory cells. Memory cells in the array of memory cells with outputs that switched to a second value different from the first value are then identified in response to decreasing and then increasing the power. A set of memory cells is then selected from the identified memory cells to use in hardware security.

Stable memory cell identification for hardware security

An apparatus includes a finite state machine and a physical structure capable of providing a response to a challenge, the physical structure such that before the physical structure is ever provided with the challenge, the response to the challenge is unpredictable. The finite state machine moves from an initial state to an intermediate state due to receiving the response from the physical structure, and moves from the intermediate state to a final state due to receiving a key. The final state indicates whether the physical structure is a counterfeit physical structure.

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Minneapolis, MN, United States of America

Hyung-Il Kim