# US 12,602,577 B2 · Neuron core with time-embedded floating point arithmetic > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,602,577 B2 - Document ID: US12602577B2 - Status: Granted - Kind: B2 - Application number: 17/579,400 - Filed: 2022-01-19 - Published: 2022-07-21 - Granted: 2026-04-14 - Earliest claimed: 2021-01-21 - Assignees: Korea Institute of Science and Technology - Applicants: Korea Institute of Science and Technology - Inventors: Jong Kil Park; In Ho Kim; Su Youn Lee; Jong Keuk Park; Joon Young Kwak; Jae Wook Kim; Yeon Joo Jeong - Web page: https://patentgrep.com/patent/US12602577B2 ## CPC - G06N 3/065: Analogue means - G06F 7/483: Computations with numbers represented by a non-linear combination of denominational numbers, e.g. rational numbers, logarithmic number system or floating-point numbers {(G06F7/4806, G06F7/4824, G06F7/49, G06F7/491, G06F7/544 take precedence)} - G06N 3/049: Temporal neural networks, e.g. delay elements, oscillating neurons or pulsed inputs - G06N 3/0499: Feedforward networks - G06N 3/08: Learning methods - G06N: COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract Provided is a method of operating a neuron in a neuromorphic system. The method includes evaluating a membrane potential value at a corresponding time when receiving an input spike, time-modulating a synaptic weight of the membrane potential value and converting the time-modulated synaptic weight into a membrane potential value at a reference time, and generating an output spike when the membrane potential value at the reference time exceeds a certain threshold value. The membrane potential value at the reference time is represented by a floating point number including a predetermined bit of exponent and mantissa, and the floating point number includes time information. The method further includes accessing a memory and scanning a neural state variable when a timer is updated to “0” to update the neural state variable to an updated value at a reference time. ## Claims ### Claim 1 A method of operating a neuron in a neuromorphic system, comprising: evaluating a membrane potential value at a corresponding time when receiving an input spike; time-modulating a synaptic weight of the membrane potential value at the corresponding time and converting the time-modulated synaptic weight into a membrane potential value at a reference time; and generating an output spike when the membrane potential value at the reference time exceeds a certain threshold value; wherein the time-modulating the synaptic weight of the membrane potential value at the corresponding time includes representing the membrane potential value at the corresponding time in a floating-point format including time information, the time information being represented as a time bias derived from a timer and reflected in the floating-point format by an integer addition operation, and accessing a memory to scan neural state variables corresponding to the membrane potential value at the corresponding time only when the timer is updated to “0”, and updating a neural state variable in response to an input event. ### Claim 2 (depends on 1) The method of claim 1, wherein the synaptic weight is converted into the membrane potential value at the reference time by adding the time bias to the synaptic weight. ### Claim 3 (depends on 2) The method of claim 2, further comprising: modulating a synaptic weight of a new input spike into the reference time using a second time bias when the new input spike is received; adding the modulated synaptic weight of the new input spike to the membrane potential value at the reference time; and generating an output spike when the added modulated synaptic weight of the new input spike exceeds the certain threshold value. ### Claim 4 (depends on 1) The method of claim 1, wherein the membrane potential value at the reference time is represented by a floating point number including a predetermined bit of exponent and a predetermined bit of mantissa. ### Claim 5 (depends on 4) The method of claim 4, wherein the floating point number includes the time information. ### Claim 6 (depends on 5) The method of claim 5, wherein the time information is valid for a timer cycle. ### Claim 7 A neuron core unit comprising: a timer that indicates a current time of a neuron core; a controller configured to, upon receipt of an input synaptic event, convert a membrane potential value at the current time indicated by the timer into a membrane potential value at a reference time for an input synaptic event and to output an output spike when a membrane potential value at the reference time exceeds a certain threshold value; and a memory that includes a neural state variable; wherein the controller, to convert the membrane potential value at the current time indicated by the timer into the membrane potential value at the reference time and to output the output spike, represents the membrane potential value at the current time indicated by the timer in a floating-point format including time information, the time information being represented as a time bias derived from the timer and reflected in the floating-point format by an integer addition operation, accesses the memory and scans neural state variables corresponding to the membrane potential value at the current time indicated by the timer only when the timer is updated to “0” or in response to an input event. ### Claim 8 (depends on 7) The neuron core unit of claim 7, wherein the synaptic weight is converted into the membrane potential value at the reference time by adding the time bias to the synaptic weight. ### Claim 9 (depends on 8) The neuron core unit of claim 8, wherein the controller modulates a synaptic weight of a new input spike into the reference time using a second time bias when the new input spike is received, adds the modulated synaptic weight of the new input spike to the membrane potential value at the reference time, and generates an output spike when the added modulated synaptic weight of the new input spike exceeds a certain threshold value. ### Claim 10 (depends on 7) The neuron core unit of claim 7, wherein the membrane potential value at the reference time is represented by a floating point number including a predetermined bit of exponent and a predetermined bit of mantissa. ### Claim 11 (depends on 10) The neuron core unit of claim 10, wherein the floating point number includes the time information. ### Claim 12 (depends on 11) The neuron core unit of claim 11, wherein the time information is valid for a timer cycle.