Encoder and operation method thereof

A method of operating an encoder configured to provide an input spike signal to an spike neural network (SNN) circuit, the method comprising:

• generating a plurality of event signals, whose activations are determined based on a plurality of events occur, respectively;
• applying a weight to each of the plurality of event signals;
• accumulating a voltage at a first node, at which a voltage level is continuously reduced, based on a weight applied to an activated event signal from among the plurality of event signals;
• and
• outputting the input spike signal of which a firing period is changed based on the voltage level of the first node,
• wherein the firing period is a first time interval when the voltage level of the first node is a first level, and is a second time interval longer than the first time interval when the voltage level of the first node is a second level lower than the first level.

A neuromorphic system comprising:

• an spike neural network (SNN) circuit implemented by a rate-coding method;
• and
• an encoder configured to provide an input spike signal to the SNN circuit,
• wherein the encoder includes a first node, and includes a spike generation circuit configured to generate the input spike signal based on a voltage level of the first node,
• wherein the voltage level of the first node is continuously reduced, increases by a first voltage when a first event occurs, and increases by a second voltage when a second event occurs, and
• wherein a firing period of the input spike signal is reduced when the voltage level of the first node increases.