Neuron circuit, system, and switch circuit

A system comprising:

• neuron circuits each including:
• an input terminal to which a spike signal is continuously input,
• a first switch element that has a first end coupled to the input terminal and a second end coupled to an intermediate node, remains in a high resistance state even when a single spike signal is input, and goes into a low resistance state, of which a resistance value is lower than that of the high resistance state, when a plurality of spike signals are input within a first time period,
• a feedback circuit coupled to the intermediate node, and causing the input terminal to be at a predetermined level when the first switch element goes into the low resistance state, and
• a second switch element that is connected in series with the first switch element between the input terminal and the intermediate node, remains in a low resistance state even when one or more spike signals are input to the input terminal, and goes into a high resistance state when the input terminal becomes at a predetermined level;
• and
• a synaptic circuit connecting the neuron circuits.

A switch circuit comprising:

• an input terminal to which an input signal is input;
• an output terminal;
• and
• a switch element including:
• a first end coupled to the input terminal,
• a second end coupled to the output terminal, and
• a resistor that is connected between the first end, and the second end, is in a high resistance state when an internal state quantity is less than a first threshold value, is in a low resistance state, of which a resistance value is less than that of the high resistance state, when the internal state quantity is greater than a second threshold value, wherein
• the internal state quantity S(T0) at time T0 is
• S(T0)=∫0T0f(V10(T0−T))e−T/τdecdT
• where a voltage between the first end and the second end is represented by V10, an effect of V10 on an internal state quantity is represented by f(V10), and a relaxation time of the internal state quantity is represented by τdec, and
• a cycle period of variation in the input signal is shorter than the relaxation time.