Driving method of synapse circuit
AssigneeTohoku University
InventorsYitao Ma, Tetsuo Endoh
Life of this patent
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Abstract
Provided is a simplified driving method of a synapse circuit. In a case where a first pre-spike pulse precedes a first post-spike pulse, a second pre-spike pulse from an input circuit is used as a time window that allows writing of a coupling weight, and the first post-spike pulse from a neuron circuit is used as a write pulse for controlling a write timing of the coupling weight. In a case where the first post-spike pulse precedes the first pre-spike pulse, a second post-spike pulse from the neuron circuit is used as the time window, and the first pre-spike pulse from the input circuit is used as the write pulse. The second pre-spike pulse and the second post-spike pulse are output in synchronization with the first pre-spike pulse and the first post-spike pulse, respectively.
Claims11
A driving method of a synapse circuit, the synapse circuit comprising a weight storage unit that stores one of a first coupling weight and a second coupling weight as a synaptic coupling weight, the synapse circuit being connected between a pre-neuron circuit and a post-neuron circuit, the synapse circuit being configured to output, to the post-neuron circuit, a weighted pre-spike pulse obtained by weighting a pre-spike pulse input from the pre-neuron circuit with the synaptic coupling weight and write the synaptic coupling weight based on a pulse time difference and an order of the pre-spike pulse and a post-spike pulse, the post-spike pulse is output from the post-neuron circuit, the driving method comprising:
- inputting, from one of the pre-neuron circuit and the post-neuron circuit to the synapse circuit, a first time window pulse that defines a first time window that allows writing of the synaptic coupling weight to the weight storage unit in a case where the pre-spike pulse precedes the post-spike pulse, and inputting, from the other one of the pre-neuron circuit and the post-neuron circuit to the synapse circuit, a first write pulse having a pulse width smaller than that of the first time window pulse, the first write pulse being a write timing of writing the synaptic coupling weight of the weight storage unit,
- inputting, from one of the pre-neuron circuit and the post-neuron circuit to the synapse circuit, a second time window pulse that defines a second time window that allows writing of the synaptic coupling weight to the weight storage unit in a case where the post-spike pulse precedes the pre-spike pulse, and inputting, from the other one of the pre-neuron circuit and the post-neuron circuit to the synapse circuit, a second write pulse having a pulse width smaller than that of the second time window pulse, the second write pulse being a write timing of writing the synaptic coupling weight of the weight storage unit, and
- performing a write operation by the weight storage unit when the first time window pulse and the first write pulse are simultaneously input to the synapse circuit and when the second time window pulse and the second write pulse are simultaneously input to the synapse circuit.
A neural network circuit device comprising:
- a pre-neuron circuit configured to output a pre-spike pulse;
- a post-neuron circuit configured to output a post-spike pulse;
- a synapse circuit including a weight storage unit that stores one of a first coupling weight and a second coupling weight as a synaptic coupling weight, the synapse circuit being connected between the pre-neuron circuit and the post-neuron circuit, the synapse circuit being configured to output, to the post-neuron circuit, a weighted pre-spike pulse obtained by weighting the pre-spike pulse with the synaptic coupling weight and write the synaptic coupling weight based on a pulse time difference and an order of the pre-spike pulse and the post-spike pulse;
- a first pulse generator configured to input, to the synapse circuit, a first time window pulse that defines a first time window that allows writing of the synaptic coupling weight to the weight storage unit in a case where the pre-spike pulse precedes the post-spike pulse;
- a second pulse generator configured to input, to the synapse circuit, a first write pulse having a pulse width smaller than that of the first time window pulse and being a write timing of writing the synaptic coupling weight of the weight storage unit;
- a third pulse generator configured to input, to the synapse circuit, a second time window pulse that defines a second time window that allows writing of the synaptic coupling weight to the weight storage unit in a case where the post-spike pulse precedes the pre-spike pulse;
- and
- a fourth pulse generator configured to input, to the synapse circuit, a second write pulse having a pulse width smaller than that of the second time window pulse and being a write timing of writing the synaptic coupling weight of the weight storage unit, wherein
- one of the pre-neuron circuit and the post-neuron circuit is provided with the first pulse generator, and the other one is provided with the second pulse generator,
- one of the pre-neuron circuit and the post-neuron circuit is provided with the third pulse generator, and the other one is provided with the fourth pulse generator, and
- the synapse circuit writes the synaptic coupling weight to the weight storage unit when the first time window pulse and the first write pulse are input at a same time and when the second time window pulse and the second write pulse are input at the same time.
Dependencies are inferred from the claim text.