Homeostatic circuit for neural networks

A homeostatic circuit for neural networks configured to keep a total synaptic driving current in a predetermined range around an optimal operating point, the homeostatic circuit for neural networks comprising:

• a feedback circuit;
• a first electronic switch;
• a synapse circuit;
• a second electronic switch;
• a third electronic switch;
• a first capacitor;
• and
• a fourth electronic switch;
• wherein:
• the feedback circuit is configured to receive the total synaptic driving current and output a feedback voltage which varies with the total synaptic driving current;
• the first electronic switch is electrically connected with the synapse circuit and the second electronic switch and configured to receive the feedback voltage and output a current control signal according to the feedback voltage;
• the gate electrode of the first electronic switch is electrically connected with the feedback circuit;
• the second electronic switch is electrically connected with the synapse circuit and the third electronic switch and configured to output a first voltage signal according to the current control signal;
• the drain electrode of the third electronic switch is electrically connected with the feedback circuit;
• the third electronic switch is configured to adjust the total synaptic driving current in a direction opposite to variation tendency of the total synaptic driving current according to the first voltage signal so as to keep the total synaptic driving current in the predetermined range;
• one end of the first capacitor is electrically connected with a power supply voltage while the other end of the first capacitor is electrically connected with the third electronic switch;
• the total synaptic driving current is produced by the integrating effect of the homeostatic circuit for neural networks through the first capacitor;
• the fourth electronic switch is electrically connected with the second electronic switch and configured to provide a constant current for the second electronic switch so that variation tendency of the first voltage signal is the same as variation tendency of the current control signal;
• the feedback circuit comprises a comparator and a control voltage generator which are electrically connected with each other;
• the comparator comprises a first input port, a second input port and an output port;
• the first input port is configured to receive a reference current, the second input port being configured to receive the total synaptic driving current and the output port being configured to output a second voltage signal;
• the control voltage generator is configured to receive the second voltage signal and produce the feedback voltage;
• the control voltage generator comprises a fifth electronic switch, a first voltage module, a second voltage module, a third voltage module and a second capacitor, the fifth electronic switch being electrically connected with the first voltage module, the second voltage module, the third voltage module and the second capacitor;
• the first voltage module is configured to provide a first comparison voltage for the fifth electronic switch;
• the second voltage module is configured to provide a second comparison voltage for the fifth electronic switch;
• the third voltage module is configured to control conducting state of the fifth electronic switch;
• the second capacitor is configured to output the feedback voltage;
• when the first comparison voltage is greater than the second comparison voltage, the second capacitor is controlled by the fifth electronic switch to be charged;
• and
• when the first comparison voltage is lower than the second comparison voltage, the fifth electronic switch controls the second capacitor to be discharged so as to control the feedback voltage to vary slowly.