QUALCOMM Incorporated
Compute-in-memory (CIM) cell circuits employing capacitive storage circuits for reduced area and CIM bit cell array circuits

Abstract:

A CIM bit cell circuit employing a capacitive storage circuit to store a binary weight data as a voltage occupies half or less of the area of a 6T SRAM CIM bit cell circuit, reducing the increase in area incurred in the addition of a CIM bit cell array circuit to an IC. The CIM bit cell circuit includes a capacitive storage circuit that stores binary weight data in a capacitor and generates a product voltage indicating a binary product resulting from a logical AND-based operation of the stored binary weight data and an activation signal. The capacitive storage circuit may include a capacitor and a read access switch or a transistor. The CIM bit cell circuit includes a write access switch to couple a write bit voltage to the capacitive storage circuit. In a CIM bit cell array circuit, the product voltages are summed in a MAC operation.