Charge domain mathematical engine and method
A multiplier has a pair of charge reservoirs. The pair of charge reservoirs are connected in series. A first charge movement device induces charge movement to or from the pair of charge reservoirs at a same rate. A second charge movement device induces charge movement to or from one of the pair of reservoirs, the rate of charge movement programmed to one of add or remove charges at a rate proportional to the first charge movement device. The first charge movement device loads a first charge into a first of the pair of charge reservoirs during a first cycle. The first charge movement device and the second charge movement device remove charges at a proportional rate from the pair of charge reservoirs during a second cycle until the first of the pair of charge reservoirs is depleted of the first charge. The second charge reservoir thereafter holding the multiplied result.
1. A weighted summer comprising:
a single charge reservoir;
a plurality of input charge movement devices each coupled to the single charge reservoir, each one of coupling or removing charges to or from the single charge reservoir in a first cycle, wherein for each of the input charge movement devices a rate of charge movement conforms to weighted multiplicands and are proportional to an output charge movement device rate of charge movement; and
an output charge movement device one of coupling or removing the charges to or from the single charge reservoir so as to return the single charge reservoir to a starting charge level during a second cycle after which charge movement ends.
2. The weighted summer of claim 1 wherein:
the plurality of input charge movement devices couple or remove the charges at rates proportional to the rate that the output charge movement device will couple or remove the charges during the second cycle, but where the plurality of input charge movement devices are each individually gated in time in conformance with input information and;
wherein during the second cycle a time during which the output charge movement device is coupling or removing the charges to return the single charge reservoir to the starting charge level represents an output of the weighted summer.
3. The weighted summer of claim 1 , wherein the summer comprises a spiking circuit having a comparator, the comparator initiating an interrupt to a controller circuit when the single charge reservoir reaches a predetermined level.