Event driven mathematical engine and method
An event driven device has a network collecting data. A device is coupled to the network for determining changes in the data collected, wherein the device signals the network to process the data collected when the device determines desired changes in the data collected. In a second embodiment a level shift adjusts the band diagram of a spill and fill circuit to allow processing only if a change in input value occurs. This is extended to teach a means by which the subset of an image or incoming audio data might be used to trigger an event. It could also be used for always on operation at lower power than alternative solutions.
1. An event driven device comprising a neural network whose input layer comprises pixel charge data coupled through transfer gates to a plurality of analog multiply and sum devices, the multiply and add devices comprising level shifts which are used to adjust a reset level of the analog multiply and sum devices;
wherein after the processing of each exposure by the analog multiply and sum devices, the reset level of the analog multiply and sum devices are set to the potential of the exposure such that in a subsequent exposure a spill and fill circuit will transfer no charge to the multiply and sum devices unless a pixel value has changed.
2. The event driven device of claim 1 wherein an output pulse reflects only a difference in pixel value between exposures as a result of a new input value.
3. The event driven device of claim 2 comprising an adjustment device to set the reset level to program a desired minimum change in pixel value before performing multiply and add functions.
4. The event driven device of claim 1 where the reset level is set by storing an initial floating diffusion (FD) potential using a sample and hold circuit which is coupled to a level shift coupled in series with a source of a common source transistor of a single transistor multiplier.
5. The event driven device of claim 4 wherein a pair of gated current sources adjust the reset level in conformance with a desired threshold.
6. The event driven device of claim 5 where an upper threshold and a lower threshold are programmed in two separate multiply and sum circuits.
7. The event driven device of claim 6 programmed in conformance with a response template so that if a desired response occurs the resulting pulse triggers an event.