CMOS image sensor with noise cancellation

摘要

A memory comprises a two dimensional array of memory cells. Each memory cell comprises a first transistor, a second transistor and a capacitor. A multi-bit datum is stored as one of a plurality of voltage signal levels driven over a vertical input signal line and further across a source and a drain of the first transistor to be stored onto a gate of the second transistor. The first transistor is selected by a horizontal WR control line. The gate of the second transistor is connected to a first terminal of the capacitor. A second terminal of the capacitor is connected to a horizontal RD control line. The RD control line is driven to couple the second transistor to drive a signal onto a vertical output signal line during a read of the stored signal on the gate.

主权项

1. A semiconductor memory, comprising:
a row decoder; a plurality of memory cells, each memory cell comprising:
a first transistor selectable by a WR line controlled by the row decoder;a second transistor having a gate coupled to receive an input voltage signal from a vertical input signal line via the first transistor when the first transistor is selected; anda capacitor having a first terminal connected to the gate and a second terminal connected to an RD line controlled by the row decoder, the RD line being driven to couple the gate through the capacitor to turn on the second transistor during a read of said each memory cell so that the second transistor outputs an output signal; a digital-to-analog converter that converts a multi-bit input datum into an analog input signal to be stored into one of the plurality of memory cells at a time; an analog-to-digital that retrieves an analog output signal from one of the plurality of memory cells at a time and converts it to a multi-bit digital output datum; and a reference memory cell,wherein a storage reference signal is stored in the reference memory cell and then subtracted from the analog output signal before the analog output signal is converted to digital.