Solid-state image pickup device and method for driving the same in solid-state imaging pickup device and method for driving the same in a number of modes
A system and method for driving a solid-state image pickup device including a pixel array unit including unit pixels. Each unit pixel includes a photoelectric converter, column signal lines and a number of analog-digital converting units. The unit pixels are selectively controlled in units of rows. Analog signals output from the unit pixels in a row selected by the selective control though the column signal lines are converted to digital signals via the analog-digital converting units. The digital signals are added among a number of unit pixels via the analog-digital converting units. The added digital signals from the analog-digital converting units are read. Each unit pixel in the pixel array unit is selectively controlled in units of arbitrary rows, the analog-distal converting units being operable to performing the converting in a (a) normal-frame-rate mode and a (b) high-frame-rate mode in response to control signals.
1. A solid-state image pickup device comprising:
a pixel array unit including unit pixels which are two-dimensionally arranged in a matrix pattern, each unit pixel including a photoelectric converter, and column signal lines corresponding to respective columns of the matrix pattern;
a row scanning unit selectively controlling each unit pixel of the pixel array unit in units of rows;
a pair of column processing units, each including a plurality of analog-digital converting units, each converting an analog signal output from a respective one of the unit pixels in each row selectively-controlled by the row scanning unit through the column signal lines to a respective digital signal;
a pair of column scanning units controlling output of the digital signals from the respective analog-digital converting units, a first portion of the unit pixels and their analog-digital converting units associated with one of the column scanning units, a second portion of the unit pixels and their analog-digital converting units associated with the other of the column scanning units;
respective selecting switches between the pixel array unit and the column scanning units, wherein each of the selecting switches operate in a complimentary manner so as to connect one of two adjoining column signal lines to a first one of the column processing units when the other of the two adjoining column signal lines is connected to a second one of the column processing units;
a respective pair of output lines for transmitting the digital signals output from the analog-digital converting units under control by the column scanning units; and
a digital adder unit to which the output lines are connected and which adds together digital signals output from the column processing units, wherein only digital signals for pixels associated with one color are added together.
2. A solid-state image pickup device according to claim 1 , comprising a pair of reference voltage sources which provide respective reference voltages to the analog-digital converting unit, and wherein each analog-digital converter comprises a comparator for comparing the analog signal output from a unit pixel with a respective reference voltage.
3. A solid-state image pickup device according to claim 2 , wherein each analog-digital converting unit comprises a measuring unit for measuring comparison time in the comparator from the start to the end of a comparing operation, the measuring unit performing addition prior to the digital signals being output from the column processing units.
4. A solid-state image pickup device according to claim 3 , wherein the measuring unit is a counter which adds signals by repeating a count operation on each analog signal of the plurality of unit pixels.
5. A solid-state image pickup device, comprising:
a pixel array unit including unit pixels which are two-dimensionally arranged in a matrix pattern, each unit pixel including a photoelectric converter, and column signal lines corresponding to respective columns of the matrix pattern;
a row scanning unit selectively controlling each unit pixel of the pixel array unit in units of rows;
a pair of column processing units, each including a plurality of analog-digital converting units, each converting an analog signal output from a respective one of the unit pixels in each row selectively-controlled by the row scanning unit through the column signal lines to a respective digital signal;
a pair of column scanning units controlling output of the digital signals from the respective analog-digital converting units, a first portion of the unit pixels and their analog-digital converting units associated with one of the column scanning units, a second portion of the unit pixels and their analog-digital converting units associated with the other of the column scanning units;
respective selecting switches between the pixel array unit and the column scanning units, wherein each of the selecting switches operate in a complimentary manner so as to connect one of two adjoining column signal lines to a first one of the column processing units when the other of the two adjoining column signal lines is connected to a second one of the column processing units;
a respective pair of output lines for transmitting the digital signals output from the analog-digital converting units under control by the column scanning units; and
a digital adder unit to which the output lines are connected and which adds together digital signals output from the column processing units,
wherein,
each analog-digital converting means comprises (a) comparing means for comparing the analog signal output from each unit pixel with a reference voltage, and (b) measuring means for measuring comparison time in the comparing means from the start to the end of a comparing operation, the measuring means performing addition prior to the digital signals being output from the column processing units,
the measuring means is a counter which forms the digital signals by repeating a count operation on each analog signal of the plurality of unit pixels, and
the counter is an up/down counter, which performs subtraction by performing a down count and an up count on first and second analog signals output from one of the unit pixels and which performs addition by repeating an up count on each analog signal of the plurality of unit pixels.