Image sensor, method of driving an image sensor, electronic apparatus, and program
View Patent ↗The present disclosure relates to: an imaging element and an imaging-element drive method which enable negative-voltage fluctuation to be suppressed without increasing negative-voltage capacitance; an electronic device; and a program. A dual circuit is prepared for negative voltages. At times other than during exposure and reset, the negative voltage is supplied to readout transistors in lines other than a readout line. At timings other than these times, the negative voltage is supplied to the aforementioned readout transistors. Accordingly, even if the negative voltage fluctuates during exposure and reset, a stable negative voltage is supplied at timings at which other pixel data is read out, and thus fluctuation is suppressed. The present disclosure is applicable to imaging elements.
1. An image sensor, comprising:
photodiodes, each of the photodiodes generating an electric charge corresponding to an intensity of incident light for each pixel;
readout transistors, each of the readout transistors reading the electric charge generated by each of the photodiodes;
a first negative voltage supplier that supplies a negative voltage to the readout transistors when the readout transistors are not turned on; and
a second negative voltage supplier that supplies a negative voltage to the readout transistors when the readout transistors are not turned on, wherein
one of the first negative voltage generator and the second negative voltage generator is selected and supplies the negative voltage.
2. The image sensor according to claim 1 , wherein
the first negative voltage supplier is selected and supplies the negative voltage at a time of start of exposure of the photodiodes to light and at a time of resetting, and the second negative voltage supplier is selected and supplies the negative voltage at times other than those times.
3. The image sensor according to claim 2 , further comprising:
a pulse generator that generates a pulse signal, wherein
the first negative voltage supplier is selected and supplies the negative voltage at a time of start of exposure of the photodiodes to light and at a time of resetting, and the second negative voltage supplier is selected and supplies the negative voltage at times other than those times, on the basis of a pulse generated by the pulse generator.
4. The image sensor according to claim 1 , wherein
the first negative voltage supplier is a first negative voltage capacitor, and the second negative voltage supplier is a second negative voltage capacitor.
5. The image sensor according to claim 4 , wherein
each of the first negative voltage capacitor and the second negative voltage capacitor is charged by a charge pump circuit.
6. The image sensor according to claim 1 , wherein
the first negative voltage supplier is selected and supplies the negative voltage to the readout transistors of rows sharing a floating diffusion with a transistor of a readout row out of the readout transistors not turned on, and the second negative voltage supplier is selected and supplies the negative voltage to the readout transistors of non-selected rows other than those rows.
7. The image sensor according to claim 6 , wherein
the first negative voltage supplier supplies the negative voltage to a predetermined percentage of the non-selected rows at predetermined intervals.
8. A method of driving an image sensor including:
photodiodes, each of the photodiodes generating an electric charge corresponding to an intensity of incident light for each pixel,
readout transistors, each of the readout transistors reading the electric charge generated by each of the photodiodes,
a first negative voltage supplier that supplies a negative voltage to the readout transistors when the readout transistors are not turned on, and
a second negative voltage supplier that supplies a negative voltage to the readout transistors when the readout transistors are not turned on,
the method comprising:
selecting one of the first negative voltage generator and the second negative voltage generator, and supplying the negative voltage by the selected negative voltage generator.
9. A non-transitory computer-readable medium storing a program, which causes a computer to control an image sensor including: photodiodes, each of the photodiodes generating an electric charge corresponding to an intensity of incident light for each pixel, readout transistors, each of the readout transistors reading the electric charge generated by each of the photodiodes, a first negative voltage supplier that supplies a negative voltage to the readout transistors when the readout transistors are not turned on, and a second negative voltage supplier that supplies a negative voltage to the readout transistors when the readout transistors are not turned on, to select one of the first negative voltage generator and the second negative voltage generator, and supply the negative voltage by the selected negative voltage generator.
10. An electronic apparatus, comprising:
photodiodes, each of the photodiodes generating an electric charge corresponding to an intensity of incident light for each pixel;
readout transistors, each of the readout transistors reading the electric charge generated by each of the photodiodes;
a first negative voltage supplier that supplies a negative voltage to the readout transistors when the readout transistors are not turned on; and
a second negative voltage supplier that supplies a negative voltage to the readout transistors when the readout transistors are not turned on, wherein
one of the first negative voltage generator and the second negative voltage generator is selected and supplies the negative voltage.