Ramp waveform generation circuit, analog/digital conversion circuit, imaging device and control method of imaging device
AssigneeFujitsu Limited
InventorsSeiji Yamagata, Jun Funakoshi, Tsuyoshi Higuchi, Toshitaka Mizuguchi
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Abstract
A ramp waveform generation circuit which comprises a first reference power supply, and supplies a ramp waveform signal to an analog/digital conversion circuit further comprises a connection circuit for reflecting the amount of fluctuation of the output potential of a second reference power supply which is installed in a noise elimination circuit for eliminating the noise of an analog signal inputted to the analog/digital conversion circuit in the output potential of the first reference power supply.
Claims18
A ramp waveform generation circuit which comprises a first reference power supply and supplies an analog/digital conversion circuit with a ramp waveform signal, further comprising
- a connection circuit for reflecting an amount of fluctuation of an output potential of a second reference power supply which is installed in a noise elimination circuit for eliminating the noise of an analog signal inputted to the analog/digital conversion circuit in an output potential of the first reference power supply.
An analog/digital conversion device which comprises a comparator to which a ramp waveform signal inputted from a ramp waveform generation circuit, an analog signal inputted through a noise elimination circuit and a clock signal are inputted, and which converts the analog signal into a digital signal, based on a count value of the clock signal, needed until a level of the ramp waveform generation signal reaches that of the analog signal, further comprising:
- a connection circuit for reflecting amount of fluctuation of an output potential of a second reference power supply which is installed in the noise elimination circuit to an output potential of a first reference power supply which is installed in the ramp waveform generation circuit.
An imaging device which comprises an optical/electrical conversion device and a reading circuit provided with a noise elimination circuit which is disposed on an output route of an optically/electrically converted signal outputted from the analog/digital conversion device and eliminates a noise of the optically/electrically converted signal and the analog/digital conversion circuit for converting the optically/electrically converted signal after noise elimination into a digital signal, further comprising
- a connection circuit for reflecting an amount of fluctuation of an output potential of the second reference power supply installed in the noise elimination circuit in an output potential of a first reference power supply installed in a ramp waveform generation circuit.
A control method of an imaging device which comprises an optical/electrical conversion device and a reading circuit provided with a noise elimination circuit which is disposed on an output route of an optically/electrically converted signal outputted from the analog/digital conversion device and eliminates a noise of the optically/electrically converted signal and the analog/digital conversion circuit for converting the optically/electrically converted signal after the noise elimination into a digital signal, comprising:
- temporarily short-circuiting the output line of a first reference power supply installed in a ramp waveform generation circuit for supplying the analog/digital conversion circuit with a ramp waveform and an output line of a second reference power supply installed in the noise elimination circuit and accumulating electrical charge corresponding to a potential difference between the first and second reference power supplies in a capacitor device provided for the output line of the first reference power supply;
- and
- outputting a ramp waveform signal generated by the output potential from the first reference power supply through the capacitor device.
Dependencies are inferred from the claim text.