Reference voltage circuit and image-capture circuit
AssigneeSony Corporation
InventorHayato Wakabayashi
Life of this patent
Estimating the term…
Abstract
A reference voltage circuit for generating a reference voltage to be referred when a pixel signal is digitally converted, includes ramp voltage generating means for generating a ramp voltage which drops from a predetermined initial voltage at a certain gradient, a transistor for forming, together with the ramp voltage generating means, a current mirror circuit, and gain change means for changing a current value of a current flowing from a predetermined power supply via the transistor to change the gradient of the ramp voltage generated by the ramp voltage generating means.
Claims11
An imaging device comprising:
- a pixel that outputs an analog signal;
- a comparator that receive the analog signal and a reference signal;
- a reference signal generating circuit including:
- a ramp voltage generating circuit that generates a ramp voltage;
- a first transistor;
- a second transistor;
- an amplifier;
- a resistance, wherein
- the reference signal generating circuit is configured to output the reference signal,
- a gate of the first transistor is configured to electrically connect to the ramp voltage generating circuit and a drain of the first transistor,
- a source of the first transistor is configured to electrically connect to a first predetermined voltage,
- a drain of the second transistor is configured to electrically connect to the drain of the first transistor,
- a gate of the second transistor is configured to electrically connect to an output terminal of the amplifier,
- an input terminal of the amplifier is configured to electrically connect to a second predetermined voltage, and
- the resistance is configured to electrically connect to a source of the second transistor.
An imaging device comprising:
- a pixel that outputs an analog signal;
- a comparator that receive the analog signal and a reference signal;
- a reference signal generating circuit including:
- a ramp voltage generating circuit that generates a ramp voltage;
- an offset generating circuit;
- a first transistor;
- a second transistor;
- a switch;
- a third transistor;
- a fourth transistor;
- a first resistance;
- a second resistance;
- wherein
- the reference signal generating circuit is configured to output the reference signal,
- a gate of the first transistor is configured to electrically connect to the ramp voltage generating circuit and a drain of the first transistor,
- a source of the first transistor is configured to electrically connect to a first predetermined voltage,
- a drain of the second transistor is configured to electrically connect to the drain of the first transistor,
- a gate of the second transistor is configured to electrically connect to the switch,
- the first resistance is configured to electrically connect to a source of the second transistor,
- a gate of third transistor is configured to electrically connect to the offset generating circuit and a drain of the third transistor,
- a gate of the fourth transistor is configured to electrically connect to an output terminal of the amplifier and the switch,
- a drain of the fourth transistor is configured to electrically connect to the drain of the third transistor,
- an input terminal of the amplifier is configured to electrically connect to a second predetermined voltage, and
- a source of the fourth transistor is configured to electrically connect to the second resistance.
Dependencies are inferred from the claim text.