AD CONVERTER AND SOLID-STATE IMAGING APPARATUS USING THE SAME

摘要

There is a need to provide an AD converter capable of reducing occurrence of a noise. An AD converter includes an operational amplifier and a clip circuit. The operational amplifier receives ramp voltage and voltage for an analog signal and allows output terminal voltage to transition from an H level to an L level when a change in the ramp voltage reaches the voltage for the analog signal. The clip circuit fixes an output terminal of the operational amplifier to clipping voltage after output voltage for the operational amplifier reaches threshold voltage for a latch circuit. Therefore, the AD converter can limit a range of output voltage, as a source of noise, for the operational amplifier and eliminate an unnecessary change in the output voltage after the threshold voltage for the latch circuit is reached.

主权项

1. A solid-state imaging apparatus comprising:
a plurality of pixel circuits, each of which outputs an analog signal responding to an amount of incident light; a plurality of row selection lines and a plurality of signal lines coupled to the plurality of pixel circuits; a plurality of AD converters, each of which is coupled to one of the signal lines and is configured to convert an analog signal from an activated pixel circuit in the plurality of pixel circuits into a digital signal, each of the AD converters comprising:
an operational amplifier having an input node for inputting the analog signal from the activated pixel circuit via the signal line, andan output node; and a bias voltage supply line configured to supply a bias voltage to each of the plurality of AD converters, wherein a power supply voltage is supplied to the operational amplifier in each of the AD converters, wherein a clip circuit is coupled to the output node of the operational amplifier, which is configured to make an amplitude of a voltage level of the output node of the operational amplifier less than the power supply voltage.