# US 2014/0152879 A1 · Ad converter and solid-state imaging apparatus using the same

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2014/0152879 A1
- Document ID: US20140152879A1
- Status: Published application
- Kind: A1
- Application number: 14/174,236
- Filed: 2014-02-06
- Published: 2014-06-05
- Earliest claimed: 2011-12-08
- Assignees: Renesas Electronics Corporation
- Applicants: Renesas Electronics Corporation
- Inventors: Osamu NISHIKIDO; Yasutoshi Aibara; Hirokazu Shimizu; Satoshi Tatsukawa; Takayoshi Shigekura
- Web page: https://patentgrep.com/patent/US20140152879A1

## CPC

- H03M 1/50: with intermediate conversion to time interval (H03M1/64 takes precedence)
- H03M 1/0863: {of switching transients, e.g. glitches}
- H03M 1/56: Input signal compared with linear ramp
- H04N 25/78: Readout circuits for addressed sensors, e.g. output amplifiers or A/D converters
- H03M 1/123: {Simultaneous, i.e. using one converter per channel but with common control or reference circuits for multiple converters}
- H04N 25/617: for reducing electromagnetic interference, e.g. clocking noise
- H04N 25/76: Addressed sensors, e.g. MOS or CMOS sensors
- H03M: CODING; DECODING; CODE CONVERSION IN GENERAL (using fluidic means F15C4/00; optical analogue/digital converters G02F7/00; coding, decoding or code conversion, specially adapted for particular applications, see the relevant subclasses, e.g. G01D, G01R, G06F, G06T, G09G, G10L, G11B, G11C, H04B, H04L, H04M, H04N; ciphering or deciphering for cryptography or other purposes involving the need for secrecy G09C)
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

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.

## Claims

### Claim 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, and
an 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.

### Claim 2 (depends on 1)

A solid-state imaging apparatus according to claim 1,
wherein the clip circuit is comprised of an N-type MOSFET,
wherein the power supply voltage is supplied to a drain electrode of the N-type MOSFET,
wherein a source electrode of the N-type MOSFET is coupled to the output node of the operational amplifier.

### Claim 3 (depends on 1)

A solid-state imaging apparatus according to claim 1,
wherein the plurality of pixel circuits are disposed in rows and columns.

### Claim 4 (depends on 1)

A solid-state imaging apparatus according to claim 1,
wherein a control circuit configured to select one of the row selection lines and activate each pixel circuit is disposed.

### Claim 5 (depends on 1)

A solid-state imaging apparatus according to claim 1,
wherein the bias voltage is supplied to the operational amplifier.

### Claim 6 (depends on 4)

A solid-state imaging apparatus according to claim 4,
wherein the operational amplifier is comprised of a plurality of MOSFETs,
wherein the bias voltage is supplied to agate electrode of a MOSFET in the plurality of MOSFETs.

### Claim 7 (depends on 1)

A solid-state imaging apparatus according to claim 1,
wherein the operational amplifier includes a current mirror circuit.

### Claim 8 (depends on 1)

A solid-state imaging apparatus according to claim 1,
wherein a latch circuit is coupled to the output node of the operational amplifier.