Column ADC Gain Switching in Solid-State Image Sensors

Solution Overview

Problem

Conventional single-slope integration type column ADCs in solid-state imaging apparatuses require generating multiple reference signals with different slopes to change analog gain, leading to increased circuit size and power consumption.

Innovation Solution

A solid-state imaging apparatus with a voltage generator outputting multiple reference voltages and switches to changeover these voltages, allowing for adjustable analog gain without expanding circuit area or increasing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple reference signals with different slopes are generated to change analog gain in single-slope integration type column ADC, then the analog gain can be adjusted for each color or unit pixel, but the circuit scale enlarges and power consumption increases

Engineering Contradiction:

Improveanalog gain adjustment capabilityVSAvoidcircuit scale

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Multiple reference voltage signals are merged into a single reference voltage line. Instead of providing separate reference voltage generators for each column ADC, a single reference voltage line supplies all column ADCs, and analog gain adjustment is achieved by changing the connection timing rather than generating multiple separate reference signals.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The reference voltage connection timing is made dynamic and adjustable. By controlling when each column ADC connects to the reference voltage line during the conversion period, the effective reference voltage duration varies, enabling analog gain adjustment without requiring multiple static reference voltage generators.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If multiple reference signals with different slopes are generated to change analog gain in single-slope integration type column ADC, then the analog gain can be adjusted for each color or unit pixel, but power consumption increases

Engineering Contradiction:

Improveanalog gain adjustment capabilityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by stationary object

Solution Approach 1:

Multiple reference voltage signals are merged into a single reference voltage line. Instead of providing separate reference voltage generators for each column ADC, a single reference voltage line supplies all column ADCs, and analog gain adjustment is achieved by changing the connection timing rather than generating multiple separate reference signals.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

A single reference voltage line serves multiple functions by being shared across all column ADCs. The same reference voltage line can serve different column ADCs with different analog gain requirements by adjusting connection timing, making the reference voltage generation system universal rather than dedicated to each ADC.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If individual voltage generators are provided for each voltage value to change analog gain, then the analog gain can be changed for each converter, but the area expands

Engineering Contradiction:

Improveanalog gain adjustability per converterVSAvoidcircuit area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

Multiple reference voltage signals are merged into a single reference voltage line. Instead of providing separate reference voltage generators for each column ADC, a single reference voltage line supplies all column ADCs, and analog gain adjustment is achieved by changing the connection timing rather than generating multiple separate reference signals.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

A switch acts as an intermediary between the single reference voltage line and multiple column ADCs. The switch controls which column ADCs connect to the reference voltage line and for how long, enabling individual analog gain adjustment for each converter without requiring individual voltage generators.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11405571B2Solid-state imaging apparatus and electronic apparatus

Publication Date: 2022.08.02 SONY SEMICON SOLUTIONS CORP

AI summary

Changing the analog gain for each of columns while suppressing an expansion of area and an increase in power consumption. A solid-state imaging apparatus (1, 1A) according to an embodiment includes: converters (10A to 10D) connected to a vertical signal line (VSL) extending from a pixel array unit (30); a voltage generator (20) that is connected to a plurality of voltage lines and outputs reference voltages having mutually different voltage values individually to the plurality of voltage lines; wiring lines (L10 to L31, L20 to L23) connecting the converter and the plurality of voltage lines; and switches (SW0 to SW3) provided on the wiring line and configured to perform changeover of the voltage lines connected to the converter to one of the plurality of voltage lines.