Single-slope comparison device with low-noise, and analog-to-digital conversion device and CMOS image sensor including the same

Patent metadata

Field	Value
Publication number	US-10498992-B2
Application number	US-201816177944-A
Country	US
Kind code	B2
Filing date	Nov 1, 2018
Priority date	Nov 17, 2017
Publication date	Dec 3, 2019
Grant date	Dec 3, 2019

Abstract

A comparison device includes an MSB voltage generation circuit that includes a control signal terminal to generate an MSB voltage; a comparison circuit including a first input terminal receiving a first input signal and a second input terminal receiving a second input signal modified by the MSB voltage outputted from the MSB voltage generation circuit to move to a desired voltage range by comparing the first input signal with the modified second input signal to output an MSB comparison result signal, the comparison circuit, after the first input signal has reached the desired voltage range, comparing the first input signal with a residue voltage and outputting an LSB comparison result signal; and a control circuit receiving the comparison signal and operable to detect a crossing of the first input signal and the second input signal according to the MSB comparison result signal and to output the MSB voltage control signal.

First claim

What is claimed is:

1. A comparison device, comprising:
a most significant bit (MSB) voltage generation circuit that includes a control signal terminal to receive an MSB voltage control signal and is structured to generate an MSB voltage;
a comparison circuit including a first input terminal coupled to receive a first input signal and a second input terminal coupled to receive a second input signal that is modified by the MSB voltage outputted from the MSB voltage generation circuit to output an MSB comparison result signal, the comparison circuit comparing the first input signal with a residue voltage and outputting a least significant bit (LSB) comparison result signal; and
a control circuit coupled to the comparison circuit to receive the comparison signal and operable to detect a crossing of the first input signal and the second input signal according to the MSB comparison result signal and to output the MSB voltage control signal to the MSB voltage generation circuit.

2. The comparison device of claim 1 , wherein comparison circuit moves the first input signal to a desired voltage range by comparing the first input signal with the modified second input signal, and, after the first input signal has reached the desired voltage range, the comparison circuit compares the first input signal with a residue voltage and outputs the LSB comparison result signal.

3. The comparison device of claim 1 , wherein the comparison circuit repeatedly performs a comparison process multiple times during an analog-to-digital conversion, and wherein the comparison process compares the first input signal with the modified second input signal by the MSB voltage to find out how many MSB voltage steps are needed for the first input signal to move to the desired voltage range and produces the MSB comparison result signal at an initial time, and after the initial time, compares the first input signal of a residue range with the residue voltage to output the LSB comparison result signal.

4. The comparison device of claim 1 , wherein the control circuit includes:
a crossing detector structured to detect a crossing of the first input signal and the second input signal according to the MSB comparison result signal outputted from the comparison circuit to produce an output indicating a detection result of the crossing and to output an MSB voltage generation control signal to the MSB voltage generation circuit; and
an MSB voltage size controller coupled to the crossing detector to receive the output thereof and operable to output an MSB voltage size control signal to the MSB voltage generation circuit according to a crossing detection result outputted from the crossing detector.

5. The comparison device of claim 4 , wherein the control circuit further includes:
an MSB voltage update controller coupled to the MSB voltage generation circuit to output an MSB voltage update control signal to the MSB voltage generation circuit.

6. The comparison device of claim 1 , wherein the MSB voltage generation circuit includes:
an MSB voltage size adjuster coupled to the control circuit to receive the MSB voltage size control signal to adjust a magnitude of the MSB voltage;
an MSB voltage controller coupled to the control circuit to receive the MSB voltage generation control signal to control the generation of the MSB voltage; and
an MSB voltage generator coupled to the MSB voltage size adjuster and the MSB voltage controller to generate the MSB voltage of which the size is adjusted by the MSB voltage size adjuster according to the control of the MSB voltage controller.

7. The comparison device of claim 6 , wherein the MSB voltage generation circuit further includes:
an MSB voltage updater coupled to the MSB voltage size adjuster to update the MSB voltage outputted from the MSB voltage generator according to an MSB voltage update control signal outputted from the control circuit.

8. The comparison device of claim 1 , wherein the first input signal is a pixel signal and the second input signal is an offset reference voltage.

9. The comparison device of claim 1 , wherein the first input signal is an offset reference voltage or a ramp signal and the second input signal is obtained by adding or subtracting the MSB voltage to or from a pixel signal.

10. An analog-to-digital conversion device, comprising:
a most significant bit (MSB) voltage generation circuit that includes a control signal terminal to receive an MSB voltage control signal and is structured to generate an MSB voltage;
a comparison circuit including a first input terminal coupled to receive a first input signal and a second input terminal coupled to receive a second input signal that is modified by the MSB voltage outputted from the MSB voltage generation circuit to output an MSB comparison result signal, the comparison circuit comparing the first input signal with a residue voltage and outputting a least significant bit (LSB) comparison result signal;
a control circuit coupled to the comparison circuit to receive the comparison signal and operable to detect a crossing of the first input signal and the second input signal according to the MSB comparison result signal and to output the MSB voltage control signal to the MSB voltage generation circuit; and
a counting circuit coupled to the comparison circuit to perform an MSB counting operation according to the MSB comparison result signal outputted from the comparison circuit and to perform an LSB counting operation according to the LSB comparison result signal.

11. The comparison device of claim 10 , wherein comparison circuit moves the first input signal to a desired voltage range by comparing the first input signal with the modified second input signal, and, after the first input signal has reached the desired voltage range, the comparison circuit compares the first input signal with a residue voltage and outputs the LSB comparison result signal.

12. The analog-to-digital conversion device of claim 10 , wherein the comparison circuit repeatedly performs a comparison process multiple times during an analog-to-digital conversion, and wherein the comparison process compares the first input signal with the modified second input signal by the MSB voltage to find out how many MSB voltage steps are needed for the first input signal to move to the desired voltage range and produces the MSB comparison result signal at an initial time, and after the initial time, compares the first input signal of a residue range with the residue voltage to output the LSB comparison result signal.

13. The analog-to-digital conversion device of claim 10 , wherein the control circuit includes:
a crossing detector structured to detect a crossing of the first input signal and the second input signal according to the MSB comparison result signal outputted from the comparison circuit to produce an output indicating a detection result of the crossing and to output an MSB voltage generation control signal to the MSB voltage generation circuit; and
an MSB voltage size controller coupled to the crossing detector to receive the output thereof and operable to output an MSB voltage size control signal to the MSB voltage generation circuit according to a crossing detection result outputted from the crossing detector.

14. The analog-to-digital conversion device of claim 13 , wherein the control circuit further includes:
an MSB voltage update controller coupled to the MSB voltage generation circuit to output an MSB voltage update control signal to the MSB voltage generation circuit.

15. The comparison device of claim 10 , wherein the MSB voltage generation circuit includes:
an MSB

Assignees

• Sk Hynix Inc

Inventors

• Kim Hyeon-June

Classifications

• G11C27/024 Primary

  using a capacitive memory element (G11C27/04 takes precedence) · CPC title

• H04N25/766

  comprising control or output lines used for a plurality of functions, e.g. for pixel output, driving, reset or power · CPC title

• G11C2207/068

  Integrator type sense amplifier · CPC title

• H04N5/3741

  Electricity · mapped topic

• G11C7/06 Primary

  Sense amplifiers; Associated circuits {, e.g. timing or triggering circuits} · CPC title