US 2022/0070404 A1Published application

Pixel circuit outputting pulse width signals and performing analog operation

AssigneePixart Imaging Inc.

InventorsRen-Chieh LIU, Chih-Huan WU, Yi-Hsien KO, Han-Chi LIU

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Abstract

There is provided a pixel circuit for performing analog operation including a photodiode, a first temporal circuit, a second temporal circuit and an operation circuit. Within a first interval, the photodiode detects first light energy to be stored in the first temporal circuit. Within a second interval, the photodiode detects second light energy to be stored in the second temporal circuit. Within an operation interval, the first temporal circuit outputs a first detection signal having a first pulse width according to the first light energy and outputs a second detection signal having a second pulse width according to the second light energy for being calculated by the operation circuit.

Claims20

Dependent claims

A pixel circuit, comprising:

a photodiode, configured to generate light energy;
a first temporal circuit, configured to store first light energy generated by the photodiode in a first interval, and output a first detection signal having a first pulse width according to the first light energy in an operation interval, the first temporal circuit comprising:
a first capacitor, having a first end coupled to the photodiode, and configured to store the first light energy;
a first transistor, configured to be controlled by a first control signal to convert the first light energy to the first detection signal;
a second transistor, coupled between the first capacitor and the first transistor, wherein the second transistor is not conducted in a second interval;
and
a third transistor, coupled between a second end of the first capacitor and a ground voltage;
and
a second temporal circuit, configured to store second light energy generated by the photodiode in the second interval, and output a second detection signal having a second pulse width according to the second light energy in the operation interval.

6 more elements

An analog operation pixel circuit, comprising:

a photodiode, configured to generate light energy;
a first temporal circuit, configured to store first light energy generated by the photodiode in a first interval, and output a first detection signal having a first pulse width according to the first light energy in an operation interval;
a second temporal circuit, configured to store second light energy generated by the photodiode in a second interval, and output a second detection signal having a second pulse width according to the second light energy in the operation interval;
and
an addition circuit, coupled to the first temporal circuit and the second temporal circuit, and comprising:
an operation capacitor;
a first operation transistor, configured to control a first charging time of a first current to charge the operation capacitor according to the first pulse width in the operation interval;
and
a second operation transistor, configured to control a second charging time of a second current to charge the operation capacitor according to the second pulse width in the operation interval.

6 more elements

An analog operation pixel circuit, comprising:

a photodiode, configured to generate light energy;
a first temporal circuit, configured to store first light energy generated by the photodiode in a first interval, and output a first detection signal having a first pulse width according to the first light energy in an operation interval;
a second temporal circuit, configured to store second light energy generated by the photodiode in a second interval, and output a second detection signal having a second pulse width according to the second light energy in the operation interval;
and
a subtraction circuit, coupled to the first temporal circuit and the second temporal circuit, and comprising:
an operation capacitor;
a first operation transistor, configured to control a charging time of a first current to charge the operation capacitor according to the first pulse width in the operation interval;
and
a second operation transistor, configured to control a discharging time of a second current to discharge the operation capacitor according to the second pulse width in the operation interval.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/009,417Filed 1 Sep 2020
Published: 3 Mar 2022
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

H04N 25/772
Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components: comprising A/D, V/T, V/F, I/T or I/F…
H10F 39/18
Image sensors: complementary metal-oxide-semiconductor [CMOS] image sensors; Photodiode array image sensors
H04N 25/77
Addressed sensors, e.g. MOS or CMOS sensors: pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components
H04N 25/771
Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components: comprising storage means other than…