US 2006/0139471 A1 · Cmos active pixel and a operating method there of

Abstract

Provided is a CMOS active pixel and a driving method thereof. The timing of the transmission control signal and the reset control signal generated in the read-out section is performed in advance in the reset section. Thus, the potential wall between the photodiode area and the transmission transistor having a size corresponding to one generated in the read-to section is generated in the reset section in advance and the photodiode area is filled with charges. Thus, a dead region is reduced in the read-out section. Thus, a minimum light amount characteristic of an image sensor is improved. Also, in the reset section, the transmission transistor connecting the collection node to accumulate the signal charges generated from the photodiode and the floating diffusive node is turned on once or two time or more. Thus, a difference between the initial voltage of the collection node and the voltage of the reset level of the floating diffusive node is much reduced. Therefore, the low brightness characteristic of the image sensor is remarkably improved according to the method of driving a CMOS active pixel according to the present invention.

Claims15

Dependent claims

A method of driving a CMOS active pixel which includes a photodiode generating signal charges according to received photons, a transmission transistor providing the signal charges to a predetermined floating diffusive node in response to a transmission control signal activated during a read-out section of an image sensor, the floating diffusive node receiving the signal charges transmitted by the transmission transistor, a reset transistor resetting the floating diffusive node in response to a reset control signal activated in a predetermined reset section that does not overlap the read-out section, a driving transistor controlled by a voltage level of the floating diffusive node, and a select transistor transmitting the voltage transmitted by the driving transistor to a corresponding data line in response to a predetermined row select signal, the method comprising:

(a) performing a section A to initialize the photodiode by simultaneously turning on the reset transistor and the transmission transistor;
(b) performing a section B to generate a timing of the reset control signal and the transmission control signal, before entering a section C to sense electrons generated from the photodiode;
and
(c) performing the sensing operation of the section C and performing a section D (a read-out section) to read out the charges stored in the photodiode.

1 more element

A method of driving a CMOS active pixel which includes a photodiode generating signal charges according to received photons at a predetermined collection node, a transmission transistor providing the signal charges to a predetermined floating diffusive node in response to a predetermined transmission control signal, the floating diffusive node receiving the signal charges transmitted by the transmission transistor, a reset transistor resetting the floating diffusive node in response to a predetermined reset control signal, a driving transistor controlled by a voltage level of the floating diffusive node, and a select transistor transmitting the voltage transmitted by the driving transistor to a corresponding data line in response to a predetermined row select signal, the method comprising:

(a) performing a reset sampling section to sample a reset level of the data line according to a voltage of the reset floating diffusive node;
(b) performing a data sampling section to transmit the signal charges generated in the photodiode to the floating diffusive node and sample a data level of the data line according to a voltage of the floating diffusive node which is determined by the signal charges;
and
(c) performing a preliminary section to match the voltage of the collection node before the action (b) is performed and the voltage of the floating diffusive node after the action (b) is performed,
wherein the preliminary section comprises a first equalization region in which the reset control signal is deactivated and the transmission control signal is activated.

2 more elements

(a) performing a reset sampling section to sample a reset level of the data line according to a voltage of the reset floating diffusive node;
(b) after the action (a), performing a data sampling section to transmit the signal charges generated in the photodiode to the floating diffusive node and sample a data level of the data line according to a voltage of the floating diffusive node which is determined by the signal charges;
and
(c) performing a preliminary section to match the voltage of the collection node before the action (b) is performed and the voltage of the floating diffusive node after the action (b) is performed,
wherein the preliminary section comprises a preparation region in which the reset control signal is deactivated in a state in which the transmission control signal is deactivated.

2 more elements

Dependencies are inferred from the claim text.

Cmos active pixel and a operating method there of

Life of this patent

Cmos active pixel and a operating method there of

Life of this patent

Abstract

Claims15