CMOS active pixel and method of driving the same
In a driving method of a complementary metal oxide semiconductor active pixel, timing of a transmission control signal and a reset control signal generated in a read-out section is performed in advance in a reset section. A potential wall between a photodiode area and a transmission transistor having a size corresponding to one generated in the read-out section is generated in the reset section in advance and the photodiode area is filled with charges. A dead region is reduced in the read-out section. In the reset section, the transmission transistor connecting a collection node to accumulate the signal charges generated from the photodiode and the floating diffusive node is turned on at least one time, and a difference between an initial voltage of the collection node and a voltage of the reset level of the floating diffusive node is reduced.
1. A method of driving a complementary metal oxide semiconductor 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. The method of claim 1 , wherein the preliminary section further comprises:
a separation region in which the transmission control signal is deactivated and the reset control signal is activated, after the first equalization region is performed; and
a second equalization region in which the reset control signal is deactivated and the transmission control signal is activated, after the separation region is performed.
3. A method of driving a complementary metal oxide semiconductor 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) 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.
4. The method of claim 3 , wherein the preliminary section further comprises:
a first equalization region in which the reset control signal is deactivated and the transmission control signal is activated, after the preparation section is performed;
a separation region in which the transmission control signal is deactivated and the reset control signal is activated, after the first equalization region is performed; and
a second equalization region in which the reset control signal is deactivated and the transmission control signal is activated, after the separation region is performed.