Solid-state imaging device driving method
View Patent ↗Photosensitive cells each includes a photodiode ( 1 ), a transfer gate ( 2 ), a floating diffusion layer portion ( 3 ), an amplifying transistor ( 4 ), and a reset transistor ( 5 ). Drains of the amplifying transistors ( 4 ) of the photosensitive cells are connected to a power supply line ( 10 ), and a pulsed power supply voltage (VddC) is applied to the power supply line ( 10 ). Here, a low-level potential (VddC_L) of the power supply voltage has a predetermined potential higher than zero potential. Specifically, by making the low-level potential (VddC_L) higher than channel potentials obtained when a low level is applied to the reset transistors ( 5 ), or channel potentials obtained when a low level is applied to the transfer gates ( 2 ), or channel potentials of the photodiodes ( 1 ), a reproduced image with low noise is read.
1. A method of driving a solid-state imaging device comprising:
a photosensitive region having photosensitive cells arranged two-dimensionally in row and column directions on a semiconductor substrate, each photosensitive cell including a photodiode for accumulating a signal charge obtained by converting incoming light into electricity; a transfer transistor for transferring the signal charge accumulated in the photodiode; a floating diffusion layer portion for temporarily accumulating the transferred signal charge; an amplifying transistor for amplifying the signal charge accumulated in the floating diffusion layer portion; and a reset transistor for resetting the signal charge accumulated in the floating diffusion layer portion;
a power supply line commonly connected to drains of the amplifying transistors;
a vertical driver circuit for individually driving transfer transistors arranged in a same row and reset transistors arranged in the same row;
a plurality of vertical signal lines each having commonly connected thereto corresponding amplifying transistors arranged in a same column;
a plurality of load transistors connected to the vertical signal lines, respectively;
a noise suppression circuit for suppressing noise of signals outputted to the vertical signal lines;
a plurality of horizontal transistors which are arranged in the row direction, and to which outputs from the noise suppression circuit are inputted; and
a horizontal driver circuit for allowing the horizontal transistors to sequentially and selectively operate, and thereby sequentially outputting the outputs from the noise suppression circuit, the method comprising the steps of:
pulse-driving the power supply line on a per horizontal period basis;
sequentially selecting different rows on a per horizontal period basis using the horizontal driver circuit, and allowing corresponding reset transistors and corresponding transfer transistors included in corresponding photosensitive cells arranged in a selected row to successively operate while the power supply line is driven, and thereafter allowing the corresponding reset transistors to operate while the power supply line is not driven; and
sequentially outputting outputs from the noise suppression circuit on a per horizontal period basis using the horizontal driver circuit, wherein
a low-level potential of the power supply line has a predetermined potential higher than zero potential.
2. The method of driving the solid-state imaging device according to claim 1 , wherein the predetermined potential is higher than channel potentials obtained when a low level is applied to the reset transistors.
3. The method of driving the solid-state imaging device according to claim 1 , wherein the predetermined potential is higher than channel potentials obtained when a low level is applied to the transfer transistors.
4. The method of driving the solid-state imaging device according to claim 1 , wherein the predetermined potential is higher than channel potentials of the photodiodes.
5. The method of driving the solid-state imaging device according to claim 1 , wherein the photosensitive region is formed on a p-type substrate.
6. The method of driving the solid-state imaging device according to claim 1 , wherein the photosensitive region is formed in a p-type well on an n-type substrate.