Solid-state image pickup device having lower power consumption
View Patent ↗The invention is intended to raise the potential at an amplification transistor without increasing a source voltage, and to operate each pixel unit at a lower voltage. A reset transistor and a transfer transistor are serially connected between a driving power source (driving voltage Vdd) and an output of a PD. A floating diffusion (FD) node is provided between a source of the reset transistor and a drain of the transfer transistor. A selection transistor and an amplification transistor are serially connected between a vertical signal line and the driving power source. A gate of the amplification transistor is connected to the FD node. The amplification transistor and the selection transistor are connected at positions reversal to those in a conventional device; namely the amplification transistor is disposed on the side nearer to the vertical signal line. Then, the selection transistor is turned on after the end of reset operation by the reset transistor.
1. A solid-state image pickup device having pixels each provided with photoelectrically converting means for accumulating photo-charges depending on an amount of light received, a floating diffusion node for receiving the photo-charges accumulated by said photoelectrically converting means, transfer means for transferring the photo-charges accumulated by said photoelectrically converting means to said floating diffusion node, an amplification transistor for taking out a signal corresponding to the photo-charges from said floating diffusion node, a reset transistor for resetting said floating diffusion node, and a selection transistor connected to said amplification transistor and selectively providing an output from said amplification transistor to a signal line,
said amplification transistor being disposed between said selection transistor and said signal line, and said selection transistor being turned on after the end of reset operation by said reset transistor,
wherein said selection transistor is constituted as a depletion transistor having a threshold set to such a low level that there occurs substantially no voltage lowering due to a threshold of said selection transistor when turned on.
2. A solid-state image pickup device having pixels each provided with photoelectrically converting means for accumulating photo-charges depending on an amount of light received, a floating diffusion node for receiving the photo-charges accumulated by said photoelectrically converting means, transfer means for transferring the photo-charges accumulated by said photoelectrically converting means to said floating diffusion node, an amplification transistor for taking out a signal corresponding to the photo-charges from said floating diffusion node, a reset transistor for resetting said floating diffusion node, and a selection transistor connected to said amplification transistor and selectively providing an output from said amplification transistor to a signal line,
said amplification transistor being disposed between said selection transistor and said signal line and said selection transistor being turned on after the end of reset operation by said reset transistor,
wherein a high level of a selection pulse applied to a gate of said selection transistor is set to be higher than a source voltage to such a level that said selection transistor causes substantially no voltage lowering due to a threshold thereof.
3. A solid-state image pickup device having pixels each provided with photoelectrically converting means for accumulating photo-charges depending on an amount of light received, a floating diffusion node for receiving the photo-charges accumulated by said photoelectrically converting means, transfer means for transferring the photo-charges accumulated by said photoelectrically converting means to said floating diffusion node, an amplification transistor for taking out a signal corresponding to the photo-charges from said floating diffusion node, a reset transistor for resetting said floating diffusion node, and a selection transistor connected to said amplification transistor and selectively providing an output from said amplification transistor to a signal line,
said amplification transistor being disposed between said selection transistor and said signal line, and said selection transistor being turned on after the end of reset operation by said reset transistor.
wherein said reset transistor is constituted as a depletion transistor having a threshold set to such a low level that a voltage at said floating diffusion node is reset to substantially the source voltage when turned on.
4. A solid-state image pickup device having pixels each provided with photoelectrically converting means for accumulating photo-charges depending on an amount of light received, a floating diffusion node for receiving the photo-charges accumulated by said photoelectrically converting means, transfer means for transferring the photo-charges accumulated by said photoelectrically converting means to said floating diffusion node, an amplification transistor for taking out a signal corresponding to the photo-charges from said floating diffusion node, a reset transistor for resetting said floating diffusion node, and a selection transistor connected to said amplification transistor and selectively providing an output from said amplification transistor to a signal line,
said amplification transistor being disposed between said selection transistor and said signal line, and said selection transistor being turned on after the end of reset operation by said reset transistor,
wherein a high level of a reset pulse applied to a gate of said reset transistor is set to be higher than the source voltage to such a level that a voltage at the floating diffusion node is reset to substantially the source voltage when turned on.