Image sensor for minimizing variation of control signal level
View Patent ↗There is provided an image sensor capable of minimizing level variations of a control signal inputted to a unit pixel. The image sensor includes a plurality of unit pixels, each supplied with a first power voltage for converting an inputted signal into an electrical signal; and a control block supplied with a second power voltage for providing control signals to each unit pixel in order to stably operate each unit pixel, wherein the control block includes a conversion unit for outputting the control signals under the first power voltage, not the second power voltage.
1. An image sensor comprising:
a unit pixel configured to use a first power voltage; and
a decoder configured to use the first power voltage and a second power voltage;
wherein:
the unit pixel includes a reset transistor configured to receive a reset signal;
the second power voltage is different from the first power voltage; and
the decoder includes a first output terminal configured to provide the reset signal, receive a first signal generated from the second power voltage, and responsively generate the reset signal from the first power voltage.
2. The image sensor of claim 1 , wherein the first power voltage comprises an analog block power voltage, and wherein the second power voltage comprises a digital block power voltage.
3. The image sensor of claim 2 , wherein a variation of the second power voltage is greater than a variation of the first power voltage such that the second power voltage is less stable than the first power voltage.
4. The image sensor of claim 1 , wherein the first output terminal comprises an inverter, and wherein the inverter includes a PMOS transistor configured to receive the first power voltage at a source, to receive the first signal at a gate, and to provide the reset signal from a drain.
5. The image sensor of claim 4 , wherein the reset transistor is configured to receive the reset signal at the gate and to responsively set a floating diffusion node voltage to substantially the first power voltage.
6. The image sensor of claim 1 , wherein:
the unit pixel further comprises a transfer transistor configured to receive a transfer signal;
the decoder further comprises a second output terminal configured to provide the transfer signal; and
the second output terminal is configured to receive a second signal generated from the second power voltage and to responsively generate the transfer signal from the first power voltage.
7. A method for sensing an image, the method comprising:
providing a first power voltage to a unit pixel, wherein the unit pixel includes a reset transistor;
providing a second power voltage to a decoder, wherein the second power voltage is different from the first power voltage and the decoder includes a first output terminal;
generating, at the decoder, a first control signal from the second power voltage;
receiving the first control signal at the first output terminal;
generating, at the first output terminal, a reset signal from the first power voltage; and
receiving the reset signal at the reset transistor.
8. The method of claim 7 , wherein the unit pixel further comprises a transfer transistor, and wherein the decoder further comprises a second output terminal, the method further comprising:
generating, at the decoder, a second control signal from the second power voltage;
receiving the second control signal at the second output terminal;
generating, at the second output terminal, a transfer signal from the first power voltage; and
receiving the transfer signal at the transfer transistor.
9. The method of claim 7 , wherein the first power voltage comprises an analog block power voltage, and wherein the second power voltage comprises a digital block power voltage.
10. The method of claim 9 , wherein a variation of the second power voltage is greater than a variation of the first power voltage such that the second power voltage is less stable than the first power voltage.