High dynamic range CMOS image sensor by pixel-embedded signal amplification and method thereof

A method for improving a dynamic range of a CMOS image sensor by pixel-embedded amplification, the method comprising:

• receiving, by a CMOS image sensor, an electromagnetic radiation for a predetermined duration on a pixel array when a reset switch is deactivated, wherein the pixel array comprises of a plurality of photodiodes;
• releasing, by the CMOS image sensor, an input electronic signal by an excitation of a depletion region of the plurality of photodiodes, wherein the released input electronic signal, due to the releasing of electrons, is temporarily stored in a storage node;
• transferring, by the CMOS image sensor, the input electronic signal from the storage node to a gate of an in-pixel amplifier, wherein the in-pixel amplifier is configured as a capacitor;
• modulating the capacitance of the in-pixel amplifier by changing the depletion and/or inversion state of the in-pixel amplifier, for a voltage-build, wherein the voltage build-up augments gain of the input electronic signal to a predetermined level;
• alternating, by the CMOS image sensor, the in-pixel amplifier to a switched biasing mode for suppression of low-frequency noise signals;
• rendering, by the CMOS image sensor, a resultant output electronic signal with increased gain;
• and
• an in-pixel switch, for dynamically toggling the in-pixel amplifier as a capacitor and as a source follower.

A method for improving a dynamic range of a CMOS image sensor by pixel-embedded amplification, the method comprising:

• receiving, by a CMOS image sensor, an electromagnetic radiation for a predetermined duration on a pixel array when a reset switch is deactivated, wherein the pixel array comprises of a plurality of photodiodes;
• releasing, by the CMOS image sensor, an input electronic signal by an excitation of a depletion region of the plurality of photodiodes, wherein the released input electronic signal, due to the releasing of electrons, is temporarily stored in a storage node;
• transferring, by the CMOS image sensor, the input electronic signal from the storage node to a gate of an in-pixel amplifier, wherein the in-pixel amplifier is configured as a capacitor;
• modulating the capacitance of the in-pixel amplifier by changing the depletion and/or inversion state of the in-pixel amplifier, for a voltage-build, wherein the voltage build-up augments gain of the input electronic signal to a predetermined level;
• alternating, by the CMOS image sensor, the in-pixel amplifier to a switched biasing mode for suppression of low-frequency noise signals;
• rendering, by the CMOS image sensor, a resultant output electronic signal with increased gain;
• and
• processing the resultant output electronic signal, by suppression of low-frequency noise signals, wherein the processing comprises:
• segregating the input signal from the low-frequency noise signals during the voltage build-up in the capacitance mode;
• and
• suppressing residual noise signals by a parasitic capacitance operation by grounding the residual noise signals in the switched biasing mode.

A CMOS image sensor which enhances a signal to noise ratio in a low-light environment, the CMOS image sensor, comprising:

• a processor;
• and
• a memory communicatively coupled to the processor, wherein the memory stores processor instructions, which on execution, causes the pixel array to:
• receive an electromagnetic radiation, for a predetermined duration on a pixel array when a reset switch is deactivated, wherein the pixel array comprises a plurality of photodiodes;
• release an input electronic signal by an excitation of a depletion region of the plurality of photodiodes, wherein the released input electronic signal, due to release of electrons, is temporarily stored in a storage node;
• transfer the input electronic signal from the storage node to a gate of an in-pixel amplifier, wherein the in-pixel amplifier is configured as a capacitor;
• the in-pixel amplifier is modulated to vary the capacitance of the sense node for a voltage build-up, wherein the voltage build-up augments gain of the input electronic signal to a predetermined level;
• alternate the in-pixel amplifier to a switched biasing mode for suppression of low-frequency noise signals;
• and
• render a resultant output electronic signal with an increased gain.

An improved high dynamic range CMOS image sensor uses in-pixel amplification and switched biasing of the in-pixel amplifier to enhance a signal to noise ratio in the low-light environment, the CMOS image sensor comprises of:

• a photodetector, comprising of photodiodes, which receives electromagnetic radiation for a predetermined duration on a pixel array, wherein the predetermined duration is an integration time or an exposure time;
• an in-pixel amplifier, configured to alternate between modes of capacitance and switched biasing;
• an in-pixel switch, configured to dynamically toggle the in-pixel amplifier between the capacitance mode and the switched biasing mode;
• a parasitic capacitor, connected to the ground and which is further configured to remove stray noise signals to the ground;
• a storage node, configured to temporarily store accumulated electrons, generated due to the photoelectric effect on the photodiode;
• and
• a plurality of switches which is configured to act as control switches.