Active pixel with precharging circuit

An image sensor including an array of a plurality of active pixels, at least one of the plurality of active pixels comprising:

• a sensor circuit to generate a signal in response to electromagnetic radiation received on a photodetector included therein;
• a sample and hold (S/H) stage coupled to an output of the sensor circuit to read-out and store the signal, the S/H stage including a sample switching-element to couple the signal from the sensor circuit to a capacitor element in the S/H stage to store the signal;
• a buffer/multiplexer circuit including a row-select switching-element coupled to an output node of the capacitor element to couple the signal to a column in the array;
• and
• a precharge circuit including a precharge switching-element coupled between the output node of the capacitor element and the column to precharge the capacitor element to a column precharge voltage applied to the column when the S/H stage is not reading-out the signal therefrom.

A method for precharging a capacitor element in an in-pixel sample and hold (S/H) stage of an active pixel, the method comprising:

• electrically decoupling a sensor circuit in the active pixel from the S/H stage;
• electrically coupling an output node of the capacitor element to a column through a precharge transistor, the precharge transistor having a drain coupled to the output node of the capacitor element and a source coupled to the column;
• and
• applying a precharge voltage to the column to precharge the capacitor element and the column.