What is Photodiode?
A diode that generates charge (current) when it receives light. Used as the light-receiving element in image sensor pixels.
Photodiode in the explanations
Reverse-biasing a photodiode widens the depletion region, where light-generated electrons and holes are quickly separated by the field, producing a photocurrent proportional to light intensity.
How is a photodiode generally used to detect light?An APD is a photodiode biased near breakdown so that light-generated carriers are multiplied tens to hundreds of times by avalanche multiplication.
Which is a characteristic of an avalanche photodiode (APD)?Holding the photodiode at nearly 0 V improves speed and linearity.
Which circuit converts a photodiode current into a voltage …
Questions that mention Photodiode (17)
- How is a photodiode generally used to detect light?
- Which is a characteristic of an avalanche photodiode (APD)?
- Which circuit converts a photodiode current into a voltage by feeding the current into the inverting input of an op-amp and converting it with a feedback resistor?
- In the buried (pinned) photodiode of a CMOS image sensor, what is the main purpose of the heavily doped p+ layer at the surface?
- In the typical four-transistor pixel of a CMOS image sensor, which transistor moves the charge from the photodiode to the floating diffusion?
- When the light falling on a reverse-biased photodiode becomes stronger, how does the current (photocurrent) change?
- In a CMOS image sensor, what problem occurs when charge transfer from the photodiode to the floating diffusion is incomplete?
- In each pixel of a CMOS image sensor, which element converts light into charge?
- What is the main advantage of a backside-illuminated (BSI) CMOS image sensor?
- What is the role of the microlens placed over each pixel of an image sensor?
- Which correctly describes dark current in an image sensor?
- Why is it difficult to increase the near-infrared sensitivity of silicon image sensors?
- What is the purpose of correlated double sampling (CDS) used in CMOS image sensor readout?
- What is the maximum number of electrons that one pixel of an image sensor can store called?
- In image sensors that capture color images, why must color filters be placed over the pixels?
Related terms
CMOS image sensor Dark current Interface states Correlated double sampling (CDS) Junction capacitance (depletion capacitance) SPAD (single-photon avalanche diode) Operational amplifier (op-amp) Transimpedance amplifier Scanner Pinned photodiode