PYTHON25K Datasheet, PDF (13/87 Pages) ON Semiconductor – PYTHON 25K/16K/12K/10K Global Shutter CMOS Image Sensors

NOIP1SN025KA, NOIP1SN016KA, NOIP1SN012KA, NOIP1SN010KA
OPERATING MODES
Global Shutter Mode
The PYTHON operates in pipelined or triggered global
shutter modes. In this mode, light integration takes place on
all pixels in parallel, although subsequent readout is
sequential. Figure 10 shows the integration and readout
sequence for the global shutter mode. All pixels are light
sensitive at the same period of time. The whole pixel core is
reset simultaneously and after the integration time all pixel
values are sampled together on the storage node inside each
pixel. The pixel core is read out line by line after integration.
Note that the integration and readout can occur in parallel or
sequentially. The integration starts at a certain period,
relative to the frame start.
Pipelined Global Shutter Mode
In pipelined global shutter mode, the integration and
readout are done in parallel. Images are continuously read
and integration of frame N is ongoing during readout of the
previous frame N–1. The readout of every frame starts with
a frame overhead time (FOT), during which the analog value
on the pixel diode is transferred to the pixel memory
element. After the FOT, the sensor is read out line by line and
the readout of each line is preceded by the row overhead time
(ROT). Figure 11 shows the exposure and readout time line
in pipelined global shutter mode.
Figure 10. Global Shutter Operation
Master Mode
In this operation mode, the integration time is set through
the register interface and the sensor integrates and reads out
the images autonomously. The sensor acquires images
without any user interaction.
Slave Mode
The slave mode adds more manual control to the sensor.
The integration time registers are ignored in this mode and
the integration time is instead controlled by an external pin.
As soon as the control pin is asserted, the pixel array goes out
of reset and integration starts. The integration continues
until the user or system deasserts the external pin. Upon a
falling edge of the trigger input, the image is sampled and the
readout begins.
Integration Tim e
Handling
Reset
N
Exposure Time N
FOT
Reset
N+1
Exposure Time N+1
FOT
Readout
Handling
ÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉ ^FOT
Readout Fram e N -1
FOT
R eadout Fram e N
FOT
ROT
Line Readout
Figure 11. Pipelined Shutter Operation in Master Mode
External Trigger
Integration Time
Handling
Reset
N
Exposure Time N
FOT
Reset
N+1
Exposure T im e N+1
FOT
Readout
Handling
FOT
Readout N−1
FOT
Readout N
FOT
ÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉ
ROT
Line Readout
Figure 12. Pipelined Shutter Operation in Slave Mode
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