CYIL1SM1300AA_09 CYPRESS [Cypress Semiconductor], CYIL1SM1300AA_09 Datasheet - Page 27

• Manufacturer Part Number: CYIL1SM1300AA_09
• Description: LUPA-1300 1.3 MPxl High Speed CMOS Image Sensor
• Manufacturer: CYPRESS [Cypress Semiconductor]

Q: How does the dual slope extended dynamic range mode works?
A:
The green lines are the analog signal on the photodiode, which decrease as a result of exposure. The slope is determined by the
amount of light at each pixel (the more light the steeper the slope). When the pixels reach the saturation level the analog signal will
not change despite further exposure. As you can see without any double slope pulse pixels p3 and p4 will reach saturation before the
sample moment of the analog values, no signal will be acquired without double slope. When double slope is enabled a second reset
pulse will be given (blue line) at a certain time before the end of the integration time. This double slope reset pulse resets the analog
signal of the pixels BELOW this level to the reset level. After the reset the analog signal starts to decrease with the same slope as
before the double slope reset pulse. If the double slope reset pulse is placed at the end of the integration time (90% for instance) the
analog signal that would have reach the saturation levels aren't saturated anymore (this increases the optical dynamic range) at read
out. It's important to notice that pixel signals above the double slope reset level will not be influenced by this double slope reset pulse
(p1 and p2).
Look at the website to find pictures taken with double slope mode on:
Document Number: 38-05711 Rev. *D
Reset
Total integration time
Double slope reset
Figure 24. Dual Slope Diagram
Read
p1
p4
p2
p3
http://www.fillfactory.be/htm/technology/htm/dual-slope.htm.
Double slope reset time (usually 5-10% of the total
integration time)
Reset level 1
Reset level 2
Saturation level
CYIL1SM1300AA
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