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The ISL29021 is an integrated proximity and infrared sensor with a built-in IR LED driver and I2C Interface (SMBus Compatible). This device provides infrared sensing to allow
proximity estimation featured with interrupt function.
For infrared and proximity sensing, an internal ADC has been designed based on the charge-balancing A/D conversion technique.
The ADC is used to digitize the output signal from the photodiode array when the internal IR LED driver is turned on and off for the programmed time periods under user-selected modulation
frequency to drive the external IR LED. As this proximity sensor employs a noise cancellation scheme to highly reject unwanted IR noise, the digital output of proximity sensing decreases
with distance. The driver output current is user selectable up to 100mA to drive different types of IR emitters LEDs.
Four different modes of operation can be selected via the I2C interface: programmable IR sensing once, programmable proximity sensing once, programmable continuous IR sensing and
programmable continuous proximity sensing. The programmable one-time operation modes greatly reduce power because an immediate automatic shutdown reduces overall supply current less than
0.5
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