Datasheet

TSL2591 – 2 Datasheet - Apr. 2013 - ams163.5
Figure TSL2591 – 2:
Block Diagram
The TSL2591 contains two integrating analog-to-digital
converters (ADC) that integrate currents from two photodiodes.
Integration of both channels occurs simultaneously. Upon
completion of the conversion cycle, the conversion result is
transferred to the Channel 0 and Channel 1 data registers,
respectively. The transfers are double-buffered to ensure that
the integrity of the data is maintained. After the transfer, the
device automatically begins the next integration cycle.
Communication with the device is accomplished through a
standard, two-wire I
2
C serial bus. Consequently, the TSL2591
can be easily connected to a microcontroller or embedded
controller. No external circuitry is required for signal
conditioning. Because the output of the device is digital, the
output is effectively immune to noise when compared to an
analog signal.
The TSL2591 also supports an interrupt feature that simplifies
and improves system efficiency by eliminating the need to poll
a sensor for a light intensity value. The primary purpose of the
interrupt function is to detect a meaningful change in light
intensity. The concept of a meaningful change can be defined
by the user both in terms of light intensity and time, or
persistence, of that change in intensity. The device has the
ability to define two sets of thresholds, both above and below
the current light level. An interrupt is generated when the value
of a conversion exceeds either of these limits. One set of
thresholds can be configured to trigger an interrupt only when
the ambient light exceeds them for a configurable amount of
time (persistence) while the other set can be configured to
trigger an immediate interrupt.
Detailed Description