inside the ALS window (only in non-latched

mode).

Like

stated

above,

it

is

recommended to use a hysteresis by

defining the thresholds in order to avoid

flickering of the interrupt event.

12.4.2 Operation of the PS

Fig. 22 illustrates the flowchart for a

microcontroller based proximity sensing

example. Operating the SFH 7773 in the

stand alone mode plus using the interrupt

functionality helps to save battery power.

The interrupt (set to active low) alerts the

microcontroller only in case an object

passes

a

certain

distance

threshold

(towards the sensor, e.g. in a mobile

phone). This allows the mobile phone to

turn-off the display e.g. during a call to save

battery power.

A new threshold (with hysteresis) and the

inverting of the interrupt logic of the SFH

7773 - after an event has taken place - allow

to adapt the sensor to detect the motion in

the opposite direction (only for non-latched

interrupt mode). By adapting dynamically

new thresholds it is recommended to set a

certain hysteresis level to avoid flickering of

the interrupt event.

Fig. 21: Flowchart for a microcontroller based ambient light sensing example.

December 12, 2011

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