User manual

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VL6180X Functional description
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2.13.3 ALS dynamic range
Table 13 shows the range of measurable light at all gains both with and without glass. In
most applications operating at a single gain setting should be possible.
2.13.4 ALS count to lux conversion
The output from the ambient light sensor is a 16-bit register, RESULT__ALS_VAL{0x50}.
The count output is proportional to the light level and can be converted into lux using the
following equation:
The factory calibrated ALS lux resolution is 0.32 lux/count for an analog gain of 1 (calibrated
without glass). The ALS lux resolution will require re-calibration in the final system where
cover glass is used. This can be done by recording the count output with and without glass
under the same conditions and multiplying the ALS lux resolution by the ratio of the two
counts as follows:
Table 13. ALS dynamic range
(1)
1. ALS lux resolution = 0.32 lux/count
Analogue
gain setting
Dynamic range (no glass)
Dynamic range (10%
transmissive glass)
Min. (Lux)
(2)
2. Minimum of 10 counts
Max. (Lux) Minimum (Lux) Maximum (Lux)
1 3.20 20800 32.0 >100,000
1.25 2.56 16640 25.6 >100,000
1.67 1.93 12530 19.3 >100,000
2.5 1.28 8320 12.8 83,200
5 0.64 4160 6.4 41,600
10 0.32 2080 3.2 20,800
20 0.16 1040 1.6 10,400
40 0.08 520 0.8 5,200
Light level (in lux) ALS lux resolution
RESULT__ALS_VAL
Analog gain
--------------------------------------------------------
100 ms
ALS integration time
----------------------------------------------------- -××=
ALS lux resolution (with glass)
RESULT__ALS_VAL (without glass)
RESULT__ALS_VAL (with glass)
------------------------------------------------------------------------------------------------ ALS lux resolution (without glass)×=