VL6180X Datasheet, PDF (31/79 Pages) STMicroelectronics – Proximity and ambient light sensing module

VL6180X
Functional description
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.
Analogue
gain setting
Table 13. ALS dynamic range⁽¹⁾
Dynamic range (no glass)
Dynamic range (10%
transmissive glass)
Min. (Lux)⁽²⁾ Max. (Lux) Minimum (Lux) Maximum (Lux)
1
3.20
20800
1.25
2.56
16640
1.67
1.93
12530
2.5
1.28
8320
5
0.64
4160
10
0.32
2080
20
0.16
1040
40
0.08
520
1. ALS lux resolution = 0.32 lux/count
2. Minimum of 10 counts
32.0
>100,000
25.6
>100,000
19.3
>100,000
12.8
83,200
6.4
41,600
3.2
20,800
1.6
10,400
0.8
5,200
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:
Light level (in lux) = ALS lux resolution × ^R-----^E----^S----_AU----_nL---_a-^T---_{l_}-_o---^_g---^A--_g--^L--_a-^S--_i-_n-^_----^V----^A----^L- × _A-----_L---_S-----_i--_n---^1t--_e-⁰--_g-⁰---_r--_am---_t--_is-_o---_n-----_t--_i-_m-----_e--
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:
ALS lux resolution (with glass) = ^R-----_RE----^SE----^US----_UL----^TL---^_-_T---^__---^A-_{_}---^LA---^S-_L---^_S----^V_----^AV----^LA----_L-⁽--^w--₍--_wi-^t--^h-_i-_t-^o-_h---^u--_g-^t--_l-^g-_a---^ls-^a--_s-^s--₎-^s----⁾ × ALS lux resolution (without glass)
DocID026171 Rev 6
31/79
78