Datasheet

AD7142
Rev. A | Page 19 of 72
PROXIMITY DETECTION
(INTERNAL)
CALIBRATION
(INTERNAL)
12345678910111213141516
CDC CONVERSION SEQUENCE
(INTERNAL)
05702-017
CALIBRATION ENABLED
CALIBRATION DISABLED
t
CONV_FP
USER LE
A
V
ES SENSOR
AREA HERE
USER APPROACHES
SENSOR HERE
t
CALDIS
Figure 28. Full Power Mode Proximity Detection Example with FP_PROXIMITY_CNT = 1
05702-018
NOTES
1. SEQUENCE CONVERSION TIME
t
CONV_LP
= t
CONV_FP
+ LP_CONV_DELAY
2. PROXIMITY IS SET WHEN USER APPROACHES THE SENSOR AT WHICH TIME THE INTERNAL CALIBRATION IS DISABLED.
3.
t
CALDIS
= ( t
CONV_LP
× LP_PROXIMITY_CNT × 4)
CALIBRATION ENABLEDCALIBRATION DISABLED
PROXIMITY DETECTION
(INTERNAL)
CALIBRATION
(INTERNAL)
t
CALDIS
t
CONV_LP
12345678910111213141516
CDC CONVERSION SEQUENCE
(INTERNAL)
USER LEAVES
SENSOR
AREA HERE
USER
APPROACHES
SENSOR HERE
1718 1920 21 222324
Figure 29. Low Power Mode Proximity Detection with LP_PROXIMITY_CNT = 4
CALIBRATION ENABLED
t
RECAL_TIMEOUT
16 30
70
t
CONV_FP
MEASURED CDC VALUE > STORED AMBIENT
BY PROXIMITY_RECAL _LVL
RECALIBRATION TIME-OUT
PROXIMITY DETECTION
(INTERNAL)
CALIBRATION
(INTERNAL)
C
DC CONVERSION SEQUENCE
(INTERNAL)
RECALIBRATION COUNTER
(INTERNAL)
05702-019
NOTES
1. SEQUENCE CONVERSION TIME
t
CONV_FP
DETERMINED FROM TABLE 10
2.
t
CALDIS
= t
CONV_FP
× FP_PROXIMITY_CNT ×16
3.
t
RECAL_TIMEOUT
= t
CONV_FP
× FP_PROXIMITY_RECAL
4.
t
RECAL
= 2 × t
CONV_FP
USER APPROACHES
SENSOR HERE
USER LEAVES SENSOR
AREA HERE
t
CALDIS
t
RECAL
CALIBRATION DISABLED
Figure 30. Full Power Mode Proximity Detection with Forced Recalibration Example with FP_PROXIMITY_CNT = 1 and FP_PROXIMITY_RECAL = 40