Microchip Technology MGC3140 GestIC, Руководство пользователя по настройке, Страница: 14 / 26

3.2.8 Position Tracking
3.2.10 Sensing Area
3.2.6 Approach Detection
Approach Detection is used to preserve power, by placing the MGC3140 into a Lower-Power Sleep mode
with infrequent scans.
If configured, any combination of the Rx electrodes can be enabled for Approach Detection, and a hand
will be detected by just one electrode. The Approach Electrode Selection window controls which
electrodes are enabled for Approach Detection.
3.2.6.1 Approach Detection Power Tuning
A lack of activity for a specified time by the Idle Time-out parameter will result in the MGC3140 entering
Sleep mode. When in Sleep mode, the MGC3140 periodically performs a scan looking for the presence
of a hand. The interval between scans is set by the Approach Scan Interval parameter. The bigger the
interval, the lower the power consumption, as shown in
Figure 3-8 .
When detecting a hand, the MGC3140 leaves Approach mode and reverts to normal continuous
scanning.
Figure 3-8. Current Consumption Variation with Approach Scan Period and AFA Frequency
0%
5%
10%
15%
20%
25%
30%
35%
40%
0
0.5
1
1.5
2
2.5
0 50 100 150 200 250 300 350 400 450 500
C
ur
rent
m
A
Approach scan period ms
Current Consumption Variation with Approach Scan Period
120 Second AFA scan
600 Second AFA scan
% AFA difference
Note: AFA = Automatic Frequency Adaption
3.2.6.2 Approach Range
The approach range is determined by the sensor configuration, size and sensitivity setting, as shown in
the figure below.
MGC3140
Tuning
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2018 Microchip Technology Inc.
User Guide
DS40002055A-page 14