最新免费av在线观看,亚洲综合一区成人在线,中文字幕精品无码一区二区三区,中文人妻av高清一区二区,中文字幕乱偷无码av先锋

AD7142 Datasheet

  • AD7142

  • Programmable Capacitance-to-Digital Converter with Environme...

  • 66頁

  • AD

掃碼查看芯片數(shù)據(jù)手冊

上傳產(chǎn)品規(guī)格書

PDF預覽

AD7142
ENVIRONMENTAL CALIBRATION
The AD7142 provides on-chip capacitance sensor calibration to
automatically adjust for environmental conditions that have an
effect on the capacitance sensor ambient levels. Capacitance
sensor output levels are sensitive to temperature, humidity, and
in some cases, dirt. The AD7142 achieves optimal and reliable
sensor performance by continuously monitoring the CDC
ambient levels and correcting for any changes by adjusting the
STAGE_HIGH_THRESHOLD and STAGE_LOW_
THRESHOLD register values. The CDC ambient level is
defined as the capacitance sensor output level during periods
when the user is not approaching or in contact with the sensor.
The compensation logic runs automatically on every conversion
after configuration when the AD7142 is not being touched. This
allows the AD7142 to account for rapidly changing environ-
mental conditions.
The ambient compensation control registers give the host access
to general setup and controls for the compensation algorithm.
The RAM stores the compensation data for each conversion
stage, as well as setup information specific to each stage.
Figure 31 shows an example of an ideal capacitance sensor
behavior where the CDC ambient level remains constant
regardless of the environmental conditions. The CDC output
shown is for a pair of differential button sensors, where one
sensor caused an increase, and the other a decrease in measured
capacitance when activated. The positive and negative sensor
threshold levels are calculated as a percentage of the
STAGE_OFFSET_HIGH and STAGE_OFFSET_LOW values
based on the threshold sensitivity settings and the ambient
value. These values are sufficient to detect a sensor contact,
resulting with the AD7142 asserting the INT output when the
threshold levels are exceeded.
SENSOR 1 INT
ASSERTED
STAGE_HIGH_THRESHOLD
CAPACITANCE SENSOR BEHAVIOR WITHOUT
CALIBRATION
Figure 32 shows the typical behavior of a capacitance sensor
with no applied calibration. This figure shows ambient levels
drifting over time as environmental conditions change. The
ambient level drift has resulted in the detection of a missed user
contact on Sensor 2. This is a result of the initial low offset level
remaining constant while the ambient levels drifted upward
beyond the detection range.
The Capacitance Sensor Behavior with Calibration section
describes how the AD7142 adaptive calibration algorithm
prevents errors such as this from occurring.
SENSOR 1 INT
ASSERTED
STAGE_HIGH_THRESHOLD
CDC OUTPUT CODES
CCDC AMBIENT
VALUE DRIFTING
STAGE_LOW_THRESHOLD
SENSOR 2 INT
NOT ASSERTED
t
CHANGING ENVIRONMENTAL CONDITIONS
05702-023
Figure 32. Typical Sensor Behavior Without Calibration Applied
CDC OUTPUT CODES
CDC AMBIENT VALUE
STAGE_LOW_THRESHOLD
SENSOR 2 INT
ASSERTED
t
CHANGING ENVIRONMENTAL CONDITIONS
05702-022
Figure 31. Ideal Sensor Behavior with a Constant Ambient Level
Rev. 0 | Page 22 of 68

AD7142 PDF文件相關型號

AD7142-1

AD7142相關型號PDF文件下載

您可能感興趣的PDF文件資料

熱門IC型號推薦

掃碼下載APP，
一鍵連接廣大的電子世界。

在線人工客服

買家服務：
賣家服務：
技術(shù)客服：

0571-85317607

網(wǎng)站技術(shù)支持

13606545031

客服在線時間周一至周五
9:00-17:30

關注官方微信號，
第一時間獲取資訊。

建議反饋
返回頂部

建議反饋

聯(lián)系人：

聯(lián)系方式：

按住滑塊，拖拽到最右邊
>>
感謝您向阿庫提出的寶貴意見，您的參與是維庫提升服務的動力！意見一經(jīng)采納，將有感恩紅包奉上哦！