Invention Grant
- Patent Title: Multiple channel capacitive voltage divider scanning method and apparatus
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Application No.: US14503702Application Date: 2014-10-01
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Publication No.: US09857394B2Publication Date: 2018-01-02
- Inventor: Xiang Gao
- Applicant: Microchip Technology Incorporated
- Applicant Address: US AZ Chandler
- Assignee: MICROCHIP TECHNOLOGY INCORPORATED
- Current Assignee: MICROCHIP TECHNOLOGY INCORPORATED
- Current Assignee Address: US AZ Chandler
- Agency: Slayden Grubert Beard PLLC
- Main IPC: G01R27/26
- IPC: G01R27/26 ; G01R15/00 ; G01R1/30 ; H03M1/12

Abstract:
Relative capacitance of a plurality of capacitive sensors may be monitored by using only one ADC conversion. A plurality of capacitive sensors individually charges a sample and hold capacitor. After all of the plurality of capacitive sensors have charged the sample and hold capacitor, a digital conversion of the resulting analog on the sample and hold capacitor is made and stored in a memory. This stored digital collective voltage is compared to a previously stored one and if different then a proximity/touch event may have occurred. Therefore, an entire panel of capacitive sensors may be quickly monitored for a change in the “group” capacitance thereof, or portions of the capacitive sensors may be monitored for a change in the “subgroup” capacitance thereof. By knowing which subgroup of capacitive sensors has changed its collective capacitive value, a more focused and selective capacitive sensor measurement can be made that uses less power.
Public/Granted literature
- US20150097583A1 MULTIPLE CHANNEL CAPACITIVE VOLTAGE DIVIDER SCANNING METHOD AND APPARATUS Public/Granted day:2015-04-09
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