Invention Grant
- Patent Title: Low EMI keypad circuitry
- Patent Title (中): 低EMI键盘电路
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Application No.: US13233214Application Date: 2011-09-15
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Publication No.: US09240295B2Publication Date: 2016-01-19
- Inventor: Hong Chean Choo , Kien Beng Tan , Gee Heng Loh
- Applicant: Hong Chean Choo , Kien Beng Tan , Gee Heng Loh
- Applicant Address: SG Singapore
- Assignee: STMicroelectronics Asia Pacific Pte Ltd
- Current Assignee: STMicroelectronics Asia Pacific Pte Ltd
- Current Assignee Address: SG Singapore
- Agency: Gardere Wynne Sewell LLP
- Main IPC: H03K17/94
- IPC: H03K17/94 ; H03M11/00 ; H03K17/62 ; H01H13/70

Abstract:
Disclosed is keypad circuitry operable to detect a pressed key while reducing electromagnetic interference (EMI). The keypad circuitry is operable to reduce EMI in two ways: a) reducing the voltage swing occurring at the row circuitry and column circuitry of the keypad, and b) reducing the number of signal transitions by restricting the signal transitions to occurring at the column and row corresponding to a pressed key. By limiting signal transitions to occurring only at the row and column corresponding to a pressed key, fewer signal transitions occur, and thus, less EMI is produced. Additionally, reduced voltage swings at the row circuitry and column circuitry results in reduced EMI.
Public/Granted literature
- US20130069805A1 LOW EMI KEYPAD CIRCUITRY Public/Granted day:2013-03-21
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