发明名称 |
Current sensing of capacitive keyboard arrays |
摘要 |
Current sensing circuits especially adapted for use with either capacitive touch plate or mechanical switch keys. The circuits include a transistor whose base is connected to a constant voltage source and whose emitter-collector circuit is connected between the touch plate or switch keys and an input to a comparator. A second transistor and a capacitor are interconnected with the first transistor to provide transient surge protection. The circuits distinguish between differing values of current and activate the comparator which produces a signal indicative of the existing condition.
|
申请公布号 |
US4405918(A) |
申请公布日期 |
1983.09.20 |
申请号 |
US19800126601 |
申请日期 |
1980.03.03 |
申请人 |
TEXAS INSTRUMENTS INCORPORATED |
发明人 |
WALL, FREDERICK G.;KWAN, STEPHEN C. |
分类号 |
H03K17/96;(IPC1-7):G06F3/02 |
主分类号 |
H03K17/96 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|