| 摘要 |
<p>Aspects of a switch matrix circuit (100) are provided. In accordance with a circuit aspect, a plurality of switches (S1'-S16') are organized in a row and column configuration. Coupled to the plurality of switches (S1'-S16') is a current sensing circuit. The current sensing circuit includes a transistor (Q1, Q2, Q3, Q4) and at least one resistor (R17, R18, R19, R20) per column of the plurality of switches. Current amplified by the transistor and converted by the at least one resistor in a column is sensed as a logic level indicative of a switch status within the column for a selected row. The current sensing arrangement may also be used in an embodiment utilizing bi-directional signal control to minimize the number of I/O lines required to scan the switch matrix. The bi-directional signal scanning may also be implemented in another embodiment that senses voltage levels to determine switch closures.</p> |
