| 摘要 |
The present invention relates to a key input apparatus using a switching matrix, the apparatus comprising: a column scan control unit, which includes switches showing one-to-one correspondence with lines in a column scan direction in response to a column scan signal and an enable signal (EN) from a main controller, the switches receiving one input voltage selected out of two input voltages (Vup, VA) per column in a normal scan mode and receiving a standby voltage (Vh) in a power saving mode, thereby executing a column scan operation according to the modes; and a row scan control unit, which executes, in the normal scan mode, a row scan operation in response to a row scan signal from the main controller, with the row scan signal being given synchronously with a column scan signal for the column scan control unit and which operates in the power saving mode in response to the enable signal (EN). Accordingly, with a key input apparatus of the present invention utilizing switches of simple configuration to control the switching matrix, there can be no ghost key, the key input apparatus can be operated in the power saving mode and costs of manufacturing can be cut down. |
