| 摘要 |
A circuit for preventing switch bounce of a keypad of a mobile terminal is provided to enhance quality of a mobile terminal by preventing malfunction of the mobile terminal generated by bounce noise in advance. First and second pull-up resistors(R1,R2) output an internal bias voltage of a certain high level. The first NAND gate(ND1) has one input terminal to which a voltage signal of a high level outputted from the first pull-up resistor(R1) is applied and the other input terminal to which an output of the second NAND gate(ND2) is applied. The second NAND gate has one input terminal to which a voltage signal of a high level outputted from the second pull-up resistor(R2) is applied, and the other input terminal to which an output of the first NAND gate is applied. A button switch(SW1) selectively controls switching such that the internal bias voltage of the high level applied to respective on input terminals of the first and second NAND gates after being outputted from the first and second pull-up resistors are grounded. |
