| 摘要 |
<p>PURPOSE:To prevent the variance of an induced voltage level by connecting plural 2nd analog switches to the outputs of plural analog block connected to the outputs of plural sense lines. CONSTITUTION:When a coordinate indicator 6 is driven, the voltage is induced on a sense line 7 set close to the indicator 6. The analog switch blocks 2 and 3 are successively selected by a control signal 11 received from a coordinate arithmetic circuit 9 and the internal switches are successively closed. The voltage if induced on the line 7 at this time point is supplied to the circuit 9. If the block 3 is selected under such conditions, an internal switch 14 of an analog switch block 1 corresponding to the block 3 is closed with other internal switches opened respectively. Therefore, the output side of the block 3 is separated from the output side of the block 2 at the inside of the block 1. Thus, the parasitic capacities 4 of blocks 2 and 3 are never connected in parallel with each other. As a result, the influence of the variance of the ON resistance of a switch is reduced to the signals to be transmitted.</p> |
