Patent ID: 6987507
Filing Date: 2006-01-17
Classification: G06F

Abstract:
1. A current feed circuit for feeding a high frequency current to a plurality of sensor coils included in an electromagnetic inductive coordinate input device, the circuit comprising: a first high-frequency signal transmitting circuit for generating a first high-frequency current corresponding to a positive half-wave high-frequency signal input; a second high-frequency signal transmitting circuit for generating a second high-frequency current corresponding to a negative half-wave high-frequency signal input; a first plurality of driver transistors, each being provided between said first high-frequency signal transmitting circuit and each of a plurality of sensor coils for transmitting the first high-frequency current to the corresponding sensor coil; a second plurality of driver transistors, each being provided between the second high-frequency signal transmitting circuit and each of a plurality of sensor coils for transmitting the second high-frequency current to the corresponding sensor coil; a first plurality of switches, each being provided with respect to each of said first plurality of driver transistors for turning on/off the corresponding driver transistor; a second plurality of switches, each being provided with respect to each of said second plurality of driver transistors for turning on/off the corresponding driver transistor; and a circuit element for combining the first high-frequency current transmitted from said first plurality of driver transistors with the second high-frequency current transmitted from said second plurality of driver transistors to transmit the combined current to each of the plurality of sensor coils.