| 摘要 |
A low-voltage drive circuit for driving a sensor coil in a coordinate input device at a constant current includes a DC coupling capacitor and a constant-current output bias circuit unit. The DC coupling capacitor is provided between an output of a constant-current output drive circuit unit and a sensor coil. The constant-current output bias circuit unit controls a DC bias voltage of the output of the constant-current output drive circuit unit to be a midpoint potential of an operating voltage range for the constant-current output drive circuit unit. The constant-current output drive circuit unit may include a drive source circuit segment and a drive sink circuit segment that function as a complementary constant-current circuit unit. Preferably, the drive source circuit segment and the drive sink circuit segment are connected to respective constant-current output bias circuit units.
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