US Patent 10025423 Driven shield control

In an embodiment, a circuit comprises: an analog driver operable to drive a sensor voltage on a capacitive sensor; a digital driver; a shield drive control coupled to the analog driver and the digital driver, the shield drive control operable to: during a one or more phases of a capacitive measurement of the capacitive sensor, disable the analog driver and enable the digital driver to drive a driven shield; and during one or more other phases of a capacitive measurement of the capacitive sensor, disable the digital driver and enable the analog driver to drive the driven shield with a driven shield voltage that replicates the sensor voltage.