Patent ID: 8378660

Claim:
An integrated circuit device configured as a programmable analog front end for supporting inductive touch sensing, said integrated circuit device comprising: a synchronous detector having a first input coupled to an inductive reference coil external connection, wherein the inductive reference coil external connection is adapted for coupling to an inductive reference coil; a second input coupled to an inductive touch sensor coil external connection, wherein the inductive touch sensor coil external connection is adapted for coupling to at least one inductive touch sensor coil; a third input coupled to a reference select external connection, wherein the reference select external connection is adapted for coupling to a reference select signal; and a fourth input coupled to a clock external connection, wherein the clock external connection is adapted for coupling to a clock signal, a coil driver having an output coupled to a coil drive output external connection, an input coupled to a coil drive input external connection; an amplifier configured with a low-pass filter and having inputs coupled to the synchronous detector and an output having voltage values representative of inductance values of the at least one inductive touch sensor coil and the inductive reference coil, the output of the amplifier is coupled to a voltage detector output external connection; and an interface and control module having a communications port, wherein the interface and control module controls at least one characteristic of the programmable analog front end; wherein the synchronous detector mixes the clock signal with a signal from the inductive reference coil or the at least one inductive touch sensor coil, as selected by the reference select signal, to produce sum and difference mixing products, whereby the amplifier amplifies the sum and difference mixing products and substantially attenuates the sum mixing product and passes the difference mixing product at the output of the amplifier.