A synchronous chopping technique and implementation for high-frequency precision sensing

A new architecture front-end for high-frequency electronic sensing is introduced. The architecture combines synchronous detection with chopping in a fully-differential topology. The proposed technique does not require the offset to be measured before a measurement is taken as in the prior art through the use of a microcontroller. An integrated circuit was designed in a 0.35-mum CMOS technology and tested with high-frequency inductive position sensors. The typical input-referred offset is 87 muV at a chopping frequency of 500 kHz.