Stylus and stylus circuitry for capacitive touch screens

摘要

A stylus for a capacitive touch screen includes an inverting charge integrator circuit is connected to a conductive tip for providing an output signal proportional to a charge induced at the conductive tip. An inverting amplifier generates an amplified signal proportional to the signal output from the inverting charge integrator. A conductive contact provides electrical or capacitive coupling between the amplified signal and an exterior of the stylus which may provide electrical or capacitive coupling with a person holding the stylus. In other embodiments, the order of the inverting charge integrator and the inverting amplifier may be reversed. A power supply circuit powers the inverting charge integrator and the inverting amplifier. Shielding may be implemented to isolate the stylus circuitry and prevent oscillation. The provided circuitry may enable a ball point or other fine point stylus tip configurations.

主权项

1. A circuit for a capacitive touch screen stylus, the circuit comprising:
a. a conductive tip for providing capacitive coupling with a capacitive touch screen; b. an inverting charge integrator connected to the conductive tip for providing an output signal proportional to a charge induced at the conductive tip; c. an inverting amplifier for generating an amplified signal proportional to the signal output from the inverting charge integrator; d. a conductive contact for providing electrical or capacitive coupling between the amplified signal and an exterior of the stylus; and e. a power supply circuit for powering the inverting charge integrator and the inverting amplifier.