Patent 11526240 was granted and assigned to Apple (company) on December, 2022 by the United States Patent and Trademark Office.
An input device such as a stylus for providing input to a touch-sensitive surface with reduced sensitivity to leakage current variations over temperature is disclosed. A passive stylus may include one or more diodes in parallel with one or more bleed resistors. The non-linear load of the diode and resistor network can be operative to provide a stylus electric field in response to a stimulation signal from an electronic device that can be capacitively coupled to, and sensed by, the electronic device. The signal sensed by the electronic device can be a function of the total leakage current, which can vary greatly as a function of temperature and frequency. In order to improve performance, the diode and resistor network, including the bleed resistor(s) and diodes within that network, can be selected and/or designed to provide a reduced variation in the leakage current and more accurate stylus detection.