Timing synchronization of active stylus and touch sensor

A controller integrated circuit configured to control a stylus, wherein the stylus transmits a transmission signal to a touch-sensor controller and the stylus includes a tip and one or more electrodes included in the tip, the controller integrated circuit comprising:

• (a) an analog front end configured to receive signals transmitted from a touch sensor coupled to the touch-sensor controller, and to convert the signals into sequences of digital signals;
• and
• (b) a correlator coupled to a memory, configured to feed the sequence of digital signals received in different periods into the memory, and correlate each of the sequences of digital signals with a digital data defined by a wide-band code to generate multiple correlations,
• wherein the controller integrated circuit is configured to transmit the transmission signal to the touch-sensor controller according to a synchronization timing determined based at least in part on one or more of the multiple correlations.

A system including a stylus and a sensor controller,

• wherein, the sensor controller is coupled to a touch sensor and is configured to transmit signals defined by a wide-band code via the touch sensor, and
• wherein the stylus is configured to transmit a transmission signal to the sensor controller, the stylus comprising:
• one or more electrodes included in a tip;
• and
• a computer-readable non-transitory storage medium embodying logic that is configured when executed to:
• receive, by the one or more electrodes and an analog front end, the signals transmitted from the touch sensor coupled to the sensor controller, and convert the signals into sequences of digital signals;
• feed the sequences of digital signals received in different periods into a memory;
• correlate each of the sequences of digital signals with a digital data defined by the wide-band code to generate multiple correlations;
• and
• transmit the transmission signal to the sensor controller according to a synchronization timing determined based at least in part on one or more of the multiple correlations.