Semiconductor device for determining whether touch electrode is touched by human body, and touch sensor using the semiconductor device
AssigneeRenesas Technology Corp.
InventorsTeruyuki KOGO, Kazuhiro Umemoto
Life of this patent
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Abstract
A touch sensor IC includes a switch for connecting, to an external terminal with its voltage to be sensed, a selected one of a plurality of external terminals to which a plurality of touch electrodes is connected. Only one set of two capacitors and a resistor element may therefore be provided for a plurality of touch electrodes. Thus, the number of required components is smaller as compared with a conventional sensor requiring two capacitors and a resistor element for each touch electrode.
Claims15
A semiconductor device comprising:
- a plurality of first terminals connected to a plurality of touch electrodes, respectively;
- a second terminal connected via a capacitor to a line of a reference voltage;
- a switch circuit for connecting, to a predetermined node, one of said plurality of first terminals that is associated with a touch electrode selected from said plurality of touch electrodes;
- and
- a charging and discharging circuit for performing a charging operation of charging said capacitor, a discharging operation of releasing a charge of said selected touch electrode, and a distributing operation of distributing a charge of said capacitor via said predetermined node to said selected touch electrode,
- whether said selected touch electrode is touched by a human body being determined based on a voltage of said predetermined node.
A touch sensor comprising a plurality of touch electrodes, a capacitor and a semiconductor device,
- said semiconductor device including:
- a plurality of first terminals connected to said plurality of touch electrodes, respectively;
- a second terminal connected via said capacitor to a line of a reference voltage;
- a switch circuit for connecting, to a predetermined node, one of said plurality of first terminals that is associated with a touch electrode selected from said plurality of touch electrodes;
- and
- a charging and discharging circuit for performing a charging operation of charging said capacitor, a discharging operation of releasing a charge of said selected touch electrode, and a distributing operation of distributing a charge of said capacitor via said predetermined node to said selected touch electrode,
- whether said selected touch electrode is touched by a human body being determined based on a voltage of said predetermined node.
Dependencies are inferred from the claim text.