Analog circuit, position indicator, and system
AssigneeWacom Co., Ltd.
InventorsYuji Katsurahira, Takeshi Koike, Hideyuki Hara
Life of this patent
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Abstract
A low-power-consumption, noise-immune analog circuit for a position indicator is provided. The analog circuit provided by the present disclosure is connected to an electrode that receives a control signal by capacitive coupling, and includes an edge detection circuit and a waveform restoration circuit. The edge detection circuit detects rising and falling edges of the control signal received by the electrode. The waveform restoration circuit restores the waveform of the control signal in accordance with the rising and falling edges detected by the edge detection circuit.
Claims16
An integrated circuit used to control operation of a stylus, wherein the stylus includes an electrode and receives a control signal from a sensor via capacitive coupling of the electrode with the sensor, the integrated circuit comprising:
- a differential circuit that receives, as an input, the control signal received by the electrode,
- a positive comparator that detects rising edges of the control signal using positive voltages generated based on positive peak voltage outputs from the differential circuit;
- a negative comparator that detects falling edges of the control signal using negative voltages generated based on negative peak voltage outputs from the differential circuit;
- and
- a detection circuit that detects the control signal based on outputs from the positive comparator and the negative comparator.
A system including:
- a stylus including an electrode;
- and
- a sensor controller coupled to a sensor that transmits a control signal to the electrode of the stylus via capacitive coupling,
- wherein the stylus includes:
- a differential circuit that receives, as an input, the control signal received by the electrode,
- a positive comparator that detects rising edges of the control signal using positive voltages generated based on positive peak voltage outputs from the differential circuit;
- a negative comparator that detects falling edges of the control signal using negative voltages generated based on negative peak voltage outputs from the differential circuit;
- and
- a detection circuit that detects the control signal based on outputs from the positive comparator and the negative comparator.
Dependencies are inferred from the claim text.