CAPACITIVE TOUCHING APPARATUS
First Claim
1. A capacitive touching apparatus, comprising:
- at least an equivalent capacitor module, having a first terminal and a second terminal, wherein the first terminal receives a periodic driving signal and an output voltage is produced at the second terminal of the equivalent capacitor module according to the driving signal;
a first comparator, coupled to the equivalent capacitor module, receiving the output voltage and comparing the output voltage with a first reference voltage so as to produce a first comparison result;
a first reference current generator, coupled to the equivalent capacitor module and the first comparator and producing a first reference current and a second reference current according to a base current, wherein the first reference current generator decides whether to respectively output the first reference current and the second reference current according to the first comparison result, and the first reference current is output to the second terminal of the equivalent capacitor module; and
a first detection capacitor module, coupled to the first reference current generator to receive the second reference current and to thereby produce a first detection output signal.
1 Assignment
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Accused Products
Abstract
The invention provides a capacitive touching apparatus, which includes at least an equivalent capacitor module, a first comparator, a first reference current generator, a first detection capacitor module and a selection switch module. The equivalent capacitor module receives a periodic driving signal and produces an output voltage according to the driving signal. The first comparator compares the output voltage with a first reference voltage and thereby produces a first comparison result. The first reference current generator produces a first reference current and a second reference current according to a base current, in which the first reference current generator decides whether to respectively output the first reference current and the second reference current according to the first comparison result, and the first reference current is output to the equivalent capacitor module. The first detection capacitor module produces a first detection output signal according to the second reference current.
14 Citations
21 Claims
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1. A capacitive touching apparatus, comprising:
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at least an equivalent capacitor module, having a first terminal and a second terminal, wherein the first terminal receives a periodic driving signal and an output voltage is produced at the second terminal of the equivalent capacitor module according to the driving signal; a first comparator, coupled to the equivalent capacitor module, receiving the output voltage and comparing the output voltage with a first reference voltage so as to produce a first comparison result; a first reference current generator, coupled to the equivalent capacitor module and the first comparator and producing a first reference current and a second reference current according to a base current, wherein the first reference current generator decides whether to respectively output the first reference current and the second reference current according to the first comparison result, and the first reference current is output to the second terminal of the equivalent capacitor module; and a first detection capacitor module, coupled to the first reference current generator to receive the second reference current and to thereby produce a first detection output signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A capacitive touching apparatus, comprising:
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at least a touch capacitor; a charging current source, providing a charging current; a first capacitor; a selection switch module, coupled between the touch capacitor and the charging current source for charging the first capacitor by using the charging current, making the touch capacitor coupled to a ground voltage so as to be discharged or making the first capacitor coupled to the touch capacitor for assigning charges according to a selection signal; a comparator, coupled to the first capacitor and the selection switch module and making the result of assigning charge between the first capacitor and the touch capacitor compared with a reference voltage so as to produce a comparison result; a reference current generator, coupled to the comparator and the first capacitor so as to produce a first reference current and a second reference current according to a base current, wherein the reference current generator decides whether to respectively output the first reference current and the second reference current according to the comparison result and a control signal, wherein the first reference current is output to the first capacitor; and a detection capacitor module, coupled to the reference current generator to receive the second reference current so as to produce a detection output signal. - View Dependent Claims (18, 19, 20, 21)
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Specification