US 8,711,107 B2Granted

Signal conversion control circuit for touch screen and method thereof

AssigneeMyson Century, Inc.

InventorsKee Lih Fann, Fang Zhang

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Abstract

A signal conversion control circuit comprises an analog-to-digital converter, a first sample-and-hold circuit, a second sample-and-hold circuit, a first switch, a second switch, a third switch, and a fourth switch. The analog-to-digital converter has an input end for receiving an output signal of a touch screen. The first sample-and-hold circuit is configured to provide the analog-to-digital converter with a high-level reference voltage. The second sample-and-hold circuit is configured to provide the analog-to-digital converter with a low-level reference voltage. The first switch connects a supplied voltage to the touch screen. The second switch connects the touch screen to a ground potential. The third switch connects the supplied voltage to the first sample-and-hold circuit through the first switch. The fourth switch connects the ground potential to the second sample-and-hold circuit through the second switch.

Claims7

Dependent claims

A signal conversion control circuit applied to a touch screen, comprising:

an analog-to-digital converter having an input end for receiving an output signal of a touch screen;
a first sample-and-hold circuit configured to provide the analog-to-digital converter with a high-level reference voltage;
a second sample-and-hold circuit configured to provide the analog-to-digital converter with a low-level reference voltage;
a first switch connecting a supplied voltage to the touch screen;
a second switch connecting the touch screen to a ground potential;
a third switch connecting the supplied voltage to the first sample-and-hold circuit through the first switch;
and
a fourth switch connecting the ground potential to the second sample-and-hold circuit through the second switch;
wherein the first sample-and-hold circuit includes a first operational amplifier and a capacitor and a non-inverting input terminal of the first operational amplifier is connected to the third switch and the capacitor, an inverting input terminal of the first operational amplifier is connected to an output terminal of the first operational amplifier, and an output terminal of the first operational amplifier is connected to a high-level reference voltage terminal of the analog-to-digital converter.

6 more elements

Dependencies are inferred from the claim text.