US 8,711,119 B2Granted

Display systems with touch screens

AssigneeO2Micro, Inc.

InventorsDa Liu, Horia Udrea Spenea

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Abstract

A display system includes a touch screen and a driving circuit. The touch screen includes touch sensors and a light source. A converter of the driving circuit receives an input voltage and provides a first output voltage to the light source according to a driving signal. A controller of the driving circuit converts the first output voltage to a second output voltage to drive the touch sensors, compares a voltage feedback signal indicating whether the second output voltage reaches a desired voltage level with a current feedback signal indicating whether a current through the light source reaches a desired current level, selects a feedback signal from the voltage feedback signal and the current feedback signal according to the comparison, and generates the driving signal to adjust the first output voltage according to the selected feedback signal.

Claims33

Dependent claims

a display system comprising:

a touch screen comprising a plurality of touch sensors and a light source that backlights a display panel;
and
a driving circuit coupled to said touch screen, said driving circuit comprising:
a converter that receives an input voltage generated by a power source, and that provides a first output voltage to said light source according to a driving signal;
and
a controller, coupled to said converter, that converts said first output voltage to a second output voltage to drive said touch sensors, that generates a voltage feedback signal indicating whether said second output voltage reaches a desired voltage level, and that generates a current feedback signal indicating whether a current flowing through said light source reaches a desired current level, wherein said controller compares said voltage feedback signal with said current feedback signal and selects a feedback signal from said voltage feedback signal and said current feedback signal according to a result of said comparison, wherein said controller generates said driving signal to adjust said first output voltage according to said selected feedback signal, such that said current and said second output voltage are adjusted to said desired current level and said desired voltage level, respectively.

3 more elements

A method for controlling a touch screen, wherein said touch screen comprises a plurality of touch sensors and a light source that backlights said touch screen, and wherein said method comprises:

providing a first output voltage to said light source according to a driving signal;
converting said first output voltage to a second output voltage to drive said touch sensors;
generating a voltage feedback signal indicating whether said second output voltage reaches a desired voltage level;
generating a current feedback signal indicating whether a current flowing through said light source reaches a desired current level;
comparing said voltage feedback signal with said current feedback signal;
selecting a feedback signal from said voltage feedback signal and said current feedback signal according to a result of said comparison;
and
generating said driving signal to adjust said first output voltage according to said selected feedback signal, such that said current and said second output voltage are adjusted to said desired current level and said desired voltage level, respectively.

5 more elements

A controller for controlling a touch screen, wherein said touch screen comprises a plurality of touch sensors and a light source that backlights said touch screen, and wherein said controller comprises:

a voltage control circuit that receives a first voltage for powering said light source, that generates a second voltage according to said first voltage to drive said touch sensors, and that generates a voltage feedback signal indicating whether said second voltage is adjusted to a desired voltage level;
a current control circuit that monitors a current flowing through said light source, and that generates a current feedback signal indicating whether said current is adjusted to a desired current level;
and
a voltage regulator, coupled to said voltage control circuit and said current control circuit, that compares said voltage feedback signal and said current feedback signal, that selects a feedback signal from said voltage feedback signal and said current feedback signal according to a result of the comparison, and that generates a driving signal according to said selected feedback signal to regulate said first voltage, such that said current and said second voltage are adjusted to said desired current level and said desired voltage level, respectively.

1 more element

Dependencies are inferred from the claim text.