Patent ID: 9639198
Date: 2017-05-02
CPC Classifications: G06F,G09G,Y02D

Claim:
1. A semiconductor device capable of being connected to a display panel including a touch sensor, wherein the display panel is a liquid crystal display panel, and wherein the touch sensor is formed integrally with the liquid crystal display panel in an in-cell type using an arrangement of capacitors, and can detect a touch state and a position by detecting a change in capacitance, the semiconductor device comprising: a driving circuit configured to drive the liquid crystal display panel; a touch sensing circuit configured to be connected to the integrally-formed touch sensor; a power supply circuit that supplies a power source to the liquid crystal driving circuit and the touch sensing circuit; and a bias control circuit that supplies a first control signal to the driving circuit to control a first bias current flowing through the liquid crystal driving circuit and a second control signal to the touch sensing circuit to control a second bias current flowing through the touch sensing circuit, the second control signal being separate and independent from the first control signal, wherein the semiconductor device is able to perform a time-division operation including a display driving period in which the liquid crystal display panel is driven and a touch state is not detected and a sensing period in which a touch state is detected and a driving state of the liquid crystal display panel is not changed, one or more display driving period and one or more sensing periods are included in one frame period of an image which is displayed by the liquid crystal display panel, in the display driving period, the power supply circuit reduces power supply capability to the touch sensing circuit further than that in the sensing period, and/or the bias control circuit reduces the second bias current further than that in the sensing period by controlling a signal level output of the second control signal, and in the sensing period, the power supply circuit reduces power supply capability to the liquid crystal driving circuit further than that in the display driving period, and/or the bias control circuit reduces the first bias current further than that in the display driving period by controlling a signal level output of the first control signal.