The APT7846 is enhance function of APT7843 added battery and temperature monitor function and offer of a bandgap reference voltage for system user. The APT7846 Touch Screen Controller IC provides all the screen driver , A/D converter and control circuits to easily interface to 4 wire resistive touch screen. The IC continually monitors the screen waiting for a touch. When the screen touched , the IC performs A/D converter to determine the location of touch. Also , this device has 1 auxiliary input to A/D converter , allowing for the measurement of other input signal.