Using Serial Resistors to Reduce the Power Consumption of Resistive Touch Panels

In this paper we analyze the characteristics of the resistive touch panel to find a simple way to reduce power consumption. A touch panel´s current consumption is less than 1 muA while waiting, with the different of kinds of touch panels there is a 50 mA to 100 mA difference in the current consumption while operating. This difference has a great effect on the operation time of consumer electronic products. In this paper we propose a method according to Ohm´s law of adding in serial resistors to reduce current consumption. As the serial resistors inserted are higher, the current consumption becomes lower, and the analog sensed voltage becomes lower, too. However, a small sensed voltage may produce the wrong output signal based on the resolution of the A/D conversion, and then the touch panel may show an unstable phenomenon. Through experiments we have found which values for the serial resistor both save power consumption and still maintain the similar operation sensitivity of the resistive touch panel.