Capacitive touchscreens for thermostats using smaller capacitors in standby mode

摘要

Exemplary embodiments are disclosed of touchscreen devices for thermostats and other electronic devices. In an exemplary embodiment, a capacitive touchscreen device includes a touchscreen having touch regions. Each touch region is coupled with at least one first capacitor and at least one second capacitor. The second capacitors are connected in parallel and have smaller capacitance than the first capacitors. The capacitive touchscreen device may be configured to be operable in a standby mode in which the second capacitors are charged and an active mode in which the first capacitors are charged.

主权项

1. A capacitive touchscreen device comprising:
a controller; a plurality of single first capacitors, each having an individual unique input port to the controller; a plurality of single second capacitors connected in parallel and having a common input port to the controller that is separate from any of the first capacitor input ports, each single second capacitor being different from each single first capacitor and having a smaller individual capacitance than an individual capacitance of any of the single first capacitors; and a touchscreen including a plurality of mutually isolated touch regions, each said touch region being coupled with one of the single first capacitors and one of the single second capacitors; whereby the capacitive touchscreen device is configured to be operable in a standby mode in which the single second capacitors are charged and the single first capacitors are not charged to reduce power consumption by the single first capacitors, and to switch to an active mode in which the single first capacitors are charged in response to a detection of a change in capacitance of one or more of the single second capacitors by the controller; wherein in the standby mode the single second capacitors are charged via the common input port and in the active mode the single first capacitors are charged via each corresponding individual unique input port; and wherein the controller is configured to scan only the single first capacitors for a change in capacitance during the active mode to determine which touch region is being touched by a user.