21 February 2009
Six channel touch controller with integral led
Atmel’s AT42QT1060 is a touch control chip that integrates six channels of touch sensing with the ability to drive up to seven low current leds directly through a pulse width modulated (PWM) output function.
The device operates from 5.5 down to 1.8VDC and consumes less than 1uA in standby mode to give long battery life; it comes in a 4 x 4mm MLF28 package, making it suitable for use in mobile phones and other handheld devices. The AT42QT1060 is another addition to Atmel's range of capacitive touch controllers based on Quantum Research Group's charge-transfer technology. These include QTouch and QMatrix based controllers for single and multiple touch buttons, touch sliders and touch wheels.
The AT42QT1060 is designed for use in portable electronics products. An inbuilt capacitive guard channel feature helps prevent false triggering, for example, where moisture is an issue. This feature also prevents against erroneous commands that can occur when devices such as MP3 players are carried in a pocket, or in the case of a cellular phone, when it is held against the ear.
The sensor chip is based on Quantum’s QTouch charge transfer sensing method. This technology uses spread spectrum modulation to achieve high immunity to electrical noise and a patented technique - Adjacent Key Suppression (AKS) - ensures that only the intended key is activated by the touch of a finger. The guard channel feature uses AKS to eliminate false triggering of nearby keys. The device automatically recalibrates on power up, compensating for build up of moisture or other contaminants on the touch surface. Individual key sensitivity is host selectable.
A host wake up function allows the host to sleep and be woken up when a user triggers the corresponding input and additional GPIO expansion can be achieved by the use of spare IC pins.
The AT42QT1060 functions through any insulating panel including glass or plastic up to 3mm thick. Electrodes can be made from copper, silver, carbon, indium tin oxide (ITO) or Orgacon conductive ink and must be 6 x 6mm or larger. Widely different electrode sizes and shapes are possible, giving the product designer great flexibility in tailoring the user interface.
Author
Chris Shaw
Supporting Information
Websites
http://www.atmel.com
Companies
Atmel
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