New automotive touchscreen controllers support thick cover lenses with multi-finger touch and address automotive functional safety requirements
A new family of automotive touchscreen controller chips from Microchip Technology support screens up to 20 inches in size, and are designed to bring consumers the touchscreen user experience they expect in vehicles.
“Even as touchscreen displays in the car grow larger, drivers expect screens to operate with the same touch experience as mobile phones. However, screens in automobiles need to meet stringent head impact and vibration tests, and consequently have thicker cover lenses that potentially impact the touch interface performance. As screens get larger, they are also more likely to interfere with other frequencies such as AM radio and car access systems. All of these factors become a major challenge in the design of modern automotive capacitive touch systems. The new products were designed to address these issues”, Microchip noted in the announcement.
Easing design of modern automotive capacitive touch screens
The maXTouch touchscreen controllers build upon Microchip’s existing maXTouch touchscreen technology that the company notes is widely adopted by manufacturers worldwide.
The MXT2912TD-A has nearly 3,000 touch sensing nodes, and MXT2113TD-A has more than 2,000 nodes, to bring consumers the touchscreen user experience they expect in vehicles.
The new devices offer superior signal-to-noise capability to address the requirements of thick lenses, even supporting multiple finger touches through thick gloves and in the presence of moisture, the company claims.
As automakers use screens to replace mechanical switches on the dash for sleeker interior designs, safe and reliable operation becomes even more critical.
To address this, the MXT2912TD and MXT2113TD devices incorporate self- and sensor-diagnostic functions, which constantly monitor the integrity of the touch system. These smart diagnostic features support the Automotive Safety Integrity Level (ASIL) classification index as defined by the ISO 26262 Functional Safety Specification for Passenger Vehicles.
The new devices feature technology that enables adaptive touch utilizing self-capacitance and mutual-capacitance measurements, so all touches are recognized and false touch detections are avoided.
They are also said to utilize a new signal shaping technology that significantly lowers emissions to help large touchscreens using maXTouch controllers meet CISPR-25 Level 5 requirements for electromagnetic interference in automobiles.
The new touch controllers also meet automotive temperature grade 3 (-40 to +85°C) and grade 2 (-40 to +105°C) operating ranges and are AEC-Q100 qualified.
“The new devices build on this success and address the current trends of increasing screen sizes and reduced finger touch separation in vehicles”, according to Microchip.
Microchip offers an evaluation kit which includes a Printed Circuit Board (PCB) with the maXTouch touchscreen controller, a touch sensor on a clear glass lens, the Flat Printed Circuit (FPC) to connect to the sensor display, a converter PCB to connect the kit to the host computer via USB, as well as cables, software and documentation.
All parts are also compatible with maXTouch Studio, a full software development environment to support the evaluation of maXTouch touchscreen controllers.
Pricing and Availability
The MXT2912TD-A and MXT2113TD-A devices are available now in sampling and volume quantities in LQFP176 and LQFP144 packages, respectively. Pricing is available upon request.
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