Secondary displays in vehicles can be integrated in car interiors and exterior features using what are claimed to be the industry’s smallest automotive grade packaged touch screen controllers. The MXT288UD touch controller family, the MXT288UD-AM and the MXT144UD-AM, offer low power mode, weatherproof operation and glove touch detection in multi-function displays, touchpad and smart surfaces for vehicles, motorcycles, e-bikes and car-sharing services.

Secondary touch surfaces can be placed in handlebars, doors, electronic mirrors, control knobs, steering wheels, between seats or in an armrest. The MXT288UD is provided in a small 7.0 x 7.0mm automotive grade VQFN56 package to reduce board space by 75% and minimise the bill of materials costs. The low power, wait for touch mode consumes less than 50µA and remains responsive for the user, even if the display switches off to save power or to avoid disturbing the driver at night. The system will wake by a touch event anywhere on the touch surface.

The MXT288UD-AM and the MXT144UD-AM devices enable detection and tracking of multi-finger thick gloves through a variety of overlay materials and thicknesses (for example, leather, wood or across uneven surfaces, even in the presence of moisture), says the company. Normally the dielectric constant of these overlay materials would limit the detection of the touch, but these devices reliably detect and track multi fingers with a high signal to noise ratio (SNR) and through a proprietary differential mutual acquisition scheme.

For example, in car sharing applications or motorcycles, this touch functionality helps users access a car from the outside by tracking touch co-ordinates on an exterior display in any environment, like rain, snow or extreme heat.

The MXT288UD family provides proven firmware, developed according to Automotive SPICE processes.  

Development tools and design services are available. Software tools includes maXTouch Studio and a maXTouch analyser. For the MXT288UD, hardware includes an evaluation kit with a PCB and a 5.0-inch capacitive touch panel. The MXT144UD’s evaluation kit includes a PCB and a 2.9-inch capacitive touch pad. For both devices, a bridge PCB is included with a USB connection for interfacing to a computer when running maXTouch Studio.

Microchip is taking part in PCIM 2020 (7-8 July)