Microchip Has added two new members to its IEC/UL 60730 Class B certified touchscreen controller family. The new MXT448UD-HA and MXT640UD-HA increase the class B device portfolio to more than 10 inches and, therefore, offer customers specialized solutions with larger screen sizes and scalability. Networking and connected home appliances allow users and manufacturers to communicate with them over the Internet. For example, users of kitchen ovens can look up new recipes online, or manufacturers can perform remote diagnostics or upgrade firmware over a wireless network. Displays and touch sensors are key to this.
In addition to class B, these new devices comply with the iec61000-4-6 class A specification with conducted noise immunity up to 10Vrms(class 3 for industrial use). This allows products with touch-screen interfaces to operate in harsh factory environments where conveyor belts, power rails or assembly machinery can generate electromagnetic interference. Appliance manufacturers will benefit from increased reliability and output. This is a big improvement for consumers who use unprotected touch screens on their ovens or washing machines, which can lead to errors or missing touch screens due to unprotected power transmission, electromagnetic interference from motors and adjacent electrical equipment.
These new touch screen controllers also provide two serial interfaces (SPI and I²C) that provide redundancy in design by combining security features, such as separate communication between the touch screen controller and the host master control board in addition to the secure MCU. Touch events are provided to both processors simultaneously. This unique architecture reduces time-to-market and reduces development costs because all security-critical firmware can be produced on a dedicated security-certified MCU independent of the main processor running the device GUI (source code review is mandatory by the IEC/UL test lab).
"As the product adds more control through the touch screen, the interface must work reliably to meet the requirements of users and protect users," said Clayton pillion, head of microchip's human-computer interface business unit. "Maxtouch technology provides excellent anti noise performance, making it operate safely and steadily throughout its service life. We have worked closely with customers to launch the first series of functional safety touch controllers, and achieved high application in anti noise, which is very important to the success of the product."
In addition to complying with IEC standards, the range also supports operating temperatures up to 105C, which is a major requirement for cooktops and ovens due to the proximity of HMI systems to heating elements.
