Touch controllers for buttons, sliders and wheels with parallel sensing

As appliance and equipment manufacturers look for ways to reduce system costs, many are replacing displays with Human Machine Interfaces (HMIs) using high-end decoration and illuminated capacitive-touch buttons, sliders and wheels. These interfaces often require a large number of touch sensors which can increase acquisition time and reduce the signal-to-noise ratio (SNR) when using conventional controllers.

To address these challenges, Microchip Technology has expanded its turnkey capacitive-touch family with the launch of  MTCH3380P and MTCH3240P controllers, helping manufacturers create visually appealing, display-free HMIs at lower system cost and with less design complexity. The first in Microchip’s touch turnkey controller portfolio to incorporate parallel sensing for buttons, sliders and wheels, the devices support IEC/UL 60730 Class B functional safety certification and operation up to 105°C, making them well suited for home appliance, outdoor and industrial applications.

By acquiring data from multiple sensors simultaneously, the MTCH3380P and MTCH3240P can support a large number of buttons, sliders and wheels while maintaining fast response times, a high signal-to-noise ratio (SNR) and reliable touch detection in noisy operating environments. This performance is enabled by 12 on-chip analogue-to-digital converters (ADCs) operating in parallel. The MTCH3380P supports up to 38 sensors in self-capacitance mode and 64 sensors in mutual-capacitance mode, while the MTCH3240P supports up to 24 and 32 sensors, respectively, without the acquisition-time penalties often associated with high sensor counts.

Enhanced touch sensitivity and noise immunity enable reliable touch detection through thick cover materials and when users are wearing gloves. These capabilities are especially valuable in-home appliances such as ovens, cooktops, refrigerators and washing machines, where moisture and gloved operation are common, as well as in outdoor applications including EV chargers, parking meters and kiosks that require durable protective covers and dependable operation in cold-weather conditions.

“Manufacturers are increasingly looking for ways to reduce system cost while still delivering intuitive and visually appealing user interfaces. As display-free HMIs incorporate more touch controls, maintaining responsive and reliable touch performance becomes increasingly challenging,” said Giovanni Fontana, senior director of Microchip’s human machine interface division. “Our MTCH3380P and MTCH3240P controllers address the touch-sensing challenges associated with display-free interfaces by delivering fast touch acquisition and high signal-to-noise ratio, helping enable responsive, reliable operation even in demanding applications.”

With support for customer driven IEC 60730 Class B functional safety certification, the MTCH3380P and MTCH3240P devices help manufacturers work towards meeting regulatory requirements. Microchip’s touch-sensing ecosystem and turnkey controllers are designed to provide the hardware, software and development resources needed to accelerate design, evaluation and testing. Support includes the mTouch Studio development environment and evaluation hardware, including host drivers for Linux and Zephyr.