Cypress adds ultra-low-power proximity detection to CapSense

Paul Boughton

Cypress Semiconductor has updated its leading CapSense sensors with low noise QuietZone technology and ultra-low-power proximity sensor to improve user interfaces in consumer equipment using buttons.

The CY8C20xx7/S CapSense and CapSense Plus controllers offers the industry’s best proximity detection of up to 30cm. Its low power enables proximity designs in battery-powered applications, such as “wake-on-approach” for mice that provides lower system power consumption by allowing the device to sleep until a user’s hand approaches.

As a result it consumes 28µA/sensor in run time with a wake-up and scan once every 125ms. The family also has driven shield capability, which enhances water tolerance capabilities in applications that face the challenges of mist, water droplets or streaming water. [Page Break]

The target applications range from Bluetooth headsets, smart phones and tablets that require lower operating voltages to white goods, small home appliances, TV, monitors and printers which require high SNR for robust touch performance. These devices are also ideal for enabling wake-on approach features in applications such as PC peripherals.

The QuietZOne technology in the CY8C20xx7/S enhances the immunity to radiated and conducted noise and so provides a high signal to noise ratio (SNR) to provide robust touch performance even in extreme noise environments. Its high sensitivity can determine changes in finger capacitance as low as 0.1pF using Cypress’s patented Capacitive Sigma Delta (CSD) Plus sensing algorithm. [Page Break]

The CY8C20xx7S devices feature SmartSense Auto-tuning that automatically sets and monitors the performance of each sensor and dynamically compensates for noise and environmental variations during runtime to deliver optimal sensor performance and uniform button response. This technology also adapts to manufacturing variations in PCBs, overlays, and tunes out noise generators such as LCD inverters, AC lines and switched-mode power supplies, saving engineers precious development time in implementing capacitive touch designs. It tunes all design parameters for both proximity detection and water tolerance features, with separate fine tuning for proximity distance. SmartSense simplifies the design process and satisfies the rigorous demands of the industrial and white goods markets.

 “We have included technology advancements of all kinds in this family, including power management, autotuning, noise immunity, proximity detection and water tolerance. Customers from a wide variety of markets are eager to design with this solution,” said Dirk Franklin, Cypress CapSense Business Unit Director. [Page Break]

Availability and Starter Kit

The CY8C20xx7/S CapSense controller family is currently in production in 16-QFN, 30-WLCSP, 24-QFN, 32-QFN, 48-QFN and 16-SOIC packages. The CY8C20xx7/S Controllers can be evaluated using the AEK-CY8C20xx7 QuietZone Starter Kit from Artaflex. Based on the CY8C20247S-24LKXI, the US$9.99 Starter Kit allows designers to develop proof of concepts by directly connecting to the target design boards.

More information on the kit is available at Cypress’ design partner solution webpage