Cypress Semiconductor Corp. has unveiled a breakthrough feature for its TrueTouch™ touchscreen controllers that enables touchscreens in handsets, cameras, GPS systems and other mobile systems to function seamlessly while connected to noisy chargers. Low-cost, third-party and after-market battery chargers emit large levels of common-mode noise that adversely affects touchscreen performance, often resulting in inaccurate touch readings or phantom touches. Cypress’s new Charger Armor™ feature allows TrueTouch touchscreens to operate normally in the presence of extreme AC noise.
The new feature, which is available in Cypress’s CY8CTMA3XX TrueTouch family, is unique in the industry, and solves a common problem that mobile device manufacturers are struggling to overcome. Low cost chargers lack critical noise suppression components, and can generate tens of volts (peak to peak) across the frequency spectrum of 1Hz to 1MHz. These voltage spikes can go directly into the touch panel during the presence of touch, severely impacting touch performance. As such, many of the mobile phone vendors have worked together to create EN 62684 and EN301489, standards which regulate the noise spectrum for battery chargers. While Cypress’s TrueTouch technology alone can suppress noise at the levels of these standards, Charger Armor allows Cypress to go beyond the standards to deliver truly revolutionary charger noise immunity to the market, enabling mobile devices to operate with the lowest-cost chargers.
“Many of our customers struggle to overcome charger noise,” said Dhwani Vyas, vice president of the User Interface Business Unit at Cypress. “They are pleased to see an easy-to-implement, cost-effective solution to this problem. The flexibility of the PSoC-based TrueTouch architecture enables us to goes beyond simple frequency hopping and hardware filtering to address a wider range of noise issues than other touchscreen controllers. This is yet another example of Cypress’s leadership in providing innovative touchscreen solutions to problems such as LCD noise rejection, stylus support, water rejection, hover detection and others.”