Novel touchscreen controller enables touchscreens to function seamlessly with noisy battery chargers

February 14, 2011 // By Paul Buckley
Cypress Semiconductor Corp., has unveiled a new feature for the company’s 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  AC noise.

The new feature, which is available in Cypress’s CY8CTMA3XX TrueTouch family, 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 1 Hz to 1 MHz. The voltage spikes can go directly into the touch panel during the presence of touch, 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.


The Charger Armor feature is available today, and Cypress expects customers to introduce systems with Charger Armor in the first half of 2011.

For more information about the TrueTouch solution visit