Renesas improves capacitive touch IP

Later this year, Renesas will sample a 5x improvement in its IP for capacitive touch sensing.

The IP is for home appliances and healthcare equipment such as blood pressure and blood glucose meters.

‘The IP achieves touch sensitivity five times superior to Renesas’ R8C/3xT microcontrollers (MCUs),’ says the company.

The IP supports the mutual capacitance method which is more reliable and versatile than the common self-capacitance method.

Renesas will also provide development tools.

For human machine interface (HMI) applications for electric and electronic equipment, touch-key interfaces have been the subject of increasing attention.System manufacturers are now developing new touch interfaces with a curved surface, instead of the flat panels that have been mainstream up to now.

For home appliances used in the kitchen, it is often the case that the appliance will be splashed with water or the user will be wearing gloves. Furthermore, there is also equipment, such as IH stoves, that emit strong electromagnetic fields. This means that a technology that achieves both high sensitivity and high noise immunity at the same time is required to reliably respond to the static capacitance when such end products are operated by the user’s hand.

The Renesas IP provides characteristics that allow reliable sensing even with acrylic panels with thicknesses in excess of 10 mm. The technology can implement flexible designs, for example products that implement curved panels, and works with gloved hands and proximity sensing where there is no actual touch.

Since the IP passes the electromagnetic noise testing stipulated in the International Electrotechnical Commission (IEC) 61000-4-3 and IEC 61000-4-6 (Note 2) standards, it enables the design of robust systems even under noisy conditions.

Because the IP supports the mutual capacitance method, it is easier to implement moisture proofing measures in end products, so that false detections do not occur even if there is water on the touch key area.

The IP also supports embedding touch keys in a matrix configuration to eliminate false ghost detections, a phenomenon associated with devices implementing the self-capacitance method. This allows the number of touch keys to be increased with minimal number of pins.


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