ASICs: Providing resolution to industrial touchscreens

Thanks to touch-screen technology, interaction with a computer can be as instinctive as a conversation between two humans. Application Specific Integrated Circuits (ASICs) play an integral role in optimising touchscreens, creating seamless and intuitive user experiences. ?

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Touchscreens now feature extensively in our daily lives:

??Mobile devices

???Retail

?? Healthcare

??Industrial settings

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But more niche applications, such as those in a manufacturing facility, call for specialised touchscreens that can detect a human finger through thick glass, gloves, or at a distance above the screen’s surface.

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Electronic challenges ??

Most modern touchscreens use the 'projected capacitance' technique, where a matrix of invisible conductors is embedded within the display. At each crossing point, conductors form coupling capacitances. These couplings are reduced when a finger is in close proximity ??

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The touchscreen controller measures these capacitances, driving each wire in turn with voltage stimulus. Measuring the many tiny currents simultaneously, it is possible to observe any touches effect and calculating where they occur.

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Signals from each wire pass through filtering components to eliminate interference, then get amplified, sampled and digitised by an analogue-to-digital converter (ADC). Replicating all this componentry, to serve the numerous wires in the panel, represents a significant challenge to the cost and form factor of the electronics.

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Due to the subtle changes in capacitance, noise management is critical. High-frequency operation is needed to maintain a responsive ‘frame rate’ from the touch panel. Matching between the channels must be good to simplify subsequent processing, calling for tight control over circuit properties and stray capacitances.

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The application of ASICs to solve these challenges

ASICs are necessary for touchscreen solutions in applications, such as industrial control panels, medical devices, automotive systems and certain consumer electronics. Tailoring an ASICs use to touchscreen functionality can create:

??Faster response times

??Better signal processing

??Improved power efficiency

??Accurately predict and mitigate noise

??Optimised performance

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ASICs also allow for features and functionalities specific to industrial touchscreen requirements, enabling manufacturers to differentiate their products and meet specific market demands.

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Developing ASICs

Swindon offers a full turnkey (FTK) service to guide development projects for touchscreen ASICs, from the definition of the ASIC to the design-in.

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?This process starts with a solutions requirement analysis, defining the functional requirements and performance specifications based on the industrial target application.

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?Next, architecture design. This includes the integration of required components, communication interfaces, power management features, circuit design, transistor-level designs, signal processing blocks and power distribution.

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?After verification and testing stage, the ASIC can be integrated into the touchscreen device's circuitry, ensuring proper functionality and compatibility with other components.

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Touch-panels are just one application of ASICs, but they demonstrate the value that integration can bring. The benefits are such that an ASIC sits behind every touch-panel we encounter in our daily lives and are critical to the production of many items we use, whether we know it or not.

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Do you have an application that could benefit from an ASIC? Contact a member of the team for a no-obligation first discussion.

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