Maxim MAX11836 TacTouch haptic actuator controller

Maxim has introduced the MAX11836, a TacTouch haptic actuator controller for single-/multilayer piezo actuators and electroactive polymers (EAPs) in touch-enabled devices.

Building on the company’s MAX11835, the MAX11836 adds drive/sense circuitry for connecting up to four external force-sense resistors to measure touch pressure.

Using FSRs with a capacitive touch-screen controller (C-TSC) helps avoid false touches and saves system power, as the C-TSC can remain in a power-down state during system idle times and wake up only when a touch is detected.

A single-chip solution, the device simplifies adding haptic feedback to any end application with a touch screen or touch buttons. Targeted devices include mobile phones, portable media players, digital photo frames, multifunction printers, digital still/video cameras, point-of-sale terminals, e-readers, tablet PCs, and notebooks.

The actuator features built-in storage of user-defined haptic patterns, playout logic, output-configurable DC-DC conversion and output drivers for capacitive loads.

This integration enables the device to drive a wide range of haptic actuators, such as single- or multilayer piezo actuators. The device’s internal boost converter supports actuators from 10 to 250 V.

While other solutions require the host processor to store the haptic waveforms and perform playout in real time to a discrete DC-DC conversion/driver circuit, the 11836 only requires a low-voltage supply and a serial I²C interface to the host processor. The host processor downloads user-defined haptic patterns at power-up through the serial interface.

During operation, playout from on-chip memory is triggered in one of three ways: through a serial interface command, through the built-in touch-detect function, or through a proprietary single-wire link that is compatible with other company products.

This single-wire interface determines the trigger instant and identifies which waveform from up to 16 patterns can be simultaneously stored in on-chip memory.