Maxim introduces TacTouch tactile actuator controller with integrated touch pressure measurement circuit

Maxim Integrated Products introduces the TacTouch tactile actuator controller MAX11836, which is suitable for single/multilayer piezoelectric actuators and electroactive polymer actuators (EAP) in tactile actuator devices. The MAX11836 expands Maxim's TacTouch product line for touch processing and tactile feedback applications. The integrated touch pressure measurement function of this component can effectively avoid false touch operations and is suitable for cellular phones, portable media players, digital photo frames, multi-function printers, digital cameras/camcorders, point-of-sale (POS) terminals, e- books , PCs and notebooks.

The MAX11836 is based on Maxim's previous generation MAX11835 device and adds a drive /detection circuit that can be used to connect up to four external force-sensing resistors (FSRs) to measure touch pressure. FSRs, when used with a capacitive touchscreen controller (C-TSC), help avoid false touches and reduce system power consumption, because the C-TSC is powered down when the system is idle and wakes up only when a touch is detected. As a single- chip solution, the MAX11836 makes it easy to add tactile feedback to terminal applications with touchscreens or touch buttons.

The MAX11836 stores user-defined tactile templates, playback logic, and has a configurable output DC-DC converter circuit and an output driver for larger capacitive loads. This integrated feature enables the component to drive a variety of tactile stimuli, such as single/multilayer piezoelectric stimuli. The boost converter inside the component supports an excitation voltage range of 10V to 250V.

Unlike other solutions that require haptic waveforms to be stored in the host processor and played back in real time to drive discrete DC-DC conversion/driver circuits, the MAX11836 requires only a low-voltage power supply and a serial I2C interface from the host processor. The host processor downloads user-defined haptic templates through the serial interface at power-up. During operation, playback from the on-chip memory can be triggered by three methods: serial port commands, built-in touch detection, or a proprietary single-wire link compatible with other Maxim products (MAX11835). The single-wire interface determines the triggering moment and determines which of the 16 templates can be stored in the on-chip memory at the same time. Compared with other solutions, the Maxim haptic solution has the advantage of near-zero latency in haptic output because the operating system is installed in the host processor and therefore does not introduce latency to the components. This provides users with a realistic tactile experience, even when typing quickly on a multi-touch screen keyboard.

The MAX11836 is available in an ultra-small 1.6mm x 1.6mm, 25-bump wafer-level package (WLP) to support small form factor end products.