"Feel the touch" haptic feedback touch buttons

Tiny haptic piezo controller drives single-layer and multilayer piezo actuators; built-in Maxim’s new MAX11835 is a novel haptic solution that provides customers with an enhanced, true "touch" experience with touch screens.

Consumers are accustomed to "feeling" the button press on keyboards, keypads, and many modern devices. Touch screens and capacitive sensors provide an interactive user interface, but the user cannot feel the touch because there is no mechanical button. The MAX11835 adds the feeling of mechanical feedback to touch screens and capacitive buttons. The product can be used with any touch-screen or touch-button controller. However, as part of its new TacTouch concept, Maxim provides design-in support and reference designs guaranteeing an optimal touch experience and simplified design-in when combined with the company's touch-screen controllers.

Target applications are any consumer or industrial equipment that has touch-screen displays or traditionally has mechanical buttons. Typical examples include cell phones, MIDs (mobile Internet devices), MP3 players, portable media players, digital photo frames, multifunction printers, digital still/video cameras, and POS (point-of-sale) terminals.

The MAX11835 drives both single-layer and multilayer piezo actuators over a wide 5V to 250V voltage range. The wide output voltage range not only lets designers choose between these two types of piezo actuators, but also guarantees a future-proof solution for alternative actuator technologies. By integrating a user-programmable haptic pattern generator, programmable boost converter, and high-voltage, high capacitive load driver, the MAX11835 generates a user-configurable, slew-rate-limited, boosted voltage output.

The MAX11835 is designed for use in low-power handheld equipment and includes several power-saving modes, including an automatic power-saving mode between haptic events. A 400 kHz I2C serial interface allows programming of various modes of operation, status checking, and the programming of haptic waveforms. The MAX11835 is packaged in a 25-pin WLP to support the miniaturization of end products. An EV (evaluation) kit is available to speed designs. To enable full system emulation and provide a total reference design, this EV kit comes with a resistive touch panel with piezo actuators mounted for evaluating the device's haptic feedback.