Proximity sensor shrinks by 30% for TWS earbuds

ams has launched the TMD2636, a fully integrated proximity sensor for true wireless stereo (TWS) earbuds. Claiming that it is 30% smaller than currently available solutions, the proximity sensor for in-ear detection enables TWS earbud manufacturers to reduce the size of the earbuds or provide new functionality by integrating multiple proximity sensors or other components that previously could not be accommodated.

By using one or more TMD2636 sensors, the earbud can automatically power up when inserted in the ear and power down when removed, which improves power savings when the earbud is not in use. In addition, with multiple TMD2636 sensors, earbud in-ear detection and power management can be more intelligent, said ams.

The TMD2636 sensor module integrates a 940-nm infrared (IR) vertical-cavity surface-emitting laser (VCSEL) emitter, IR-sensing photodiodes, control circuitry, and a clear-mold overlay in a 2.0 × 1.0 × 0.35 mm package. The average active-mode current consumption of the sensor is 70 µA and 0.7 µA in sleep mode.

The TMD2636 features several of the company’s innovations including photodetector technology, optical package design, and factory test and calibration. In addition, the TMD2636 digital I2C interface provides a patented solution for two devices to reside on the same bus, which simplifies the system design for dual devices, said ams.

Other features include proximity crosstalk compensation and automatic ambient light subtraction for improved proximity detection results. The proximity engine features advanced crosstalk noise cancellation via a range of offset adjustments to compensate for unwanted IR energy reflection at the sensor. In addition, along with noise, sensitivity and power consumption can be optimized with adjustable timing and power.

The TMD2636 proximity sensor is available for sampling. The company also offers an evaluation kit that includes a main controller board with a PIC microcontroller, an USB 2.0 interface (with an USB cable), a TMD2636 module daughter card, “plug-n-play” USB HID class drivers, software documentation, and GUI software.

Other earbud innovations include the ams AS3460 digital audio processor for loose-fit true wireless earbuds. Incorporating the unique Adaptive Leakage Compensation technology, the AS3460 dynamically adjusts the frequency coverage and depth of noise attenuation to cancel out noise. ams claims that the AS3460 is the first audio chip to provide up to 40 dB of noise attenuation in the loose-fit type of wireless earbud over a broad range of audible frequencies.