Azoteq IQS269A: Space-Saving Solution for TWS Headsets That Senses Four Parameters With A Single Chip
Azoteq’s IQS269A, an eight-channel capacitive proximity and touch controller with additional Hall effect and inductive sensing capabilities, enables manufacturers of True Wireless Stereo (TWS) earbuds to save space and power by implementing multiple sensing functions with a single chip.
A single IQS269A IC in a TWS headset can implement a touch interface, and detect whether the earbuds are being worn, when the device is placed in or removed from its charging case, and whether the charging case is open or closed.
The touch interface can support common operations such as:
- Single tap for play/pause
- Tap-and-hold for heart-rate monitoring or for enabling/disabling active noise cancellation
- Swipe gestures to skip forward/backward and for volume control
The same IC can be used to wake up the Bluetooth® radio controller for pairing.
Part of the ProxFusion® family of multi-functional sensor ICs, the Azoteq IQS269A offers built-in compensation for temperature and humidity changes, which can impair the operation of capacitive sensors. This environmental parameter tracking ensures that the earbuds are not affected by false wear or false release signals.
The IQS269A also incorporates Hall effect sensing with a digital output: this may be used to detect whether the docking case is open or closed, and whether the earbuds are docked. The signal from the Hall effect sensor may be used to automatically disable the Bluetooth radio and initiate charging.
By reducing the number of analog components required to implement these multiple sensing functions, the IQS269A enables headset manufacturers to reduce component count and bill-of-materials cost, reduce assembly costs and save space. It also simplifies the board layout, thus reducing development time and shortening time-to-market.