PMIC & audio processor support next-generation hearing aid designs

October 26, 2015 // By Graham Prophet
ON Semiconductor has recently announced support for advanced wireless and recharging features in hearing aids; audio digital signal processing, & power management devices, are key to state-of-the-art hearing aids.

Next-generation hearing aids, ON Semi comments, will interact wirelessly with their users’ smartphones (control will be a via an app on the phone); and are moving in the direction of using rechargeable batteries rather than the typical zinc-air cells. Supporting these trends, HPM10 is a Power Management Integrated Circuit (PMIC); and Ezairo 7150 SL is a wireless-enabled audio processor.

Ezairo 7150 SL uses ON Semi’s own digital signal processing (DSP) technology and brings wireless connectivity to hearing aids and cochlear implants. It comes as a hybrid module designed to form the core of a complete hearing aid, ands centred on the Ezairo 7100 open-programmable 24 bit mixed-signal DSP platform. The System in Package (SiP) solution provides wireless multi-protocol operation and is optimised for 2.4 GHz band applications, including Bluetooth Low-Energy (BLE). Ezairo 7150 SL integrates EA2M, a low power 2 Mb serial CMOS EEPROM used for storing hearing aid firmware and important parameters. The chip works with microphones specific to the hearing-aid function; ON notes that the noise floor of the microphone channel used in (for example) smartphones is too high.

A complete reference design of a behind-the-ear (BTE) hearing aid includes software, hardware, and firmware which enable advanced wireless features. The control over BLE (CoBLE) function allows hearing aid users to control an array of parameters from their smartphone. The user can adjust the hearing aid’s volume, make program changes, check the battery status, and receive phone alerts (such as incoming calls or text messages). It also features a ‘Find Me’ function to help users quickly locate a misplaced hearing aid. The stereo audio streaming proprietary protocol enables music to be streamed from any external audio source (smartphones, tablet computers, televisions, etc.) through a remote dongle. The connectivity range can reach up to 10m in good surrounding conditions.

The HPM10 is a Power Management IC (PMIC) enables use of rechargeable batteries in hearing aids and hearing implant devices. The