class D driving a hearing aid speaker !!

[terminator12]

hi friends,

Am doing an integrated-circuit design for driving high impedance load like that of a speaker inside a hearing-aid. I am adopting a closed-loop PWM class-D which is of non-self oscillating type. I am currently facing some issues which I am unable to solve myself.

The first is that am finding it difficult to find the appropriate speaker models for that used within a hearing aid. I tried a lot of googling but I am not able to get any. Any help would be greatly appreciated.

thanks in advance,

 

[Cheegii]

Me too

 

[gooki]

Just buy a complete unit and strip for parts:
DealExtreme: Search for hearing aid (101 products in 30 categories)

 

[Andrew Eckhardt]

The issue of power consumption and distortion in hearing aids is so serious it might only be competitive to design the amplifier for a particular driver design. I imagine the variation in load impedance of commercially available product could be as wild as seen in headphones, except for maybe a more limited supply voltage range.

 

[phase_accurate]

Just curious: Why are you given the task to develop a class-d amp for a hearing aid and at the same time you will not be provided with the properties of the transducer involved ? Or are you developing a solution that should cover a wide range of transducers ?

Regards

Charles

 

[Cheegii]

First Hearing aid is expensive in our country? Second, analog hearing aid's battery no long lasting and self oscillating. Beep! I would try to build another design like small mp3 player.

 

[Trocadero]

Try in-ear receivers from:
Star Micronics (used in e.g., Etymotic earphones)
Subminiature Speakers :: Knowles
Sonion
Regards,
Erik Ostlin