(57) An electronic battery-powered hearing instrument (10) comprises
- a first power supply terminal (1) and a second power supply terminal (2) arranged
to contact a battery (3),
- a rectifier circuit (6) for providing a positive supply voltage (Up) and a negative
supply voltage (Un) regardless of a polarity of the battery (3) relative to the first
and second power supply terminal (2),
- primary function means (7) arranged to provide at least one drive signal (Ud) to a
drive circuit (20) for driving an electroacoustic conversion means (13) by controlling
electrical valve means (14, 15, 16, 17).
The drive circuit (20) is electrically connected to the first power supply terminal
(1) and to the second power supply terminal (2), and the electrical valve means (14,
15, 16, 17) are polarity-independent, that is, they are able to operate regardless
of the polarity of the voltage applied to their terminals.
As a result, the current path from the battery (3) to the electroacoustic conversion
means (13) and back again comprises at the most two electrical valve means (14, 15,
16, 17), e.g. transistors, minimising voltage drop and power loss.
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