| 摘要 |
A hearing aid has a microphone, an amplifier, an earphone, and a battery as a source for an operating voltage. A switching amplifier is provided as an output stage. A delta voltage generator forms a base signal generator for a pulse-duration-modulated signal with which the switching amplifier can be controlled. The delta voltage generator comprises at least one integrator whose integration direction is reversible, dependent on an input signal thereto. A quotient of an operating voltage and a peak value of a delta voltage of the delta voltage generator remains at least largely constant given a changing operating voltage. For that purpose, the integrator is in an interactive connection with a switch at its input side and with a comparison circuit at its output side. The comparison circuit controls the switch by which the input signal can be supplied to the integrator, dependent on at least one threshold voltage derived from the operating voltage.
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