| 摘要 |
<p>A digital, three-level output driver (7) of the H-bridge variety for a hearing aid (20) obtains a reduced capacitive interference by providing a primary voltage (3) and a secondary voltage (8) for the output driver (7) and applying the secondary voltage (8) to both sides of the output driver (7) whenever the middle level of the three-level output driver (7) is present in the input signal for the output driver (7). The output driver (7) may be controlled from a pulse-width modulated signal, a sigma-delta pulse-density modulated signal, or a combination of those signals. The output driver (7) produces a clocked output signal consisting of a positive level, a negative level, and a zero level for driving an acoustic output transducer of the hearing aid (20). If the secondary voltage (8) is half the value of the primary voltage (3), the positive level and the negative level is defined with respect to the level of the secondary voltage (8), and capacitive interference may thus be kept at a minimum while maintaining the power consumption benefits of a three-level output stage. The invention provides a hearing aid (20) and a method of driving an output stage (7) of a hearing aid (20).</p> |
