Output stage for a hearing aid and method of driving output stage
First Claim
1. An output stage for a hearing aid, said hearing aid comprising an input transducer device, an AD-converter, a digital signal processor, a single bit Sigma-Delta modulator, an output driver and an output transducer, said output driver having an H-bridge with two branches, each branch having a respective output terminal for connection to the output transducer, a first one of the branches being controlled by a first binary control signal, and a second one of the branches being controlled by a second binary control signal, which second binary control signal is derived as a time-delayed version of the first binary control signal.
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Abstract
In an output stage for a hearing aid (62), a reduction in the power consumption for low level input signals is obtained through the use of a time-averaging output driver (42), whereby the output transducer is subject to three different conditions of operations, this being obtained through the generation of three-state control signals for control of a H-bridge. The three-state control signals are generated through the use of a time-averaging device whereby the two-level output of a single bit Sigma-Delta modulator (21) is transformed to a set of control signals that, at any given time, can assume one of three states. In a preferred embodiment the time-averaging device is a delay (40).
6 Citations
10 Claims
- 1. An output stage for a hearing aid, said hearing aid comprising an input transducer device, an AD-converter, a digital signal processor, a single bit Sigma-Delta modulator, an output driver and an output transducer, said output driver having an H-bridge with two branches, each branch having a respective output terminal for connection to the output transducer, a first one of the branches being controlled by a first binary control signal, and a second one of the branches being controlled by a second binary control signal, which second binary control signal is derived as a time-delayed version of the first binary control signal.
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7. A hearing aid comprising an input transducer device, an AD-converter, a digital signal processor and an output stage, said output stage comprising a single bit Sigma-Delta modulator and an output transducer, said output stage further comprising an output driver, said output driver having an H-bridge with two branches, each branch having a respective output terminal for connection to the output transducer, a first one of the branches being controlled by a first binary control signal, and a second one of the branches being controlled by a second binary control signal, which second binary control signal is derived as a time-delayed version of the first binary control signal.
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8. A method of driving an output transducer in a hearing aid, comprising
producing a first binary control signal, producing a second binary control signal in the form of a delayed version of the first binary control signal, selecting an H-bridge having a first branch and a second branch, connecting a respective output terminal of each of said first and said second branch with a respective terminal of the output transducer, controlling said first branch by the first binary control signal, and controlling said second branch by the second binary control signal.
Specification