| 摘要 |
<p>A programmable low voltage compressor circuit suitable for use with hearing aids is described. The compressor (200) has a continuously variable compression ratio wherein the gain of the compressor (200) may be programmably controlled over a wide range and the compressor (200) may be powered from a power source (425) as low as 1.1 volt. The compressor (200) employs a variolosser (202) wherein the gain is controlled by the ratio of the currents flowing out of first and second control terminals (Ia, Ib). A control circuit (204) coupled to the variolosser (202) wherein the gain is controlled by the ratio of the currents flowing out of the first and second control terminals (Ia, Ib). The control circuit (204) includes a peak detector (206) which generates a signal related to the peak positive envelope of the signal input to the compressor (200). A voltage to current converter (344, 346, 350, 352) is coupled to the peak detector (206) for increasing the magnitude of the current flowing out of one of the control terminals of the variolosser (202) as the voltage output of the peak detector (206) increases. Furthermore, the gain and compression ratio of the compressor (200) over a wide range is programmably controllable.</p> |
