| 摘要 |
Alert amplifier (10) has a peak detector (22) and an operational amplifier (30) that dynamically set a bias voltage of a transducer (32) to minimize the standby current. In the absence of an input ring signal at an input terminal (12), the standby current in the transducer (32) is zero. The bias voltage to the transducer (32) is adjusted from a reference voltage downward in accordance with the input ring signal to minimize the current in the transducer (32) during the activation of the alert amplifier (10).
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