Patent ID: 9537473
Date: 2017-01-03
CPC Classifications: A61B,H03K

Claim:
1. A circuit for expanding a dynamic range comprising: a transducer generating a signal current on an output terminal in response to a physical quantity, the signal current comprising an AC current and a DC current; a dynamic range enhancement circuit having a digital control signal input terminal and producing a variable opposition current at an output terminal in response to a digital signal applied to the digital control signal input terminal, the output terminal of the dynamic range enhancement circuit being in electrical communication with the transducer output terminal; a transimpendance amplifier having a input terminal and an output terminal, the input terminal of the transimpendnce amplifier in electrical communication with the output terminal of the dynamic range enhancement circuit and the transducer output terminal; an analog to digital converter having an input terminal in electrical communication with the output terminal of the transimpedance amplifier and having an output terminal; and a digital feedback circuit having an input terminal in electrical communication with the output terminal of the analog to digital converter and having an output terminal in electrical communication with the digital control signal input terminal of the dynamic range enhancement circuit, wherein the opposition current from the dynamic range enhancement circuit is set substantially equal to the DC current portion of the signal current from the transducer by the digital feedback circuit in response to the difference between DC current portion of the signal current and the opposition current.