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US 4,728,828 AGranted
Switched capacitor transresistance amplifier
AssigneeSanta Barbara Research Center
InventorMark A. Goodnough
Life of this patent
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Abstract
A transresistance amplifier particularly adapted for use in a radiation detection system. The amplifier includes a feedback gain stage with a switched capacitor load. The amplifier is arranged to provide an average detector voltage approximating zero thus substantially reducing detector noise and also providing a low equivalent input impedance for increasing injection efficiency. A switched capacitor output load is also provided which allows the total transresistance to be determined by simply selecting an appropriate capacitance value.
Claims7
An improved transresistance amplifier providing low input impedance comprising:
- a first transistor having an input terminal, an output terminal and a gate, said input terminal thereof being coupled to an input port of the transresistance amplifier, said output terminal thereof being coupled to an output port of the transresistance amplifier;
- a first capacitor coupled to the output port of the transresistance amplifier;
- switched voltage means coupled to said first capacitor, said switched voltage means periodically resetting a voltage across said capacitor to a first predetermined reference level;
- and
- feedback amplifier means coupled between said gate and said input terminal of said transistor, said feedback amplifier means having a switched capacitor load operatively coupled thereto and to said gate to provide gain to said amplifier for reducing a voltage across the input port of the transresistance amplifier in response to a current applied to the input port of the transresistance amplifier;
- whereby the voltage across said first capacitor may be periodically sampled before being reset to obtain an indication of the current applied to the input port of said transresistance amplifier.
3 more elements
Dependencies are inferred from the claim text.