| 摘要 |
An improved transresistance amplifier for generating an output voltage from an input current includes: a current buffer for shifting a dominant pole associated with the input current to a higher frequency, thereby increasing the bandwidth of the transresistance amplifier; a current amplifier for amplifying the buffered input current, thereby generating a high transresistance for the transresistance amplifier; and an I/V amplifier for converting the buffered and amplified input current into the output voltage. The current amplifier includes a current mirror and a current source that draws current from the mirrored side of the current mirror. Also, the current buffer includes a buffering transistor that draws current from the input side of the current mirror, and a differential amplifier having an output that controls the flow of current through the buffering transistor, part of which is drawn by another current source connected to the buffering transistor, and part of which is drawn to make up the input current. The improved transresistance amplifier is particularly useful as part of a pick-up circuit in CD and DVD-ROM applications.
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