Patent ID: 7236056
Filing Date: 2007-06-26
Classification: H03F

Abstract:
1. A direct current (DC) offset canceling circuit of trans-impedance amplifier used for filtering a DC component of an input current, comprising: a trans-impedance amplifier having an input end and an output end, wherein the input end is used for receiving the input current, and converting the input current into a first voltage signal to be output by the output end, said trans-impedance amplifier comprising: a DC detector for retrieving and comparing the signals at any sample node, thereby generating a trigger signal; a DC eliminator connected to the input end of the trans-impedance amplifier, for providing a path to the DC component of the input current in response to the triggering by the trigger signal, to eliminate the DC component; a reference voltage unit for outputting a reference voltage value; and a voltage output amplifier for comparing the reference voltage and the first voltage signals, to amplify the output of a second voltage signal.