Patent ID: 7319220
Filing Date: 2008-01-15
Classification: H03F

Abstract:
1. A trans-impedance amplifier configured to receive an input current and operable to generate an output voltage responsive to the input current, the amplifier responsive to an increased range of input currents and having a wide bandwidth, comprising: an input stage having a first and a second transistor connected in series, the input stage coupled between a supply voltage and ground and configured to receive the input current; an output stage coupled to the input stage, the output stage having a third and a fourth transistor connected in series, the output stage coupled between the supply voltage and ground; a feedback loop coupled to the input stage, the feedback loop operable to reduce the input impedance of the amplifier; a variable resistor connected in series with the third and fourth transistors and the supply voltage, the variable resister being operable to adjust the current in the output stage; a variable current source being operable to supply a variable current to the output stage, wherein an increase in the variable current by the variable current source causes a decrease in the current flowing through the variable resistor and wherein a decrease in the variable current by the variable current source causes an increase in the current flowing through the variable resistor; and an output driver having at least a fifth transistor coupled to the output stage and being operable to provide the output voltage and to reduce the output impedance of the amplifier.