Industrial Technology Research Institute

Chien-Fu Chang

Li-Ren Huang

A gain-controlled transimpedance amplifier circuit that comprises a first gain unit including an input for receiving a first current and an output, a current source for providing a second current, a second gain unit including an input and an output, a first impedance unit of a first impedance coupled in parallel with the second gain unit, and a comparator including an output, a first input coupled to the output of the first gain unit, and a second input coupled to the output of the second gain unit.

Auto gain controller

A direct current (DC) offset canceling circuit of a trans-impedance amplifier and an automatic gain control trans-impedance amplifier is provided, including: a trans-impedance amplifier for receiving an input current and converting the input current into a first voltage signal, while the trans-impedance amplifier is provided with a plurality of inverters connected in series, wherein a sample node is defined between each inverter; a DC detector for retrieving and comparing the signals at any sample node, thereby generating a trigger signal according to the comparison; a DC eliminator for providing a path to the DC component of the input current in response to the triggering by the signal trigger, 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 signal, to amplify the output of a second voltage signal.

Direct current offset canceling circuit of trans-impedance amplifier and automatic gain control trans-impedance amplifier thereof

A high frequency amplifier comprising a first trans-impedance amplifier, a second trans-impedance amplifier, a third amplifier, and a variant current source is provided. The first trans-impedance amplifier receives an input current and outputs a first output voltage accordingly. The second trans-impedance outputs a second voltage. The third amplifier receives the first and the second voltage. The variant current source is connected between the input terminal of the second trans-impedance and a ground terminal or a power supply source. The variant current source delivers a variant current to change the second voltage such that the second voltage may follow the first voltage. The input current flows into the first trans-impedance amplifier, while the variant current flows into the second trans-impedance amplifier. The input current flows out the first trans-impedance amplifier, while the variant current flows out the second trans-impedance amplifier.

Growing community of inventors

Hsinchu, Taiwan

Chien-Fu Chang