Apparatus and method for transimpedance amplifiers with wide input current ranges

摘要

Improved preamplifier circuits for converting single-ended input current signals to differential output voltage signals, including first and second transimpedance amplifiers with input transistors operating according to bias currents from a biasing circuit, output transistors and adjustable feedback impedances modified using an automatic gain control circuit, as well as a reference circuit controlling the bias currents according to an on-board reference current and the single-ended input or the differential output voltage signals from the transimpedance amplifiers.

主权项

1. A preamplifier circuit for converting an input current into an output voltage, the preamplifier circuit comprising:
a first transimpedance amplifier receiving an input signal representing the input current and providing a first voltage output signal; a second transimpedance amplifier matched to the first transimpedance amplifier and providing a second voltage output signal; a biasing circuit providing first and second biasing currents to the respective first and second transimpedance amplifiers at least partially according to a reference current; a reference circuit controlling the reference current provided to the biasing circuit at least partially according to an offset signal; and an offset circuit providing the offset signal to the reference circuit according to a differential voltage output signal derived from the first and second voltage output signals.