Abstract: A DC feedback control circuit for compensating for a DC voltage level shift in a transimpedance amplifier circuit (12) having a transistor (20) as a high speed switching device. The DC feedback control circuit includes a filter (30) for determining a DC voltage level at an output of the amplifier circuit (12) and a differential pair (36) of transistors for comparing the DC voltage level with a reference voltage (41). A pair of current mirrors (44 and 50) mirror a current dependent on the comparison of the DC voltage level with the reference voltage and apply the mirrored current to an emitter of the transistor (20) so as to maintain a substantially constant bias current through the switching transistor (20).