Impedance converter circuit for video, audio or communications apparatus

摘要

The circuit includes a high-impedance biasing circuit (Q1,Q2,Ve,12-15,Q3-Q6,R11-R13) for DC-biasing an impedance circuit (11). A first differential pair (Q7,Q8) supplies a drive current to the first and second terminals of the impedance circuit (11) based on the voltage of a first and second input terminal. A second differential pair (Q9,Q10, Q5,Q6,14,15,18,19,R15) causes current to flow from the first to the second input terminal based on the voltage of the first or second terminal of the impedance circuit. A video apparatus, an audio apparatus and a communications apparatus are also claimed.