Patent ID: 7054439
Filing Date: 2006-05-30
Classification: H03F

Abstract:
1. Differential input stage ( 1 ) of electronic equipment, comprising means for reducing the interference caused by a voltage or current applied in common mode to two inputs (A; B) of this stage; this stage comprising two channels each connecting one input (A; B) to one output (a; b); each channel comprising first means for reducing interference, these first means comprising, on each of the channels, means (S 3 ; S 4 ) for adding to the input voltage of the channel concerned a first feedback voltage (V 1 ), and means (R 1 , R 2 , I 3 ) for supplying a first feedback voltage that is equal to half the sum of the voltages (VA; VB) present at the inputs (A; B), respectively, with the opposite sign; characterized in that, to reduce the effect of a delay, introduced by the components of the means (R 1 , R 2 , I 3 ) for supplying the first feedback voltage (V 1 ), this stage further comprises means (S 5 ; S 6 ) for further adding to the input voltage of each channel a second feedback voltage (Va 1 ; Vb 1 ) and means (R 1 , R 2 ; I 1 , S 1 ; I 2 , S 2 ) for supplying a second feedback voltage (Va 1 ; Vb 1 ) that is a function of the voltage (VA; VB) at the input corresponding to this channel, with the opposite sign, and with a delay identical to that caused by the components of the means (R 1 , R 2 , I 3 ) for supplying the first feedback voltage (V 1 ).