Patent ID: 9520849
Filing Date: 2016-12-13
CPC Classification: H03F

Claim Text:
1. A differential input apparatus, comprising: a tail-connected primary differential pair to receive first and second input signals and to pass load current to first and second loads responsive to the first and second input signals, respectively; a tail-connected secondary differential pair to receive downward level-shifted versions of the first and second input signals, at least one of the primary or secondary differential pair to conduct current as a common-mode component of the first and second input signals approaches a positive voltage rail such as to present a constant transconductance in series with each of the first and second loads; a tail current source communicatively coupled to the primary and secondary differential pairs, conduction by the primary and secondary differential pairs to prevent linear region operation at the tail current source; and a tail current shunt device in series between the tail current source and the secondary differential pair, the tail current shunt device to supply tail current to the secondary differential pair as the first and second input signals approach a positive voltage rail and as the primary differential pair approaches a cut-off condition.