Patent ID: 8212616
Filing Date: 2012-07-03
Classification: G05F,H03F

Abstract:
1. A biasing circuit for controlling the current flowing through a differential pair of a differential amplifying circuit, the biasing circuit comprising: first and second branches each coupled between first and second supply voltages, the first branch comprising a first resistor, a first transistor device and a second transistor device coupled in series, and the second branch comprising a second resistor, a third transistor device and a fourth transistor device coupled in series, a control node of the third transistor device being coupled to a first node between the first resistor and the first transistor device, and a control node of the first transistor device being coupled to a second node between the second resistor and the third transistor device; and an operational amplifier having a first input coupled to a node between the first and second transistor devices, a second input coupled to a node between the third and fourth transistor devices, and an output node coupled to control nodes of the second and fourth transistor devices, said output node providing an output signal for controlling the current flowing through said differential pair.