Patent ID: 6492874
Filing Date: 2002-12-10
Classification: H03F

Abstract:
An active bias circuit connected to a power amplifier, comprising:first and second current mirror circuits connected to the power amplifier for maintaining a DC quiescent current to the power amplifier at a generally fixed value over a wide temperature range, wherein the power amplifier is an element of the second current mirror circuit; a temperature compensation circuit connected to the first current mirror circuit for providing temperature compensation therewith; a first reference voltage source connected to the first current mirror circuit by way of the temperature compensation circuit for providing a first reference voltage Vref to the first current mirror circuit; a current sink connected to the first current mirror circuit; a voltage source adjustment circuit connected to the first current mirror circuit for setting a voltage provided to the first current mirror circuit; the first current mirror circuit comprises: a first transistor having a source, a drain and a gate; a second transistor having a gate connected to the drain of the first transistor and a source connected to the gate of the first transistor at a first node; and a fourth transistor having a drain connected to a second reference voltage source and receiving a second reference voltage Vabc, a source connected to ground, and a gate connected to the source of the second transistor and the gate of the first transistor at the first node.