Class-B biased gilbert cells and quadrature modulators

DETAILED DESCRIPTION Embodiments of the present invention can provide quadrature modulators that comprise a quadrature splitter and a pair of Gilbert Multiplier Cells coupled to the quadrature splitter that are biased in Class-B.
As is well known to those having skill in the art, a Class-B circuit is biased at zero DC current so that a transistor in a Class-B stage conducts for only half of the cycle of an input sine wave.
In contrast, a Class-A circuit is biased at a current that is greater than the amplitude of the signal current, so that a transistor in Class-A conducts for the entire cycle of the input signal.
The quiescent current bias in the Gilbert Multiplier Cells may be substantially zero.
Accordingly, reduced power consumption may be provided.
Each of the Gilbert Multiplier Cells may comprise a pair of cross-coupled, emitter-coupled transistor pairs and a driver circuit that is coupled to at least one of the emitter-coupled transistor pairs and that is biased in Class-B.
The driver circuit may include at least one current mirror circuit that is coupled to at least one of the emitter-coupled transistor pairs.
The driver circuit also may comprise at least one current source that selectively applies current to at least one of the emitter-coupled transistor pairs, more specifically by selectively applying current to the at least one current mirror circuit.
Accordingly, the Gilbert Multiplier Cell is biased in Class-B.