System and method for controlling a gain circuit

DETAILED DESCRIPTION In accordance with the present invention, a system and method for controlling a gain circuit is provided which substantially eliminates or reduces disadvantages and problems associated with prior systems and methods.
More particularly, one embodiment of the present invention controls the gain of a gain cell with a control current.
The system comprises a circuit for generating a control current and a circuit for establishing a reference voltage.
The system generates a differential control signal using the control current and reference voltage.
The system comprises a circuit for generating a first output control voltage and a circuit for generating a second output control voltage.
The first and second control voltages comprise the differential control signal.
The control signal is a function of the control current.
The differential control signal is provided to a gain circuit.
Ultimately, the gain of the gain circuit is exponentially related to the control current of the system.
A technical advantage of the present invention inheres in the fact that the gain of the differential gain circuit is not affected by temperature.
Therefore, the gain of the gain circuit should not vary with changes in the temperature of the operating environment.
Another technical advantage of the present invention inheres in the fact that it provides differential control of a differential gain circuit using a single-ended control current.
The gain control circuit of the present invention converts a digital code word to an analog current.
The control circuit uses the control current to create differential control signals that produce a percentage change in gain of the gain cell for a unit change in input current.