Temperature compensated exponential gain control circuit

The present invention is directed to apparatus for providing temperature compensated exponential gain voltage to an AGC amplifier. The present invention uses emitter coupled pairs of transistors to implement an exponential gain control function. The present invention adds additional circuitry to drive the bases of the transistor pairs. The additional circuitry adds one gain stage in which the bias current is proportional to temperature and a second gain stage with a bias current which is constant over temperature. These gain stages, in combination with the transistor pairs, have no temperature dependence and retain the exponential gain function. This circuitry of the present invention allows a user to set the gain of the amplifier by an external voltage source providing a gain which is temperature independent. An advantage of the present invention is the cancellation of temperature dependence without the use of any temperature sensitive components. In addition, the circuitry of the present invention may used by any bipolar process.