Variable gain amplifier with temperature compensated gain

An amplifier with a temperature compensated gain control comprising:

• an amplifier configured to amplify a received signal to create an amplified signal, the amplifier having a temperature coefficient that causes the gain to vary with changes in temperature such that the gain is determined based on a gain control signal;
• a gain control circuit configured to generate the gain control signal based on a control signal, wherein the gain control circuit comprises:
• two or more devices that function as variable resistors;
• a buffer which receives the control signal and a gain offset signal, and modifies the control signal based on the gain offset signal;
• a temperature compensation circuit configured to generate thea gain offset signal which selectively modifies the gain control signal such that the temperature compensation circuit has a temperature coefficient that is inverse to that of the amplifier;
• and
• a feedback loop, that is part of the temperature compensation circuit, the feedback loop configured with an operational amplifier which generates the gain offset signal such that the gain offset signal changes with changes in temperature.

A method for temperature compensating amplifier gain comprising:

• providing an amplifier having a temperature coefficient that causes the gain of the amplifier to change with changes in temperature;
• providing a temperature compensation circuit that generates a gain offset signal such that the temperature compensation circuit has a temperature coefficient which is the inverse of the amplifier's temperature compensation circuit;
• receiving an input signal for amplification;
• amplifying the signal with an amplifier to create an amplified signal, the level of amplification determined by a gain control signal;
• generating a gain offset signal with the temperature compensation circuit such that the gain offset signal counteracts the effects of temperate change induced gain variation in the amplifier to thereby maintain linearity in the amplified signal over temperature;
• and
• receiving a control signal and the gain offset signal at a buffer and modifying the control signal with the gain offset signal to generate the gain control signal.