DC coupled amplifier having pre-driver and bias control

A method for amplifying a signal with an amplifier system comprising:

• providing a pre-driver, an amplifier and a bias control circuit on the same die;
• providing one or more input signals and one or more bias signals to the pre-driver;
• amplifying the one or more input signals with the pre-driver to create one or more pre-amplified signals;
• providing one or more pre-amplified signals to the amplifier;
• amplifying the one or more pre-amplified signals to create one or more amplified signals and one or more bias control circuit input currents;
• providing the bias control circuit with the one or more bias control circuit input currents from the amplifier to a level shifter circuit comprising one or more transistors which are controlled by a control voltage such that the control voltage is generated by a resistive voltage divider circuit and the control voltage is proportional to the one or more bias control circuit input currents;
• generating, with a current mirror, a gate bias voltage, and providing the gate bias voltage to the pre-driver to bias a gate voltage of one or more transistors in the pre-driver;
• generating the one or more bias signals with the bias control circuit;
• and
• providing the one or more bias signals to the pre-driver.

An amplifier system, comprising:

• a pre-driver having two or more stages, the pre-driver configured to;
• receive one or more input signals and one or more bias signals,
• receive one or more gate bias signals from a current mirror, the one or more gate bias signals proportional to and derived from at least one bias control circuit input current provided to the pre-driver from the amplifier;
• and
• pre-amplify the one or more input signals to create one or more pre-amplified signals;
• an amplifier configured to receive and amplify the one or more pre-amplified signals to create one or more amplified signals;
• and
• a bias control circuit connected between the pre-driver and the amplifier, the bias control circuit configured to receive, the at least one bias control circuit input current from the amplifier, at one or more drain terminals of one or more transistors in a level shifter circuit and generate the one or more bias signals which are proportional to the at least one bias control circuit input current from the amplifier, wherein the pre-driver, the bias control circuit, and the amplifier are formed on one die.