Thermal droop compensation in power amplifiers

An amplifier chain comprising:

• a power amplifier;
• an active bias circuit coupled to the power amplifier, the active bias circuit comprising a heat-sensitive element;
• a droop circuit coupled to the heat-sensitive element, the droop circuit comprising a current mirror configured to draw current responsive to changes in the heat-sensitive element and generate a trigger signal, wherein the droop circuit further comprises an operational amplifier (op-amp) coupled to the current mirror through a common node, wherein an output of the op-amp is configured to generate the trigger signal;
• and
• a correction circuit coupled to the power amplifier and the droop circuit and configured to:
• receive the trigger signal;
• and
• responsive to receipt of the trigger signal, provide a thermal droop correction to the power.

A method of correcting thermal droop in an amplifier chain, comprising:

• responsive to heat changes in a heat-sensitive element caused by a proximate power amplifier, triggering a current draw through a gate in a current mirror coupled to the heat-sensitive element by the gate;
• causing a voltage imbalance between inputs of an operational amplifier (op-amp);
• responsive to the voltage imbalance creating a trigger current at the op-amp for a correction circuit;
• and
• responsive to the trigger current, changing an input signal for the proximate power amplifier with the correction circuit.

A wireless communication device comprising:

• an amplifier chain comprising:
• a power amplifier;
• an active bias circuit coupled to the power amplifier, the active bias circuit comprising a heat-sensitive element;
• a droop circuit coupled to the heat-sensitive element, the droop circuit comprising a current mirror configured to draw current responsive to heat changes in the heat-sensitive element and generate a trigger signal, wherein the droop circuit further comprise an operational amplifier (op-amp) coupled to the current through a common node, wherein an output of the op-amp is configured to generate the trigger signal;
• and
• a correction circuit coupled to the power amplifier and the droop circuit and configured to:
• receive the trigger signal;
• and
• responsive to receipt of the trigger signal, provide a thermal droop correction to the power amplifier.