Bias adjustment circuitry for balanced amplifiers

摘要

Circuitry includes a balanced amplifier and bias adjustment circuitry. The bias adjustment circuitry is coupled to the balanced amplifier and is configured to measure an RF termination voltage across an output termination impedance of the balanced amplifier and adjust a bias voltage supplied to the balanced amplifier based on the RF termination voltage. Notably, the RF termination voltage is proportional to a voltage standing wave ratio (VSWR) of the balanced amplifier, and thus enables an accurate measurement thereof. By using the RF termination voltage to adjust a bias voltage supplied to the balanced amplifier, overvoltage and/or thermally stressing conditions of the balanced amplifier as a result of high VSWR may be avoided while simultaneously avoiding the need for large or expensive isolation circuitry.

主权项

1. Circuitry comprising:
a balanced amplifier comprising:
an input quadrature coupler;an output quadrature coupler; anda first amplifying element and a second amplifying element coupled between the input quadrature coupler and the output quadrature coupler; and bias adjustment circuitry coupled to the balanced amplifier and configured to:
measure an RF termination voltage across an output termination impedance coupled to the output quadrature coupler of the balanced amplifier, wherein the RF termination voltage is proportional to a voltage standing wave ratio (VSWR) of the balanced amplifier; andadjust a bias voltage supplied to the balanced amplifier based on the RF termination voltage.