Power Amplifier Bias Current Adjustment Under Rising Control Voltage

The patent implements a feedback mechanism where the bias controller continuously monitors the bias current and adjusts it according to the input control voltage. The bias controller includes a bias current generator that generates bias current based on the control voltage, and a bias voltage generator that adjusts the bias current to maintain it within the predetermined range, ensuring stable operation even when control voltage varies.

The patent changes the operating parameters of the bias controller to adapt to varying control voltages. Specifically, the bias controller adjusts its internal reference voltages and current thresholds dynamically, allowing it to maintain appropriate bias current control across different power amplifier output levels, preventing the bias current from exceeding the predetermined range.

The patent applies preliminary action by pre-charging the bias current through a rapid current injection mechanism. When the power amplifier is activated, a startup circuit immediately supplies a larger bias current before the bias controller fully initializes, eliminating the temporal delay. This preliminary current injection ensures the power amplifier reaches operational state without waiting for the bias controller to stabilize.

The patent introduces dynamic control of the bias current by implementing a time-variant bias controller that adjusts its response characteristics based on the startup phase. During initialization, the bias controller operates in a fast-response mode that allows rapid bias current establishment, then transitions to a stable control mode once operational, effectively managing both the speed and stability requirements.

The patent employs feedback control where the bias controller monitors the power amplifier's operating characteristics and adjusts the bias current accordingly. The bias voltage generator receives feedback signals from the power amplifier and dynamically adjusts the bias current to maintain optimal operating conditions, preventing characteristic deterioration even at higher power output levels.

The patent uses a composite control architecture combining multiple control mechanisms: a bias current generator for basic biasing, a bias voltage generator for fine adjustment, and a control circuit that integrates both control voltages. This composite approach allows the system to maintain precise control over power amplifier characteristics across the full power range, preventing distortion and characteristic degradation.