Load insensitive balanced power amplifier and related operating method

A balanced power amplifier for driving a load, the balanced power amplifier comprising:

• an input coupler device configured to produce an in-phase signal component and a quadrature signal component from an input signal, the in-phase signal component being provided at an in-phase signal node, and the quadrature signal component being provided at a quadrature signal node;
• a first amplifier device for a first branch of the balanced power amplifier, the first amplifier device having a first amplifier input node and a first amplifier output node;
• a second amplifier device for a second branch of the balanced power amplifier, the second amplifier device having a second amplifier input node and a second amplifier output node;
• a first level adjustment component coupled between the in-phase signal node and the first amplifier input node;
• a second level adjustment component coupled between the quadrature signal node and the second amplifier input node;
• and
• an output coupler device coupled to the first amplifier output node and to the second amplifier output node, the output coupler device being configured to generate a combined output signal;
• wherein
• the first level adjustment component is configured to adaptively perform signal level tuning on the in-phase signal component, resulting in an adjusted first amplifier input signal;
• the second level adjustment component is configured to adaptively perform signal level tuning on the quadrature signal component, resulting in an adjusted second amplifier input signal;
• and
• signal level tuning performed by the first level adjustment component and signal level tuning performed by the second level adjustment component is based on a measured gain of the first amplifier device and the second amplifier device, respectively.

A method of adaptively adjusting operating characteristics of a balanced power amplifier having an input coupler device, an output coupler device, a first amplifier device coupled between the input coupler device and the output coupler device in a first branch, and a second amplifier device coupled between the input coupler device and the output coupler device in a second branch, the method comprising:

• adaptively adjusting the level of a first signal component generated by the input coupler device in response to impedance characteristics of a load being driven by the balanced power amplifier, resulting in an adjusted first amplifier input signal;
• adaptively adjusting the level of a second signal component generated by the input coupler device in response to the impedance characteristics of the load, resulting in an adjusted second amplifier input signal
• detecting gain of the first amplifier device;
• and
• detecting gain of the second amplifier device;
• wherein
• the balanced power amplifier comprises a first level adjustment component coupled between the input coupler device and the first amplifier device;
• the balanced power amplifier comprises a second level adjustment component coupled between the input coupler device and the second amplifier device;
• adaptively adjusting the level of the first signal component comprises dynamically tuning attenuation/gain of the first level adjustment component;
• adaptively adjusting the level of the second signal component comprises dynamically tuning attenuation/gain of the second level adjustment component;
• dynamically tuning attenuation/gain of the first level adjustment component is influenced by the gain of the first amplifier device;
• and
• dynamically tuning attenuation/gain of the second level adjustment component is influenced by the gain of the second amplifier device.