Doherty amplifier circuit

An amplifier comprising a plurality of Doherty amplifier cells, each Doherty amplifier cell comprising:

• an input and an output respectively connected to an input and an output of the amplifier;
• a main amplifier stage;
• a peak amplifier stage;
• a signal combining circuit configured to combine signals from outputs of the main and peak amplifiers and provide a combined signal to the output of the Doherty amplifier cell;
• a control circuit configured to determine an amplitude of a signal at the input or output of the amplifier and provide a splitter control signal to each controllable splitter in response to the signal amplitude;
• and
• a controllable input power splitter having an input connected to the input of the Doherty amplifier cell,
• wherein the controllable input power splitter is configured to modify an amplitude and phase of a signal at the input of the Doherty amplifier cell in response to a received splitter control signal and provide a first modified signal to the input of the main amplifier stage and a second modified signal to the input of the peak amplifier stage.