A power generator includes a plurality of amplifier blocks and a combiner. Each of the amplifier blocks include one or more amplifiers, and the combiner combines modulated power signals output from the amplifier blocks to generate an RF power signal of a load. The amplifier blocks are controlled to outphase the modulated power signals based on a phase angle. Ones of the amplifier blocks may perform discrete modulation to generate a respective one of the modulated power signals. The discrete modulation includes selecting different combinations of the amplifiers in one or more of the amplifier blocks to change the RF power signal in discrete steps. In embodiments, the amplifiers may be radio frequency power amplifiers.