High-Efficiency Push–Pull Power Amplifier With High Operation Voltage

A highly efficient push-pull class D power amplifier (PA) with a high operation voltage is presented. The high voltage is realized by stacking dc biases of two push-pull amplifiers through the virtual ground point, while the radio frequency powers are series combined. The drain supply voltage is increased to 44V, which is double of the rated bias voltage (22V) of the active devices. The LDMOS PA provides an output power of 40.6dBm with a power-added efficiency (PAE) of 58.7% at 836.5MHz. Each push-pull amplifier provides 38-dBm output with a PAE of 64%