An efficient power control scheme for a 2.4GHz class-E PA in 0.13-μm CMOS

A novel circuit technique that does not compromise the efficiency, while varying the output power of power amplifiers, suitable for wireless sensor networks is reported in this paper. For robustness sake, the technique allows to distribute the voltage swing among three cascoded transistors. While PA voltage supply is swept for power level control, one of its common gate transistors conduction angle is varied through a mirrored current source to guarantee high efficiency at all power levels. To validate the concept, a self-biased triple cascode class E power amplifier for Bluetooth Class 1 has been designed using a 0.13μm CMOS process. Measurements show that the power added efficiency (PAE) decreases only by 17.2% from the maximum value of 59.2% over an 18dB power control range with +20dBm maximum output power. Compared to other state of the work, proposed technique demonstrates a PAE improvement of 15.6% at the highest power, 35% when operated at the lowest power.