A new wide-bandwidth hybrid supply modulator for LTE-A power amplifiers

This paper proposed a new wide-bandwidth hybrid supply modulator for LTE-A power amplifier. The proposed wide-bandwidth hybrid supply modulator is for long term evolution (LTE)-advanced power amplifier. This proposed modulator uses simple linear amplifier structure to achieve 100MHz tracking speed. This proposed modulator proposes a bandwidth control to improve the efficiency of the supply modulator in low bandwidth envelope. The proposed buck converter uses a power MOS width control technique to reduce the power losses in light load. The paper also presented a new sensing circuit to reduce the chip area, power consumption, and propagation delay. This modulator was fabricated with a 0.18μm CMOS process and the chip area is 1561μm × 1178μm. With 3.5V input voltage, the output voltage can be regulated between 0.9 and 2.3V. Furthermore, it achieves the peak efficiency of 81% under the condition of the output power POUT equal to 4.5W. The experimental results demonstrate that tracking speed of this work is faster than the other state-of-the-art designs.