The design of power amplifier switch mode power supply for handset applications

This paper presents a design of switch mode power supply that can be used in the handheld power amplifier MRF9742 for the TD-LTE signal. This power supply uses PWM mode buck-convertor structure and envelopes tracking technology, which can acquire the envelope of input signal to dynamically adjust the MRF9742 power amplifier´s supply voltage. Therefore, the DC power can be as low as possible with no effect on the output compared with the LDO power supply and the PAE can be increased. The PA with switching mode power supply can increase its PAE about 10% compared with LDO. The handheld devices with switching mode power supply can enhance the efficiency of the power supply to extend the working time of themselves.