A High-Efficient CMOS RF Power Amplifier With Automatic Adaptive Bias Control

A High-Efficient CMOS RF Power AmplifierWith Automatic Adaptive Bias Control Chen, Y.-J.E.; Liu, C.-Y.; Luo, T.-N.; Heo, D.; Microwave and Wireless Components Letters, IEEE Volume 16, Issue 11, Nov. 2006 Page(s):615 - 617 Digital Object Identifier 10.1109/LMWC.2006.884909 指導教授：林志明老師研究生：林高慶學號：95662002

Outline • Abstract • Introduction • the CMOS PA with the adaptive bias control circuit • Simulation • Measurement results • Conclusions

Abstract • A 2.4-GHz Doherty power amplifier is developed in 0.18- m CMOS technology • Operated at 3 V, the P1dBand PAE of the PA are 21 dBm and 33%

Introduction • Specific data sequences will lead to a large peak-to-average power ratio (PAPR) of the output signal • The Doherty PA architecture is a promising solution to the high PAPR issue since it can maintain high efficiency at the backoff output power • A novel adaptive bias control circuit is proposed for the auxiliary PA biasing to enhance the efficiency and output power characteristics of the Doherty PA

The CMOS PA with the adaptive bias control circuit

Characteristics of adaptive bias voltage with respect to input power for R1

Characteristics of adaptive bias voltage with respect to input power for R4

Simulation

Measurement results • The P1dB is 21.4 dBm and the corresponding PAE is 33%. The PAE at the power 6-dB backoff from P1dB is 21% • The measured PAE degradation due to 6-dB backoff from P1dB, γ(6 dB), of the CMOS Doherty PA is only 36%

Conclusions • An automatic adaptive bias control circuit is integrated with the auxiliary PA to improve the performance of the Doherty PA

A High-Efficient CMOS RF Power Amplifier With Automatic Adaptive Bias Control