4.1 A Watt-Level Phase-Interleaved Multi-Subharmonic Switching Digital Power Amplifier Achieving 31.4% Average Drain Efficiency
4.1 A Watt-Level Phase-Interleaved Multi-Subharmonic Switching Digital Power Amplifier Achieving 31.4% Average Drain Efficiency
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DOI：
10.1109/isscc.2019.8662511
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发表时间：
2019-02
期刊：
影响因子：
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通讯作者：
Aoyang Zhang;M. Chen
中科院分区：
文献类型：
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作者：
Aoyang Zhang;M. Chen
在给定有限带宽的情况下，现代无线通信系统通常利用频谱高效调制方案以获得更高的数据吞吐量。这种类型的调制方案，例如正交频分复用（OFDM），导致发射信号的高峰均功率比（PAPR）。因此，功率回退（PBO）区域中的功率放大器效率已成为重要的设计目标。同时，获得高输出功率和高平均效率仍然是开发集成CMOS PA时的关键设计挑战。最近，在[1]中报道了一种次谐波开关（SHS）数字PA架构。它在载波频率（Fc）的次谐波分量处切换PA单元以实现功率回退。较慢的切换速率降低了开关PA中的动态和传导损耗，从而导致更好的PBO效率。然而，SHS PA需要匹配网络中的次谐波分量的附加陷波滤波。因此，我们提出了一种相位交错的架构，结合三个SHS功率放大器，以增加输出功率（瓦特级），并内在地消除PBO模式中的次谐波分量，从而减轻匹配网络的负担。此外，利用多个次谐波分量来在PBO区域中产生更大数量的效率峰值。这被称为多SHS方案。最后，混合G类操作，结合多SHS方案，用于进一步提高平均效率。
Modern wireless communication systems often utilize spectrum-efficient modulation schemes for higher data throughput, given the finite bandwidth. This type of modulation schemes, such as Orthogonal Frequency Division Multiplexing (OFDM), results in a high peak-to-average power ratio (PAPR) for the transmitted signal. Therefore, power amplifier efficiency in the power back-off (PBO) region has become an important design target. Meanwhile, obtaining high output power and high average efficiency still remains a key design challenge when developing an integrated CMOS PA. Recently, a subharmonic switching (SHS) digital PA architecture was reported in [1]. It toggles the PA cell at the subharmonic component of the carrier frequency (Fc) to achieve power back-off. The slower toggling rate reduces dynamic and conduction loss in the switching PA, resulting in better PBO efficiency. However, the SHS PA requires additional notch filtering of the subharmonic components in the matching network. Therefore, we propose a phase-interleaved architecture that combines three SHS PAs to increase output power (Watt-level) and inherently cancel the subharmonic components in the PBO mode, thereby alleviating the burden of the matching network. Moreover, multiple subharmonic components are utilized to create a greater number of efficiency peaks in the PBO region. This is referred to as a multi-SHS scheme. Lastly, a hybrid Class-G operation, in combination with the multi-SHS scheme, is used to further enhance average efficiency.