Behaviors of EER Transmitter with Class―E Amplifier due to MOSFET Parasitic Capacitances
Behaviors of EER Transmitter with Class―E Amplifier due to MOSFET Parasitic Capacitances
复制标题
带有 E 类放大器的 EER 发送器因 MOSFET 寄生电容而产生的行为
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
H. Sekiya
中科院分区：
文献类型：
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作者：
Xiuqin Wei;T. Nagashima;H. Sekiya
E类放大器[1]-[11]被认为是下一代数字无线功率发射机。由于非开关功率放大器在高回退区的固有功率损耗，导致其功率转换效率较低。因此，D类和E类开关功率放大器被认为是提高便携式设备的功率转换效率和延长电池寿命的补救措施。为了调制开关放大器输出信号的幅值和相位，人们提出了几种方法[1]、[2]。其中，包络消除与恢复(EER)由于不需要在放大器的输出端设置功率合成电路而备受关注。在使用E类放大器的EER发射机中，输出电压幅度是通过改变E类放大器的直流电源电压来调制的。众所周知，如果E类放大器的并联电容是线性的，则输出幅度与直流电源电压[3]-[5]成正比。然而，高频时，MOSFET漏-源极寄生电容在并联电容中占主导地位，具有非线性特性[6]-[8]。并联电容的这种非线性导致输出幅度与直流电源电压不成比例。此外，MOSFET栅漏电容会影响E类放大器的波形[9]。此外，在[9]中指出，驱动电压还通过MOSFET栅漏电容影响E类放大器的行为。因此，我们认为E类放大器的栅极到栅极和漏极到源极的寄生电容以及驱动信号都会影响EER发射机的特性。本文研究了MOSFET寄生电容对带E类放大器的EER发射机输出包络的影响。本文不仅考虑了MOSFET漏极到源极的非线性电容，还考虑了MOSFET栅极到漏极的线性电容。分析结果表明，驱动电压波形也影响驱动电压和输出电压之间的关系。通常情况下，在EER系统中，驱动信号应该只精确地表示频率和相位。本文的研究结果表明，视频功率调节器包络探测器直流电源(调制)的设计具有重要意义。
The class-E amplifier [1]-[11] is remarked as the next candidate of digital wireless power transmitters. Non-switching power amplifiers suffer from low power-conversion efficiency due to their inherent power loss in high back off area. Hence, switching power amplifiers such as class-D and E are remarked as a remedy for improving power-conversion efficiency and prolonging battery lifetime of portable devices. In order to modulate the amplitude and phase of output signal of the switching amplifier, several methods were proposed [1], [2]. Among them, envelope elimination and restoration (EER) is remarked because it does not require power combining circuit at output port of the amplifier. In the EER transmitter using a class-E amplifier, the output-voltage amplitude is modulated with varying the dc-supply voltage of the class-E amplifier. It is well known that if the shunt capacitance of the class-E amplifier is linear, the output amplitude is in proportion to the dc-supply voltage [3]-[5]. However, the MOSFET drain-to-source parasitic capacitance is dominant in the shunt capacitance at high frequencies, which has a nonlinear characteristic [6]-[8]. This nonlinearity of the shunt capacitance results in the output amplitude not being in proportion to the dc-supply voltage. In addition, the MOSFET gate-to-drain capacitance affects waveforms of the class-E amplifier [9]. Additionally, it was stated in [9] that the driving voltage also affects the class-E-amplifier behavior through the MOSFET gate-to-drain capacitance. Therefore, it is thought that EER transmitter characteristics are affected by the MOSFET gate-to-drain and drain-to-source parasitic capacitances of the class-E amplifier as well as the driving signal. This paper presents the MOSFET-parasitic-capacitance effects on the output envelope of the EER transmitter with the class-E amplifier. This paper considers not only the MOSFET drain-to-source nonlinear capacitance but also the MOSFET gate-to-drain linear capacitance. It is clarified from analytical results that the driving-voltage waveform also affects the relationship between the driving and output voltages. Generally, it is stated that the driving signal should expresses only the frequency and the phase exactly in EER system. The results of this paper suggest that it is important to design Video power conditioner Envelope detector dc supply (modulated)