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WP 013 eGaN ® FETs for Envelope Tracking eGaN ® FETs for Envelope Tracking EFFICIENT POWER CONVERSION
| Content Provider | Semantic Scholar |
|---|---|
| Author | Strydom, Johan |
| Copyright Year | 2013 |
| Abstract | INTroducTIoN The concept of envelope tracking (ET) for radio frequency (RF) amplifiers is not new. But with the ever increasing need for improved cell phone battery life, better base station energy efficiency, and more output power from very costly RF transmitters, the need for improving the RF Power Amplifier (PA) system efficiency through ET has become an intense topic of research and development. There are many papers on the basics and advantages of envelope tracking [1-6]. The key to their ability to improve efficiency lies in the PA’s peak to average power (PAPR) requirements [3]. As shown in Figure 1 it is possible to achieve peak PA efficiencies as high as 65% with a fixed supply, but given PAPRs as high as 10, the average efficiency is likely to be lower than 25%. Through modulation of the PA supply voltage, this can be improved to over 50% essentially doubling the efficiency and reducing PA losses by two thirds! This will not only reduce power consumption, but also lower the cost of operation, cooling requirements, size etc. [7]. But how to generate the required fast moving supply voltage, the bandwidth of which can be in the tens of megahertz range [3]? A variety of different approaches have been investigated to achieve this. One such method would be implemented through the use of a hybrid linear-amplifier and multi-phase buck converter as shown in Figure 2 [8], where the buck converter supplies only the high-power, but lower-frequency transient components. Alternative methods employing boost converters [9] or Class-S amplifiers have also been discussed. Regardless of the implementation, Gallium nitride is being seen an as enabling technology for both ET converters and wide bandwidth RFPA designs. Implementing a multi-phase buck converter would traditionally require switching frequencies 5-10 times higher than the required ET bandwidth, but research into raising the converter’s effective bandwidth through hybrid solutions [8] and/or non-linear control [10] allows the required buck converter switching frequency to be greatly reduced. Even so, a large number of interleaved phases may still be required to achieve acceptable efficiency and bandwidth. The aim of this paper is to show what power and efficiency levels are readily realizable using current eGaN FETs and the LM5113 eGaN FET half-bridge driver [11]. Johan Strydom, Ph.D., V.P., Applications, Efficient Power Conversion Corporation (www.epc-co.com) |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://epc-co.com/epc/Portals/0/epc/documents/papers/eGaN%20FETs%20for%20Envelope%20Tracking%20Applications.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
