IHS Markit: Envelope Tracking ICs Increase Smartphone Power Efficiency, Protect Battery Life, Provide Other Benefits to the Mobile Ecosystem

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Highlights:

  • Battery capacity has increased twice as fast as screen size over the same period
  • Average smartphone screen size will peak at between 5.5 and six inches in the future, causing battery capacity to level off
  • OEMs can improve efficiency of power amplifiers and RFFE by deploying envelope tracking (ET) solutions within their devices

The battery life of smartphones is under attack. Increasing screen sizes and activities such as video consumption – as well as camera- and navigation-based applications – are putting increasing stress on the battery life of mobile devices. Improved battery life can be achieved with the use of sophisticated power management integrated circuits (ICs) for power-hungry LTE radios, and envelope tracking ICs have become a key component in extending the useful life of mobile devices.

  • Battery capacity has increased twice as fast as screen size over the same period, highlighting the importance of achieving the longest possible battery life with each device design. The average screen size of a smartphone will reach a peak of between 5.5 and six inches in the future; as a smartphone’s screen size generally provides a footprint limitation for battery size, battery capacity will also begin to level off.
  • Between 15 and 40 percent of a phone’s battery life is taken by the RF front-end (RFFE), and within the RFFE, power amplifiers voraciously consume energy. OEMs can improve the efficiency of power amplifiers and the RFFE by deploying ET solutions within their devices.

Envelope tracking ICs: allowing for more efficient communication

  • Envelope tracking ICs are transforming the power efficiency of the RF front-end by dynamically adjusting the input voltage to the power amplifier, to match only what is needed. ET ICs have become commonplace in high-end smartphones since their introduction in 2013, and they increasing are penetrating mid-range handsets as well.
  • The importance of ET ICs has increased over time, and continues to do so as the smartphone market moves closer to the 5G era.
  • Compared to a competing technology called average power tracking (APT), ET can deliver improved performance and up to a 30-percent boost in power efficiency. As with any electrical system, wasted energy translates into heat, as such smartphones with ET are literally cooler than those which lack the technology. 

HPUE and the implications for ET ICs

  • In order to make its vast spectrum holding at 2.5GHz more effective, Sprint and other mobile ecosystem participants pursued high power user equipment (HPUE) technology, which increased the maximum Power Class 2 signal power output of a device from 23 dBm to 26 dBm, corresponding to a doubling of output power.
  • For ET ICs, the prevalence of HPUE has clear implications, as ET shines in scenarios with high peak-to-average power ratios. An ET enabled phone can benefit from higher power output, achieving a wider range of coverage while consuming a similar amount of power as APT solutions would at lower power output levels. Also, ET can more efficiently consume power at the same output level relative to APT. 

ET-enabled smartphones benefit end users, OEMs, and network operators

  • Power efficiency is the main benefit to OEMs and their smartphone designs as battery life is a potential differentiator among consumers.
  • On the network side, ET solutions will help support the sustained functionality of HPUE, and uplink carrier aggregation-equipped smartphones that network operators can reach from further distances – with less infrastructure – than they otherwise could. Uplink carrier aggregation will also reduce the time required for end users to be on the network performing tasks such as uploading video or posting to social media, which will ultimately increase network capacity. 

The future of the ET IC market

  • ET solutions are now available in very high volume, mid-range smartphone platforms such as the Qualcomm Snapdragon 630 and 660, and are also being adopted in China by OEMs such as OnePlus and Xiaomi.
  • IHS Markit expects that ET IC-enabled smartphone shipments will grow from 411 million units in 2015 to over 748 million by 2021, which represents a compound annual growth rate (CAGR) of over 10 percent. IHS Markit anticipates that 42 percent of total smartphones shipped in 2021 will be equipped with envelope tracking ICs.

Some of the Sub 6-GHz 5G frequency bands will be located on spectrum higher than band 41 (2.5GHz), could also require high power output, and have high peak-to-average power ratios which will benefit from the use of envelope tracking ICs. Future smartphones will need closed loop ET solutions to obtain adequate power efficiency and be able to provide 5G functionality while still offering an acceptable battery life for end-users.
Smartphone Power Efficiency
Many of the themes discussed in this research note are explored in greater depth in the IHS Markit Mobile, Consumer & Connected Devices, Mobile & Telecom, and Semiconductors research areas.

By: Brad Shaffer, senior analyst, mobile devices & network at IHS Markit and Wayne Lam, principal analyst, mobile devices & networks at IHS Markit

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