Description:
Market Opportunity
Modern radiofrequency (RF) communication systems have high spectral efficiency modulations, which lead to large peak to average power ratios (PAPRs). To prevent excessive amplification of these peaks and other nonlinearities, power amplifiers (PAs) need to “back off” from operating at maximum linear power, and instead operate using lower power in the power back-off region (PBO). Of all the blocks in an RF transceiver, the PA consumes the most power. Therefore, it is important to maximize the PA’s power efficiency in the PBO region so the system’s battery life can be prolonged. Current PA architectures, such as the envelope-tracking PA, can provide high efficiencies, but with added limitations in terms of bandwidth.
USC Solution
USC researchers have developed a subharmonic switching (SHS) technique for maximizing PA power efficiency by using the subharmonics of the PA switching waveform to toggle the PA, reducing both its power consumed and its switching frequency. This technique uses a frequency divider and a multiplexer to select the subharmonic frequency at the PA input, while filtering out undesirable frequencies. The proof-of-concept silicon prototype demonstrates that the trade-offs in terms of area and power are small within the PA system, and the added circuitry also allows for wideband operation. The SHS technique can be combined with other PBO efficiency enhancement techniques, such as class G operation.?
Value Proposition
- Improves power amplifier operation efficiency?
- Enables wideband operation?
- Prolongs battery life?
- Can be combined with other efficiency enhancement techniques
Applications
- RF communication system design
- Wireless transmission
Publications
A Subharmonic Switching Digital Power Amplifier for Power Back-Off Efficiency Enhancement, IEEE Journal of Solid State Circuits, Vol. 54 Iss. 4, Apr. 2019
Stage of Development
- Proof-of-concept
- prototype developed