by Peter Markowski, Envelope Power, Ansonia, Conn., How2Power Today, Aug 15 2014
Focus:
This article presents an example of a high-performance FPGA-based digital power supply controller used in an envelope tracking (ET) voltage modulator. This ET modulator design takes advantage of an integrated power stage component (Vishay’s SiP2204) with very high switching frequency capability, practically no dead time, very low delay and excellent timing accuracy. The combination of a low-cost FPGA controller with the integrated power stage enables design of a new topology multilevel converter that overcomes the limitations of other circuit solutions for ET, which sacrifice efficiency gains in order to limit switching frequency to a manageable level. Those alternative approaches are briefly discussed before the author describes implementation of a 16-level envelope tracking power converter. In presenting this design, the author describes techniques for overcoming random noise coming from the PWM pattern and voltage distortion caused by variations in the control-to-switching node delay among the different subconverters. Other topics discussed include optimization of the power stage and techniques for minimizing PWM propagation delay.
What you’ll learn:
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