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Technical Lecture

Digital Control-MCUs, DSPs, FPGAs, ASICs

T12.4 - High-Frequency Flying Capacitor Four-Level Drain Supply Modulator

Wednesday, March 19, 2025
9:30 AM – 9:50 AM ET
Location: Level Three, A311
This paper presents a high-frequency, four-level drain supply modulator (DSM) based on a flying capacitor multilevel (FCML) architecture, designed for envelope tracking in radio-frequency power amplifier applications. Operating from a single dc supply voltage, the proposed FCML-DSM employs a simple state-machine-based active balancing of the flying capacitors and control of the output voltage levels at switching rates up to 25 MHz. A hardware prototype of the FCML-DSM is presented, utilizing an FPGA controller and GaN transistors as switching devices in the power stage. The experimental prototype has an output voltage range from 0V to 20 V, discretized into equally-spaced levels, and achieves an average efficiency of 95.4% for output powers exceeding 10W while tracking a 35MHz 16-QAM signal envelope.