Optimized delta sigma modulation for Class-S power amplifiers based on GaN switching transistors

Abstract

A novel modulation concept based on ∆-Σ modulation dedicated for a Class-S Amplifier based on GaN technology is presented. This paper includes system considerations of efficient modulation schemes for GaN switching transistors, which suffer from many limits. The analyses are focused on evaluating the impact of modulation scheme on the switching conditions of the transistors. Moreover practical figures of merits are introduced for defining optimum modulation strategy. Simulations are performed for a carrier frequency of 890.88 MHz for UMTS 5 MHz bandwidth signal. Results describe the main differences and limits of modulation schemes dedicated for switching mode power amplifiers.

An All-Digital Gigahertz Class-S Transmitter in a 65-nm CMOS

“…Samulak et al [16] and Johnson et al [17] proposed an architecture of a Manchester encoded modulator (Man modulator) to enhance higher harmonic, as shown in Fig. 10(a).…”

“…Since v(t) is a 1-bit sequence, the multiplication can be realized by a simple XOR operation. This operation increases the time-domain signal resolution to 1/(2n f s ) and the signal spectrum envelop is shaped by the S a ( f ) function [16] as…”

Design of High-Efficiency Voltage-Mode Class-D RF Power Amplifier for Class-S Transmitter Using Signal Analysis and Additional Multi-Section Bandpass Filter

“…Fig. 4 Ideal and non-ideal switch models The parasitic reactance is related to the shape of input and output pulse signals of transistor, and it causes the deterioration of performance of class-S transmitter [3,7]. The effect of Q factor and parasitic reactance is described in Table 3.…”

“…The quantized signal drives SMPA, and the amplified quantized signal is converted into the replica of input RF signal with a BPF. A current mode class-D (CMCD) power amplifier (PA) and a voltage mode class-D (VMCD) PA are usually used in class-S design [2,3,4,5].…”