A two-phase switching hybrid supply modulator for polar transmitters with 9% efficiency improvement

Emerging polar transmitters for highly efficient and linear power amplifiers (PAs) demand for high-efficiency, high-bandwidth and low-ripple supply modulators. In [1], a linear regulator is used; however, its efficiency is low at low power levels. A switched-mode power supply (SMPS) is used in [2]; but the high switching loss due to high switching frequency (necessary for high bandwidth) limits the maximum efficiency to ∼76%. A hybrid amplifier (HA) topology combining both linear amplifier (LA) and switching amplifier (SA) is used in some recent work [3, 4]. In this topology, a high-bandwidth LA replicates the input envelope voltage Vin at its output V o; while the high-efficiency SA supplies most of the load current within its bandwidth. Yet, the tracking bandwidth is finite in [3]; and the LA in [4] needs to supply most of the high-frequency load current due to the exceptionally large inductor (20μH) used for realizing small output ripple; and therefore, limiting the dynamic efficiency. Figure 10.1.1 shows the proposed wideband HA featuring two-phase switching (2PHSW) for reducing ripple and improving static efficiency, and a feedforward bandpass filter (FF-BBF) for enhancing dynamic efficiency. ©2010 IEEE

A piezoelectric energy harvesting interface circuit using one-shot pulse transformer boost converter based on water bucket fountain strategy

Recent advancement in commercial MEMS-based piezoelectric energy harvesters has enabled further reduction of both system cost and size as the device dimension scales down. A nature inspired interface circuit by mimicking water bucket fountain to harvest piezoelectric charge is presented. The proposed architecture offers built-in input voltage protection, harvests electrical energy using minimal switching activity and does not cause mechanical dampening to the piezoelectric cantilever. System simulation and measurement using a standard CMOS 0.13μm process verified the proposed architecture. The pulse transformer boost converter has self-start voltage as low as 45mV and peak efficiency up to 75%, whereas the remaining digital control and voltage processing circuits require less than 1.5μW to operate. © 2014 IEEE

A Switched-Capacitor DC-DC Converter with Pseudo-Continuous Output Regulation using a Three-Stage Switchable Opamp

SC dc-dc converters with continuous-output regulation (COR) for delivering hundred-milliwatt output power have been recently reported [1,2]. The control schemes of these converters can reduce both input-current ripple [1] and output-voltage ripple [2]. These converters, however, require one extra power transistor cascaded either in front of [1] or behind [2] the power stage for output regulation. The additional power transistor increases the chip area of the converter. This paper proposes a new control scheme for the regulated SC dc-dc converter to achieve COR without using any additional power transistor. Moreover, a three-stage switchable opamp in the proposed control is developed to improve both load-transient response and light-load power efficiency of the converter

Design of monolithic RF power amplifier using bulk BiCMOS process

A low-voltage monolithic 900MHz power amplifier has been fabricated in a commercial 0.8μm bulk BiCMOS process with an integrated output tuned circuit. The tuned circuit is implemented by a monolithic inductor of 2.6nH with 54μm metal width. The output power of the amplifier is 14dBm

Self-aligned trenched cathode lateral insulated gate bipolar transistor with high latch-up resistance

This paper discusses a modified insulated gate bipolar transistor (LIGBT) structure using a self-aligned trenched contact at the cathode of the device which significantly reduces the parasitic p-base resistance underneath the n+ cathode region to suppress the latch-up. The trenched cathode LIGBT (TC-LIGBT) structure is BiCMOS compatible and the LIGBT's with latching current densities over 1200 A/cm2 have been obtained using a 4 μm technology