Design Methodology of Tightly Regulated Dual-Output LLC Resonant Converter Using PFM-APWM Hybrid Control Method

A dual-output LLC resonant converter using pulse frequency modulation (PFM) and asymmetrical pulse width modulation (APWM) can achieve tight output voltage regulation, high power density, and high cost-effectiveness. However, an improper resonant tank design cannot achieve tight cross regulation of the dual-output channels at the worst-case load conditions. In addition, proper magnetizing inductance is required to achieve zero voltage switching (ZVS) of the power MOSFETs in the LLC resonant converter. In this paper, voltage gain of modulation methods and steady state operations are analyzed to implement the hybrid control method. In addition, the operation of the hybrid control algorithm is analyzed to achieve tight cross regulation performance. From this analysis, the design methodology of the resonant tank and the magnetizing inductance are proposed to compensate the output error of both outputs and to achieve ZVS over the entire load range. The cross regulation performance is verified with simulation and experimental results using a 190 W prototype converter

Experimental Realization of Zenneck Type Wave-based Non-Radiative, Non-Coupled Wireless Power Transmission

A decade ago, non-radiative wireless power transmission re-emerged as a promising alternative to deliver electrical power to devices where a physical wiring proved impracticable. However, conventional "coupling-based" approaches face performance issues when multiple devices are involved, as they are restricted by factors like coupling and external environments. Zenneck waves are excited at interfaces, like surface plasmons and have the potential to deliver electrical power to devices placed on a conducting surface. Here, we demonstrate, efficient and long range delivery of electrical power by exciting non-radiative waves over metal surfaces to multiple loads. Our modeling and simulation using Maxwell's equation with proper boundary conditions shows Zenneck type behavior for the excited waves and are in excellent agreement with experimental results. In conclusion, we physically realize a radically different class of power transfer system, based on a wave, whose existence has been fiercely debated for over a century

A 1.9-GHz triple-mode class-E power amplifier for a polar transmitter

A 1.9-GHz CMOS power amplifier for polar transmitters was implemented with a 0.25-mu m radio frequency CMOS process. All the matching components, including the input and output transformers, were fully integrated. The concepts of mode locking and adaptive load were applied in order to increase the efficiency and dynamic range of the amplifier. The amplifier achieved a drain efficiency of 33% at a maximum output power of 28 dBm. The measured dynamic range was 34 dB for a supply voltage that ranged from 0.7 to 3.3 V. The measured improvement of the low power efficiency was 140% at an output power of 16 dBm.ope

A 1.9-GHz CMOS power amplifier using three-port asymmetric transmission line transformer for a polar transmitter

A 1.9-GHz CMOS differential power amplifier for a polar transmitter is implemented with a 0.18-mu m RF CMOS process. All of the matching components, including the input and output transformers, are fully integrated. The concepts of injection locking and variable load are applied to increase the efficiency and dynamic range of the amplifier. An asymmetric three-port transmission line transformer is proposed to embody the variable load effectively. The power amplifier achieved a power-added efficiency of 40% at a maximum output power of 32 dBm. The dynamic range was 20 dB at supply voltages ranging from 0.5 to 3.3 V. The improvement of the low power efficiency was 290% at an output power of 16 dBm.ope

Fully integrated 1.9-GHz CMOS power amplifier for polar transmitter applications

A 1.9-GHz CMOS differential power amplifier for polar transmitter applications was implemented with a 0.25 mu m RF CMOS process. All of the matching components, input transformer, and output transformer are fully integrated with 50 Omega input and output matching. Each power transistor in each differential branch is split again and controlled separately to obtain a high power mode and a low power mode. The amplifier achieved a drain efficiency of 32% at the maximum output power of 29.5 dBm. The dynamic range is measured at approximately 275 dB with a supply voltage range of 0.7 similar to 3.3 V.ope

A CMOS RF power amplifier using an off-chip transmision line transformer with 62% PAE

In this letter, a two-stage 900-MHz CMOS differential power amplifier (PA) is designed and implemented in a 0.18-mu m radio frequency CMOS process. A transmission line transformer on a printed circuit board is used as an output power combiner and matching circuits of a class-E power stage. To drive the power stage effectively, cascaded class-D amplifiers are used as driver amplifiers. The PA delivers an output power of 31.7 dBm and a power-added efficiency of 62.4% with a power gain of 30.3 dB, including the losses of the bond-wires and the output transformer.ope

A 1.8-GHz CMOS power amplifier using a dual-primary transformer with improved efficiency in the low power region

A 1.8-GHz CMOS power amplifier for a polar transmitter is implemented with a 0.18-mu m RF CMOS process. The matching components, including the input and output transformers, were integrated. A dual-primary transformer is proposed in order to increase the efficiency in the low power region of the amplifier. The loss induced by the matching network for the low-output power region is minimized using the dual-primary transformer. The amplifier achieved a power-added efficiency of 40.7% at a maximum output power of 31.6 dBm. The dynamic range was 34 dB for a supply voltage that ranged from 0.5 to 3.3 V. The low power efficiency was 32% at the output power of 16 dBm.ope

Bluetooth Load-Cell-Based Support-Monitoring System for Safety Management at a Construction Site

At construction sites, temporary facilities have caused continuous collapse accidents, causing damage to human life. If the concrete placing height is high and the worker is pushed into one place at the time of placing, the working load may be exceeded and a collapse accident may occur. In order to solve this problem, in this research, we developed a monitoring load-measurement program based on a Bluetooth wireless load cell (load-cell sensor) so that the load can be converted to digital and the numerical value can be confirmed by the pressure sensor. The load cell using Bluetooth was designed and manufactured according to the support. Then, the performance was verified through 3D finite element analysis by modeling and experimental tests. In addition, we constructed a system to generate notifications and warnings step by step when the load is close to a dangerous load, confirmed the load distribution pattern by position, and established a method to confirm real-time data numerically and graphically. Finally, we evaluated the practical application of the load-monitoring system using field-test data using a wireless load-cell

Analysis and Design Techniques of CMOS Charge-Pump-Based Radio-Frequency Antenna-Switch Controllers

Analysis and design techniques of charge-pump-based RF antenna-switch controllers are presented. Loading effects of RF antenna switches that cause voltage drop of the controller have been identified and embedded in the analysis. The proposed analysis also captures effects of MOS-switch on-resistance and parasitic capacitances, so more precise descriptions of the charge-pump output voltage can be obtained. Furthermore, the body biasing technique has been employed to prevent latch-up. The analysis and the design techniques have been verified using a 0.35-mu m CMOS technology. RF antenna-switch performances with the designed controller have also been measured and presented.ope

A 32-dB SNR Readout IC with 20-Vpp Tx Using On-Chip DM-TISM in HV BCD Process for Mutual-Capacitive Fingerprint Sensor

This brief presents a readout IC with a 20 V high-voltage (HV) transmitter (Tx) and On-Chip Differentially Modulated Time-Interleaved Sensing Method (DM-TISM) in a BCD process for a mutual-capacitive Transparent Fingerprint Sensor (TFPS) in order to achieve high SNR, AC & DC offset reduction, high noise immunity, and compensate for the signal loss under thick cover glass. A proposed readout IC with on-chip DM-TISM is composed of 42 identical HV Tx channels, 32 identical Rx channels, and a diamond-patterned TFPS. The performance results including those for transient noise show that the DM-TISM achieves greater SNR than conventional TISM. The measured raw data show that the proposed readout IC achieves SNR of 32 dB with current consumption of 25 mA for the Tx and 13 mA for the Rx. It can be applied to any type of mobile device that needs fingerprint recognition. The ICs for the Tx and Rx are fabricated using 0.25-mu m BCD process and 0.18-mu m CMOS process with 1.6 mm x 3.5 mm and 2.5 mm x 2.5 mm areas, respectively