Power cycling test (PCT) is an effective method to evaluate the SiC mosfet s' long-term reliability, including lifetime and degradation mechanisms. Some of the aging precursors of PCT have been identified in the previous literature. But when multiple failure mechanisms compete with each other, the individual precursors are nullified. Although PCT is mainly used to evaluate the package reliability, there are still unresolved problems due to the gate oxide reliability of SiC mosfet , and the repeated gate stress of the power cycling has different effects on the devices with different gate structures. This article presents a comprehensive investigation of the aging precursors and failure mechanism of three typical commercial SiC mosfet s with different gate structures through PCTs under two different conduction modes. Degradation-related essential precursors and possible causes behind them are discussed. The failure mechanisms and correlation with the degradation state of different devices are studied in depth. In addition, the effects of PCT under different conduction modes on failure mechanism and lifetime have been investigated.

Aluminum electrolytic capacitors (AEC) are widely used in switching mode power supply (SMPS) as smoothing capacitor, but they are the weakest among power components in DC-DC converter. It is very important to monitor its electrical parameters, mainly the equivalent series resistance (ESR). A monitoring method of capacitor's ESR for buck converters is proposed in this paper. Based on the calculation model of ESR, the target parameter is monitored by sampling output ripple voltage. The proposed method needs no current sensor. Whether the circuit is in continuous conduction mode (CCM) or discontinuous conduction mode (DCM), it is convenient to monitor the capacitor. Implementation of the monitoring system is presented. The experimental results validate the effectiveness of the method.

Owing to its relatively high efficiency, extended transmission range, and less exposure to radio frequency radiation, near-field resonant wireless power transfer (R-WPT) has been widely used in consumer electronics and bio-implants. For most applications, a well-regulated output voltage is required against the coupling and loading variations, and thus a regulation scheme should be employed in an R-WPT system. To achieve an optimal receiver (RX) or overall efficiency, together with a reduced cost overhead, several regulation schemes have been proposed in recent years, where the regulation can be implemented at either the RX or transmitter (TX) side, or both. These regulation schemes have been reviewed and comprehensively discussed in this paper. Hence, the main contribution of this paper is to provide a guideline for designing the regulation scheme in R-WPT systems. Moreover, potential new topologies of regulation are investigated here.

An energy‐efficient switching scheme for successive approximation register (SAR) analogue‐to‐digital converter (ADC) is proposed. Based on closed‐loop charge recycling method, the proposed switching scheme achieves 100% less switching energy over the conventional switching scheme. Furthermore, the common‐mode voltage of the comparator is always V _cm and only two reference voltages are used.

This article presents a frontend amplifier based on the 50- $\mu \text{m}$ channel length n-type only indium–tin-oxide (ITO)-stabilized ZnO thin-film transistors (TFTs) on glass substrate. The amplifier has an external-bias ac-coupled, open-loop capacitor bootstrap structure. The area and power consumption are 41 mm ² and 0.1 mW (8-V supply), respectively. Electrical measurement results show a gain of 20 dB, a bandwidth of 3 Hz–6 kHz, a common-mode rejection ratio (CMRR) up to 42 dB, an input impedance of 100 $\text{M}\Omega $ , and an input-referred noise of $106 ~\mu \text{V}_{rms}$ (integrated from 1 to 200 Hz). The noise efficiency factor (NEF) and power efficiency factor (PEF) of the amplifier are, respectively, 248 and $4.9\times10$ ⁵ , which is comparable among the state of the arts. The amplifier is successfully used to measure the heart-rate signal, which demonstrates its practicality.

Nitrogenous octadecylamine (ODA) self-assembled multilayers (SAMs) are prepared as passivation layers by the vapor-phase process for amorphous InSnZnO (ITZO) thin-film transistors (TFTs). The vapor-phase proposed ODA SAMs show excellent properties as a barrier against the atmosphere and serve as an effective nitrogen doping (N doping) source. After the self-assembled process, the distribution of the oxygen vacancies is modified by N-doping in the channel of the ITZO TFTs, wherefore the ITZO TFTs with ODA SAMs demonstrate an improvement of electrical properties. In addition, the oxygen and water adsorption/desorption reactions at the back channel are suppressed by the atmosphere isolation and N-doping effect, leading to an improvement of the positive bias stability. These results indicate that the nitrogenous ODA SAMs can be likely passivation layers for high-performance oxide TFT devices.