This paper proposes an adaptive one-way SLC/TLC mode conversion, to balance the capacity and the I/O performance in the use of high density TLC SSDs. Considering the space demand of the early stage of SSD devices is limited and the total amount of valid data basically keeps increasing, we initialize all SSD cells work in the SLC-mode for yielding better I/O performance. Then, when the available capacity of high density SSDs is lower than the space demand of applications, certain SLC-mode cells will be converted into the TLC mode to increase available space of SSDs. To this end, we build a mathematical model to better guide one-way SLC/TLC mode conversions, that can help determining the time and the quantity of conversions from the SLC mode to the TLC mode.
A general vector network analyzer employs a super-heterodyne scheme to expand a measuring frequency band. The circuit structure is complicated because of implementing mixers, local oscillators, and amplifiers, therefore, the cost is not affordable. In order to simplify the circuit structure and be affordable, we employ a homodyne scheme, that is the six-port method. In this report, we demonstrated the performance of a six-port reflectometer in the V-band based on a waveguide standing wave detector.
In 3D NAND Flash, new read operation scheme is proposed to optimize read disturb in unselected strings. During read operation, the two types of read disturb occur, which are soft programming and HCI-induced read disturb. These are caused by repetitive Fowler-Nordheim (F-N) stress and boosting channel potential difference, respectively. In this letter, we show optimization of two read disturb phenomena through technology computer-aided design (TCAD) simulation with partial-boosting channel potential. Furthermore, the various conditions that affect channel potential in read operation are investigated. These results will be basis of the practical 3D NAND read operation analysis.
In this paper, a novel compact wideband Wilkinson Power Divider (WPD) is proposed and is analyzed by using the even- and odd-mode theory. The even-mode equivalent circuit of the WPD is designed to have both a wide stopband and a wide passband. The passband is then used as the wide operating frequency band of the WPD with low return loss. The even-mode circuit parameters are determined by using the derived formulas and an optimization algorithm. The remaining circuit parameters of the WPD are obtained from the analysis of the odd-mode circuit of the WPD. Finally, a microstrip WPD is designed with a center frequency of 3.0 GHz and an operating frequency band covering 1.5 ∼ 4.5 GHz (FBW=100%). The microstrip WPD is compact, occupying an area of only 0.20λg×0.13λg, and its measured performance satisfies the design specifications quite well.
This paper presents a K-band two-stage power amplifier (PA) with a compact circuit size of 1.8×0.87mm2. To guarantee broadband high-gain output performance, the optimal impedance domain and power cell are determined through load/source-pull simulation and K-point method, respectively. Reactive/resistive matching networks are carefully employed to reduce the equivalent gate capacitance, improve stability and compensate for the device’s negative gain roll-off slope. Meanwhile, combining with feedback technique adopted in driver stage, the entire operation bandwidth can be further extended. Under 12V pulse voltage supply, 37.4% of peak power-added efficiency (PAE) at 26GHz and 24±0.5dB of small-signal gain, 30.3-31.6dBm of saturated output power (Psat) across 22-27GHz are obtained as shown in the experimental results.
For a vector-summing phase shifter, the quadrature signal generation (QSG) network is crucial. Among the existing QSG networks, a one-stage quadrature all-pass filter (QAF) provides the same bandwidth as a two-stage R-C polyphase filter while exhibiting 6-dB higher voltage gain. Despite all the advantages, the major disadvantage of the conventional QAF is that it contains two inductors, which occupy large chip area. In this work, magnetically coupled QAF (MCQAF) is proposed. In the proposed MCQAF, the two inductors in the QAF are intertwined to reduce the occupied chip area, dispelling the major disadvantage of the conventional QAF. With the magnetic coupling between the inductors considered, the design equation for the inductance in the MCQAF is derived. An MCQAF is designed at 2 GHz in a GaAs integrated passive device process along with a conventional QAF for comparison. The results of this work show that, except for a slightly larger amplitude error, the proposed MCQAF exhibits performances comparable to those of the conventional QAF while the occupied chip area is reduced by approximately 1/3.
To realize the in-situ temperature monitoring of power device, three kinds of Schottky barrier diodes (SBDs) are designed to reveal the effect of geometry on the temperature sensitivity. The current-voltage characteristics at different temperature demonstrate that all the circular-, finger-, and 8-finger- SBDs show good rectification. The forward voltage at a specific sub-threshold current level presents good linearity versus temperature. In addition, the deduced sensitivity presents no dependency on the geometry but is determined by the ideality factor and current density. The sensing mechanism of SBD sensor is explained by the thermionic emission model. Those results are beneficial to the design and fabrication of temperature sensor.
Aiming at the problems of slow response speed and chattering phenomenon in general sliding mode control of permanent magnet synchronous motor, a global fast terminal sliding mode control strategy is proposed to improve the response speed and the anti-interference ability of the system. A load torque Luenberger observer is designed, and the observed value is fed back to the global fast terminal sliding mode controller of permanent magnet synchronous motor control system in order to reduce the influence of external load disturbance. A permanent magnet synchronous motor experiments platform is built to verify the performance of the proposed control strategy and the effectiveness of the observer. The experimental results show that the load torque Luenberger observer can better observe the actual load torque and track the actual speed of the motor. The global fast terminal sliding mode control strategy improves the response speed of the motor and enhances the robustness of the system.