A digital driving technique for an 8 b QVGA AMOLED display using modulation

Active-matrix organic LED (AMOLED) is one of the most promising contenders for next-generation displays. However, the VT-shift issue in thin-film transistors (TFT) has to be addressed to enable wide deployment. Voltage programming and current programming are well-known VT-shift-compensation techniques for analog driving. However, they all need more than 4 TFTs per pixel, which increases the panel complexity and decreases yield and aperture ratio. Recently, a VT-shift compensation technique that uses a 2TFT-1C pixel in an analog driving AMOLED has been reported. However, it requires OLED supply voltage programming, and shows a 14% variation in OLED current after VT-shift compensation, which is not enough for high-definition applications. Digital driving has been proposed as an alternative to mitigate the VT-shift issue with a simple pixel structure and to provide flexibility to the driver design. In this paper shows the pixel structures for voltage programming, current programming and digital driving. While the gate of the driving TFT (M2) is in the high state, the voltage across M2 is very small due to the large current-driving capability of a TFT as compared with an OLED. Hence, the current through the OLED is dominated by the supply voltage (PVDD), and minimally affected by the variations in TFT characteristics. Digital driving is also useful for true dark-level expression since the OLED can be completely turned off for black gray levels

Magnetic Pattern Recognition Using Injection-Locked Spin-Torque Nano-Oscillators

In this paper, we propose an efficient methodology for detecting magnetic field and thereby magnetic patterns using an injection-locked spin-torque nano-oscillator (STNO) array. We demonstrate the methodology with the implementation of a physical STNO model based on the Landau-Lifshitz-Gilbert-Slonczewski equation, which is benchmarked with experimental data. Based on our simulations, we provide an analysis of how the STNO, as a field-controlled oscillator, together with injection locking, can be used to sense magnetic fields and thereby magnetic patterns. The output can be sensed using simple CMOS peripheral circuitry

Real-Time Monitoring Of Contact Behaviour Of RF MEMS Switches With A Very Low Power CMOS Capactive Sensor Interface

This paper presents the first ultra-low power, fully electronic methodology for real-time monitoring of the dynamic behavior of RF MEMS switches. The measurement is based on a capacitive readout circuit composed of 67 transistors with 105 µm x 105 µm footprint consuming as little as 60 µW. This is achieved by accurately sensing the capacitance change around the contact region at sampling rates from 10 kHz to 5 MHz. Experimental and simulation results show that times of not only the first contact event but also all subsequent contact bounces can be accurately measured with this technique without interfering with the switch performance. This demonstrates the potential of extending this technique to real-time on-chip dynamic monitoring of packaged RF MEMS switches through their entire lifetime and after their integration in their final system

Wide-bandwidth, meandering vibration energy harvester with distributed circuit board inertial mass

A wide-bandwidth, meandering piezoelectric vibration energy harvester is presented for the first time utilizing the sensor node electronics as a distributed inertial mass. The energy harvester achieves an experimental maximum power output of 198 mu W when excited with a peak acceleration of 0.2 g (where 1 g is 9.8 m/s(2)) at 35 Hz. The output power remains higher than half of the maximum power (99 mu W) for the frequency band from 34.4 to 42 Hz, achieving a half-power fractional bandwidth of 19.9%, an increase of 4x compared to typical single-mode energy harvesters. The output power remains above 20 mu W from 29.5 to 48 Hz, achieving a 20-mu W fractional bandwidth of 48%. This is the highest reported fractional bandwidth for this low 0.2 g acceleration level. The distributed inertial mass in combination with the meandering harvester\u27s close natural frequency spacing is what enables the wide bandwidth. The energy harvester is demonstrated to autonomously operate a sensor node to sense and transmit temperature through a 434 MHz on-off-keying wireless transmitter while the electronics are used as the inertial distributed mass. (C) 2012 Elsevier B.V. All rights reserved