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Driving-Scheme Algorithms for Intelligent Energy-Efficient High-Voltage Display Drivers

In this paper, different driving-scheme algorithms to reduce the energy consumption in bistable display drivers are presented. A thorough theoretical analysis as well as some results will be given. These results report the difference in energy consumption between drivers using the traditional driving schemes and drivers using the driving scheme presented in this paper and this for different image patterns. The proposed algorithms are suitable for bistable flat-panel displays like cholesteric liquid-crystal displays (LCDs), bistable nematic LCDs, or electrophoretic displays and are very important for battery-powered applications.

Miniature multiaxial optoelectronic shear stress sensing system based on a segmented photodiode

Recording shear stresses is becoming relevant in an increasing number of applications, e.g., in rehabilitation sciences, where detecting foot-sole interaction is very important. This paper describes a portable and complete system to record multiaxial shear stresses. The sensing operation itself is based on the changing coupling of light between a vertical-cavity surface-emitting laser (VCSEL) and a segmented photodiode. Applying shear stress causes lateral displacement of both optoelectronic components leading to variation in the photocurrent. By combining signals from different photodiode segments, multiaxial shear stresses can be detected. A standalone system was designed to drive the VCSEL and to readout the signals from the different photodiode segments in order to measure shear stress as well as to evaluate the sensing system performance. Furthermore, the sensor signals can be efficiently monitored and visualized on a tablet or PC in real-time using dedicated software. The design presented in this article is optimized to measure shear forces with a magnitude up to 2 N and arbitrary direction. Yet, by changing the transducer material this range can be tuned for a specific application.

New driving scheme for intelligent power‐efficient high‐voltage display drivers

— A new bistable-display driver is presented. The innovation in the developed driver is the addition of a new logical block that calculates the most energy-efficient driving waveforms. In this paper, the algorithms being applied to the row and column waveforms in order to reduce the power consumption are discussed. Some theoretical as well as experimental results are shown, proving a reduction in the power consumption by about 50%. The proposed algorithms are especially important for battery-powered applications.

Monolithic integration of an active asynchronous voltage clamp with a 12V/3A full bridge synchronous rectifier

In transformer isolated converters, a large voltage overshoot is present on the secondary side switching nodes at every switch transition. As is well known in the design of monolithically integrated high voltage circuits, the peak voltage stress in a circuit is the paramount parameter for an efficient implementation of smart-power circuits. A voltage clamping circuit that minimizes the voltage stress in the circuit is crucial for an efficient monolithic implementation of a synchronous rectifier in a smart-power technology. This paper presents a smart-power implementation of an asynchronous active clamping circuit on the same IC as a 12V/3A synchronous rectifier for a full bridge phase shifted dc-dc converter. The asynchronous clamping circuit minimizes the number and size of required external components to provide the voltage clamping, and optimizes the efficiency of the synchronous rectifier by accurately controlling the clamping operation.

Improved passive-matrix multiplexability with a modular display and UTCP technology

One of the major problems with PM displays is that, depending on the used display material, only a limited number of lines can be multiplexed. We developed a new driving technology and display setup that takes care of that problem. We divided the display into several independent parts or modules. Each module acts as an individual display and has its own display driver. With the use of the new ultra-thin chip package (UTCP), these driver chips can be embedded into the (flexible) display itself. This paper explains the setup of the fully modular display and describes the basic structure of the display drivers and its components.

A Modular and Interactive OLED-Based Lighting System

ABSTRACT The concept of a flexible, large-area, organic light emitting diode (OLED)-based lighting system with a modular structure and built-in intelligent light management is introduced. Such a flexible, thin, portable lighting system with discreetly integrated electronics is important in order to allow the implementation of the lighting system into a variety of places, such as cars and temporary expedition areas. A modular construction of an OLED lighting panel makes it possible to control each OLED cell individually. This not only enables us to counteract aging or degradation effects in the OLED cells but it also allows individual OLED module brightness control to support human or ambient interaction based on integrated or centralized sensors. Moreover, integrating the driving electronics in the backplane of an OLED module improves the energy efficiency of operating large OLED panels. The thin, modular construction and individual, dynamic control are successfully demonstrated.

Automatic load-based MOSFET segmentation for switching DC-DC converters

This paper proposes an automated approach for the optimization of the number of active segments in switching DC-DC converters with a segmented power stage. The drain-source voltage of the active power MOSFET segments is used to estimate the load current, and an automated segment controller activates an optimized number of segments. Using this approach automatically balances the switching loss and the conduction loss in the converter over the load range. The proposed concept is implemented in a prototype discrete 500 kHz boost converter, which confirms the optimized efficiency over the load range. Potential applications include high power discrete converters, where multiple power MOSFETs in parallel are already used and monolithically integrated converters, where the power MOSFET segments, drivers and control circuits are integrated on a single ASIC.