276 results about "Current–voltage characteristic" patented technology

A pixel circuit, display device, and method of driving a pixel circuit enabling source-follower output with no deterioration of luminance even with a change of the current-voltage characteristic of the light emitting element along with elapse, enabling a source-follower circuit of n-channel transistors, and able to use an n-channel transistor as an EL drive transistor while using current anode-cathode electrodes, wherein a source of a TFT 111 as a drive transistor is connected to an anode of a light emitting element 114, a drain is connected to a power source potential VCC, a capacitor C111 is connected between a gate and source of the TFT 111, and a source potential of the TFT 111 is connected to a fixed potential through a TFT 113 as a switching transistor.

The invention relates to a conditioning circuit that measures operating points of a power supply to deduce therefrom the current-voltage characteristic thereof and to determine directly the voltage corresponding to its maximum power point, without using any kind of tracking algorithm that causes the operating point of the power unit to oscillate about the maximum power point. The maximum power point voltage VMPP is supplied to a controller which regulates a power cell by slaving it to the input voltage until the output voltage of the supply is equal to the maximum power point voltage V_MPP. The invention also relates to a solar generator and an associated conditioning method. One particular application is to high-power satellites.

The invention relates to a method and a circuit arrangement for the ageing compensation of an organic light-emitting diode (OLED) which is fed from a supply voltage and is switched by means of a driver transistor operated in saturation operation, by means of a driving of the light-emitting diode. The method comprises the following steps of: storing at least one desired current-voltage value pair of a desired current-voltage characteristic curve of the light-emitting diode; transferring the driver transistor from saturation operation to linear operation during a measurement cycle; measuring a current value for the current through the light-emitting diode by means of a current measuring circuit in the measurement cycle; determining at least one present current-voltage value pair of a present current-voltage characteristic curve of the light-emitting diode by means of the measured current value; comparing the at least one present current-voltage value pair of the light-emitting diode with the desired current-voltage value pair of the light-emitting diode; and generating driving parameters for driving the light-emitting diode in a manner dependent on the result of the comparison.

A detection voltage, which is obtained by dividing the voltage of a fuel cell 1 by resistors, is compared with a first reference voltage Vref1 by a differential amplifier. The differential voltage is input to a control section. The control section performs PWM control for the circuit section according to the difference. The first reference voltage Vref1 is set according to the dividing ratio of the resistors, based on the output voltage when the fuel cell generates power at the maximum power point. To determine the output voltage for maximum power generation, a characteristic curve representing a current-voltage characteristic is approximated by an approximating line within a range excluding an area in which the output voltage changes abruptly when the output current is nearly zero, and an extrapolated voltage is obtained on the extension line of the approximating line at an output current of zero. Fifty percent of the extrapolated voltage is then determined as the output voltage when the fuel cell generates power at the maximum power point. Thus, a fuel cell control system that identifies a highly precise output voltage for power generation at a maximum power point and controls power so that the maximum power point is not exceeded could be provided.

The method of controlling rechargeable battery power is a method that includes limiting the amount of usable power during rechargeable battery charging and discharging, determining a rechargeable battery current-voltage characteristic function based on rechargeable battery charging and discharging current flow and voltage, finding a limiting discharging current I_max and/or a limiting charging current I_min from a prescribed minimum voltage V_min to prevent over-discharging and/or a prescribed maximum voltage V_max to prevent over-charging and their intersection with the current-voltage characteristic function, and controlling current such that discharging current greater than or equal to I_max and/or charging current less than or equal to I_min does not flow through the rechargeable batteries. In this fashion, the amount of usable power can be limited considering factors such as the memory effect, and the rechargeable battery can be used to its maximum capability within the range of safe operation.

An electrostatic discharge (ESD) protection clamp (61) for I/O terminals (22, 23) of integrated circuits (ICs) (24) comprises an NPN bipolar transistor (25) coupled to an integrated Zener diode (30). Variations in the break-down current-voltage characteristics (311, 312, 313, 314) of multiple prior art ESD clamps (31) in different parts of the same IC chip is avoided by forming the anode (301) of the Zener (30) in the shape of a base-coupled P+ annular ring (75) surrounded by a spaced-apart N+ annular collector ring (70) for the cathode (302) of the Zener (30). Even though an angled implant (51, 86, 98) used to form the N+ annular collector ring (70) causes location dependent variations in the width (53) of the Zener space charge (ZSC) region (69), the improved annular shaped clamp (61) always has a portion that initiates break-down at the design voltage so that variations in the width (53) of the ZSC region (69) do not cause significant variations in the clamp's current-voltage characteristics (611, 612, 613, 614).

The light-emitting element has a problem that reliability, heat-resisting stability and durability are low because of the deterioration in an organic compound layer. The TFT for driving the light-emitting element has a problem that variation readily occurs in its electrical characteristic due to the defects existing in grain boundaries. The present invention provides a light-emitting device by using the fact that, by applying to the light-emitting element a drive voltage having a polarity reverse to that in light emission during each constant period, the light-emitting element is improved in current-voltage characteristic. Furthermore, the present invention provides a light-emitting device made not dependent upon transistor characteristic, by controlling the amount of a current flowing through the light-emitting element.

A bi-layer pseudo-spin field-effect transistor (BiSFET) is disclosed. The BiSFET includes a first and second conduction layers separated by a tunnel dielectric. The BiSFET transistor also includes a first gate separated from the first conduction layer by an insulating dielectric layer, and a second gate separated from the second conduction layer by an insulating layer. These conduction layers may be composed of graphene. The voltages applied to the first and/or second gates can control the peak current and associated voltage value for current flow between top and bottom conduction channels, and interlayer current voltage characteristic exhibiting negative differential resistance. BiSFETs may be used to make a variety of logic gates. A clocked power supply scheme may be used to facilitate BiSFET-based logic.

In a solar simulator for measuring the current-voltage characteristics of photovoltaic devices, it is to provide a measurement method using a solar simulator in which locative unevenness of irradiance on the test plane of the test plane side is drastically improved, not in a light source side, and a means for adjusting irradiance and the like. when an object is the photovoltaic devices Ms, and the current-voltage characteristics are measured by a solar simulator Ss equipped with a light source composed of a lamp and a reflector, and a part for setting the object to be measured, in which it is possible to dispose an irradiated test plane of the object to be measured opposite an illuminating surface of said light source, the whole test plane of said photovoltaic devices is divided imaginarily into a plurality of sections and a selected member for adjusting irradiance is disposed opposite the test plane of each imaginary sections so as to equalize or substantially to equalize the irradiance by the light source at every irradiated test plane of the sections, after which light from said light source is directed onto the test plane of the object to be measured.

A pixel circuit, display device, and method of driving a pixel circuit enabling source-follower output with no deterioration of luminance even with a change of the current-voltage characteristic of the light emitting element along with elapse, enabling a source-follower circuit of n-channel transistors, and able to use an n-channel transistor as a drive transistor of a light emitting element while using current anode-cathode electrodes, wherein a capacitor C111 is connected between a gate and source of a TFT 111 as a drive transistor, a source side of the TFT 111 is connected to a fixed potential (for example GND) through the TFT 114, the gate and drain of the TFT 111 are connected through the TFT 113 to cancel the threshold value Vth, the threshold value Vth is charged in the capacitor C111, and the input voltage Vin is coupled with the gate of the TFT 111 from the threshold voltage Vth.

Ion implantation is used to increase the resistivity of semiconductor device layers for channeling the current through a low resistivity, unimplanted region such that carrier recombination takes place away from regions underneath the contacts. This eliminates absorption of light by the contact thereby providing higher light output power and better current-voltage characteristics to the semiconductor device. The incorporation of a regrown contact layer allows for an undamaged lateral conduction path, and the fabrication of ohmic contacts.

Disclosed is a group-III nitride-based light emitting diode. The group-III nitride-based light emitting diode includes a substrate, an n-type nitride-based cladding layer formed on the substrate, a nitride-based active layer formed on the n-type nitride-based cladding layer, a p-type nitride-based cladding layer formed on the nitride-based active layer, and a p-type multi-layered ohmic contact layer formed on the p-type nitride-based cladding layer and including thermally decomposed nitride. The thermally decomposed nitride is obtained by combining nitrogen (N) with at least one metal component selected from the group consisting of nickel (Ni), copper (Cu), zinc (Zn), indium (In) and tin (Sn). An ohmic contact characteristic is enhanced at the interfacial surface of the p-type nitride-based cladding layer of the group-III nitride-based light emitting device, thereby improving the current-voltage characteristics. In addition, since the light transmittance of the transparent electrode is improved, light efficiency and brightness of the group-III nitride-based light emitting device are also improved.

A measuring method for measuring current-voltage characteristics of a photoelectric conversion device by irradiating light to said photoelectric conversion device and a reference device corresponding to said photoelectric conversion device at the same time while detecting an irradiance of said light using said reference device, characterized in that a light responsive time constant of a irradiance detection circuit in which said reference device is used is adjusted so that said light responsive time constant of said irradiance detection circuit comes closer to a light responsive time constant of said photoelectric conversion device. An apparatus for practicing said measuring method.

A memory array is disclosed having bipolar current-voltage (IV) resistive random access memory cells with built-in “on” state rectifying IV characteristics. In one embodiment, a bipolar switching resistive random access memory cell may have a metal/solid electrolyte/semiconductor stack that forms a Schottky diode when switched to the “on” state. In another embodiment, a bipolar switching resistive random access memory cell may have a metal/solid electrolyte/tunnel barrier/electrode stack that forms a metal-insulator-metal device when switched to the “on” state. Methods of operating the memory array are also disclosed.

A nonvolatile semiconductor memory device comprises a memory cell including a variable resistance element changing its electric resistance by voltage application and having current-voltage characteristics in which a positive bias current flowing when a positive voltage is applied from one electrode as a reference electrode to the other electrode through an incorporated rectifier junction is larger than a negative bias current, a memory cell selection circuit for selecting the memory cell from the memory cell array, a voltage supply circuit for supplying a voltage to the memory cell so that a predetermined positive voltage corresponding to the reading operation is applied to the other electrode of the variable resistance element, in the reading operation, and a readout circuit for detecting the amount of the positive bias current and reading the information stored in the selected memory cell, in order to suppress the reading disturbance of the memory cell.

A reference voltage generating circuit includes a current mirror circuit having first and second current paths formed between a first power source terminal and a second power source terminal in which the current mirror circuit is operated in response to a voltage level of the second current path, a reference voltage output node for providing a reference voltage and being located on the second current path, an active resistance device formed on the first current path to be operated in a linear region of a current-voltage characteristic curve of the active resistance device, and a voltage supply circuit for supplying the active resistance device with an enable voltage to control the active resistance device to be operated in the linear region.