Biasing

About: Biasing is a research topic. Over the lifetime, 29422 publications have been published within this topic receiving 301035 citations.

Series current limiter

Abstract: Field effect transistors are used in a series current limiter circuit. The field effect transistors are depletion type transistors and are interconnected in a manner to decrease conduction when an overvoltage or overcurrent condition is sensed. Biasing resistors are used to maintain the transistors in a non-conductive state until the overvoltage or overcurrent condition is removed.

Gate-length dependence of the speed of SSI circuits using submicrometer selectively doped heterostructure transistor technology

Abstract: Frequency dividers and ring oscillators have been fabricated with submicrometer gates on selectively doped AIGaAs/GaAs heterostructure wafers. A divide-by-two frequency divider operated up to 9.15 GHz at room temperature, dissipating 25 mW for the whole circuit at a bias voltage of 1.6 V, with gate length ∼ 0.35 µm. A record propagation delay of 5.8 ps/gate was measured for a 0.35-µm gate 19- stage ring oscillator at 77 K, with a power of 1.76 mW/gate, and a bias voltage of 0.88 V. The maximum switching speed at room temperature was 10.2 ps/gate at 1.03 mW/gate and 0.8 V bias, for a ring oscillator with the same gate length. With a range of gate lengths on the same wafer fabricated by electron-beam lithography, a clear demonstration of gate-length dependence on the propagation delay was observed for both dividers and ring oscillators.

Outdoor photoluminescence imaging of photovoltaic modules with sunlight excitation

Abstract: To operate photovoltaic power plants at maximum capacity, it is desirable to identify cell or module failures in the field at the earliest possible stage. Currently used field inspection methods cannot detect many of the electronic defects that can be revealed with luminescence-based techniques. In this work, photoluminescence images are acquired using the sun as the sole illumination source by separating the weak luminescence signal from the much stronger ambient sunlight signal. This is done by using an appropriate choice of optical filtering and modulation of the cells' bias between the normal operating point and open circuit condition. The switching is achieved by periodically changing the optical generation rate of at least one cell within the module. This changes the biasing condition of all other cells that are connected to the same bypass diode. This method has the advantage that it can deliver high quality images revealing electrical defects in individual cells and entire modules, without requiring any changes to the electrical connections of the photovoltaic system.

Method for changing the weight of a synaptic element

Abstract: An analog storage array according to the present invention is disposed on a semiconductor substrate. The array is arranged as a plurality of rows and a plurality of columns and includes a plurality of N-channel MOS transistors disposed in the rows and columns in a p-well in the semiconductor substrate. Each of the MOS transistors includes a source, a drain, and a floating gate forming a tunneling junction with a tunneling electrode. An input line is associated with each of the rows in the array. Each input line is connected to the source of each of the N-channel MOS transistors disposed in the row with which the input line is associated. A bias line is associated with each of the rows in the array. Each bias line is capacitively coupled to the floating gate of each of the N-channel MOS transistors disposed in the row with which the bias line is associated. A tunnel line is associated with each of the columns in the array. Each tunnel line connected to the tunneling electrode of each of the N-channel MOS transistors disposed in the column with which the bias line is associated. A current-sum line is associated with each of the columns in the array. Each current-sum line is connected to the drain of each of the N-channel MOS transistors disposed in the column with which the bias line is associated. Circuitry is provided for forward biasing said p-well with respect to the substrate. Circuitry is provided for simultaneously driving a selected one of the bias lines low while driving a selected one of the tunnel lines high, for raising the floating gate voltage of the one of the N-channel MOS transistors common to the selected one of the bias lines and the selected one of the tunnel lines.

Method of and device for driving optical modulator, and optical communications system

Abstract: A device and a method for driving an electro-absorption optical modulator for receiving carrier light emitted from a light source and outputting signal light subjected to intensity modulation according to the absorption of the carrier light. A bias circuit generates a bias voltage determined so that the optical modulator has a given chirping parameter. A driving circuit generates a modulating signal corresponding to an input signal, superimposes the modulating signal on the bias voltage, and supplies the superimposed signal to the optical modulator. A control circuit controls at least one parameter selected from a parameter group including the amplitude and duty of the modulating signal and the power of the carrier light, based on the bias voltage. It can be possible to provide a method of and a device for driving an optical modulator capable of arbitrarily setting a chirping parameter.