Biasing

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

Two-micron-wavelength germanium-tin photodiodes with low dark current and gigahertz bandwidth.

Abstract: We report the demonstration of a germanium-tin (Ge0.9Sn0.1) multiple-quantum-well p-i-n photodiode on silicon (Si) substrate for 2 μm-wavelength light detection. Characterization of the photodetector in both direct current (DC) and radio frequency (RF) regimes was performed. At the bias voltage of -1 V, a dark current density of 0.031 A/cm2 is realized at room-temperature, which is among the lowest reported values for Ge1-xSnx-on-Si p-i-n photodiodes. In addition, for the first time, a 3 dB bandwidth (f3dB) of around 1.2 GHz is achieved in Ge1-xSnx photodetectors operating at 2 μm. It is anticipated that further device optimization would extend the f3dB to above 10 GHz.

Dispersive Thermometry with a Josephson Junction Coupled to a Resonator

Abstract: We have embedded a small Josephson junction in a microwave resonator that allows simultaneous dc biasing and dispersive readout. Thermal fluctuations drive the junction into phase diffusion and induce a temperature-dependent shift in the resonance frequency. By sensing the thermal noise of a remote resistor in this manner, we demonstrate primary thermometry in the range from 300 mK to below 100 mK, and high-bandwidth (7.5 MHz) operation with a noise-equivalent temperature of better than 10 $\mathrm{\mu K/\sqrt{Hz}}$. At a finite bias voltage close to a Fiske resonance, amplification of the microwave probe signal is observed. We develop an accurate theoretical model of our device based on the theory of dynamical Coulomb blockade.

Three-terminal, low voltage pulse width modulation controller ic

Abstract: A three-terminal low-voltage PWM controller chip includes a first terminal for receiving operating bias current supply and a feedback control signal related to an output parameter of an electrical circuit to be controlled; a second terminal connected to an output switch providing digital width-modulated control pulses to control duty cycle of the electrical circuit; a third terminal ground connection; a clocked pulse width modulation circuit responsive to current flow between the second terminal and the third terminal and the feedback control value for controlling the digital output switch; and, feedback signal separation circuitry for separating the feedback control signal from the operating bias current supply. A start-up circuit is also provided.

Multisource type X-ray CT apparatus

Abstract: A multisource type X-ray CT apparatus including a fixed sensor array, a fixed vacuum chamber, and an X-ray generation unit. The X-ray generation unit includes a cathode and an anode which are fixed in the vacuum chamber so as to surround the sensor array, a gate array including a plurality of grid electrodes which are densely fixed between the cathode and anode and which include holes for passing the electron beams, a power source which applies a bias voltage to the grid electrodes of the gate array, and a controller which controls the power supply operation from the power source so as to select the grid electrode suitable for image pickup from the gate array in accordance with an image pickup portion of the subject and to release the bias voltage applied to the selected grid electrode.

Ultra-low quiescent current low dropout (LDO) voltage regulator with dynamic bias and bandwidth

Abstract: An LDO regulator automatically switches from the SLEEP mode to the ON mode without the need for an externally generated control signal. The LDO regulator utilizes a pair of drive amplifiers to drive a SLEEP mode pass transistor and a normal ON mode pass transistor, respectively. The regulator also has a circuit for adjusting the bias applied to the amplifiers for each mode of operation.