Voltage regulator

About: Voltage regulator is a research topic. Over the lifetime, 33536 publications have been published within this topic receiving 350859 citations.

Arc control and switching element protection for pulsed dc cathode sputtering power supply

Abstract: A dc sputtering process applies a pulsating dc voltage in which each cycle includes a pulse portion of negative dc voltage of -300 to -700 volts alternating with a reverse bias (positive) pulse of about +50 to +300 volts The reverse bias pulse portion will reduce or eliminate sources for arcing in most cases To combat sticky or persistent arcing, the negative pulse portion is monitored If, during a window portion of the negative pulse portion, the applied voltage drops into a range characteristic of arcing for two successive cycles, then the applied power is interrupted for a period, eg, 200 microseconds, and reverse bias is applied An overvoltage detection and clamping circuit monitors the applied voltage for extreme voltage excursions, and if an overvoltage threshold is exceeded for two successive cycles, the applied power is interrupted The overvoltage detection and clamping circuit can comprise a string of zener diodes or equivalent voltage limiting devices connected to the applied voltage This circuit absorbs the voltage excursions beyond the threshold and protects the power supply and the substrate in the plasma chamber

Cross regulation in an energy-storage DC-to-DC converter with two regulated outputs

Abstract: A model of a two-output voltage step-up/current step-up dc-to-dc converter is presented which demonstrates how the leakage flux associated with the energy-storage transformer affects cross regulation. First, expressions are derived which show the strong influence that leakage flux has on the secondary current waveforms. Then, after imposing steady-state constraints on the two equations describing the secondary current waveshapes, the cross regulation performance of the converter can be predicted. A comparison of predicted and observed results suggests that this model can be a useful tool for understanding converter cross regulation performance as well as for guiding the design of the energy-storage transformer in a multiple-output converter.

Charge pump regulation control for improved power efficiency

Abstract: Techniques for efficiently generating an output voltage for use within an electronic device, such as a memory system, are disclosed. A voltage generation circuit generates the output voltage. The voltage generation circuit includes regulation circuitry that controls regulation of the output voltage to maintain the output voltage at a substantially constant level. According to one aspect, regulation is enabled when needed but disabled when regulation is not necessary, thereby reducing power consumption by the regulation circuitry. The voltage generation circuit is therefore able to operate with improved power efficiency.

PWM controller having adaptive off-time modulation for power saving

Abstract: An adaptive off-time modulator of a PWM controller is provided for power saving in the light-load and no-load conditions. The maximum on-time is kept as a constant and a bias current of the oscillator in the PWM controller is moderated to achieve the off-time modulation. Reduction of the bias current increases the off-time of the switching period. The bias current is a function of the supply voltage and the feedback voltage, which is derived from a voltage feedback loop. A threshold voltage defines the level of the light load. A limit voltage defines the low level of the supply voltage. A bias current synthesizer generates the bias current. Once the feedback voltage is decreased lower than the threshold voltage, the bias current is reduced linearly and the off-time of the switching period is increased gradually. When the supply voltage is lower than the limit voltage, the bias current increases and determines a maximum off-time of the switching period. The maximum on-time and off-time of the switching period determines the PWM frequency. As the limit voltage varies in every switching cycle, the frequency spectrum of PWM signal spreads in light-load and no-load conditions; and therefore, the acoustic noise is suppressed. The feedback voltage and the supply voltage determine the switching period of the PWM signal. The maximum on-time is kept constant and the switching period is increased by increasing the off-time, such that the magnetic components, such as inductors and transformers, are prevented from being saturated.

Fast-decoupled three-phase load flow

Abstract: Using as a reference the single-phase fast-decoupled algorithm, this paper describes the modifications required to produce an efficient three-phase fast-decoupled load flow. The compound-coil concept is used in the representation of power-system components, and the effect of automatic voltage regulators is modelled as part of the reactive-power Jacobian-matrix equation. It is shown that the three-phase modified fast-decoupled load flow displays all the characteristics of the original single-phase version.