An Ultra-Low Quiescent Current Under-Voltage Lockout Circuit for a High-Voltage Gate Driver IC

An ultra-low quiescent current under-voltage lockout (UVLO) circuit for a high-voltage gate driver integrated circuit (HVIC) is described for application in portable devices. The UVLO circuit consumes the static current in the high-side circuitry and the resistive divider used to detect the supply-voltage was the major consumer of power in the circuit. Hence, a supply-voltage sensor based on a diode-connected metal–oxide–semiconductor field-effect transistor (MOSFET) with a voltage limiter design is proposed to ensure low power consumption. Unlike the conventional UVLO design, where a resistive divider is used, the proposed structure dissipates the negligible current at a low supply-voltage and significantly reduces the static current at the nominal and high supply-voltage. The high-side quiescent current using the proposed design and the conventional designs at various supply-voltage levels are analyzed. In the proposed structure, the size of the voltage sensor is considerably smaller when compared with those in conventional designs.

Modeling and simulation of a fuzzy heat distribution controlled high-voltage DC resistive divider

In order to improve quality in manufacturing, the measuring instruments used in production process should regularly be monitored and corrected according to international or national standards. Calibration of high-voltage equipment and precise measurements of DC high voltages are accomplished by standard voltage divider. Self-heating effect is the main error source of measurement in high-voltage DC resistive dividers. Therefore, precise control systems should be designed to keep stability of the ambient temperature and to regulate the heat distribution along the high-voltage DC resistive divider. For this purpose, a heat controlled resistive divider whose input voltage ( Vin) is up to 5 kV was designed. This study is focused on heat convention and the dissipation model of the resistive divider and executes some control simulations under various conditions that aim to find the appropriate control method. Responses of the high-voltage DC resistive divider model are compared with and are validated by the responses of the designed actual system. The model provides us faster analyze and design solutions for novel methods. In this way, analyzing and controlling higher voltage dividers, such as 100 KV, will reduce just into a parameter change on the model. The fuzzy control method is suggested since the system dynamic has non-linear characteristics. Fuzzy temperature difference controller keeps temperature at a certain degree where fuzzy vertical temperature gradient controller keeps vertical temperature gradient around zero. Actual system and model responses for the fuzzy control are compared and interpreted.

Analysis and Mitigation of Stray Capacitance Effects in Resistive High-Voltage Dividers

This work analyzes the effects of the parasitic or stray distributed capacitance to ground in high-voltage environments and assesses the effectiveness of different corrective actions to minimize such effects. To this end, the stray capacitance of a 130 kV RMS high-voltage resistive divider is studied because it can severely influence the behavior of such devices when operating under alternating current or transient conditions. The stray capacitance is calculated by means of three-dimensional finite element analysis (FEA) simulations. Different laboratory experiments under direct current (DC) and alternating current (AC) supply are conducted to corroborate the theoretical findings, and different possibilities to mitigate stray capacitance effects are analyzed and discussed. The effects of the capacitance are important in applications, such as large electrical machines including transformers, motors, and generators or in high-voltage applications involving voltage dividers, conductors or insulator strings, among others. The paper also proves the usefulness of FEA simulations in predicting the stray capacitance, since they can deal with a wide range of configurations and allow determining the effectiveness of different corrective configurations.

Thermal and aerodynamic tests of a digital combined current and voltage transformer

This study examines the results of thermal and aerodynamic tests of a digital combined current and voltage transformer conducted in an environmental chamber. This measuring instruments consist of current and voltage transformers, featuring a resistive divider, and are used for commercial and technical electric power accounting. Different ambient temperatures, airflow rates and levels of insolation were set for the environmental chamber, with simulation of transformer functioning in emergency modes. It was established that heat release at transformer outer surface with natural convection depends to a larger extent on the difference between the temperature at the transformer surface and ambient temperature, while with forced convection this heat release depends more on air mass speed, with greater heat release on the surface of an upward facing rib than on the surface of a downward facing rib. The results of our study have been used in developing algorithms for diagnostics of the thermal state of digital combined transformers.

Voltage dividers

Voltage dividers provide accelerating voltages to generate multiplier gain. Dynode voltages must remain constant and independent of the light input to maintain stable gain. The standard resistive divider never quite satisfies this requirement, although acceptable performance can be achieved by careful design. The inclusion of zener diodes improves performance but field-effect transistor (FET) circuits can provide gain stability at high mean anode currents, regardless of whether the application is pulsed or analogue. Design procedures for active and semi-active voltage dividers are presented. Dividers based on the Cockcroft–Walton (CW) principle are particularly suited to portable instrumentation because of their low standing current. Consideration is given to pulsed operation, decoupling, switch-on transients, ripple, dynode signals, single cable dividers, and equivalent circuits at high frequencies. Gating is used to protect a photomultiplier, in the presence of high light levels, by reducing the gain electronically. Various methods for gating a voltage divider are presented.