The undervoltage-lockout (UVLO) is an
electronic circuit
An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow. It is a type of electrical ...
used to turn off the power of an electronic device in the event of the
voltage dropping below the operational value that could cause unpredictable system behavior. For instance, in
battery powered
embedded devices, UVLOs can be used to monitor the battery voltage and turn off the embedded device's circuit if the battery voltage drops below a specific threshold, thus protecting the associated equipment. Some variants may also have unique values for power-up (positive-going) and power-down (negative-going) thresholds.
Usages
Typical usages include:
*
Electrical ballast circuits to switch them off in the event of voltage falling below the operational value.
*
Switched-mode power supplies. When the system supply
output impedance is higher than the input impedance of the
regulator, an UVLO with a higher
hysteresis
Hysteresis is the dependence of the state of a system on its history. For example, a magnet may have more than one possible magnetic moment in a given magnetic field, depending on how the field changed in the past. Plots of a single component of ...
should be used to prevent oscillations before settling down to a steady state and possible malfunctions of the
regulator.
[ Sokal, N. O., System Oscillations From Negative Input Resistance at Power Input Port of Switching-Mode Regulator, Amplifier, DC/DC Converter, or DC/AC Inverter, IEEE Power Electronics Specialists Conference - 1973 Record, pp. 138-140. PESC][https://www.prosoft.ru/cms/f/469211.pdf p.88 RU]
See also
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No-volt release
A dangerous restart occurs when power or energy is applied to a device whose "on / off" switch was in the "on" position when power was applied. In the United States the National Institute for Occupational Safety and Health (NIOSH) refers to thi ...
References
Electronic engineering
Voltage stability
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